New approaches to the reduction of non-target mortality in beam trawling

Abstract

This paper presents experiments with modified beam trawls aimed at reducing discard rates and direct mortality of benthic in-fauna and epi-fauna without affecting the level of landings. Drop-out panels made of large meshes in the belly of the net were effective in reducing by-catch, but the penalty was a loss in landings (particularly sole, plaice, dab). Effective release of heavy invertebrates (quahog, prickly cockle) seems possible. An alternative parabolic tickler chain arrangement did not reduce landings nor by-catch. Parallel chains seemed to offer more potential in reducing by-catch, particularly shellfish, but significant losses in landings also occurred. The configuration used here, with ticklers fitted on the ground rope, caused an increase in direct mortality of benthic invertebrates and is therefore not recommended.