species family sole member genus characterized wedge like shape pectoral fin disc wider long pointed teeth sexes whip like tail extremely long tail spine uniform violet blue green coloration generally reaches width worldwide distribution waters warmer spend summer closer continental shelf higher latitudes exclusively inhabits open ocean species typically found surface waters depth consequence habits swimming style evolved feature motion pectoral fins opposed disc margin dwelling diet consists free swimming invertebrates bony fishes active hunter pectoral fins trap food mouth known advantage seasonal feeding opportunities spawning squid like viviparous meaning embryos sustained initially yolk later milk short gestation period months females bear litters pups year generally occurs warm water near equator exception mediterranean_sea timing varying regions rarely encountered fishery workers inflict severe fatal wound tail spine species caught range little economic value usually discarded high mortality evidence numbers increasing owing heavy fishing natural predators competitors sharks global distribution prolific life history led assess concern taxonomy phylogeny originally described french naturalist volume fauna named latin viola purple designated specimens collected italy species genus american zoologist placed newly created subgenus greek fin broad later authors elevated rank genus dispute species distinct warrant separation phylogenetic analysis based morphology found basal members family sister taxon clade contains species common names include blue violet distribution habitat distribution extends nearly worldwide tropical warm temperate waters latitudes western atlantic reported north_carolina northern gulf_of_mexico brazil eastern atlantic species recorded north_sea including mediterranean_sea cape south_africa pacific known japan australia new_zealand west british_columbia chile west oceanic islands including hawaii reports species indian_ocean known common southwestern portion indonesia unique inhabiting open ocean sea floor generally found surface depth deep water caught depth ridge indicating occasionally approaches species prefers water temperatures die temperature drops performs seasonal following warm water masses northwestern atlantic found near december april moves north stream gather near continental shelf july september similar migration occur mediterranean unknown pacific species apparently spends winter oceanic waters near equator higher latitudes coast spring pacific populations known near central_america california central pacific far japan british_columbia southeastern brazil displaced coast cold water late spring summer years pushed waters deep description thick wedge shaped pectoral fin disc wider long broadly curved leading margins angular outer corners nearly straight trailing margins snout short rounded tip eyes minute unlike body paired respiratory openings follow immediate short broad curtain skin nostrils weakly fringed rear margin mouth small gently arched deep furrows corners tiny projection center upper jaw fits lower jaw like structures row floor mouth upper tooth rows lower tooth rows teeth sexes single pointed adult males longer adult females margins pelvic fins nearly straight rounded tips whip like tail measures twice long disc thick base significantly extremely long spine placed approximately halfway length spines present replacement grows original drops posterior spine origin low ventral fin fold reach spine tip young rays completely smooth skinned age small appear center row small eyes origin spine species plain dark purple blue green extending tail fold slightly lighter shade captured handled thick black covers body typically grows long largest individuals record captive experiment conducted male reached female biology ecology adopting lifestyle exhibits characteristics different dwelling relatives propel disc margins species pectoral fins manner approaching underwater flying employed eagle rays fin motions generate lift improving cruising efficiency open water cost adept swimming backwards compensate lower fine control offered swimming mode vision important ray finding food compared members family species density underside cover smaller area small eagle rays evenly distributed ventral dorsal surfaces ray detect electric field distance able pick minute electric fields produced moving sea water lateral line complex system detect nearby movement ocean currents remains similar covering greater area ventral dorsal surface species responsive mechanical visual sex vertically males found deeper water females horizontally captive individuals act highly aggressively ocean biting particularly hungry species preyed oceanic sharks great white sharks toothed large ocean going dark coloration likely serves camouflage habitat venom tail spine potent causing avoided fishes known parasites species include feeding active predator captures prey wrapping pectoral fins manipulating mouth sexes pointed teeth cutting slippery prey wide variety organisms represented diet crustaceans including crabs including squid octopus bony fishes including herring sea horses worms california hunt large mating squid form november april brazil species follows groups atlantic coast january february predators seeking small schooling fishes juvenile rays consume body weight food day declines adults life history like viviparous developing embryos yolk later supplanted milk containing proteins mother delivers numerous thread like extensions called feed enlarged embryo females functional left produce litters year mating occurs march june northwestern atlantic late spring southwestern atlantic females capable storing sperm internally year allowing wait favorable environmental conditions young passed batch eggs contained single capsule tapered ends shortly capsule release eggs expelled gestation period shortest shark ray lasting months time embryos increase mass pacific females birth winter november march nursery area near central_america prior northward migration similarly northwestern atlantic occur winter females warm southerly waters possibly west_indies records exist possibly females pregnant earlier year given birth august september southward migration southwestern atlantic occurs summer january warmer water equator opposed regions mediterranean females birth summer moving warmer waters litter size ranges average increase size female measure rays captivity ample food grow average annual rate disc width rays wild grow average annual rate food intake growth rate adults highest january february july august lowest march april october november males reach sexual maturity years age females years age species live years prolific rays population growth rate year human interactions aggressive rarely encountered habitat preferences long tail spine demands extreme caution exercised handling responsible known fatalities worker captured ray fishery worker succumbed days species kept public century meat utilized example indonesia species considered worthless discarded caught susceptible purse captured incidentally large numbers range rays caught suffer high mortality wary remove rays hooks smashing boat causing severe damage mouth jaws extent regardless surveys pacific suggest numbers increased 1950s possibly commercial fisheries dominant predators ecosystem sharks lack population declines coupled wide distribution high reproductive rate led list species concern recent research conducted reducing switching larger hooks
Pelagic stingray