COMPOSITION AND FATE OF THE CATCH AND BYCATCH IN THE FARNE-DEEP (NORTH-SEA) NEPHROPS FISHERY

Landings of Nephrops in the North Sea Fame Deep Nephrops fishery repre sented only 12% of the original catch by weight. The bycatch included 34 species of fish and 23 invertebrate taxa, as well as undersized and unmarketable Nephrops. There were small landings of lemon sole, plaic e, whiting, cod, haddock, and starry ray, but the large majority of th e bycatch was of juvenile fish or species of no commercial value and t hey were discarded. Survival of discarded Nephrops and fish was probab ly minimal. The discards were usually on deck for several hours before they were thrown overboard, by which time the large majority of fish and a high proportion of Nephrops were dead. Nephrops and some fish sa nk when they were returned to seawater, but other species of fish floa ted on the surface. In all cases, seabirds took the majority of discar ds (>70%) when they were thrown overboard. Those Nephrops landing on t he seafloor alive are likely to have suffered further mortality becaus e: (1) the bycatch was often discarded distant from the fishing ground s (i.e. the natural habitat), at places where conditions were probably unsuitable for their survival; (2) a high proportion of Nephrops was injured in the trawl and it is evident from laboratory tests that such injuries may cause death several days later; and (3) laboratory studi es suggest that injured Nephrops may have difficulty re-establishing t hemselves on the seafloor because they compete unsuccessfully with con specifics for food or shelter. There is concern that, in addition to t he impact of the Nephrops fishery on stocks of Nephrops and the commer cially important fish (especially whiting) which are caught in large n umbers in the bycatch, it may have profound effects on the ecology of the seabed. The fishery effectively transfers organic matter from the seafloor to the surface of the sea, where most of it is removed for hu man food or by seabirds. Little of the fish or Nephrops catch returns to the seabed, dead or alive.