pacific electric ray known pacific electric ray species electric ray family endemic coastal waters northeastern pacific_ocean baja california british_columbia generally inhabits sandy flats rocky reefs forests surface depth known open ocean measuring long species smooth paired respiratory openings eyes dark gray slate brown dorsal coloration dark spots body form typical genus rounded pectoral fin disc wider long thick tail bearing dorsal fins unequal size developed caudal fin solitary nocturnal pacific electric ray generate volts electricity purposes prey self defense feeds mainly bony fishes substrate day actively hunting night reproduction viviparous meaning embryos initially yolk later supplemented milk produced mother females bear litters pups probably year care exercised pacific electric ray known act aggressively provoked electric shock potentially electric rays model organisms research listed species concern significant numbers taxonomy pacific electric ray described american curator named state discovered science published account inaugural volume academy proceedings type specimens designated placed species newly created genus basis smooth later authors generally regarded subgenus torpedo closely similar electric rays found peru chile japan species common names ray include california torpedo ray pacific torpedo simply electric ray torpedo ray species placed genus distribution habitat electric ray found western north_america pacific electric ray occurs far south baja california far north northern british_columbia common south point conception california rays north point representing separate populations california pacific electric ray generally encountered depth baja california typically observed depth reported deep species prefers temperatures sandy flats rocky reefs forests individual west point california swimming surface water deep observations suggest species makes periodic away shallow coastal habitats zone description pacific electric ray soft body devoid dermal denticles oval pectoral fin disc times wide long nearly straight margin pair kidney shaped electric organs visible beneath skin eyes small followed smooth space snout tip times distance curtain skin nostrils reaches mouth arched deep furrows corners distance mouth snout tip equal mouth width times distance nostrils upper tooth rows lower tooth rows tooth tiny smooth single sharp dorsal fins present twice size second positioned opposite large pelvic fins tail short terminating large triangular caudal fin nearly straight trailing margin ray dark gray slate brown small darker spots increase number age underside white males attain maximum known length females maximum recorded weight biology ecology sizable liver low density tissues pacific electric ray water column little effort power provided muscular tail disc held rigid studies shown species primarily night enters reefs habitats high terrain relief spends day nearby open areas buried sediment nomadic solitary individuals rest area like members family pacific electric ray produces powerful electric attack defense paired electric organs derived muscle comprise approximately total weight consisting thousands filled electric plates stacked hundreds high vertical columns columns function essentially like batteries connected parallel large adult ray generate volts electricity power output low internal resistance electric organs discharge direct current lasting attacking prey moments ray normally produces rate second slowing time thousand produced depending long takes prey subdued pulse rate increases water temperature large size formidable defenses pacific electric ray seldom falls prey animals record fed killer whale cooper specialized parasite ray possibly dwelling fishes attracted chemicals contained ray surface makes small cut ventral surface ray uses suck blood known parasites species include feeding pacific electric ray feeds mainly bony fishes including herring bass cephalopods invertebrates given opportunity jaws highly allowing swallow surprisingly large prey female long observed silver salmon nearly half length day pacific electric ray ambush predator fish approaches head ray jumps forward resting place disc delivering strong fish subdued ray swallow head entire process takes minutes night fishes descend water column inactive short distance pacific electric ray switches active hunting strategy fish slowly swimming simply drifting water closes prey forward prey disc delivering better secure fish disc ray short kicks tail send barrel rolls finally stunned prey mouth disc recorded case long female captured consumed long jack seconds nighttime net sampling surface captured pacific electric rays surprising numbers suggesting rise upward feed small fishes pacific electric ray feed hour responds prey quickly night day prey captures occur darkness conditions eyes largely useless instead relies locate food experiments field shown attack artificially generated electric fields metal mechanical sensory cues detected lateral line play important role species observed attacking faster moving prey closer food item available life history pacific electric ray exhibits developing embryos receiving yolk later milk enriched proteins fat produced mother delivered specialized lining mature females functional reproduction occurs year round males apparently capable mating year females year gestation period unknown reported litter sizes range number number young increases size female measure long double size year life adding length male grow faster females reach smaller ultimate size sexual maturity attained length age seven years males length age years females oldest documented individuals years age growth curves maximum lifespan species upwards years human interactions shock generated pacific electric ray knock adult human treated caution especially night active known charge divers mouth harassed known responsible fatalities involved unexplained fatal diving accidents species poorly captivity usually refuses feed introduced success keeping pacific electric rays offering moving food pacific electric ray relatives model organisms research electric organs contain abundance important nervous system proteins 1970s 1980s species electric ray isolated considered landmark success field led number advances significant underlying disease small commercial fishery southern california supplies pacific electric rays research purposes fishery employed ray economic value caught incidentally commercial fisheries hook line sport activities appear little impact population leading listed concern fishing ray managed
Pacific electric ray