shark shark species requiem shark family found western atlantic_ocean north_carolina brazil forms large schools shallow coastal waters following warm water relatively small slender bodied shark shark identified needle like teeth dark blue gray dorsal coloration long gill slits maximum length diet species consists primarily small bony fishes particular like members family viviparous females giving birth pups nursery areas year valued meat shark forms important component commercial shark fishery operating southeastern united_states population assessments suggest fishery currently pose threat populations species listed shark concern fishery data available species south_america shark known pose danger humans vigorously captured handled caution taxonomy phylogeny shark originally described french zoologist der type specimen juvenile male possibly caught new_york species later moved genus specific epithet means equal teeth greek refers similar number teeth upper lower jaws species referred shark shark night shark usually case species attempts analyze shark phylogenetic relationships yielded variable results grouped species spinner shark shark graceful shark smooth tooth shark basis morphological characters analysis found shark second basal member genus shark study based dna suggested closest relative shark shark species form clade apart species description body shark slender streamlined snout long pointed preceded short broadly triangular flaps skin eyes large round membranes protective mouth broad defined furrows corners tooth rows occur upper jaw tooth rows lower jaw tooth small needle like narrow central smooth edges pairs gill slits long measuring half length dorsal fin base dorsal fin high triangular pointed apex originating forward free rear tips pectoral fins second dorsal fin relatively large originates anal fin ridge runs dorsal fins pectoral fins small shaped pointed tips dermal denticles small overlapping bearing horizontal ridges leading marginal teeth living sharks distinctive dark bluish gray white faint pale stripe flanks prominent fin markings individuals florida green eyes males average length females largest shark record long distribution habitat north american waters shark common found north_carolina northern gulf_of_mexico occasionally far north new_york waters rare occur widely presently known having reported trinidad caribbean_sea southern brazil northwestern atlantic gulf_of_mexico south_america populations distinct little interchange old records exist species eastern atlantic guinea likely represent spinner sharks shark found near beaches bays inhabits extremely shallow waters deeper summer deep winter historically known venture rivers gulf coastal plain texas paths area blocked dams northwestern atlantic population species strongly migratory juveniles followed adults arrive south_carolina late march early water temperature rises remain september mid october water temperature drops south florida movements populations unknown biology ecology adult juvenile sharks form large schools energetic fast moving predator feeds mainly small bony fishes entering surf zone day hunt important prey species northwestern atlantic atlantic sharks ages northwestern florida eat head removed known prey species include spot spanish shrimp case juvenile atlantic shark shrimp shark preyed larger sharks parasites documented species include unidentified species genera life history like requiem sharks shark viviparous developing embryos yolk weeks depleted yolk sac develops connection mother females produce litters pups year northwestern atlantic mating occurs early early june young born time following year month gestation period males bite female hold male large mass inside female individual embedded called function short lived structure unknown newborn sharks measure long shallow bays serve critical nursery areas juveniles female sharks grow slowly larger ultimate size males individuals northwestern atlantic population larger body size reach sexual maturation later gulf_of_mexico population males populations grow similar rates northwestern atlantic females grow slowly gulf mexico females northwestern atlantic males mature fork length length snout tip caudal fin fork females corresponding ages years respectively gulf_of_mexico males mature fork length females corresponding ages years respectively maximum lifespan estimated years males years females human interactions shark implicated attack humans caught shark range people attempting handle sharks human consumption fresh dried southeastern united_states species little commercial importance small occurs water shallow commercial recreational fisheries generally fast swimming caught shrimp small numbers taken incidentally floating hook line species susceptible low reproductive rate habitat degradation habits substantial numbers sharks caught drift operated shark fishery southeastern united_states peaked tons landed stock assessments conducted suggested populations catch rate assessments conducted concluded catch rates exceed sustainable levels populations stable fishing species waters regulated fisheries management plan atlantic gulf_of_mexico sharks classified small coastal shark purposes commercial recreational bag limits result iucn assessed shark concern overall mexico concern species south_america numbers naturally low potentially heavy pressure widespread intensive coastal fisheries iucn sufficient data assess status region
Finetooth shark