Better redfish selectivity with four-panel codend
A team from the Marine Research Institute and the Marine Institute of Memorial University of Newfoundland joined skipper Heimir Guðbjörnsson and HB Grandi’s fresher trawler Helga María for a trip on redfish to assess the selectivity of a T90 codend.
The test gear consisted of a codend made in double 6mm PE netting in a 110mm mesh size and rigged on Hampidjan’s QuickLines. A covernet in 50mm mesh was rigged around the codend to retain fish escaping from the gear, allowing researchers to assess the composition of the fish catch escaping from the fishing gear.
According to research project leader Haraldur Arnar Einarsson of the Marine Research Institute, the conclusion was that this codend showed a 7.3cm better effectiveness in separating golden redfish than the conventional redfish codend in 135mm diamond mesh.
“Although more small redfish were released from the T90 codend, it was also shown to retain more of the over 33cm reference size redfish,” he said, commenting that the selectivity index line rises much more sharply with a T90 codend.
He said that there are clear arguments in favour of this codend as a being an improvement in respect of the way marine resources are treated, but added that more research into the amounts of gilled fish in the codend would be worthwhile.
HB Grandi has had a derogation to test this one codend made to these specifications so as to collect data, both for visual information and to assess gilled fish numbers, as well as to examine how well the codend performs.“In a few months we can expect to have more information on the value of this codend, allowing decisions to be made regarding its further use,” Haraldur Arnar Einarsson said.