Case Studies

Inshore Fishery - Galway Bay Nephrops

Fig. 3. The Galway Bay Nephrops Fishery Grounds in Functional Unit 17. (From ICES Advice, June 2010 ECOREGION Celtic Sea STOCK Nephrops in Subarea VII)

The nephrops fishery in functional unit (FU) 17 in the Celtic Sea was chosen for this study. The Galway Bay/Aran Grounds Nephrops fishery accounts for almost 50% of the total annual Irish Nephrops landings. French vessels predominantly fished the grounds in the 1970-80's until the Irish fleet developed in the late 1980's. Since then the Irish fleet has been the major harvester of Nephrops in the area with only a marginal amount taken by French and UK vessels.

The area has 3 main fishing grounds, the Aran Grounds, which are the most productive, the Galway Bay grounds and the Slyne Grounds. The Aran grounds can be characterised as an area of relatively high density of small Nephrops. The sex ratio in the catches has a strongly seasonally pattern. In the last couple of years the fishery has exploited more of the male component of the stock as a higher proportion of catches have been taken in the autumn. In 2009 ~80% of the landings were male whereas prior to that ~60% of the landings were male. A maximum sustainable yield, MSY, of 950T has been set for the fishery for 2011.

The number of vessels has increased in recent years with a fear that they may target grounds where effort control has not yet been put in place. Otter trawls were the main method of catching the nephrops but recently there has been a move towards using twin-rig trawls and it is now estimated that >90% of the vessels now use the latter type. Discards are usually 20% by weight and 30% by number and the fishery also has bycatch of hake, megrim and monkfish.

Surveys were carried out in 2008 and 2009 using underwater TV surveys to determine the size of the Nephrops stock, which could then be used to determine management measures. Indicators used include size structure of the catches, sex ratio and landings per unit effort (LPUE). The density of the Nephrops in considered high despite recent low harvests and a stock size that fluctuates. The effort has decreased in recent years but an increase in technological efficiency has meant that the LPUE has increased in the same time.

For more information see:

Nephrops fisheries in the Galway Bay and Aran GRounds, BIM

ICES Advice, June 2010 ECOREGION Celtic Sea STOCK Nephrops in Subarea VII

FU17 Nephrops on the Aran Grounds

Study Areas

Hosted by Queen's University School of Biological Sciences