Browsing Nephrops Under Water TV Surveys by Author "Lynch, D."
FU19 Nephrops grounds 2019 UWTV survey report and catch scenarios for 2020.Doyle, J.; Aristegui, M.; O’ Brien, S.; Lynch, D.; Vacherot, J.P.; Fitzgerald, R. (Marine Institute, 2019)This report provides the main results of the tenth underwater television survey of the various Nephrops patches in Functional Unit 19. The survey was multidisciplinary in nature collecting UWTV, multi-beam and other ecosystem data. In 2019 a total 44 UWTV stations were successfully completed. The mean density estimates varied considerably across the different patches. The 2019 raised abundance estimate was a 220% increase from the 2018 estimate and at 386 million burrows is below the MSY Btrigger (430 million). Using the 2019 estimate of abundance and updated stock data implies catch in 2020 that correspond to the F ranges in the EU multi annual plan for Western Waters are between 749 and 839 tonnes (assuming that discard rates and fishery selection patterns do not change from the average of 2016–2018). Two species of sea pen were observed; Virgularia mirabilis and Pennatula phosphorea which have been observed on previous surveys of FU19. Trawl marks were observed at 12 % of the stations surveyed.
Porcupine Bank Nephrops Grounds (FU16) 2020 UWTV Survey Report and catch scenarios for 2021Aristegui, M.; Blaszkowski, M.; Doyle, J.; Hehir, I.; Lynch, D.; Ryan, G.; Lordan, C. (Marine Institute, 2020)This report provides the results of the eighth underwater television on the ‘Porcupine Bank Nephrops grounds’ ICES assessment area; Functional Unit 16. The survey was multi-disciplinary in nature collecting UWTV and other ecosystem data. In total 65 UWTV stations were successfully completed in a randomised 6 nautical mile isometric grid covering the full spatial extent of the stock. The mean burrow density observed in 2020, adjusted for edge effect, was 0.17 burrows/m². The final krigged abundance estimate was 1264 million burrows with a CV of 4% and an estimated stock area of 7,130 km2. The 2020 abundance estimate was 25% higher than in 2019. Using the 2020 estimate of abundance and updated stock data implies catches between 2653 and 3290 tonnes in 2021 that correspond to the F ranges in the EU multiannual plan for Western Waters (assuming that all catch is landed). Four species of sea-pen; Virgularia mirabilis, Funiculina quadrangularis, Pennatula phosphorea and the deepwater sea-pen Kophobelemnon stelliferum were observed during the survey. Trawl marks were also observed on 22% of the stations surveyed.