Research Document 1998/139

Effects of Scotian Shelf Small Mesh Gear Fishery Regulations on the catch rate of silver hake and bycatch rates of cod, haddock and pollock in the period 1983-98

By R. Branton

Abstract

Changes to catch and bycatch rates from the Scotia Shelf (Div. 4VWX) foreign small mesh otter trawl fishery are examined for the period 1983-98 to determine what affects if any can be attributed to the bycatch reduction measures that were introduced at the start of the 1994 fishing year. The cod, haddock and pollock bycatch reductions after 1994 were the combined result of decreased fishing effort, reduced abundance of t bycatch species, mandatory use of separator grates, and restriction on fishing area. The distribution of fishing effort, however, did not change greatly after the initial introduction of restrictions in 1994 due to subsequent modifications and the granting of exemptions to the new rules. As a result, the expected benefits from the restriction on area were not realized as predicted by the scientific advice underlying them, It was however still possible to confirm that the original advice was valid by demonstrating that catch rates of silver hake were not affected by the fishing area restrictions and that bycatches would have been reduced even further had there been no modifications and exemptions. The analysis shows that fishing area restriction effectively reduce the accidental capture of small haddock which are the same size as mature silver hake and hence not released by the separator grates. Given that the 1994 regulatory changes do not reduce silver hake catch rate, yet could reduce bycatch considerably, it was concluded that there appear to be no rationale to the allowing of exemptions.

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