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
Journal/Publisher Name
Fisheries Research Report, Department of Fisheries of Western Australia
Volume (Issue #)
171
Page #s
24
Contact information
+61 8 9203 0111
library@fish.wa.gov.au
Summary
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

ant

Study Type
Field study in the wild
Location
Western Australia
Target catch
red emperor, scarlet perch, spangled emperor, Rankin cod, blue spot emperor, rosy threadfin brea, flagfish, frypan snapper, red snapper and goldband snapper
Effect on bycatch species
Reduced dolphin bycatch by almost 50% and reduced bycatch of sea turtles, large sharks and large rays
Effect on target catch
Not reported
Bycatch species
Small Cetaceans (maximum length < 7.5 meters)
Reduction technique
Excluder devices
Fishing Gear
Trawls

Field Study 305

Study Type
Field study in the wild
Location
Western Australia
Target catch
Red emperor, scarlet perch, spangled emperor, Rankin cod, blue spot emperor, rosy threadfin brea, flagfish, frypan snapper, red snapper and goldband snapper
Effect on bycatch species
Reduced capture of sharks larger than 100 cm with largest reductions occuring at lengths greater than 180 cm
Effect on target catch
None reported
Bycatch species
Sharks
Reduction technique
Excluder devices
Fishing Gear
Trawls

Field Study 554

Study Type
Field study in the wild
Location
Western Australia
Target catch
Red emperor, scarlet perch, spangled emperor, Rankin cod, blue spot emperor, rosy threadfin brea, flagfish, frypan snapper, red snapper and goldband snapper
Effect on bycatch species
No rays larger than 120 cm were caught when the grid was used
Effect on target catch
None reported
Bycatch species
Elasmobranchs
Reduction technique
Excluder devices
Fishing Gear
Trawls

Field Study 303

Study Type
Field study in the wild
Location
Western Australia
Target catch
Red emperor, scarlet perch, spangled emperor, Rankin cod, blue spot emperor, rosy threadfin brea, flagfish, frypan snapper, red snapper and goldband snapper
Effect on bycatch species
Reduced catches rates from 26.2 (catch per 1000 shots) to 0.9
Effect on target catch
None reported
Bycatch species
Sea Turtles
Reduction technique
Excluder devices
Fishing Gear
Trawls