TABLE OF CONTENTS Page No.

10. INTAKE OF FISH AND SHELLFISH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 10.1. BACKGROUND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 10.2. KEY GENERAL POPULATION STUDIES . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 10.3. RELEVANT GENERAL POPULATION STUDIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 10.4. KEY RECREATIONAL ( MARINE FISH STUDIES) . . . . . . . . . . . . . . . . . . . . 8 10.5. RELEVANT RECREATIONAL MARINE STUDIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 10.6. KEY FRESHWATER RECREATIONAL STUDIES . . . . . . . . . . . . . . . . . . . . 12 10.7. RELEVANT FRESHWATER RECREATIONAL STUDIES . . . . . . . . . . . . . . 18 10.8. NATIVE AMERICAN FRESHWATER STUDIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 10.9. OTHER FACTORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 10.10. RECOMMENDATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 10.10.1. Recommendations  General Population . . . . . . . . . . . . . . . . . . 25 10.10.2. Recommendations  Recreational Marine Anglers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 10.10.3. Recommendations  Recreational Freshwater Anglers . . . . . . . . . . . . . . . . . . . . . . 26 10.10.4. Recommendations  Native American Subsistence Populations . . . . . . . . . . . . . . . . . . 26 10.11. REFERENCES FOR CHAPTER 10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Volume II  Food Ingestion Factors Chapter 10  Intake of Fish and Shellfish Exposure Factors Handbook Page August 1997 10 1 10. INTAKE OF FISH AND SHELLFISH 10.1. BACKGROUND Contaminated finfish and shellfish are potential survey. In order to generalize from the sample to the target sources of human exposure to toxic chemicals. Pollutants population, the probability of being sampled must be known are carried in the surface waters, but also may be stored and for each member of the target population. This probability accumulated in the sediments as a result of complex is reflected in weights assigned to each survey respondent, physical and chemical processes. Consequently, finfish and with weights being inversely proportional to sampling shellfish are exposed to these pollutants and may become probability. When all members of the target population sources of contaminated food. have the same probability of being sampled, all weights can Accurately estimating exposure to a toxic chemical be set to one and essentially ignored. among a population that consumes fish from a polluted In a mail or phone study of licensed anglers, the water body requires an estimation of intake rates of the target population is generally all licensed anglers in a caught fish by both fishermen and their families. particular area, and in the studies presented, the sampling Commercially caught fish are marketed widely, making the probability is essentially equal for all target population prediction of an individual's consumption from a particular members. In a creel study, the target population is anyone commercial source difficult. Since the catch of recreational who fishes at the locations being studied; generally, in a and subsistence fishermen is not " diluted" in this way, these creel study, the probability of being sampled is not the same individuals and their families represent the population that for all members of the target population. For instance, if the is most vulnerable to exposure by intake of contaminated survey is conducted for one day at a site, then it will include fish from a specific location. all persons who fish there daily but only about 1/ 7 of the This section focuses on intake rates of fish. Note that people who fish there weekly, 1/ 30th of the people who fish in this section the term fish refers to both finfish and there monthly, etc. In this example, the probability of being shellfish. The following subsections address intake rates for sampled ( or inverse weight) is seen to be proportional to the the general population, and recreational and subsistence frequency of fishing. However, if the survey involves fishermen. Data are presented for intake rates for both interviewers revisiting the same site on multiple days, and marine and freshwater fish, when available. The available persons are only interviewed once for the survey, then the studies have been classified as either key or relevant based probability of being in the survey is not proportional to on the guidelines given in Volume I, Section 1.3. frequency; in fact, it increases less than proportionally with Recommended intake rates are based on the results of key frequency. At the extreme of surveying the same site every studies, but other relevant studies are also presented to day over the survey period with no re interviewing, all provide the reader with added perspective on the current members of the target population would have the same state of knowledge pertaining to fish intake. probability of being sampled regardless of fishing Survey data on fish consumption have been collected frequency, implying that the survey weights should all equal using a number of different approaches which need to be one. considered in interpreting the survey results. Generally, On the other hand, if the survey protocol calls for surveys are either " creel" studies in which fishermen are individuals to be interviewed each time an interviewer interviewed while fishing, or broader population surveys encounters them ( i. e., without regard to whether they were using either mailed questionnaires or phone interviews. previously interviewed), then the inverse weights will again Both types of data can be useful for exposure assessment be proportional to fishing frequency, no matter how many purposes, but somewhat different applications and times interviewers revisit the same site. Note that when interpretations are needed. In fact, results from creel studies individuals can be interviewed multiple times, the results of have often been misinterpreted, due to inadequate each interview are included as separate records in the data knowledge of survey principles. Below, some basic facts base and the survey weights should be inversely about survey design are presented, followed by an analysis proportional to the expected number of times that an of the differences between creel and population based individual's interviews are included in the data base. studies. In the published analyses of most creel studies, there The typical survey seeks to draw inferences about a is no mention of sampling weights; by default all larger population from a smaller sample of that population. This larger population, from which the survey sample is to be taken and to which the results of the survey are to be generalized, is denoted the target population of the Volume II  Food Ingestion Factors Chapter 10  Intake of Fish and Shellfish Page Exposure Factors Handbook 10 2 August 1997 weights are set to 1, implying equal probability of sampling. this alternative approach, based on resource utilization, will However, since the sampling probabilities in a creel study, be presented, where possible, in addition to the primary even with repeated interviewing at a site, are highly approach of presenting the standard percentiles of the fish dependent on fishing frequency, the fish intake distributions intake distribution. reported for these surveys are not reflective of the It has been determined that the resource utilization corresponding target populations. Instead, those individuals approach to characterizing distributions has relevance to the with high fishing frequencies are given too big a weight interpretation of creel survey data. As mentioned above, and the distribution is skewed to the right, i. e., it most published analyses of creel surveys do not employ overestimates the target population distribution. weights reflective of sampling probability, but instead give Price et al. ( 1994) explained this problem and set out each respondent equal weight. For mathematical reasons to rectify it by adding weights to creel survey data; he used that are explained in Appendix 10A, when creel analyses data from two creel studies ( Puffer et al., 1981 and Pierce are performed in this ( equal weighting) manner, the et al., 1981) as examples. Price et al. ( 1994) used inverse calculated percentiles of the fish intake distribution do not fishing frequency as survey weights and produced revised reflect the percentiles of the target population fish intake estimates of median and 95th percentile intake for the above distribution but instead reflect ( approximately) the two studies. These revised estimates were dramatically percentiles of the " resource utilization distribution". Thus, lower than the original estimates. The approach of Price et one would not expect 50 percent of the target population to al. ( 1994) is discussed in more detail in Section 10.5 where be consuming above the median intake level as reported the Puffer et al. ( 1981) and Pierce et al. ( 1981) studies are from such a creel survey, but instead would expect that 50 summarized. percent of the total recreational fish consumption would be When the correct weights are applied to survey data, individuals consuming above this level. As with the the resulting percentiles reflect, on average, the distribution example above, and in accordance with the statement above in the target population; thus, for example, an estimated 90 that creel surveys analyzed in this manner overestimate percent of the target population will have intake levels intake distributions, the actual median level of intake in the below the 90th percentile of the survey fish intake target population will be less ( probably considerably so) distribution. There is another way, however, of than this level and, accordingly, ( considerably) less than 50 characterizing distributions in addition to the standard percent of the target population will be consuming at or percentile approach; this approach is reflected in statements above this level. These considerations are discussed when of the form " 50 percent of the income is received by, for the results of individual creel surveys are presented in later example, the top 10 percent of the population, which sections and should be kept in mind whenever estimates consists of individuals making more than $ 100,000", for based on creel survey data are utilized. example. Note that the 50th percentile ( median) of the The U. S. EPA has prepared a review of and an income distribution is well below $ 100,000. Here the evaluation of five different survey methods used for $ 100,000 level can be thought of as, not the 50th percentile obtaining fish consumption data. They are: of the population income distribution, but as the 50th percentile of the " resource utilization distribution" ( see ° Recall Telephone Survey; Appendix 10A for technical discussion of this distribution). ° Recall Mail Survey; Other percentiles of the resource utilization distribution ° Recall Personal Interview; have similar interpreta tions; e. g., the 90th percentile of the ° Diary; and resource utilization distribution ( for income) would be that ° Creel Census. level of income such that 90 percent of total income is received by individuals with incomes below this level and 10 percent by individuals with income above this level. This alternative approach to characterizing distributions is of particular interest when a relatively small fraction of individuals consumes a relatively large fraction of a resource, which is the case with regards to recreational fish consumption. In the studies of recreational anglers, The reader is referred to U. S. EPA 1992 Consumption Surveys for Fish and Shellfish for more detail on these survey methods and their advantages and limitations.

10.2. KEY GENERAL POPULATION STUDIES Tuna Research Institute Survey  The Tuna Research Institute ( TRI) funded a study of fish Volume II  Food Ingestion Factors Chapter 10  Intake of Fish and Shellfish Exposure Factors Handbook Page August 1997 10 3 consumption which was performed by the National NPD indicated that these fish consumers represented 94 Purchase Diary ( NPD) during the period of September, percent of the U. S. population. For this population of " fish 1973 to August, 1974. The data tapes from this survey were consumers", Javitz ( 1980) calculated means and obtained by the National Marine Fisheries Service ( NMFS), percentiles of fish consumption by demographic variables which later, along with the FDA, USDA and TRI, ( age, sex, race, census region and community type) and conducted an intensive effort to identify and correct errors overall ( Tables 10 1 through 10 4). The overall mean fish in the data base. Javitz ( 1980) summarized the TRI survey intake rate among fish consumers was calculated at 14.3 methodology and used the corrected tape to generate fish g/ day and the 95th percentile at 41.7 g/ day. intake distributions for various sub populations. As seen in Table 10 1, the mean and 95th percentile The TRI survey sample included 6,980 families who of fish consumption were higher for Asian Americans as were currently participating in a syndicated national compared to the other racial groups. Other differences in purchase diary panel, 2,400 additional families where the intake rates are those between gender and age groups. head of household was female and under 35 years old; and While males ( 15.6 g/ d) eat slightly more fish than females 210 additional black families ( Javitz, 1980). Of the 9,590 ( 13.2 g/ d), and adults eat more fish than children, the families in the total sample, 7,662 families ( 25,162 corresponding differences in body weight would probably individuals) completed the questionnaire, a response rate of compensate for the different intake rates in exposure 80 percent. The survey was weighted to represent the U. S. calculations ( Javitz, 1980). There appeared to be no large population based on a number of census defined controls differences in regional intake rates, although higher rates ( i. e., census region, household size, income, presence of are shown in the New England and Middle Atlantic census children, race and age). The calculations of means, regions. percentiles, etc. were performed on a weighted basis with The mean and 95th percentile intake rates by ageeach person contributing in proportion to his/ her assigned gender groups are presented in Table 10 2. Tables 10 3 survey weight. and 10 4 present the distribution of fish consumption for The survey population was divided into 12 different females and males, respectively, by age; these tables give sample segments and, for each of the 12 survey months, the percentages of females/ males in a given age bracket data were collected from a different segment. Each survey with intake rates within various ranges. Table 10 5 household was given a diary in which they recorded, over a presents mean total fish consumption by fish species. one month period, the date of any fish meals consumed and The TRI survey data were also utilized by Rupp et al. the following accompanying information: the species of fish ( 1980) to generate fish intake distributions for three age consumed, whether the fish was commercially or groups (< 11, 12 18, and 19+ years) within each of the 9 recreationally caught, the way the fish was packaged census regions and for the entire United States. Separate ( canned, frozen fresh, dried, smoked), the amount of fish distributions were derived for freshwater finfish, saltwater prepared and consumed, and the number of servings finfish and shellfish; thus, a total of 90 ( 3* 3* 10) different consumed by household members and guests. Both meals distributions were derived, each corresponding to intake of eaten at home and away from home were recorded. The a specific category of fish for a given age group within a amount of fish prepared was determined as