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Sharpnose Sevengill Shark
Threat Level: low
Scientific name........Heptranchias Perlo
Other common names........Slender sevengill shark and Perlon shark
There are only two species with seven gills, the Sharpnose Sevengill shark ( Heptranchias perlo )and the Broadnose Sevengill shark ( Notorynchus cepedianus ) in contrast to the five or six gills that most sharks possess. This is a moderately small shark with a slender, fusiform body with a narrow, pointed head, large green eyes and a long narrow mouth. It has seven pairs of gill slits and these gill openings extend down onto the throat. There is one small dorsal fin which originates over the inner margins of the pelvic fins. The anal fin and pectoral fin is also small in size.
These sharks can grow to a maximum length of 4.5 feet. Females mature at 39.5 inches and males mature at 29.6 inches. Pups are born at a length of 9.6 inches.
They have five rows of comb-shaped teeth in the lower jaw. The upper teeth are narrow with a hook-like cusp.
The color of the Sharpnose Sevengill shark is a brownish gray to olive on the dorsal surface, paling to a lighter ventral surface. They have a black blotch on the tip of the dorsal fin and caudal lobe that are prominent in the young, but these fade in the adults. Large fluorescent green eyes.
Sharpnose Sevengill sharks feed on small to moderately large demersal and pelagic fishes, small sharks, crustaceans, squid and cuttlefish. Even though it is a relatively small shark it is a voracious predator.
Poorly known, but is suggested that it is a strong swimmer. Feeding and activity appears to increase in the night time hours.
Wide-ranging but patchily distributed, in tropical and temperate seas, not northeast Pacific. While they are found close inshore to depths of ( 3,250 feet ) it is most abundant at a depth range of ( 88 to 2,345 feet ). It occurs in the continental and island sheves and upper slopes, occasionally shallower water close inshore.
This shark is ovoviviparous, giving birth to 6 to 20 pups per litter. Apparently reproduces year round.
The Sharpnose sevengill shark is considered harmless to humans. However, care must be taken when landing this shark as it is aggressive and will attempt to bite its captors.
Relatively uncommon. Although this species is of minor commercial importance, bycatch in bottom trawls and longline fisheries may cause future decline of populations.
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