Irish Sea - Key Species
Nephrops
Nephrops is one of the most valuable fisheries in the Irish Sea and occurs predominantly on the extensive mud ground in the Northwest Irish Sea. ICES considers two stocks in this area, the state of which is unknown in relation to precautionary reference points. These stocks have been sustained with high levels of fishing effort and discard rates for many years and all indicators suggest that the stocks have not declined substantially in recent years.
Cod
Cod Gadus Morhua are top predators although during their first six months, cod are pelagic and feed mainly on copepods. At a size of approximately 7 cm they adopt a demersal way of life. Food is initially comprised of crustaceans, but as they grow bigger fish become more and more important as prey.
Since the 1980s, vessels using semi-pelagic trawls have targeted cod, hake and haddock in the deeper waters of the North Channel and the western Irish Sea and are able to catch adult cod in most months of the year. The size of the Irish and UK white fish fleets has declined over time and there have been several rounds of decommissioning of UK vessels. Since the 1990s, many whitefish vessels have diversified to haddock and twin trawling for Nephrops. The emergency measures from 2000 onwards closed part or all of the cod spawning grounds to whitefish vessels from mid February to the end of April. A formal EU cod recovery plan started in 2004, imposing fishing effort restrictions on different classes of vessels in addition to the existing closure and other technical conservation measures. Cod are classified as overexploited with reduced reproductive capacity. The TAC in 2007 was 1462 t. ICES recommended that given the low stock size, recent poor recruitment, continued substantial catch well above the TAC, the uncertainty in the assessment, and the inability to reliably forecast catch, it is not possible to identify any non-zero catch which will be compatible with the precautionary approach.
Sole
Soles main preys are polychaetes and meiofauna, but large specimens also eat small fish such as gobies and dragonets. Sole is the main target species of the beam trawl fleet, which comprises vessels from Belgium, as well as the bordering countries of England, Wales, and Ireland. The fishery is located mainly on the eastern side in the relatively shallow coastal waters of England and Wales. Sole catches in the otter trawl fleet are taken mainly as by-catch in the Nephrops fishery. Sole are also taken in gill nets and trammel nets. TAC in 2007 was 816 t. Sole are considered to be overexploited with reduced reproductive capacity. ICES recommended that given the low SSB and low recruitment since 2000, it is not possible to identify any non-zero catch which will be compatible with the precautionary approach. However, a zero catch in 2007 should allow SSB to achieve Bpa (Biomass of Precautionary Approach) in 2008. If the implied 100% reduction is not possible then ICES recommends that a recovery plan be implemented which ensures a safe and rapid rebuilding of SSB to levels above Bpa.
Plaice
Plaice is predominantly benthivorous, although larger specimens also feed on small demersal fish. The beam trawl fleet principally targets sole but has important by-catch of plaice, rays, brill, turbot and anglerfish. UK and Irish otter trawlers that target Nephrops also take a small by-catch of plaice. Until the early 1990s the majority of whitefish vessels catching plaice in the Irish Sea were otter trawlers targetting cod, haddock, whiting and plaice with by-catch of anglerfish, hake and sole. Fishing effort in this fleet declined substantially between 1989 and 1994 and has since remained relatively low. Plaice TAC in 2007 was 1849 t, with the stock believed to be at full reproductive capacity and harvested sustainably.
Bass
In the Irish Sea most 40 cm bass are 5-6 years old and growth has been slightly faster since 1990, especially for bass over 10 years old. The oldest recorded bass caught in ICES zone VIIa was 27 years old and 80 cm in length. There is a believed to be a high degree of mixing between bass stocks in ICES zones VIIa, f, and g and little interchange between populations in the North Sea and Bay of Biscay. Bass fisheries are varied including many small boats using various gears including trawls, rod and line, fixed and drift nets. They are also taken as by-catch in nets or traps set for flatfish and salmon. The main bass fishery along the north coasts of Cornwall and Devon is netting and rod and lining in summer whilst trawlers also take a by-catch of bass throughout the year. In late winter, spawning bass are sometimes targeted by French mid-water pair teams and by single bottom trawlers on the Trevose Head grounds. On the south Wales coast, bass are taken between May and November by various netting methods, including drift netting, though there has recently been a move towards the commercial use of rod and line. Catches taken by trawlers in south Wales have increasingly included bass, which are landed mainly into Swansea and Milford Haven.