follows ( Javitz, given region. The analysis of Rupp et al. ( 1980) included 1980): " For fresh fish, the weight was recorded in ounces only those respondents with known age. This amounted to and may have included the weight of the head and tail. For 23,213 respondents. frozen fish, the weight was recorded in packaged ounces, Ruffle et al. ( 1994) used the percentiles data of Rupp and it was noted whether the fish was breaded or combined et al. ( 1980) to estimate the best fitting lognormal with other ingredients ( e. g., TV dinners). For canned fish, parameters for each distribution. Three methods ( non linear the weight was recorded in packaged ounces and it was optimization, first probability plot and second probability noted whether the fish was canned in water, oil, or with plot) were used to estimate optimal parameters. Ruffle et other ingredients ( e. g., soups)". al. ( 1994) determined that, of the three methods, the non Javitz ( 1980) reported that the corrected survey linear optimization method ( NLO) generally gave the best tapes contained data on 24,652 individuals who consumed results. For some of the distributions fitted by the NLO fish in the survey month and that tabulations performed by method, however, it was determined that the lognormal model did not adequately fit the empirical fish intake distribution. Ruffle et al. Volume II  Food Ingestion Factors Chapter 10  Intake of Fish and Shellfish Page Exposure Factors Handbook 10 4 August 1997 ( 1994) used a criterion of minimum sum of squares ( min other consumption studies, including the USDA National SS) less than 30 to identify which distributions provided Food Consumption Surveys, which report consumption over adequate fits. Of the 90 distributions studied, 77 were seen a 3 day to one week period. to have min SS < 30; for these, Ruffle et al. ( 1994) Another obvious limitation of this data base is that it concluded that the NLO modeled lognormal distributions is now over twenty years out of date. Ruffle et al. ( 1994) are " well suited for risk assessment". Of the remaining 13 considered this shortcoming and suggested that one may distributions, 12 had min SS > 30; for these Ruffle et al. wish to shift the distribution upward to account for the ( 1994) concluded that modeled lognormal distributions recent increase in fish consumption. Adding ln( 1+ x/ 100) to " may also be appropriate for use when exercised with due the log mean F will shift the distribution upward by x care and with sensitivity analyses". One distribution, that of percent ( e. g., adding 0.22 = ln( 1.25) increases the freshwater finfish intake for children < 11 years of age in distribution by 25 percent). Although the TRI survey New England, could not be modeled due to the absence of distinguished between recreationally and commercially any reported consumption. caught fish, Javitz ( 1980), Rupp et al. ( 1980), and Ruffle et Table 10 6 presents the optimal lognormal al. ( 1994) ( which was based on Rupp et al., 1980) did not parameters, the mean ( F ) , standard deviation ( s), and min present analyses by this variable. SS, for all 89 modeled distributions. These parameters can be used to determine percentiles of the corresponding distribution of average daily fish consumption rates through the relation DFC( p)= exp[ F + z( p) s] where DFC( p) is the pth percentile of the distribution of average daily fish consumption rates and z( p) is the z score associated with the pth percentile ( e. g., z( 50)= 0 ). The mean average daily fish consumption rate is given by exp[ F + 0.5s ]. 2 The analyses of Javitz ( 1980) and Ruffle et al. ( 1994) were based on consumers only, who are estimated to represent 94.0 percent of the U. S. population. U. S. EPA estimated the mean intake in the general population by multiplying the fraction consuming, 0.94, by the mean among consumers reported by Javitz ( 1980) of 14.3 g/ day; the resulting estimate is 13.4 g/ day. The 95th percentile estimate of Javitz ( 1980) of 41.7 g/ day among consumers would be essentially unchanged when applied to the general population; 41.7 g/ day would represent the 95.3 percentile ( i. e., 100*[ 0.95* 0.94+ 0.06]) among the general population. Advantages of the TRI data survey are that it was a large, nationally representative survey with a high response rate ( 80 percent) and was conducted over an entire year. In addition, consumption was recorded in a daily diary over a one month period; this format should be more reliable than one based on one month recall. The upper percentiles presented are derived from one month of data, and are likely to overestimate the corresponding upper percentiles of the long term ( i. e., one year or more) average daily fish intake distribution. Similarly, the standard deviation of the fitted lognormal distribution probably overestimates the standard deviation of the long term distribution. However, the period of this survey ( one month) is considerably longer than those of many U. S. EPA ( 1996a)  Daily Average Per Capita Fish Consumption Estimates Based on the Combined USDA 1989, 1990, and 1991 Continuing Survey of Food Intakes by Individuals ( CSFII)   The USDA conducts the CSFII on an ongoing basis. U. S. EPA used the 1989, 1990, and 1991 CSFII data to generate fish intake estimates. Participants in the CSFII provided 3 consecutive days of dietary data. For the first day's data, participants supplied dietary recall information to an in home interviewer. Second and third day dietary intakes were recorded by participants. Data collection for the CSFII started in April of the given year and was completed in March of the following year. The CSFII contains 469 fish related food codes; survey respondents reported consumption across 284 of these codes. Respondents estimated the weight of each food that they consumed. The fish component ( by weight) of these foods was calculated using data from the recipe file for release 7 of the USDA's Nutrient Data Base for Individual Food Intake Surveys. The amount of fish consumed by each individual was then calculated by summing, over all fish containing foods, the product of the weight of food consumed and the fish component ( i. e., the percentage fish by weight) of the food. The recipe file also contains cooking loss factors associated with each food. These were utilized to convert, for each fish containing food, the as eaten fish weight consumed into an uncooked equivalent weight of fish. Analyses of fish intake were performed on both an as eaten and uncooked basis. Each ( fish related) food code was assigned by EPA a habitat type of either freshwater/ estuarine or marine. Food codes were also designated as finfish or shellfish. Average daily individual consumption ( g/ day) for a given Volume II  Food Ingestion Factors Chapter 10  Intake of Fish and Shellfish Exposure Factors Handbook Page August 1997 10 5 fish type by habitat category ( e. g., marine finfish) was under, 15 44, 45 and older, all ages) and gender. Tables calculated by summing the amount of fish consumed by the 10 13 through 10 20 present fish intake data ( g/ day and individual across the three reporting days for all fish related mg/ kg day) on an as consumed basis for the general food codes in the given fish by habitat category and then population and Tables 10 21 through 10 28 for consumers dividing by 3. Individual consumption per day consuming only. Tables 10 29 through 10 44 provide intake data fish ( g/ day) was calculated similarly except that total fish ( g/ day and mg/ kg day) on an uncooked equivalent basis for consumption was divided by the specific number of survey the same population groups described above. days the individual reported consuming fish; this was The advantages of this study are its large size, its calculated for fish consumers only ( i. e., those consuming relative currency and its representativeness. In addition, fish on at least one of the three survey days). The reported through use of the USDA recipe files, the analysis identified body weight of the individual was used to convert all fish related food codes and estimated the percent fish consumption in g/ day to consumption in g/ kg day. content of each of these codes. By contrast, some analyses There were a total of 11,912 respondents in the of the USDA National Food Consumption Surveys combined data set who had three day dietary intake data. ( NFCSs) which reported per capita fish intake rates ( e. g., Survey weights were assigned to this data set to make it Pao et al., 1982; USDA, 1992a), excluded certain fish representative of the U. S. population with respect to various containing foods ( e. g., fish mixtures, frozen plate meals) in demographic characteristics related to food intake. their calculations. U. S. EPA ( 1996a) reported means, medians, upper Results from the 1977 1978 NFCS survey ( Pao et percentiles, and 90 percent interval estimates for the 90th, al., 1982) showed that only a small percentage of 95th, and 99th percentiles. The 90 percent interval consumers ate fish on more than one occasion per day. This estimates are nonparametric estimates from bootstrap implies that the distribution presented for fish intake per day techniques. The bootstrap estimates result from the consuming fish can be used as a surrogate for the percentile method which estimates the lower and upper distribution of fish intake per ( fish) eating occasion ( Table bounds for the interval estimate by the 100 " percentile and 10 8). 100 ( 1 " ) percentile estimates from the non parametric Also, it should be noted that the 1989 91 CSFII data distribution of the given point estimate ( U. S. EPA, 1996a). are not the most recent intake survey data. USDA has Analyses of fish intake were performed on an as recently made available data from its 1994 and 1995 CSFII. eaten as well as on an uncooked equivalent basis and on a Over 5,500 people nationwide participated in both of these g/ day and g/ kg day basis. Table 10 7 gives the mean and surveys, providing recalled food intake information for two various percentiles of the distribution of per capita fish separate days. Although the 2 day data analysis has not intake rates ( g/ day) based on uncooked equivalent weight been conducted, USDA published results for the by habitat and fish type, for the general population. The respondents' intakes on the first day surveyed ( USDA, mean per capita intake rate of finfish and shellfish from all 1996a; USDA, 1996b). USDA 1996 survey data will be habitats was 20.1 g/ day. Per capita consumption estimates made available later in 1997. As soon as 1996 data are by species are shown in Appendix 10C. Table 10 8 available, EPA will take steps to get the 3 year data ( 1994, displays the mean and various percentiles of the distribution 1995, 1996) analyzed and the food ingestion factors of total fish intake per day consuming fish, by habitat for updated. Meanwhile, comparisons between the mean daily consumers only. Also displayed is the percentage of the fish intake per individual in a day from the USDA survey population consuming fish of the specified habitat during data from years 1977 78, 1987 88, 1989 91, 1994, and the three day survey period. Tables 10 9 and 10 10 present 1995 indicate that fish intake has been relatively constant similar results as above but on a mg/ kg day basis; Tables over time. The 1 day fish intake rates were 11 g/ day, 11 10 11 and 10 12 present results in the same format for fish g/ day, 13 g/ day, 9 g/ day, and 11 g/ day for survey years intake ( g/ day) on an as eaten ( cooked) basis. 1977 78, 1987 88, 1989 91, 1994, and 1995, respectively. Tables 10 13 through 10 44 present data for daily This indicates that the 1989 91 CSFII data presented in this average per capita fish consumption by age and gender. handbook are probably adequate for assessing fish ingestion These data are presented by selected age grouping ( 4 and exposure for current populations. Volume II  Food Ingestion Factors Chapter 10  Intake of Fish and Shellfish Page Exposure Factors Handbook 10 6 August 1997 10.3. RELEVANT GENERAL POPULATION STUDIES Pao et al. ( 1982)  Foods Commonly Eaten by Individuals: Amount Per Day and Per Eating Occasion  The USDA 1977 78 Nationwide Food Consumption Survey ( NFCS) was described in Chapter 9. The survey consisted of a household and individual component. For the individual component, all members of surveyed households were asked to provide 3 consecutive days of dietary data. For the first day's data, participants supplied dietary recall information to an in home interviewer. Second and third day dietary intakes were recorded by participants. A total of 15,000 households were included in the 1977 78 NFCS and about 38,000 individuals completed the 3 day diet records. Fish intake was estimated based on consumption of fish products identified in the NFCS data base according to NFCS defined food codes. These products included fresh, breaded, floured, canned, raw and dried fish, but not fish mixtures or frozen plate meals. Pao et al. ( 1982) used the 1977 78 NFCS to examine the quantity of fish consumed per eating occasion. For each individual consuming fish in the 3 day survey period, the quantity of fish consumed per eating occasion was derived by dividing the total reported fish intake over the 3 day period by the number of occasions the individual reported eating fish. The distributions, by age and sex, for the quantity of fish consumed per eating occasion are displayed in Table 10 13 ( Pao et al., 1982). For the general population, the average quantity of fish consumed per fish meal was 117 g, with a 95th percentile of 284 g. Males in the age groups 19 34, 35 64 and 65 74 years had the highest average and 95th percentile quantities among the age sex groups presented. Pao et al. ( 1982) also used the data from this survey set to calculate per capita fish intake rates. However, because these data are now almost 20 years out of date, this analysis is not considered key with respect to assessing per capita intake ( the average quantity of fish consumed per fish meal should be less subject to change over time than is per capita intake). In addition, fish mixtures and frozen plate meals were not included in the calculation of fish intake. The per capita fish intake rate reported by Pao et al. ( 1982) was 11.8 g/ day. The 1977 1978 NFCS was a large and well designed survey and the data are representative of the U. S. population. USDA Nationwide Food Consumption Survey 1987 88  The USDA 1987 88 Nationwide Food Consumption Survey ( NFCS) was described in Chapter 9. Briefly, the survey consisted of a household and individual component. The household component asked about household food consumption over the past one week period. For the individual component, each member of a surveyed household was interviewed ( in person) and asked to recall all foods eaten the previous day; the information from this interview made up the " one day data" for the survey. In addition, members were instructed to fill out a detailed dietary record for the day of the interview and the following day. The data for this entire 3 day period made up the " 3 day diet records". A statistical sampling design was used to ensure that all seasons, geographic regions of the U. S., demographic, and socioeconomic groups were represented. Sampling weights were used to match the population distribution of 13 demographic characteristics related to food intake ( USDA, 1992a). Total fish intake was estimated based on consumption of fish products identified in the NFCS data base according to NFCS defined food codes. These products included fresh, breaded, floured, canned, raw and dried fish, but not fish mixtures or frozen plate meals. A total of 4,500 households participated in the 1987 88 survey; the household response rate was 38 percent. One day data were obtained for 10,172 ( 81 percent) of the 12,522 