Historic trawl data and recent information infers temporal change in the occurrence of squid in the diet of orange roughy (Hoplostethus atlanticus Collett) in New Zealand

Abstract

A review of historical trawl data for orange roughy on Chatham Rise and Challenger Plateau, New Zealand, between the years 1984 and 1996 infers a shift in this species’ diet, with a progressive decline in the percentage occurrence of squid being apparent. On Chatham Rise, this decline in the percentage occurrence of squid appears to be compensated for by increases in the percentage occurrence of fish and crustaceans in orange roughy diet, whereas on Challenger Plateau, decreases in all of squid, fish and crustaceans are apparent. New orange roughy dietary data for 2004 from Chatham Rise is consistent with earlier data series, with further declines in the percentage occurrence of squid apparent. Declines in the occurrence of squid in the diet of orange roughy could be attributed to declines in the abundance of squid as a consequence of fisheries activity.