Western Irish Sea Nephrops Grounds ( FU15 ) 2017 UWTV Survey Report and catch options for 2018

This report provides the main results and findings of the 17 th annual underwater television survey on the 'Irish sea west Nephrops grounds' ICES assessment area, Functional Unit 15. The survey was multidisciplinary in nature collecting UWTV and other ecosystem data. The 2019 design consisted of a randomised isometric grid of 100 stations at 4.5 nautical mile intervals out over the full known extent the stock. The resulting krigged burrow abundance estimate was 4.4 billion burrows. This was a similar result of that obtained in 2015, but a 10% lower than the abundance in 2018. In contrast to 2017 the spatial distribution of burrows shows a high density band on the central western area of the survey ground. The abundance remains within previously observed ranges and is above MSY Btrigger. 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 2020 implies a total catch option at Fmsy (=Fmax) of 10,377 tonnes estimated to result in landings of no more than 8,546 tonnes. Sea-pens were observed at 21% of stations with high densities observed in the southwest of the ground. Trawl marks were noted at 15% of the UWTV stations.