individuals in participating households; 8,468 ( 68 percent) individuals completed 3 day diet records. USDA ( 1992b) used the one day data to derive per capita fish intake rate and intake rates for consumers of total fish. These rates, calculated by sex and age group, are shown in Table 10 14. Intake rates for consumers only were calculated by dividing the per capita intake rates by the fractions of the population consuming fish in one day. The 1987 1988 NFCS was also utilized to estimate consumption of home produced fish ( as well as home produced fruits, vegetables, meats and dairy products) in the general U. S. population. The methodology for estimating home produced intake rates was rather complex and involved combining the household and individual components of the NFCS; the methodology, as well as the estimated intake rates, are described in detail in Chapter 12. However, since much of the rest of this chapter is concerned with estimating consumption of recreationally caught, i. e., home produced fish, the methods and results of Chapter 12, as they pertain to fish consumption, are summarized briefly here. Volume II  Food Ingestion Factors Chapter 10  Intake of Fish and Shellfish Exposure Factors Handbook Page August 1997 10 7 A total of 2.1 percent of the survey population but some studies used an average value; these average reported home produced fish consumption during the survey values ranged from 0.3 to 0.5. Using a factor of 0.5 would week. Among consumers, the mean intake rate was 2.07 convert the above 11.8 g/ day rate to 5.9 g/ day. This g/ kg day and the 95th percentile was 7.83 g/ kg day; the estimate, 5.9 g/ day, of the per capita fish intake rate among per capita intake rate was 0.04 g/ kg day. Note that intake members of fishing households is within the range of the rates for home produced foods were indexed to the weight per capita intake rates among recreational anglers of the survey respondent and reported in g/ kg day. addressed in sections to follow. It is possible to compare the estimates of home An advantage of analyses based on the 1987 1988 produced fish consumption derived in this analyses with USDA NFCS is that the data set is a large, geographically estimates derived from studies of recreational anglers and seasonally balanced survey of a representative sample ( described in Sections 10.4 10.8); however, the intake rates of the U. S. population. The survey response rate, however, must be put into a similar context. The home produced was low and an expert panel concluded that it was not intake rates described refer to average daily intake rates possible to establish the presence or absence of nonamong individuals consuming home produced fish in a response bias ( USDA, 1992b). Limitations of the homeweek results from recreational angler studies, however, produced analysis are given in Chapter 12 of this volume. usually report average daily rates for those eating homeproduced fish ( or for those who recreationally fish) at least some time during the year. Since many of these latter individuals eat home produced fish at a frequency of less than once per week, the average daily intake in this group would be expected to be less than that reported. The NFCS household component contains the question " Does anyone in your household fish?". For the population answering yes to this question ( 21 percent of households), the NFCS data show that 9 percent consumed home produced fish in the week of the survey; the mean intake rate for these consumers from fishing households was 2.2 g/ kg day. ( Note that 91 percent of individuals reporting home grown fish consumption for the week of the survey indicated that a household member fishes; the overall mean intake rate among home produced fish consumers, regardless of fishing status, was the above reported 2.07 g/ kg day). The per capita intake rate among those living in a fishing household is then calculated as 0.2 g/ kg day ( 2.2 * 0.09). Using the estimated average weight of survey participants of 59 kg, this translates into 11.8 g/ day. Among members of fishing households, home produced fish consumption accounted for 32.5 percent of total fish consumption. As discussed in Chapter 12 of this volume, intake rates for home produced foods, including fish, are based on the results of the household survey, and as such, reflect the weight of fish taken into the household. In most of the recreational fish surveys discussed later in this section, the weight of the fish catch ( which generally corresponds to the weight taken into the household) is multiplied by an edible fraction to convert to an uncooked equivalent of the amount consumed. This fraction may be species specific, Tsang and Klepeis ( 1996)  National Human Activity Pattern Survey ( NHAPS)  The U. S. EPA collected information for the general population on the duration and frequency of time spent in selected activities and time spent in selected microenvironments via 24 hour diaries. Over 9,000 individuals from 48 contiguous states participated in NHAPS. Approximately 4,700 participants also provided information on seafood consumption. The survey was conducted between October 1992 and September 1994. Data were collected on the ( 1) number of people that ate seafood in the last month, ( 2) the number of servings of seafood consumed, and ( 3) whether the seafood consumed was caught or purchased ( Tsang and Klepeis, 1996). The participant responses were weighted according to selected demographics such as age, gender, and race to ensure that results were representative of the U. S. population. Of those 4,700 respondents, 2,980 ( 59.6 percent) ate seafood ( including shellfish, eels, or squid) in the last month ( Table 10 15). The number of servings per month were categorized in ranges of 1 2, 3 5, 6 10, 11 19, and 20+ servings per month ( Table 10 16). The highest percentage ( 35 percent) of respondent population had an intake of 3 5 servings per month. Most ( 92 percent) of the respondents purchased the seafood they ate ( Table 10 17). Intake data were not provided in the survey. However, intake of fish can be estimated using the information on the number of servings of fish eaten from this study and serving size data from other studies. The recommended mean value in this handbook for fish serving size is 129 g/ serving ( Table 10 8). Using this mean value for serving size and assuming that the average Volume II  Food Ingestion Factors Chapter 10  Intake of Fish and Shellfish Page Exposure Factors Handbook 10 8 August 1997 individual eats 3 5 servings per month, the amount of in marine recreational fishing ( for finfish) within the state, seafood eaten per month would range from 387 to 645 as well as the total number of ( within state) fishing trips grams/ month or 12.9 to 21.5 g/ day for the highest these residents take. To estimate the total number of percentage of the population. These values are within the participants and fishing trips in the state, by coastal range of mean intake values for total fish ( 20.1 g/ day) residents and others, a ratio approach, based on the field calculated in the U. S. EPA analysis of the USDA CSFII interview data, was used. Thus, if the field survey data data. It should be noted that an all inclusive description for found that there was a 4: 1 ratio of fishing trips taken by seafood was not presented in Tsang and Klepeis ( 1996). It coastal residents as compared to trips taken by non coastal is not known if processed or canned seafood and seafood and out of state residents, then an additional 25 percent mixtures are included in the seafood category. would be added to the number of trips taken by coastal The advantages of NHAPS is that the data were residents to generate an estimate of the total number of collected for a large number of individuals and are within state trips. representative of the U. S. general population. However, The field intercept survey is essentially a creel type evaluation of seafood intake was not the primary purpose of survey. The survey utilizes a national site register which the study and the data do not reflect the actual amount of details marine fishing locations in each state. Sites for field seafood that was eaten. However, using the assumption interviews are chosen in proportion to fishing frequency at described above, the estimated seafood intake from this the site. Anglers fishing on shore, private boat, and study are comparable to those observed in the EPA CSFII charter/ party boat modes who had completed their fishing analysis. were interviewed. The field survey included questions 10.4. KEY RECREATIONAL ( MARINE FISH STUDIES) National Marine Fisheries Service ( 1986a, b, c; 1993)  The National Marine Fisheries Service ( NMFS) conducts systematic surveys, on a continuing basis, of marine recreational fishing. These surveys are designed to estimate the size of the recreational marine finfish catch by location, species and fishing mode. In addition, the surveys provide estimates for the total number of participants in marine recreational finfishing and the total number of fishing trips. The surveys are not designed to estimate individual consumption of fish from marine recreational sources, primarily because they do not attempt to estimate the number of individuals consuming the recreational catch. Intake rates for marine recreational anglers can be estimated, however, by employing assumptions derived from other data sources about the number of consumers. The NMFS surveys involve two components, telephone surveys and direct interviewing of fishermen in the field. The telephone survey randomly samples residents of coastal regions, defined generally as counties within 25 miles of the nearest seacoast, and inquires about participation in marine recreational fishing in the resident's home state in the past year, and more specifically, in the past two months. This component of the survey is used to estimate, for each coastal state, the total number of coastal region residents who participate about frequency of fishing, area of fishing, age, and place of residence. The fish catch was classified by the interviewer as either type A, type B1 or type B2 catch. The type A catch denoted fish that were taken whole from the fishing site and were available for inspection. The type B1 and B2 catch were not available for inspection; the former consisted of fish used as bait, filleted, or discarded dead while the latter was fish released alive. The type A catch was identified by species and weighed, with the weight reflecting total fish weight, including inedible parts. The type B1 catch was not weighed, but weights were estimated using the average weight derived from the type A catch for the given species, state, fishing mode and season of the year. For both the A and B1 catch, the intended disposition of the catch ( e. g., plan to eat, plan to throw away, etc.) was ascertained. EPA obtained the raw data tapes from NMFS in order to generate intake distributions and other specialized analyses. Fish intake distributions were generated using the field survey tapes. Weights proportional to the inverse of the angler's reported fishing frequency were employed to correct for the unequal probabilities of sampling; this was the same approach used by NMFS in deriving their estimates. Note that in the field survey, anglers were interviewed regardless of past interviewing experience; thus, the use of inverse fishing frequency as weights was justified ( see Section 10.1). For each angler interviewed in the field survey, the yearly amount of fish caught that was intended to be eaten Volume II  Food Ingestion Factors Chapter 10  Intake of Fish and Shellfish Exposure Factors Handbook Page August 1997 10 9 Y = [( wt of A catch) * I + ( wt of B1 catch) * I ] * [ Fishing frequency] ( Eqn. 10 1) A B ADI = Y * ( 0.5)/[ 2.5 * 365] ( Eqn. 10 2) by the angler and his/ her family or friends was estimated by number of coastal residents who participated in marine EPA as follows: finfishing in their home state was 8 million; an additional where I ( I ) are indicator variables equal to 1 if the type A total weight of the A and B1 catch by region and time of A B ( B1) catch was intended to be eaten and equal to 0 year. For each region, the greatest catches were during the otherwise. To convert Y to a daily fish intake rate by the six month period from May through October. This period angler, it was necessary to convert amount of fish caught to accounted for about 90 percent of the North and edible amount of fish, divide by the number of intended Mid Atlantic catch, about 80 percent of the Northern consumers, and convert from yearly to daily rate. Although California and Oregon catch, about 70 percent of the theoretically possible, EPA chose not to use species specific Southern Atlantic and Southern California catch and 62 edible fractions to convert overall weight to edible fish percent of the Gulf catch. Note that in the North and weight since edible fraction estimates were not readily Mid Atlantic regions, field surveys were not done in available for many marine species. Instead, an average January and February due to very low fishing activity. For value of 0.5 was employed. For the number of intended all regions, over half the catch occurred within 3 miles of consumers, EPA used an average value of 2.5 which was an the shore or in inland waterways. average derived from the results of several studies of Table 10 20 presents the mean and 95th percentile recreational fish consumption ( Chemrisk, 1991; Puffer et of average daily intake of recreationally caught marine al., 1981; West et al., 1989). Thus, the average daily intake finfish among anglers by region. The mean ADI among all rate ( ADI) for each angler was calculated as anglers was 5.6, 7.2, and 2.0 g/ day for the Atlantic, Gulf,

Note that ADI will be 0 for those anglers who either did not catch by species for the Atlantic and Gulf regions and Table intend to eat their catch or who did not catch any fish. The 10 22 for Pacific regions. distribution of ADI among anglers was calculated by region The NMFS surveys provide a large, up to date, and and coastal status ( i. e., coastal versus non coastal counties). geographically representative sample of marine angler A mean ADI for the overall population of a given area was activity in the U. S. The major limitation of this data base in calculated as follows: first the estimated number of anglers terms of estimating fish intake is the lack of information in the area was multiplied by the average number of regarding the intended number of consumers of each intended fish consumers ( 2.5) to get a total number of angler's catch. In this analysis, it was assumed that every recreational marine finfish consumers. This number was angler's catch was consumed by the same number ( 2.5) of then multiplied by the mean ADI among anglers to get the people; this number was derived from averaging the results total recreational marine finfish consumption in the area. of other studies. This assumption introduces a relatively Finally, the mean ADI in the population was calculated by low level of uncertainty in the estimated mean intake rates dividing total fish consumption by the total population in the among anglers, but a somewhat higher level of uncertainty area. in the estimated intake distributions. It should be noted that The results presented below are based on the results under the above assumption, the distributions shown here of the 1993 survey. Samples sizes were 200,000 for the pertain not only to the population of anglers, but also to the telephone survey and 120,000 for the field surveys. All entire population of recreational fish consumers, which is coastal states in the continental U. S. were included in the 2.5 times the number of anglers. If the number of survey except Texas and Washington. consumers was changed, to, for instance, 2.0, then the Table 10 18 presents the estimated number of distribution would be increased by a factor of 1.25 coastal, non coastal, and out of state fishing participants ( 2.5/ 2.0), but the estimated population of recreational fish by state and region of fishing. Florida had the greatest consumers to which the distribution would apply would number of both Atlantic and Gulf participants. The total decrease by a factor of 0.8 ( 2.0/ 2.5). Note that the mean 750,000 non coastal residents participated in marine finfishing in their home state. Table 10 19 presents the estimated and Pacific regions, respectively. Also given is the percapita ADI in the overall population ( anglers and nonanglers of the region and in the overall coastal population of the region. Table 10 21 gives the distribution of the Volume II  Food Ingestion Factors Chapter 10  Intake of Fish and Shellfish Page Exposure Factors Handbook 10 10 August 1997 ( K x N x W x F)/[ E x 365] ( Eqn. 10 3)

