Featured Elasmobranch- Pacific Sharpnose Shark

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Featured Elasmobranch- Pacific Sharpnose Shark

June 2011

Pacific Sharpnose Shark

Rhizoprionodon longurio (Jordan & Gilbert, 1882)

Family Carcharinidae (Requiem Sharks)

Identification: A small, slender-bodied requiem shark, with a long, pointed snout, widely spaced nostrils, and small fins (except for the first dorsal fin). Like other a lot of other requiem sharks, this species does not have spiracles. The first dorsal fin is positioned closer to the pectoral fins than to the pelvic fins. It is the only requiem shark of the eastern Pacific with long labial furrows and a second dorsal fin that originates well behind the anal fin. The teeth are small with smooth-edged cusps, with adults possessing upper teeth that can be finely serrated. Coloration is brown to grayish above and white below. The dorsal fins possess dusky tips and the pectoral fins have lightly colored edges. Juveniles have a darkened caudal fin margin.

Size: Males have been known to mature at 58-69 centimeters (1.9-2.3 feet) and reach of length of at least 92 centimeters (3 feet). Females have been known to mature at 103 centimeters (3.4 feet) and reach a length of at least 110 centimeters (3.6 feet), possibly even 154 centimeters (5 feet). Size at birth is 30-34 centimeters (1-1.1 feet).

Distribution: This shark is distributed in warm-temperate to tropical waters in the eastern Pacific from southern California to Peru. It is quite rare in Californian waters, and is usually seen in El Niño years. It is very common in southern Baja California and in the Gulf of California.

Habitat: This species is a poorly known requiem shark that inhabits nearshore environments from the intertidal to at least 27 meters (88.6 feet).

Biology: Little is known about the biology of this species. This shark’s reproductive mode is viviparous, with a yolk sac placenta, and litters are two to five pups. These sharks feed mostly on crabs and small bony fishes.

General interest: This species is too rare in California to be of any major importance. In the Gulf of California, where it is quite common, this shark is fished for by long-line and utilized as food for human consumption. Due to a current lack of biological information, this species is listed as Data Deficient on the IUCN Red List. This requiem shark is considered relatively harmless to humans.

By James D.S. Knuckey
Pacific Shark Research Center
Moss Landing Marine Laboratories
8272 Moss Landing Road, Moss Landing, CA 95039

knuckey.james@gmail.com