Discarding by the demersal fishery in the waters around Ireland

Abstract

This paper presents the first estimation of discarding levels by the demersal fishery in the waters around Ireland. The analysis is based on the Irish discard programme, involving observer's onboard commercial vessels that participate on a voluntary basis. The programme started in 1993 and, until 2002, 225 trips were sampled, corresponding to 2189 sampled tows. Approximately one-quarter of the catch of otter trawlers and “Scottish” seiners is discarded, while two-thirds of the catch of beam trawls is discarded. Furthermore, otter trawl fleet components (defined by the area visited, targeted species and gear used) discard between 20 and 60% of their catch. Discards usually comprise 11 fish species per haul in the 3 gears types studied. Whiting ( Merlangius merlangus), haddock ( Melanogrammus aeglefinus), bluemouth ( Helicolenus dactylopterus), megrim ( Lepidorhombus whiffiagonis) and dogfish ( Scyliorhinus spp.) are the main species discarded by otter trawlers. “Scottish” seiners discard mostly whiting, haddock and grey gurnard ( Eutrigla gurnardus). Dab ( Limanda limanda) and plaice ( Pleuronectes platessa) are the most species discarded by beam trawls. The majority of these discarded species consist of immature fish. Discarding appears to be increasing in recent years, especially in traditionally bycaught species such as haddock and whiting.