where: K = edible fraction of fish ( 0.25 to 0.5 depending on species); N = number of fish in catch; W = average weight of ( grams) fish in catch; F = frequency of fishing/ year; and E = number of fish eaters in family/ living group. intake rate of marine finfish in the overall population is No explicit survey weights were used in analyzing this independent of the assumption of number of intended fish survey; thus, each respondent's data was given equal consumers. weight. Another uncertainty involves the use of 0.5 as an A total of 1,059 anglers were interviewed for the ( average) edible fraction. This figure is somewhat survey. The ethnic and age distribution of respondents is conservative ( i. e., the true average edible fraction is shown in Table 10 23; 88 percent of respondents were probably lower); thus, the intake rates calculated here may male. The median intake rate was higher for be biased upward somewhat. Oriental/ Samoan anglers ( median 70.6 g/ day) than for other It should be noted again that the recreational fish ethnic groups and higher for those ages over 65 years intake distributions given refer only to marine finfish. In ( median 113.0 g/ day) than for other age groups. Puffer et addition, the intake rates calculated are based only on the al. ( 1981) found similar median intake rates for seasons; catch of anglers in their home state. Marine fishing 36.3 g/ day for November through March and 37.7 g/ day for performed out of state would not be included in these April through October. Puffer et al. ( 1981) also evaluated distributions. Therefore, these distributions give an fish preparation methods; these data are presented in estimate of consumption of locally caught fish. Appendix 10B. The cumulative distribution of recreational 10.5. RELEVANT RECREATIONAL MARINE STUDIES Puffer et al. ( 1981)  Intake Rates of Potentially Hazardous Marine Fish Caught in the Metropolitan Los Angeles Area  Puffer et al. ( 1981) conducted a creel survey with sport fishermen in the Los Angeles area in 1980. The survey was conducted at 12 sites in the harbor and coastal areas to evaluate intake rates of potentially hazardous marine fish and shellfish by local, non professional fishermen. It was conducted for the full 1980 calendar year, although inclement weather in January, February, and March limited the interview days. Each site was surveyed an average of three times per month, on different days, and at a different time of the day. The survey questionnaire was designed to collect information on demographic characteristics, fishing patterns, species, number of fish caught, and fish consumption patterns. Scales were used to obtain fish weights. Interviews were conducted only with anglers who had caught fish, and the anglers were interviewed only once during the entire survey period. Puffer et al. ( 1981) estimated daily consumption rates ( grams/ day) for each angler using the following equation: fish ( finfish and shellfish) consumption by survey respondents is presented in Table 10 24; this distribution was calculated only for those fishermen who indicated they eat the fish they catch. The median fish consumption rate was 37 g/ day and the 90th percentile rate was 225 g/ day ( Puffer et al., 1981). A description of catch patterns for primary fish species kept is presented in Table 10 25. As mentioned in the Background to this Chapter, intake distributions derived from analyses of creel surveys which did not employ weights reflective of sampling probabilities will overestimate the target population intake distribution and will, in fact, be more reflective of the " resource utilization distribution". Therefore, the reported median level of 37.3 g/ day does not reflect the fact that 50 percent of the target population has intake above this level; instead 50 percent of recreational fish consumption is by individuals consuming at or above 37.3 g/ day. In order to generate an intake distribution reflective of that in the target population, weights inversely proportional to sampling probability need to be employed. Price et al. ( 1994) made this attempt with the Puffer et al. ( 1981) survey data, using inverse fishing frequencies as the sampling weights. Price et al. ( 1994) was unable to get the raw data for this survey, but using frequency tables and the average level of fish consumption per fishing trip provided in Puffer et al. ( 1981), generated an approximate revised intake distribution. This distribution was dramatically lower than that obtained by Puffer et al. ( 1981); the median was estimated at 2.9 g/ day ( compared with 37.3 from Puffer et al., 1981) and the 90th percentile at 35 g/ day ( compared to 225 g/ day from Puffer et al., 1981). Volume II  Food Ingestion Factors Chapter 10  Intake of Fish and Shellfish Exposure Factors Handbook Page August 1997 10 11 There are several limitations to the interpretation of conducted from early July to mid September, 1980 and the the percentiles presented by both Puffer et al. ( 1981) and second half from mid September through most of Price et al. ( 1994). As described in Appendix 10A, the November. During the summer months, interviewers interpretation of percentiles reported from creel surveys in visited each of 4 sub areas of Commencement Bay on five terms of percentiles of the " resource utilization distribution" mornings and five evenings; in the fall the areas were is approximate and depends on several assumptions. One sampled 4 complete survey days. Interviews were of these assumptions is that sampling probability is conducted only with persons who had caught fish. The proportional to inverse fishing frequency. In this survey, anglers were interviewed only once during the survey where interviewers revisited sites numerous times and period. Data were recorded for species, wet weight, size of anglers were not interviewed more than once, this the living group ( family, place of residence, fishing assumption is not valid, though it is likely that the sampling frequency, planned uses of the fish, age, sex, and race probability is still highly dependant on fishing frequency so ( Pierce et al., 1981). The analysis of Pierce et al. ( 1981) that the assumption does hold in an approximate sense. The did not employ explicit sampling weights ( i. e., all weights validity of this assumption also impacts the interpretation of were set to 1). percentiles reported by Price et al. ( 1994) since inverse There were 304 interviews in the summer and 204 frequency was used as sampling weights. It is likely that the in the fall. About 60 percent of anglers were white, 20 value ( 2.9 g/ day) of Price et al. ( 1994) underestimates percent black, 19 percent Oriental and the rest Hispanic or somewhat the median intake in the target population, but is Native American. Table 10 26 gives the distribution of much closer to the actual value than the Puffer et al. ( 1981) fishing frequency calculated by Pierce et al. ( 1981); for both estimate of 37.3 g/ day. Similar statements would apply the summer and fall, more than half of the fishermen caught about the 90th percentile. Similarly, the 37.3 g/ day median and consumed fish weekly. The dominant ( by weight) value, if interpreted as the 50th percentile of the " resource species caught were Pacific Hake and Walleye Pollock. utilization distribution", is also somewhat of an Pierce et al. ( 1981) did not present a distribution of fish underestimate. intake or a mean fish intake rate. It should be noted again that the fish intake The U. S. EPA ( 1989a) used the Pierce et al. ( 1981) distribution generated by Puffer et al. ( 1981) ( and by Price fishing frequency distribution and an estimate of the average et al., 1994) was based only on fishermen who caught fish amount of fish consumed per angling trip to create an and ate the fish they caught. If all anglers were included, approximate intake distribution for the Pierce et al. ( 1981) intake estimates would be somewhat lower. In contrast, the survey. The estimate of the amount of fish consumed per survey assumed that the number of fish caught at the time of angling trip ( 380 g/ person trip) was based on data on mean the interview was all that would be caught that day. If it fish catch weight and mean number of consumers reported were possible to interview fishermen at the conclusion of in Pierce et. al. ( 1981) and on an edible fraction of 0.5. their fishing day, intake estimates could be potentially U. S. EPA ( 1989a) reported a median intake rate of 23 higher. An additional factor potentially affecting intake rates g/ day. is that fishing quarantines were imposed in early spring due Price et al. ( 1994) obtained the raw data from this to heavy sewage overflow ( Puffer et al., 1981). survey and performed a re analysis using sampling weights Pierce et al. ( 1981)  Commencement Bay Seafood Consumption Study  Pierce et al. ( 1981) performed a local creel survey to examine seafood consumption patterns and demographics of sport fishermen in Commencement Bay, Washington. The objectives of this survey included determining ( 1) seafood consumption habits and demographics of non commercial anglers catching seafood; ( 2) the extent to which resident fish were used as food; and ( 3) the method of preparation of the fish to be consumed. Salmon were excluded from the survey since it was believed that they had little potential for contamination. The first half of this survey was proportional to inverse fishing frequency. The rationale for these weights is explained in Section 10.1 and in the discussion above of the Puffer et al. ( 1981) study. In the reanalysis Price et al. ( 1994) found a median intake rate of 1.0 g/ day and a 90th percentile rate of 13 g/ day. The distribution of fishing frequency generated by Price et al. ( 1994) is shown in Table 10 27. Note that when equal weights were used, Price et al. ( 1994) found a median rate of 19 g/ day, which was close to the approximate U. S. EPA ( 1989a) value reported above of 23 g/ day. The same limitations apply to interpreting the results presented here to those presented above in the Volume II  Food Ingestion Factors Chapter 10  Intake of Fish and Shellfish Page Exposure Factors Handbook 10 12 August 1997 discussion of Puffer et al. ( 1981). The median intake rate because they had consumed fish or wildlife from the found by Price et al. ( 1994) ( using inverse frequency Everglades at least once per month in the last 3 months of weights) is more reflective of median intake in the target the study period. The majority of the eligible participants (> population than is the value of 19 g/ day ( or 23 g/ day); the 93 percent) were either subsistence fishermen, Everglade latter value reflects more the 50th percentile of the resource residents, or both. Of the total eligible participants, 55 utilization distribution, ( i. e., that anglers with intakes above individuals refused to participate in the survey. Useable 19 g/ day consume 50 percent of the recreational fish catch). data were obtained from 330 respondents ranging in age Similarly, the fishing frequency distribution generated by from 10 81 years of age ( mean age 39 years ± 18.8) ( U. S. Price et al. ( 1994) is more reflective of the fishing DHHS, 1995). Respondents were administered a three frequency distribution in the target population than is the page questionnaire from which demographic information, distribution presented in Pierce et al. ( 1981). Note the fishing and eating habits, and other variables were obtained target population is those anglers who fished at ( U. S. DHHS, 1995). Commencement Bay during the time period of the survey. Table 10 28 shows the ranges, means, and standard As with the Puffer et al. ( 1981) data, these values deviations of selected characteristics by subgroups of the ( 1.0 g/ day and 19 g/ day) are both probably underestimates survey population. Sixty two percent of the respondents since the sampling probabilities are less than proportional were male with a slight preponderance of black individuals to fishing frequency; thus, the true target population median ( 43 percent white, 46 percent black non Hispanic, and 11 is probably somewhat above 1.0 g/ day and the true 50th percent Hispanic) ( Table 10 28). Most of the respondents percentile of the resource utilization distribution is probably reported earning an annual income of $ 15,000 or less per somewhat higher than 19 g/ day. The data from this survey family before taxes ( U. S. DHHS, 1995). The mean number provide an indication of consumption patterns for the time of years fished along the canals by the respondents was 15.8 period around 1980 in the Commencement Bay area. years with a standard deviation of 15.8. The mean number However, the data may not reflect current consumption of times per week fish consumers reported eating fish over patterns because fishing advisories were instituted due to the last 6 months and last month of the survey period was local contamination. 1.8 and 1.5 per week with a standard deviation of 2.5 and U. S. DHHS ( 1995)  Health Study to Assess the Human Health Effects of Mercury Exposure to Fish Consumed from the Everglades  A health study was conducted in two phases in the Everglades, Florida for the U. S. Department of Health and Human Services ( U. S. DHHS, 1995). The objectives of the first phase were to: ( a) describe the human populations at risk for mercury exposure through their consumption of fish and other contaminated animals from the Everglades and ( b) evaluate the extent of mercury exposure in those persons consuming contaminated food and their compliance with the voluntary health advisory. The second phase of the study involved neurologic testing of all study participants who had total mercury levels in hair greater than 7.5 F g/ g. Study participants were identified by using special targeted screenings, mailings to residents, postings and multi media advertisements of the study throughout the Everglades region, and direct discussions with people fishing along the canals and waterways in the contaminated areas. The contaminated areas were identified by the interviewers and long term Everglade residents. Of a total of 1,794 individuals sampled, 405 individuals were eligible to participate in the study 1.4, respectively ( Table 10 28). Table 10 28 also indicates that 71 percent of the respondents reported knowing about the mercury health advisories. Of those who were aware, 26 percent reported that they had lowered their consumption of fish caught in the Everglades while the rest ( 74 percent) reported no change in consumption patterns ( U. S. DHHS, 1995). A limitation of this study is that fish intake rates ( g/ day) were not reported. Another limitation is that the survey was site limited, and, therefore, not representative of the U. S. population. An advantage of this study is that it is one of the few studies targeting subsistence fishermen.

