Blackfin gulper shark

The blackfin gulper shark, Centrophorus isodon, is a dogfish of the family Centrophoridae in the Northwest Pacific. Threats are not entirely clear but they may be bycatching from deepwater trawling and line fisheries and may also be used for cod liver oil and fish meal.

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Gulper shark

The gulper shark (Centrophorus granulosus) is a long and slender dogfish usually about three feet in length generally found in deep, murky waters all around the world. It is a light grayish brown, paler ventrally, with a long snout and large greenish eyes. This deep water shark has two dorsal fins with long, grooved spines and the second dorsal fin smaller than the first. Its upper teeth are blade-like and lower have finely serrated edges. This tertiary consumer feeds on mainly fishes such as bony fishes, but also cephalopods such as squid and other invertebrates like crustaceans. The gulper shark is currently a vulnerable species mainly because of exploitation by humans and their abnormally long gestation period and low fecundity, preventing their population from recovering.

Development and Reproduction

Gulper sharks reach maturity at around age 12 to 16 years for females, and age 7 to 8 years for males. The maturity of a gulper shark can be determined by the seven-stage maturity scale for aplacental and placental viviparous sharks. This scale is good for practical field use, but may not be as accurate as other maturity scales that have more than seven stages. Maturity for gulper sharks is considered when they are at stage 3 or above, which for males is when gonads are enlarged and filled with sperm, and sperm ducts are tightly coiled. For females, stage three is when ovaries are large and well rounded.