
%0 Journal Article
%A Graham, K. J. 
%A Andrew, N. L. 
%A Hodgson, K. E. 
%T Changes in relative abundance of sharks and rays on Australian South East Fishery trawl grounds after twenty years of fishing
%J Marine and Freshwater Research
%D 2001/09/26
%V 52
%N 4
%P 549-561
%K 
%R https://doi.org/10.1071/MF99174
%U https://www.publish.csiro.au/paper/MF99174 
%X Upper continental slope trawling grounds (200&#8211;650 m depth) off New South Wales were surveyed with the same vessel and trawl gear and similar sampling protocols in 1976&#8211;77 (during the early years of commercial exploitation) and in 1996&#8211;97. The 1996&#8211;97 mean catch rate of sharks and rays, pooled for the main 15 species (or species groups), was ~20% of the 1976&#8211;77 mean. Individual catch rates were substantially lower in 1996&#8211;97 for 13 of the 15 species or species groups. The greatest decline was observed for dogsharks of the genus Centrophorus, which were most abundant in 1976&#8211;77 but rarely caught 20 years later. In contrast, 1996&#8211;97 catch rates of spiky dogshark (Squalus megalops) and, to a lesser extent, whitefin swell shark (Cephaloscyllium sp. A) were similar to those in 1976&#8211;77. Trawling during 1979&#8211;81 provided data for nine species, albeit not corrected for larger gear size, and the pooled mean catch rate for sharks and rays in the depth range 300&#8211;525 m was ~28% of the mean for 1976&#8211;77. The results suggest that the biomass of most species of sharks and rays declined rapidly as the fishery developed and is now at very low levels. 