10.6. KEY FRESHWATER RECREATIONAL STUDIES West et al. ( 1989)  Michigan Sport Anglers Fish Consumption Survey, 1989  surveyed a stratified random sample of Michigan residents with fishing licences. The sample was divided into 18 cohorts, with one cohort receiving a mail questionnaire each week between January and May 1989. The survey included both a short term recall component recording respondents' fish intake over Volume II  Food Ingestion Factors Chapter 10  Intake of Fish and Shellfish Exposure Factors Handbook Page August 1997 10 13 a seven day period and a usual frequency component. For the percentile data. Using this lognormal distribution, the the short term component, respondents were asked to mean values for serving sizes greater than 8 oz. and for identify all household members and list all fish meals serving sizes at least 10 percent greater than 8 oz. were consumed by each household member during the past seven determined. In both cases a serving size of 12 oz. was days. The source of the fish for each meal was requested consistent with the Pao et al. ( 1982) distribution. The ( self caught, gift, market, or restaurant). Respondents were weights used in the EPA analysis then were 5, 8, and 12 oz. asked to categorize serving size by comparison with for fish meals described as less, about the same, and more pictures of 8 oz. fish portions; serving sizes could be than the 8 oz. picture, respectively. It should be noted that designated as either " about the same size", " less", or the mean serving size from Pao et al. ( 1982) was about 5 " more" than the 8 oz. picture. Data on fish species, oz., well below the value of 8 oz. most commonly reported locations of self caught fish and methods of preparation and by respondents in the West et al. ( 1989) survey. cooking were also obtained. Table 10 29 displays the mean number of total and The usual frequency component of the survey asked recreational fish meals for each household member based about the frequency of fish meals during each of the four on the seven day recall data. Also shown are mean fish seasons and requested respondents to give the overall intake rates derived by applying the weights described percentage of household fish meals that come from above to each fish meal. Intake was calculated on both a recreational sources. A sample of 2,600 individuals were grams/ day and grams/ kg body weight/ day basis. This selected from state records to receive survey questionnaires. analysis was restricted to individuals who eat fish and who A total of 2,334 survey questionnaires were deliverable and reside in households reporting some recreational fish 1,104 were completed and returned, giving a response rate consumption during the previous year. About 75 percent of of 47.3 percent among individuals receiving questionnaires. survey respondents ( i. e., licensed anglers) and about 84 In the analysis of the survey data by West et. al. percent of respondents who fished in the prior year reported ( 1989), the authors did not attempt to generate the some household recreational fish consumption. distribution of recreationally caught fish intake in the survey The EPA analysis next attempted to use the short population. EPA obtained the raw data of this survey for term data to validate the usual intake data. West et al. the purpose of generating fish intake distributions and other ( 1989) asked the main respondent in each household to specialized analyses. provide estimates of their usual frequency of fishing and As described elsewhere in this handbook, percentiles eating fish, by season, during the previous year. The survey of the distribution of average daily intake reflective of long provides a series of frequency categories for each season term consumption patterns can not in general be estimated and the respondent was asked to check the appropriate using short term ( e. g., one week) data. Such data can be range. The ranges used for all questions were: almost daily, used to estimate mean average daily intake rates ( reflective 2 4 times a week, once a week, 2 3 times a month, once a of short or long term consumption); in addition, short term month, less often, none, and don't know. For quantitative data can serve to validate estimates of usual intake based on analysis of the data it is necessary to convert this categorical longer recall. information into numerical frequency values. As some of EPA first analyzed the short term data with the intent the ranges are relatively broad, the choice of conversion of estimating mean fish intake rates. In order to compare values can have some effect on intake estimates. In order to these results with those based on usual intake, only obtain optimal values, the usual fish eating frequency respondents with information on both short term and usual reported by respondents for the season during which the intake were included in this analysis. For the analysis of the questionnaire was completed was compared to the number short term data, EPA modified the serving size weights used of fish meals reportedly consumed by respondents over the by West et al. ( 1989), which were 5, 8 and 10 oz., seven day short term recall period. The results of these respectively, for portions that were less, about the same, and comparisons are displayed in Table 10 30; it shows that, on more than the 8 oz. picture. EPA examined the percentiles average, there is general agreement between estimates made of the distribution of fish meal sizes reported in Pao et al. using one year recall and estimates based on seven day ( 1982) derived from the 1977 1978 USDA National Food recall. The average number of meals ( 1.96/ week) was at the Consumption Survey and observed that a lognormal bottom of the range for the most frequent consumption distribution provided a good visual fit to Volume II  Food Ingestion Factors Chapter 10  Intake of Fish and Shellfish Page Exposure Factors Handbook 10 14 August 1997 group with data ( 2 4 meals/ week). In contrast, for the term and usual intake data. The presence of short term data lower usual frequency categories, the average number of allowed validation of the usual intake data which was based meals was at the top, or exceeded the top of category range. on long term recall; thus, some of the problems associated This suggests some tendency for relatively infrequent fish with surveys relying on long term recall are mitigated here. eaters to underestimate their usual frequency of fish The response rate of this survey, 47 percent, was consumption. The last column of the table shows the relatively low. In addition, the usual fish intake distribution estimated fish eating frequency per week that was selected generated here employed a constant fish meal size, 8 oz.. for use in making quantitative estimates of usual fish intake. Although use of this value as an average meal size was These values were guided by the values in the second validated by the short term recall results, the use of a column, except that frequency values that were inconsistent constant meal size, even if correct on average, may seriously with the ranges provided to respondents in the survey were reduce the variation in the estimated fish intake distribution. avoided. This study was conducted in the winter and spring Using the four seasonal fish eating frequencies months of 1988. This period does not include the summer provided by respondents and the above conversions for months when peak fishing activity can be anticipated, reported intake frequency, EPA estimated the average leading to the possibility that intake results based on the 7 number of fish meals per week for each respondent. This day recall data may understate individuals' usual ( annual estimate, as well as the analysis above, pertain to the total average) fish consumption. A second survey by West et al. number of fish meals eaten ( in Michigan) regardless of the ( 1993) gathered diary data on fish intake for respondents source of the fish. Respondents were not asked to provide spaced over a full year. However, this later survey did not a seasonal breakdown for eating frequency of recreationally include questions about usual fish intake and has not been caught fish; rather, they provided an overall estimate for reanalyzed here. The mean recreational fish intake rates the past year of the percent of fish they ate that was obtained derived from the short term and usual components were from different sources. EPA estimated the annual quite similar, however, 14.0 versus 14.4 g/ day. frequency of recreationally caught fish meals by multiplying the estimated total number of fish meals by the reported percent of fish meals obtained from recreational sources; recreational sources were defined as either self caught or a gift from family or friends. The usual intake component of the survey did not include questions about the usual portion size for fish meals. In order to estimate usual fish intake, a portion size of 8 oz. was applied ( the majority of respondents reported this meal size in the 7 day recall data). Individual body weight data were used to estimate intake on a g/ kg day basis. The fish intake distribution estimated by EPA is displayed in Table 10 31. The distribution shown in Table 10 31 is based on respondents who consumed recreational caught fish. As mentioned above, these represent 75 percent of all respondents and 84 percent of respondents who reported having fished in the prior year. Among this latter population, the mean recreational fish intake rate is 14.4* 0.84= 12.1 g/ day; the value of 38.7 g/ day ( 95th percentile among consumers) corresponds to the 95.8th percentile of the fish intake distribution in this ( fishing) population. The advantages of this data set and analysis are that the survey was relatively large and contained both short Chemrisk ( 1991)  Consumption of Freshwater Fish by Maine Anglers  Chemrisk conducted a study to characterize the rates of freshwater fish consumption among Maine residents ( Chemrisk, 1991; Ebert et al., 1993). Since the only dietary source of local freshwater fish is recreational fish, the anglers in Maine were chosen as the survey population. The survey was designed to gather information on the consumption of fish caught by anglers from flowing ( rivers and streams) and standing ( lakes and ponds) water bodies. Respondents were asked to recall the frequency of fishing trips during the 1989 1990 ice fishing season and the 1990 open water season, the number of fish species caught during both seasons, and estimate the number of fish consumed from 15 fish species. The respondents were also asked to describe the number, species, and average length of each sport caught fish consumed that had been gifts from other members of their households or other household. The weight of fish consumed by anglers was calculated by first multiplying the estimated weight of the fish by the edible fraction, and then dividing this product by the number of intended consumers. Species specific regression equations were utilized to estimate weight from the reported fish length. Volume II  Food Ingestion Factors Chapter 10  Intake of Fish and Shellfish Exposure Factors Handbook Page August 1997 10 15 The edible fractions used were 0.4 for salmon, 0.78 for grams); white perch ( 380,000 grams) for lakes and ponds; Atlantic smelt, and 0.3 for all other species ( Ebert et al., and Brooktrout ( 420,000 grams) for rivers and streams 1993). ( Chemrisk, 1991). A total of 2,500 prospective survey participants were EPA obtained the raw data tapes from the marine randomly selected from a list of anglers licensed in Maine. anglers survey and performed some specialized analyses. The surveys were mailed in during October, 1990. Since One analysis involved examining the percentiles of the this was before the end of the open fishing season, " resource utilization distribution" ( this distribution was respondents were also asked to predict how many more defined in Section 10.1). The 50th, or more generally the open water fishing trips they would undertake in 1990. pth percentile of the resource utilization distribution, is Chemrisk ( 1991) and Ebert et al. ( 1993) calculated defined as the consumption level such that p percent of the distributions of freshwater fish intake for two populations, resource is consumed by individuals with consumptions " all anglers" and " consuming anglers". All anglers were below this level and 100 p percent by individuals with defined as licensed anglers who fished during either the consumptions above this level. EPA found that 90 percent 1989 1990 ice fishing season or the 1990 open water of recreational fish consumption was by individuals with season ( consumers and non consumers) and licensed intake rates above 3.1 g/ day and 50 percent was by anglers who did not fish but consumed freshwater fish individuals with intakes above 20 g/ day. Those above 3.1 caught in Maine during these seasons. " Consuming g/ day make up about 30 percent of the " all angler" anglers" were defined as those anglers who consumed population and those above 20 g/ day make up about 5 freshwater fish obtained from Maine sources during the percent of this population; thus, the top 5 percent of the 1989 1990 ice fishing or 1990 open water fishing season. angler population consumed 50 percent of the recreational In addition, the distribution of fish intake from rivers and fish catch. streams was also calculated for two populations, those EPA also performed an analysis of fish consumption fishing on rivers and streams (" river anglers") and those among anglers and their families. This analysis was possible consuming fish from rivers and streams (" consuming river because the survey included questions on the number, sex, anglers"). and age of each individual in the household and whether the A total of 1,612 surveys were returned, giving a individual consumed recreationally caught fish. The total response rate of 64 percent; 1,369 ( 85 percent) of the 1,612 population of licensed anglers in this survey and their respondents were included in the " all angler" population household members was 4,872; the average household size and 1,053 ( 65 percent) were included in the " consuming for the 1,612 anglers in the survey was thus 3.0 persons. angler" population. Freshwater fish intake distributions for Fifty six percent of the population was male and 30 percent these populations are presented in Table 10 32. The mean was 18 or under. and 95th percentile was 5.0 g/ day and 21.0 g/ day, A total of 55 percent of this population was reported respectively, for " all anglers," and 6.4 g/ day and 26.0 to consume freshwater recreationally caught fish in the year g/ day, respectively, for " consuming anglers." Table 10 32 of the survey. The sex and ethnic distribution of the also presents intake distributions for fish caught from rivers consumers was similar to that of the overall population. The and streams. Among " river anglers" the mean and 95th distribution of fish intake among the overall household percentiles were 1.9 g/ day and 6.2 g/ day, respectively, while population, or among consumers in the household, can be among " consuming river anglers" the mean was 3.7 g/ day calculated under the assumption that recreationally caught and the 95th percentile was 12.0 g/ day. Table 10 33 fish was shared equally among all