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Please use this identifier to cite or link to this item: http://hdl.handle.net/10793/913

Title: Western Irish Sea Nephrops Grounds (FU15) 2013 UWTV Survey Report and catch options for 2014
Authors: Doyle, J.
Lordan, C.
Ligas, A.
Brown, V.
Leocadio, A.
McCausland, I.
McCorriston, P.
Service, M.
Stewart, P.
Schön, P.J.
Keywords: Nephrops norvegicus
stock assessment
geostatistics
underwater television (UWTV)
benthos
Issue Date: 2013
Publisher: Marine Institute & Agri-Food and Biosciences Institute
Citation: Doyle J., Lordan C., Ligas A., Brown V., Leocadio A., McCausland I., McCorriston P., Service M., Stewart P., and Schön P.-J. 2013. Western Irish Sea Nephrops Grounds (FU15) 2013 UWTV Survey Report and catch options for 2014. Marine Institute and Agri-Food and Biosciences Institute.
Abstract: This report provides the main results and findings of the eleventh annual underwater television survey on the ‘Irish sea west Nephrops grounds’ ICES assessment area, Functional Unit 15. The survey was multi-disciplinary in nature collecting UWTV and other ecosystem data. The 2013 design consisted of a randomised isometric grid of 80 stations at 5 nautical mile intervals out over the full known extent the stock. The resulting krigged burrow abundance estimate was 4.3 billion burrows. This was a 16% decrease relative to 2012. The spatial distribution shows higher abundance in the south of the area and a larger decline in abundance is apparent in the North. Overall densities remain high and abundance remains relatively stable, well above MSY Btrigger. Reducing the number of stations in 2013 is not expected to have significantly affected the accuracy of the survey estimate. The CV (or relative standard error) of 3% is in line with previous estimates and well below the upper limit of 20% recommended by SGNEPS 2012. Total catches and landings options at various different fishing mortalities were calculated and fishing at Fmsy in 2014 implies a total catch option at Fmsy (=Fmax) of 9,914 tonnes which results in landings of no more than 8,244 tonnes. The only sea-pen species observed in 2013 was Virgularia mirabilis and the frequency of occurrence was lower than in 2012. Trawl marks were noted at 43% of the UWTV stations.
Description: Use the URI link below to search the Marine Institute Data Discovery Catalogue for datasets relevant to this report.
URI: http://hdl.handle.net/10793/913
http://catalog.marine.ie/geonetwork/srv/en/main.home
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