Biological aspects of two deep-water squalid sharks: Centroscyllium fabricii (Reinhardt, 1825) and Etmopterus princeps (Collett, 1904) in Icelandic waters

This paper describes some aspects of the biology of the black dogfish (Centroscyllium fabricii) and the greater lantern shark (Etmopterus princeps) based on material collected during surveys of Marine Research Institute, Iceland. C. fabricii was most abundant at depths between 800 and 1200 m (range 436–1653 m). The overall sex ratio was 1.00:1.19 in favour of females. Males were more numerous in shallower waters but in depths >1000 m, the sex ratio was significantly in favour of females. E. princeps was most abundant between 800 and 1000 m (range 436–1653 m). The overall sex ratio was 1.00:1.59 in favour of females, females being significantly more numerous in depths >1000 m. For both species there was a trend for a decrease in mean length with increasing depth. Both species were sexually dimorphic with females growing to a larger size than males and being larger at first maturity. Maturity stages were observed during two seasons and indicated that neither of these two species have a defined breeding season. A study of the diets showed that larger specimens of C. fabricii fed mainly on teleosts but smaller specimens seemed to feed more opportunistically on teleosts, cephalopods and crustaceans. E. princeps fed mainly on three prey categories: teleosts, cephalopods and crustaceans.

A considerable amount of these two species, and especially of C. fabricii, are likely to be discarded by the commercial fishery for Reinhardtius hippoglossoides off the West of Iceland.