members of the presents fish intake distributions by ethnic group for household reporting consumption of such fish ( note this consuming anglers. The highest mean intake rates reported assumption was used above to calculate intake rates for are for Native Americans ( 10 g/ day) and French Canadians anglers). With this assumption, the mean intake rate among ( 7.4 g/ day). Because there was a low number of consumers was 5.9 g/ day with a median of 1.8 g/ day and a respondents for Hispanics, Asian/ Pacific Islanders, and 95th percentile of 23.1 g/ day; for the overall population the African Americans, intake rates within these subgroups mean was 3.2 g/ day and the 95th percentile was 14.1 g/ day. were not calculated ( Chemrisk, 1991). The results of this survey can be put into the context The consumption, by species, of freshwater fish of the overall Maine population. The 1,612 caught is presented in Table 10 34. The largest specie consumption was salmon from ice fishing (~ 292,000 Volume II  Food Ingestion Factors Chapter 10  Intake of Fish and Shellfish Page Exposure Factors Handbook 10 16 August 1997 anglers surveyed represent about 0.7 percent of the up to the earlier 1989 Michigan survey described estimated 225,000 licensed anglers in Maine. It is previously. The major purpose of 1991 1992 survey was reasonable to assume that licensed anglers and their families to provide short term recall data of recreational fish will have the highest exposure to recreationally caught consumption over a full year period; the 1989 survey, in freshwater fish. Thus, to estimate the number of persons in contrast, was conducted over only a half year period ( West Maine with recreationally caught freshwater fish intake et al., 1993). above, for instance, 6.5 g/ day ( the 80th percentile among This survey was similar in design to the 1989 household consumers in this survey), one can assume that Michigan survey. A sample of 7,000 persons with virtually all persons came from the population of licensed Michigan fishing licenses was drawn and surveys were anglers and their families. The number of persons above 6.5 mailed in 2 week cohorts over the period January, 1991 to g/ day in the household survey population is calculated by January, 1992. Respondents were asked to report detailed taking 20 percent ( i. e., 100 percent  80 percent) of the fish consumption patterns during the preceding seven days, consuming population in the survey; this number then is as well as demographic information; they were also asked 0.2*( 0.55* 4872)= 536. Dividing this number by the if they currently eat fish. Enclosed with the survey were sampling fraction of 0.007 ( 0.7 percent) gives about 77,000 pictures of about a half pound of fish. Respondents were persons above 6.5 g/ day of recreational freshwater fish asked to indicate whether reported consumption at each consumption statewide. The 1990 census showed the meal was more, less or about the same as the picture. population of Maine to be 1.2 million people; thus the Based on responses to this question, respondents were 77,000 persons above 6.5 g/ day represent about 6 percent assumed to have consumed 10, 5 or 8 ounces of fish, of the state's population. respectively. Chemrisk ( 1991) reported that the fish consumption A total of 2,681 surveys were returned. West et al. estimates obtained from the survey were conservative ( 1993) calculated a response rate for the survey of 46.8 because of assumptions made in the analysis. The percent; this was derived by removing from the sample assumptions included: a 40 percent estimate as the edible those respondents who could not be located or who did not portion of landlocked and Atlantic salmon; inclusion of the reside in Michigan for at least six months. intended number of future fishing trips and an assumption Of these 2,681 respondents, 2,475 ( 93 percent) that the average success and consumption rates for the reported that they currently eat fish; all subsequent analyses individual angler during the trips already taken would were restricted to the current fish eaters. The mean fish continue through future trips. The data collected for this consumption rates were found to be 16.7 g/ day for sport fish study were based on recall and self reporting which may and 26.5 g/ day for total fish ( West et al., 1993). Table 10 have resulted in a biased estimate. The social desirability 35 shows mean sport fish consumption rates by of the sport and frequency of fishing are also bias demographic categories. Rates were higher among contributing factors; successful anglers are among the minorities, people with low income, and people residing in highest consumers of freshwater fish ( Chemrisk, 1991). smaller communities. Consumption rates in g/ day were also Over reporting appears to be correlated with skill level and higher in males than in females; however, this difference the importance of the activity to the individual; it is likely would likely disappear if rates were computed on a g/ kg day that the higher consumption rates may be substantially basis. overstated ( Chemrisk, 1991). Additionally, fish advisories West et al. ( 1993) estimated the 80th percentile of are in place in these areas and may affect the rate of fish the survey fish consumption distribution. More extensive consumption among anglers. The survey results showed percentile calculations were performed by U. S. EPA ( 1995) that in 1990, 23 percent of all anglers consumed no using the raw data from the West et al. ( 1993) survey and freshwater fish, and 55 percent of the river anglers ate no calculated 50th, 90th, and 95th percentiles. However, since freshwater fish. An advantage of this study is that it this survey only measured fish consumption over a short presents area specific consumption patterns and the sample ( one week) interval, the resulting distribution will not be size is rather large. indicative of the long term fish consumption distribution West et al. ( 1993)  Michigan Sport Anglers Fish Consumption Study, 1991 1992  This survey, financed by the Michigan Great Lakes Protection Fund, was a followand the upper percentiles reported from the EPA analysis will likely considerably overestimate the corresponding long term percentiles. The overall 95th percentile calculated by Volume II  Food Ingestion Factors Chapter 10  Intake of Fish and Shellfish Exposure Factors Handbook Page August 1997 10 17 U. S. EPA ( 1995) was 77.9; this is about double the 95th diary or provided diary information by telephone. Due to percentile estimated using year long consumption data from changes in health advisories for Lake Ontario which the 1989 Michigan survey. resulted in less Lake Ontario fishing in 1992, only 43 The limitations of this survey are the relatively low percent, or 366 of these 853 persons indicated that they response rate and the fact that only three categories were fished Lake Ontario during 1992. The study analyses used to assign fish portion size. The main study strengths summarized below concerning fish consumption and Lake were its relatively large size and its reliance on short term Ontario fishing participation are based on these 366 recall. persons. Connelly et al. ( 1996)  Sportfish Consumption Patterns of Lake Ontario Anglers and the Relationship to Health Advisories, 1992  The objectives of this study were to provide accurate estimates of fish consumption ( overall and sport caught) among Lake Ontario anglers and to evaluate the effect of Lake Ontario health advisory recommendations ( Connelly et al., 1996). To target Lake Ontario anglers, a sample of 2,500 names was randomly drawn from 1990 1991 New York fishing license records for licenses purchased in six counties bordering Lake Ontario. Participation in the study was solicited by mail with potential participants encouraged to enroll in the study even if they fished infrequently or consumed little or no sport caught fish. The survey design involved three survey techniques including a mail questionnaire asking for 12 month recall of 1991 fishing trips and fish consumption, self recording information in a diary for 1992 fishing trips and fish consumption, periodic telephone interviews to gather information recorded in the diary and a final telephone interview to determine awareness of health advisories ( Connelly et al., 1996). Participants were instructed to record in the diary the species of fish eaten, meal size, method by which fish was acquired ( sport caught or other), fish preparation and cooking techniques used and the number of household members eating the meal. Fish meals were defined as finfish only. Meal size was estimated by participants by comparing their meal size to pictures of 8 oz. fish steaks and fillets on dinner plates. An 8 oz. size was assumed unless participants noted their meal size was smaller than 8 oz., in which case a 4 oz. size was assumed, or they noted it was larger than 8 oz., in which case a 12 oz. size was assumed. Participants were also asked to record information on fishing trips to Lake Ontario and species and length of any fish caught. From the initial sample of 2,500 license buyers, 1,993 ( 80 percent) were reachable by phone or mail and 1,410 of these were eligible for the study, in that they intended to fish Lake Ontario in 1992. A total of 1,202 of these 1,410, or 85 percent, agreed to participate in the study. Of the 1,202 participants, 853 either returned the Anglers who fished Lake Ontario reported an average of 30.3 ( S. E. = 2.3) fish meals per person from all sources in 1992; of these meals 28 percent were sport caught ( Connelly et al., 1996). Less than 1 percent ate no fish for the year and 16 percent ate no sport caught fish. The mean fish intake rate from all sources was 17.9 g/ day and from sport caught sources was 4.9 g/ day. Table 10 36 gives the distribution of fish intake rates from all sources and from sport caught fish. The median rates were 14.1 g/ day for all sources and 2.2 g/ day for sport caught; the 95th percentiles were 42.3 g/ day and 17.9 g/ day for all sources and sport caught, respectively. As seen in Table 10 37, statistically significant differences in intake rates were seen across age and residence groups, with residents of large cities and younger people having lower intake rates on average. The main advantage of this study is the diary format. This format provides more accurate information on fishing participation and fish consumption, than studies based on 1 year recall ( Ebert et al., 1993). However, a considerable portion of diary respondents participated in the study for only a portion of the year and some errors may have been generated in extrapolating these respondents' results to the entire year ( Connelly et al., 1996). In addition, the response rate for this study was relatively low, 853 of 1,410 eligible respondents, or 60 percent, which may have engendered some non response bias. The presence of health advisories should be taken into account when evaluating the intake rates observed in this study. Nearly all respondents (> 95 percent) were aware of the Lake Ontario health advisory. This advisory counseled to eat none of 9 fish species from Lake Ontario and to eat no more than one meal per month of another 4 species. In addition, New York State issues a general advisory to eat no more than 52 sport caught fish meals per year. Among participants who fished Lake Ontario in 1992, 32 percent said they would eat more fish if health advisories did not exist. A significant fraction of respondents did not totally adhere to the fish advisory; however, 36 percent of respondents, and 72 percent of Volume II  Food Ingestion Factors Chapter 10  Intake of Fish and Shellfish Page Exposure Factors Handbook 10 18 August 1997 respondents reporting Lake Ontario fish consumption, ate Fiore et al. ( 1989) assumed a ( constant) meal size of at least one species of fish over the advisory limit. 8 ounces ( 227 grams) of fish which may over estimate Interestingly, 90 percent of those violating the advisory average meal size. Pao et al. ( 1982), using data from the reported that they believed they were eating within advisory 1977 78 USDA NFCS, reported an average fish meal size limits. of slightly less than 150 grams for adult males. EPA 10.7. RELEVANT FRESHWATER RECREATIONAL STUDIES Fiore et al. ( 1989)  Sport Fish Consumption and Body Burden Levels of Chlorinated Hydrocarbons: A Study of Wisconsin Anglers. This survey, reported by Fiore et al. ( 1989), was conducted to assess sociodemographic factors and sport fishing habits of anglers, to evaluate anglers' comprehension of and compliance with the Wisconsin Fish Consumption Advisory, to measure body burden levels of PCBs and DDE through analysis of blood serum samples and to examine the relationship between body burden levels and consumption of sport caught fish. The survey targeted all Wisconsin residents who had purchased fishing or sporting licenses in 1984 in any of 10 Consumption in New York Sport Fisheries  Connelly et al. pre selected study counties. These counties were chosen in ( 1992) conducted a study to assess the awareness and part based on their proximity to water bodies identified in knowledge of New York anglers about fishing advisories Wisconsin fish advisories. A total of 1,600 anglers were and contaminants found in fish and their fishing and fish sent survey questionnaires during the summer of 1985. consuming behaviors. The survey sample consisted of The survey questionnaire included questions about 2,000 anglers with New York State fishing licenses for the fishing history, locations fished, species targeted, kilograms year beginning October 1, 1990 through September 30, caught for consumption, overall fish consumption 1991. A questionnaire was mailed to the survey sample in ( including commercially caught) and knowledge of fish January, 1992. The questionnaire was designed to measure advisories. The recall period was one year. catch and consumption of fish, as well as methods of fish A total of 801 surveys were returned ( 50 percent preparation and knowledge of and attitudes towards health response rate). Of these, 601 ( 75 percent) were from males advisories ( Connelly et al., 1992). The survey adjusted and 200 from females; the mean age was 37 years. Fiore et response rate was 52.8 percent ( 1,030 questionnaires were al. ( 1989) reported that the mean number of fish meals for completed and 51 were not deliverable). 