night shark night shark species requiem shark family found temperate tropical waters atlantic_ocean outer continental shelf upper continental slope shark commonly occurs depths conducts vertical migration spending day deeper water moving shallower waters night northeastern brazil large numbers varying depth slender streamlined species night shark typically reaches length identified long pointed snout large green eyes alive dark grayish blue brown white night sharks quick active schooling predators feed mainly small bony fishes squid reproduction viviparous members family females mate summer birth litters usually pups gestation period year species known pose danger humans caught incidentally commercial fisheries western atlantic targeted fishery operating northeastern brazil night shark highly valued fins additionally source meat liver oil sharks caught northeastern brazil found contain unsafe concentrations mercury low reproductive rate historically documented declines areas caribbean night shark assessed vulnerable population assessment indicated species secure waters united_states true taxonomy scientific description night shark published cuban zoologist series papers entitled natural cuba based description single set jaws gave genus type specimen designated species common comes fact captured night distribution habitat distribution night shark extends outer continental shelves upper continental slopes atlantic_ocean state massachusetts argentina west including gulf_of_mexico caribbean_sea northern east united_states waters relatively common north_carolina florida particularly questionable reports species pacific_coast panama night shark species reported far occasionally ventures surface southeastern united_states usually caught depth range northeastern brazil night shark commonly found near ranging deep west_africa occurs depths temperature dissolved oxygen level annual variation cuban catch rates indicate seasonal migration description night shark slender build elongated pointed snout flanked moderately developed flaps skin eyes large circular green life irregularly shaped pupils membrane protective mouth lacks conspicuous furrows corners usually bears tooth rows jaws plus upper lower jaw tooth rows upper tooth smooth edge narrow oblique corner mouth coarse base trailing margin number size leading margin tooth increase relative trailing margin animal grows older lower teeth upright smooth edged pairs gill slits short pectoral fins fifth long total body length somewhat rounded tip dorsal fin relatively small triangular pointed originating free rear tips pectoral fins second dorsal fin smaller originates slightly ahead anal fin ridge running dorsal fins dermal denticles tightly packed overlap diamond shaped horizontal ridges leading marginal teeth number increasing juveniles adults coloration grayish blue brown whitish fin markings faint band small black spots scattered species usually grows long recorded reaching length weight respectively biology ecology fast energetic night shark feeds primarily small active bony fishes sea squid shrimp taken feeding activity occurs night common peaks dawn dusk catch records indicate species usually found schools conducts vertical migration spending day depth moving shallower night females rarely caught suggesting period stop feeding species potential predators night shark include larger sharks known parasites include attach gills skin found spiral valve parasite similar common found attached species like members family night shark viviparous developing embryos exhaust supply yolk depleted yolk sac converted connection mother delivers adult females single functional right functional divided separate compartments embryo embryos lie heads pointing direction mother information known night shark life history comes northeastern brazil hold true parts species range northeastern brazilian sharks mate summer males biting female body fins prelude year long gestation period females birth usually pups embryos varying stages development found february june suggesting takes place span months important nursery area believed exist continental shelf break latitude near southern extreme species range newborn young measure long add body length year fast rate growth serves period immediately birth small pups vulnerable predators strategy similar employed silky shark time sharks reach adulthood growth rate modest year difference growth rate sexes males mature sexually length corresponding age years females length corresponding age years oldest known individuals years old based growth curves maximum lifespan estimated years males years females human interactions habitat night shark known pose danger humans species prized large fins exported use shark fin soup utilized source meat liver oil traditionally comprised fisheries targeting western atlantic focus fishery operating northeastern brazil large numbers sharks easily captured shark ray catch area consists night sharks approximately juveniles study found night sharks northeastern brazil accumulate high levels mercury bodies likely diet sharks examined contained mercury levels higher allowed marketed fish set brazilian legislature average mercury concentration eating night shark meat day result times daily mercury content judged safe assessed night shark globally vulnerable citing slow reproductive rate historical declines fishing pressure listed vulnerable species significant cuban shark fishery comprising catch numbers dropped substantially 1970s similarly proportion night sharks shark catch southeastern fishery fell comparable decline observed catches south florida tournaments 1970s currently intense brazilian targeted fishery particular concern fishing pressure night shark fishery beginning shift fishery information night shark available eastern atlantic leading iucn assessment region listed night shark species concern meaning merits conservation concern insufficient evidence listing endangered species act atlantic sharks revised prohibit retention species including night shark prohibition species upheld amendment added night sharks suffer high mortality prohibited kept value difficulty identifying parts species population assessment concluded night shark population united_states waters stabilized increasing longer merits species concern recommended prohibition retention maintained measure species benefit time area charleston bump brazil fishing continues largely iucn members urged brazil improve catch monitoring enforcement existing regulations declare critical habitat limits implement international plan action conservation management sharks
Night shark