Evaluation of exclusion grids to reduce the bycatch of dolphins, turtles, sharks and rays in the Pilbara trawl fishery

Authors: 
Stephenson, P.C., Wells, S., King, J.A.
Year: 
2008
Journal/Publisher Name: 
Fisheries Research Report, Department of Fisheries of Western Australia
Volume/Issue #: 
171
Page #s: 
24
Publisher Address: 
Fisheries Research Division, Western Australian Fisheries and Marine Research Laboratories, PO Box 20, North Beach, Western Australia 6920
Contact information: 
+61 8 9203 0111 library@fish.wa.gov.au
A semi-flexible exclusion grid with a bar spacing of 15.5 cm reduced dolphin bycatch in the Pilbara trawl fishery by close to 50% and reduced the bycatch of sea turtles, large sharks and rays. However, the fate of the dolphins that encountered the grid and escaped is unknown.
Field Studies:
Location Fishing gear Reduction technique Bycatch species Effect on bycatch species Catch Effect on target catch Type
Western Australia Trawls Flexible sorting grid Small Cetaceans (maximum length < 7.5 meters) Reduced dolphin bycatch by almost 50% and reduced bycatch of sea turtles, large sharks and large rays red emperor, scarlet perch, spangled emperor, Rankin cod, blue spot emperor, rosy threadfin brea, flagfish, frypan snapper, red snapper and goldband snapper Not reported In the wild
Western Australia Trawls Flexible sorting grid Sea Turtles Redcuced catches rates from 26.2 (catch per 1000 shots) to 0.9 Red emperor, scarlet perch, spangled emperor, Rankin cod, blue spot emperor, rosy threadfin brea, flagfish, frypan snapper, red snapper and goldband snapper None reported In the wild
Western Australia Trawls Flexible sorting grid Sharks Reduced capture of sharks larger than 100 cm with largest reductions occuring at lengths greater than 180 cm Red emperor, scarlet perch, spangled emperor, Rankin cod, blue spot emperor, rosy threadfin brea, flagfish, frypan snapper, red snapper and goldband snapper None reported In the wild
Western Australia Trawls Flexible sorting grid Elasmobranchs No rays larger than 120 cm were caught when the grid was used Red emperor, scarlet perch, spangled emperor, Rankin cod, blue spot emperor, rosy threadfin brea, flagfish, frypan snapper, red snapper and goldband snapper None reported In the wild