1984 for all respondents was 18 for sport caught meals and The average and median number of fishing days per 24 for non sport caught meals. Fiore et al. ( 1989) assumed year were 27 and 15 days respectively ( Connelly et al. that each fish meal consisted of 8 ounces ( 227 grams) of 1992). The mean number of sport caught fish meals was fish to generate means and percentiles of fish intake. The 11. About 25 percent of anglers reported that they did not reported per capita intake rate of sport caught fish was 11.2 consume sport caught fish. g/ day; among consumers, who comprised 91 percent of all Connelly et al. ( 1992) found that 80 percent of respondents, the mean sport caught fish intake rate was anglers statewide did not eat listed species or ate them 12.3 g/ day and the 95th percentile was 37.3 g/ day. The within advisory limits and followed the 1 sport caught fish mean daily fish intake from all sources ( both sport caught meal per week recommended maximum. The other 20 and commercial) was 26.1 g/ day with a 95th percentile of percent of anglers exceeded the advisory recommendations 63.4 g/ day. The 95th percentile of 37.3 g/ day of sport in some way; 15 percent ate listed species above the limit caught fish represents 60 fish meals per year; 63.4 g/ day and 5 percent ate more than one sport caught meal per ( the 95th percentile of total fish intake) represents 102 fish week. meals per year. obtained the raw data from this study and calculated the distribution of the number of sport caught fish meals and the distribution of fish intake rates ( using 150 grams/ meal); these distributions are presented in Table 10 38. With this average meal size, the per capita estimate is 7.4 g/ day. This study is limited in its ability to accurately estimate intake rates because of the absence of data on weight of fish consumed. Another limitation of this study is that the results are based on one year recall, which may tend to over estimate the number of fishing trips ( Ebert et al., 1993). In addition, the response rate was rather low ( 50 percent). Connelly et al. ( 1992)  Effects of Health Advisory and Advisory Changes on Fishing Habits and Fish Volume II  Food Ingestion Factors Chapter 10  Intake of Fish and Shellfish Exposure Factors Handbook Page August 1997 10 19 Connelly et al. ( 1992) found that respondents eating settings. The interviews were conducted on weekends and more than one sport caught meal per week were just as weekdays during morning, midday, and evening periods. likely as those eating less than one meal per week to know The anglers were asked specific questions concerning: the recommended level of sport caught fish consumption, fishing and fish consumption habits; perceptions of although less than 1/ 3 in each group knew the level. An presence of contaminants in fish; perceptions of risks estimated 85 percent of anglers were aware of the health associated with consumption of recreationally caught fish; advisory. Over 50 percent of respondents said that they and awareness of, attitude toward, and response to fish made changes in their fishing or fish consumption behaviors consumption advisories or fishing bans. in response to health advisories. Approximately 92 percent of the survey respondents The advisory included a section on methods that can were male. The following statistics were provided by be used to reduce contaminant exposure. Respondents were Hudson River Sloop Clearwater, Inc. ( 1993). The most asked what methods they used for fish cleaning and common reason given for fishing was for recreation or cooking. Summary results on preparation and cooking enjoyment. Over 58 percent of those surveyed indicated methods are presented in Section 10.9 and in Appendix that they eat their catch. Of those anglers who eat their 10B. catch, 48 percent reported being aware of advisories. A limitation of this study with respect to estimating Approximately 24 percent of those who said they currently fish intake rates is that only the number of sport caught do not eat their catch, have done so in the past. Anglers meals was ascertained, not the weight of fish consumed. were more likely to eat their catch from the lower Hudson The fish meal data can be converted to an intake rate ( g/ day) areas where health advisories, rather than fishing bans, have by assuming a value for a fish meal such as that from Pao et been issued. Approximately 94 percent of Hispanic al. ( 1982) ( about 150 grams as the average amount of fish Americans were likely to eat their catch, while 77 percent consumed per eating occasion for adult males  males of African Americans and 47 percent of Caucasian comprised 88 percent of respondents in the current study). Americans intended to eat their catch. Of those who eat Using 150 grams/ meal the mean intake rate among the their catch, 87 percent were likely to share their meal with angler population would be 4.5 g/ day; note that about 25 others ( including women of childbearing age, and children percent of this population reported no sport caught fish under the age of fifteen). consumption. For subsistence anglers, more low income than The major focus of this study was not on upper income anglers eat their catch ( Hudson River Sloop consumption, per se, but on the knowledge of and impact of Clearwater, Inc., 1993). Approximately 10 percent of the fish health advisories; Connelly et al. ( 1992) provides respondents stated that food was their primary reason for important information on these issues. fishing; this group is more likely to be in the lowest per Hudson River Sloop Clearwater, Inc. ( 1993)  Hudson River Angler Survey  Hudson River Sloop Clearwater, Inc. ( 1993) conducted a survey of adherence to fish consumption health advisories among Hudson River anglers. All fishing has been banned on the upper Hudson River where high levels of PCB contamination are well documented; while voluntary recreational fish consumption advisories have been issued for areas south of the Troy Dam ( Hudson River Sloop Clearwater, Inc., 1993). The survey consisted of direct interviews with 336 shore based anglers between the months of June and November 1991, and April and July 1992. Sociodemographic characteristics of the respondents are presented in Table 10 39. The survey sites were selected based on observations of use by anglers, and legal accessibility. The selected sites included upper, mid, and lower Hudson River sites located in both rural and urban capita income group ( Hudson River Sloop Clearwater, Inc., 1993). The average frequency of fish consumption reported was just under one ( 0.9) meal over the previous week, and three meals over the previous month. Approximately 35 percent of all anglers who eat their catch exceeded the amounts recommended by the New York State health advisories. Less than half ( 48 percent) of all the anglers interviewed were aware of the State health advisories or fishing bans. Only 42 percent of those anglers aware of the advisories have changed their fishing habits as a result. The advantages of this study include: in person interviews with 95 percent of all anglers approached; fieldtested questions designed to minimize interviewer bias; and candid responses concerning consumption of fish from contaminated waters. The limitations of this Volume II  Food Ingestion Factors Chapter 10  Intake of Fish and Shellfish Page Exposure Factors Handbook 10 20 August 1997 study are that specific intake amounts are not indicated, and For the overall analysis, each of the 98 communities that only shore based anglers were interviewed. was treated as a single unit of analysis and the entire group 10.8. NATIVE AMERICAN FRESHWATER STUDIES Wolfe and Walker ( 1987)  Subsistence Economies in Alaska: Productivity, Geography, and Development Impacts  Wolfe and Walker ( 1987) analyzed a dataset from 98 communities for harvests of fish, land mammals, marine mammals, and other wild resources. The analysis was performed to evaluate the distribution and productivity of subsistence harvests in Alaska during the 1980s. Harvest levels were used as a measure of productivity. Wolfe and Walker ( 1987) defined harvest to represent a single year's production from a complete seasonal round. The harvest levels were derived primarily from a compilation of data from subsistence studies conducted between 1980 to 1985 by various researchers in the Alaska Department of Fish and Game, Division of Subsistence. Of the 98 communities studied, four were large urban population centers and 94 were small communities. The harvests for these latter 94 communities were documented through detailed retrospective interviews with harvesters from a sample of households ( Wolfe and Walker, 1987). Harvesters were asked to estimate the quantities of a particular species that were harvested and used by members of that household during the previous 12 month period. Wolfe and Walker ( 1987) converted harvests to a common unit for comparison, pounds dressed weight per capita per year, by multiplying the harvests of households within each community by standard factors converting total pounds to dressed weight, summing across households, and then dividing by the total number of household members in the household sample. Dressed weight varied by species and community but in general was 70 to 75 percent of total fish weight; dressed weight for fish represents that portion brought into the kitchen for use ( Wolfe and Walker, 1987). Harvests for the four urban populations were developed from a statewide data set gathered by the Alaska Department of Fish and Game Divisions of Game and Sports Fish. Urban sport fish harvest estimates were derived from a survey that was mailed to a randomly selected statewide sample of anglers ( Wolfe and Walker, 1987). Sport fish harvests were disaggregated by urban residency and the dataset was analyzed by converting the harvests into pounds and dividing by the 1983 urban population. of communities was assumed to be a sample of all communities in Alaska ( Wolfe and Walker, 1987). Each community was given equal weight, regardless of population size. Annual per capita harvests were calculated for each community. For the four urban centers, fish harvests ranged from 5 to 21 pounds per capita per year ( 6.2 g/ day to 26.2 g/ day). The range for the 94 small communities was 25 to 1,239 pounds per capita per year ( 31 g/ day to 1,541 g/ day). For these 94 communities, the median per capita fish harvest was 130 pounds per year ( 162 g/ day). In most ( 68 percent) of the 98 communities analyzed, resource harvests for fish were greater than the harvests of the other wildlife categories ( land mammal, marine mammal, and other) combined. The communities in this study were not made up entirely of Alaska Natives. For roughly half the communities, Alaska Natives comprised 80 percent or more of the population, but for about 40 percent of the communities they comprised less than 50 percent of the population. Wolfe and Walker ( 1987) performed a regression analysis which showed that the per capita harvest of a community tended to increase as a function of the percentage of Alaska Natives in the community. Although this analysis was done for total harvest ( i. e., fish, land mammal, marine mammal and others) the same result should hold for fish harvest since fish harvest is highly correlated with total harvest. A limitation of this report is that it presents ( percapita harvest rates as opposed to individual intake rates. Wolfe and Walker ( 1987) compared the per capita harvest rates reported to the results for the household component of the 1977 1978 USDA National Food Consumption Survey ( NFCS). The NFCS showed that about 222 pounds of meat, fish, and poultry were purchased and brought into the household kitchen for each person each year in the western region of the United States. This contrasts with a median total resource harvest of 260 lbs/ yr in the 94 communities studied. This comparison, and the fact that Wolfe and Walker ( 1987) state that " harvests represent that portion brought into the kitchen for use," suggest that the same factors used to convert household consumption rates in the NFCS to individual intake rates can be used to convert per capita harvest rates to individual intake rates. In Section 10.3, a factor of 0.5 was used to convert fish consumption from household to individual intake rates. Applying this factor, the median Volume II  Food Ingestion Factors Chapter 10  Intake of Fish and Shellfish Exposure Factors Handbook Page August 1997 10 21 per capita individual fish intake in the 94 communities was based on a stratified random sampling design where would be 81 g/ day and the range 15.5 to 770 g/ day. respondents were selected from patient registration files at A limitation of this study is that the data were based the Indian Health Service. Interviews were performed in on 1 year recall from a mailed survey. An advantage of the person at a central location on the member's reservation. study is that it is one of the few studies that present fish Information requested included annual and seasonal harvest patterns for subsistence populations. numbers of fish meals, average serving size per fish meal, AIHC ( 1994)  Exposure Factors Sourcebook  The Exposure Factors Sourcebook ( AIHC, 1994) provides data for non marine fish intake consistent with this document. However, the total fish intake rate recommended in AIHC ( 1994) is approximately 40 percent lower than that in this document. The fish intake rates presented in this handbook are based on more recent data from USDA CSFII ( 1989 1991). AIHC ( 1994) presents probability distributions in grams fish per kilogram of body weight for fish consumption based on data from U. S. EPA Guidance Manual, Assessing Human Health Risks from Chemically Contaminated Fish and Shellfish ( U. S. EPA, 1989b). The @ Risk formula is provided for direct use in the @ Risk simulation software. The @ Risk formula was provided for the distributions that were provided for the ingestion of freshwater finfish, saltwater finfish, and fish ( unspecified) in the U. S. general population, children ages 1 to 6 years, and males ages 13 years and above. Distributions were also provided for saltwater finfish ingestion in the general population and for females and for males 13 years of age and older. Distributions for shellfish ingestion were provided for the general population, children ages 1 to 6 years, and for males and females 13 years of age and above. Additionally, distributions for " unspecified" fish ingestion were presented for the above mentioned populations. The Sourcebook has been classified as a relevant rather than key study because it was not the primary source for the data used to make recommendations in this document. The Sourcebook is very similar to this document in the sense that it summarizes exposure factor data and recommends values. Therefore, it can be used as an alternative information source on fish intake. Columbia River Inter Tribal Fish Commission ( CRITFC) ( 1994)  A Fish Consumption Survey of the Umatilla, Nez Perce, Yakama, and Warm Springs Tribes of the Columbia River Basin  CRITFC ( 1994) conducted a fish consumption survey among four Columbia River Basin Indian tribes during the fall and winter of 1991 1992. The target population included all adult tribal members who lived on or near the Yakama, Warm Springs, Umatilla or Nez Perce reservations. The survey species and part( s) of fish consumed, preparation methods, changes in patterns of consumption over the last 20 years and during ceremonies and festivals, breast feeding practices and 24 hour dietary recall ( CRITFC, 1994). Foam sponge food models approximating four, eight, and twelve ounce fish fillets were provided to help respondents estimate average fish meal size. Fish intake rates were calculated by multiplying the annual frequency of fish meals by the average serving size per fish meal. The study was designed to give essentially equal sample sizes for each tribe. However, since the population sizes of the tribes were highly unequal, it was necessary to weight the data ( in proportion to tribal population size) in order that the survey results represent the overall population of the four tribes. Such weights were applied to the