Summary

During various trawl surveys by FRV Kapala along the NSW continental shelf and slope, about 1000 species of fish, 130 molluscs, and 160 decapod and stomatopod crustaceans were recorded. With over 20 species, demersal squaliform sharks (dogfishes) were an important component of the slope fauna. The 1976-77 upper slope survey found that they contributed to about 35% of the overall fish biomass, while in mid-slope depths (surveyed during 1983-89), about 70% of the total catch comprised dogsharks. A third survey of the upper slope (in 1996-97) found that, compared to the initial survey results, the relative abundance of upper slope sharks and rays (combined) had fallen by about 80% with catch rates of several species less than 5% of their initial levels; these declines were attributed to 20 years of commercial trawling. Although most dogsharks are similar in overall size and appearance, dietry observations revealed differences in prey preferences among the species and within genera, with some preferring mesopelagic prey while others fed mainly on demersal species.