Case study 2 - Mixed demersal fishery

French trawl fishery for roundnose grenadier ( Coryphaenoides rupestris), black scabbardfish ( Aphanopus carbo), deep-water sharks in ICES Vb, VI and VII – Case study coordinator: IFREMER (France) 

This case study is led by Ifremer. It focusses on the four main species taken in this mixed fishery:
Roundnose grenadier ( Coryphaenoides rupestris) a species widely distributed along the continental slope and deep-water banks in the North east Atlantic at depths 500-2000 m. Roundnose grenadier is characterised by a high longevity (50-70 years), late maturity (10-14 years) and slow growth.
Black scabbardfish ( Aphanopus carbo). The area of distribution of black scabbardfish overlaps to a large extend with that of roundnose grenadier and both species are exploited by the same trawl fishery to the west of the British Isles. The longevity of black scabbardfish is still very unclear as different age estimations are derived from whole and sectioned otoliths with no convincing validation work carried out so far.
Two main species of deep-water sharks the Portuguese dogfish ( Centroscymnus coelolepis) and the leafscale gulper shark ( Centrophorus squamosus). The biological parameters of these sharks are poorly known. Preliminary and unvalidated age estimations for Centrophorus squamosus suggest longevities over 50 and 60 years for males and females respectively (Clarke, 2000).