Trawl induced uanaccounted mortality, dr.gr.stip.

This project summarizes working plan and milestones for a Dr.scient. Scholarslhip in Fisheries Technology . Modern fishing practices call for the use of size selective gears to ensure the survival of juveniles until they reach an appropriate size for harv est. This implicitly assumes the survival of escapees. Previous survival studies focused on the escapement through meshes and grids have shown highly variable resulats caused by methodological problems. In this project, the techniques used in experiments on survival of mesh and grid escaped fish will be developed, and mortality of escapees assessed. Recent observations have identified several other areas as psotentially important sources of unaccounted mortality in trawl fisheries. In regions with concentrated fishing acticity, escaped fish may be subjected to repeated herding and escape through the trawl. This may have cumulative effect on stress and physical damage. Video evidence has shown that a considerable number of fish escape under the trawl;many of these are subsequently hit byt the ground gear. In this project, techniques to evaluate rate of fish escape under or overrun by the gear will be designed and tried out. the escape ratio and assessment of injury frequency and result ing mortality will be quentified.