analysis of adults; however, because the sample size for children was considered small, only an unweighted analysis was performed for this population ( CRITFC, 1994). The survey respondents consisted of 513 tribal members, 18 years old and above. Of these, 58 percent were female and 59 percent were under 40 years old. In addition, information for 204 children 5 years old and less was provided by the participating adult respondent. The overall response rate was 69 percent. The results of the survey showed that adults consumed an average of 1.71 fish meals/ week and had an average intake of 58.7 grams/ day ( CRITFC, 1994). Table 10 40 shows the adult fish intake distribution; the median was between 29 and 32 g/ day and the 95th percentile about 170 g/ day. A small percentage ( 7 percent) of respondents indicated that they were not fish consumers. Table 10 41 shows that mean intake was slightly higher in males than females ( 63 g/ d versus 56 g/ d) and was higher in the over 60 years age group ( 74.4 g/ d) than in the 18 39 years ( 57.6 g/ d) or 40 59 years ( 55.8 g/ d) age groups. Intake also tended to be higher among those living on the reservation. The mean intake for nursing mothers, 59.1 g/ d, was similar to the overall mean intake. A total of 49 percent of respondents reported that they caught fish from the Columbia River basin and its Volume II  Food Ingestion Factors Chapter 10  Intake of Fish and Shellfish Page Exposure Factors Handbook 10 22 August 1997 tributaries for personal use or for tribal ceremonies and a Northern Wisconsin reservation who consume fish caught distributions to other tribe members and 88 percent in northern Wisconsin lakes. The lakes in northern reported that they obtained fish from either self harvesting, Wisconsin are known to be contaminated with mercury and family or friends, at tribal ceremonies or from tribal the Chippewa have a reputation for high fish consumption distributions. Of all fish consumed, 41 percent came from ( Peterson et al., 1994). The Chippewa Indians fish by the self or family harvesting, 11 percent from the harvest of traditional method of spearfishing. Spearfishing ( for friends, 35 percent from tribal ceremonies or distribution, walleye) occurs for about two weeks each spring after the 9 percent from stores and 4 percent from other sources ice breaks, and although only a small number of tribal ( CRITFC, 1994). members participate in it, the spearfishing harvest is The analysis of seasonal intake showed that May and distributed widely within the tribe by an informal June tended to be high consumption months and December distribution network of family and friends and through and January low consumption months. The mean adult traditional tribal feasts ( Peterson et al., 1994). intake rate for May and June was 108 g/ d while the mean Potential survey participants, 465 adults, 18 years of intake rate for December and January was 30.7 g/ d. age and older, were randomly selected from the tribal Salmon was the species eaten by the highest number of registries ( Peterson et al., 1994). Participants were asked respondents ( 92 percent) followed by trout ( 70 percent), to complete a questionnaire describing their routine fish lamprey ( 54 percent), and smelt ( 52 percent). Table 10 42 consumption and, more extensively, their fish consumption gives the fish intake distribution for children under 5 years during the two previous months. They were also asked to of age. The mean intake rate was 19.6 g/ d and the 95th give a blood sample that would be tested for mercury percentile was approximately 70 g/ d. content. The survey was carried out in May 1990. A The authors noted that some non response bias may follow up survey was conducted for a random sample of 75 have occurred in the survey since respondents were more non respondents ( 80 percent were reachable), and their likely to live near the reservation and were more likely to be demographic and fish consumption patterns were obtained. female than non respondents. In addition, they Peterson et al. ( 1994) reported that the non respondents' hypothesized that non fish consumers may have been more socioeconomic and fish consumption were similar to the likely to be non respondents than fish consumers since non respondents. consumers may have thought their contribution to the A total of 175 of the original random sample ( 38 survey would be meaningless; if such were the case, this percent) participated in the study. In addition, 152 study would overestimate the mean intake rate. It was also nonrandomly selected participants were surveyed and noted that the timing of the survey, which was conducted included in the data analysis; these participants were during low fish consumption months, may have led to reported by Peterson et al. ( 1994) to have fish consumption underestimation of actual fish consumption; the authors rates similar to those of the randomly selected participants. conjectured that an individual may report higher annual Results from the survey showed that fish consumption consumption if interviewed during a relatively high varied seasonally, with 50 percent of the respondents consumption month and lower annual consumption if reporting April and May ( spearfishing season) as the interviewed during a relatively low consumption month. highest fish consumption months ( Peterson et al., 1994). Finally, with respect to children's intake, it was observed Table 10 43 shows the number of fish meals consumed per that some of the respondents provided the same information week during the last 2 months ( recent consumption) before for their children as for themselves, thereby the reliability of the survey was conducted and during the respondents' peak some of these data is questioned. consumption months grouped by gender, age, education, Although the authors have noted these limitations, and employment level. During peak consumption months, this study does present information on fish consumption males consumed more fish ( 1.9 meals per week) than patterns and habits for a Native American subpopulation. females ( 1.5 meals per week), respondents under 35 years It should be noted that the number of surveys that address of age consumed more fish ( 1.8 meals per week) than subsistence subpopulations is very limited. respondents 35 years of age and over ( 1.6 meals per week), Peterson et al. ( 1994)  Fish Consumption Patterns and Blood Mercury Levels in Wisconsin Chippewa Indians  Peterson et al. ( 1994) investigated the extent of exposure of methylmercury to Chippewa Indians living on and the unemployed consumed more fish ( 1.9 meals per week) than the employed ( 1.6 meals per week). During the highest fish consumption season ( April and May), 50 percent of respondents Volume II  Food Ingestion Factors Chapter 10  Intake of Fish and Shellfish Exposure Factors Handbook Page August 1997 10 23 reported eating one or less fish meals per week and only 2 behavioral patterns ( cigarette smoking and alcohol percent reported daily fish consumption ( Figures 10 consumption), drinking water source, diet, and fish 1 and 10 2). A total of 72 percent of respondents reported preparation methods ( Fitzgerald et al., 1995). The dietary Walleye consumption in the previous two months. Peterson data collected were based on recall for food intake during et al. ( 1994) also reported that the mean number of fish the index pregnancy, the year before the pregnancy, and meals usually consumed per week by the respondents was more than one year before the pregnancy. 1.2. The dietary assessment involved the report by each The mean fish consumption rate reported ( 1.2 fish participant on the consumption of various foods with meals per week, or 62.4 meals per year) in this survey was emphasis on local species of fish and game ( Fitzgerald et compared with the rate reported in a previous survey of al., 1995). This method combined food frequency and Wisconsin anglers ( Fiore et al., 1989) of 42 fish meals per dietary histories to estimate usual intake. Food frequency year. These results indicate that the Chippewa Indians do was evaluated with a checklist of foods for indicating the not consume much more fish than the general Wisconsin amount of consumption of a participant per week, month or angler population ( Peterson et al., 1994). The differences year. Information gathered for the dietary history included in the two values may be attributed to differences in study duration of consumption, changes in the diet, and food methodology ( Peterson et al., 1994). Note that this number preparation method. ( 1.2 fish meals per week) includes fish from all sources. Table 10 44 presents the number of local fish meals Peterson et al. ( 1994) noted that subsistence fishing, defined per year for both the Mohawk and control participants. The as fishing as a major food source, appears rare among the highest percentage of participants reported consuming Chippewa. Using the recommended rate in this handbook between 1 and 9 local fish meals per year. Table 10 44 of 129 g/ meal as the average weight of fish consumed per indicates that Mohawk respondents consumed statistically fish meal in the general population, the rate reported here of significantly more local fish than did control respondents 1.2 fish meals per week translates into a mean fish intake during the two time periods prior to pregnancy; for the time rate of 22 g/ day in this population. period during pregnancy there was no significant difference Fitzgerald et al. ( 1995)  Fish PCB Concentrations and Consumption Patterns Among Mohawk Women at Akwesasne  Akwesasne is a native American community of ten thousand plus persons located along the St. Lawrence River ( Fitzgerald et al., 1995). The local food chain has been contaminated with PCBs and some species have levels that exceed the U. S. FDA tolerance limits for human consumption ( Fitzgerald et al., 1995). Fitzgerald et al. ( 1995) conducted a recall study from 1986 to 1992 to determine the fish consumption patterns among nursing Mohawk women residing near three industrial sites. The study sample consisted of 97 Mohawk women and 154 nursing Caucasian controls. The Mohawk mothers were significantly younger ( mean age 24.9) than the controls ( mean age 26.4) and had significantly more years of education ( mean 13.1 for Mohawks versus 12.4 for controls). A total of 97 out of 119 Mohawk nursing women responded, a response rate of 78 percent; 154 out of 287 control nursing Caucasian women responded, a response rate of 54 percent. Potential participants were identified prior to, or shortly after, delivery. The interviews were conducted at home within one month postpartum and were structured to collect information for sociodemographics, vital statistics, use of medications, occupational and residential histories, in fish consumption between the two groups. Table 10 45 presents the mean number of local fish meals consumed per year by time period for all respondents and for those ever consuming ( consumers only). A total of 82 ( 85 percent) Mohawk mothers and 72 ( 47 percent) control mothers reported ever consuming local fish. The mean number of local fish meals consumed per year by Mohawk respondents declined over time, from 23.4 ( over one year before pregnancy) to 9.2 ( less than one year before pregnancy) to 3.9 ( during pregnancy); a similar decline was seen among consuming Mohawks only. There was also a decreasing trend over time in consumption among controls, though it was much less pronounced. Table 10 46 presents the mean number of fish meals consumed per year for all participants by time period and selected characteristics ( age, education, cigarette smoking, and alcohol consumption). Pairwise contrasts indicated that control participants over 34 years of age had the highest fish consumption of local fish meals ( 22.1) ( Table 10 46). However, neither the overall nor pairwise differences by age among the Mohawk women over 34 years old were statistically significant, and may be due to the small sample size ( N= 6) ( Fitzgerald et al., 1995). The most common fish consumed by Mohawk residue level/ g product = residue level g & fat x g & fat g & product Volume II  Food Ingestion Factors Chapter 10  Intake of Fish and Shellfish Page Exposure Factors Handbook 10 24 August 1997 ( Eqn. 10 4)

IR = IR * [( 100 W)/ 100] ( Eqn. 10 5) dw ac mothers was yellow perch; for controls the most common contaminants in cooked fish when compared with raw fish fish consumed was trout. ( San Diego County, 1990). Several studies cited in this An advantage of this study is that it presents data for section have addressed fish preparation methods and parts fish consumption patterns for Native Americans as of fish consumed. Table 10 47 provides summary results compared to a demographically similar group of from these studies on fish preparation methods; further Caucasians. Although the data are based on nursing details on preparation methods, as well as results from some mothers as participants, the study also captures studies on parts of fish consumed, are presented in consumption patterns prior to pregnancy ( up to 1 year Appendix 10B. before and more than 1 year before). Fitzgerald et al. The moisture content ( percent) and total fat content ( 1995) noted that dietary recall for a period more than one ( percent) measured and/ or calculated in various fish forms year before pregnancy may be inaccurate, but these data ( i. e., raw, cooked, smoked, etc.) for selected fish species are were the best available measure of the more distant past. presented in Table 10 48, based on data from USDA They also noted that the observed decrease in fish ( 1979 1984). The total percent fat content is based on the consumption among Mohawks from the period one year sum of saturated, monounsaturated, and polyunsaturated fat. before pregnancy to the period of pregnancy is due to a The moisture content is based on the percent of water secular trend of declining fish consumption over time in present. Mohawks. This decrease, which was more pronounced In some cases, the residue levels of contaminants in than that seen in controls, may be due to health advisories fish are reported as the concentration of contaminant per promulgated by tribal, as well as state, officials. The gram of fat. These contaminants are lipophilic compounds. authors note that this decreasing secular trend in Mohawks When using residue levels, the assessor should ensure is consistent with a survey from 1979 1980 that found an consistency in the exposure assessment calculations by overall mean of 40 fish meals per year among male and using consumption rates that are based on the amount of fat female Mohawk adults. consumed for the fish species of interest. Alternately, The data are presented as number of fish meals per residue levels for the " as consumed" portions of fish may be year; the authors did not assign an average weight to fish estimated by multiplying the levels based on fat by the meals. If assessors wanted to estimate the weight of fish fraction of fat ( Table 10 48) per product as follows: consumed, some average value of weight per fish meal The resulting residue levels may then be used in conjunction would have to be assumed. Pao et al. ( 1982) reported 104 grams as the average weight of fish consumed per eating occasion for females 19 34 years old.