• Aran, Galway Bay and Slyne Head Nephrops Grounds (FU17) 2016 UWTV Survey Report and catch options for 2017

      Doyle, J.; Lordan, C.; Stokes, D.; O'Brien, S.; Kelly, C.; Bentley, K.; Vacherot, J.P. (Marine Institute, 2016)
      This report provides the main results and findings of the fifteenth annual underwater television on the Aran, Galway Bay and Slyne head Nephrops grounds, ICES assessment area; Functional Unit 17. The survey was multi-disciplinary in nature collecting UWTV, fishing, CTD and other ecosystem data. In 2016 a total of 45 UWTV stations were successfully completed, 34 on the Aran Grounds, 7 on Galway Bay and 4 on Slyne Head patches. The mean burrow density observed in 2016, adjusted for edge effect, was medium at 0.29 burrows/m². The final krigged burrow abundance estimate for the Aran Grounds was 343 million burrows with a CV (or relative standard error) of 3 %. The final abundance estimate for Galway Bay and Slyne Head was 25 and 11 million burrows with CVs of 7% and 3% respectively. The total abundance estimates have fluctuated considerably over the time series. The 2016 combined abundance estimate was 32% lower than in 2015 and at 379 million and is below the MSY Btrigger (540 million). Using the 2016 abundance estimate and updated stock data implies catch of 489 tonnes and landings of 456 tonnes in 2017 when MSY approach is applied (assuming that discard rates and fishery selection patterns do not change from the average of 2013–2015). Virgilaria mirabilis was the only sea-pen species observed on the UWTV footage. Trawl marks were present at 20% of the Aran stations surveyed.
    • Porcupine Bank Nephrops Grounds (FU16) 2019 UWTV Survey Report and catch scenarios for 2020

      Aristegui, M.; O’ Brien, S.; Tully, D.; Galligan, S.; McCorriston, P.; Bentley, K.; Lordan, C. (Marine Institute, 2019)
      This report provides the results of the seventh underwater television on the ‘Porcupine Bank Nephrops grounds’ ICES assessment area; Functional Unit 16. The survey was multi-disciplinary in nature collecting UWTV, CTD 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 2019, adjusted for edge effect, was 0.14 burrows/m². The final krigged abundance estimate was 1010 million burrows with a relative standard error of 5% and an estimated stock area of 7,130 km2. The 2019 abundance estimate was 9.5% lower than in 2018. Using the 2019 estimate of abundance and updated stock data implies catches between 2127 and 2637 tonnes in 2020 that correspond to the F ranges in the EU multi annual 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 31% of the stations surveyed.
    • Porcupine Bank Nephrops Grounds (FU16) 2021 UWTV Survey Report and catch scenarios for 2022

      Aristegui, M.; Blaszkowski, M.; Doyle, Jennifer; O'Brien, S.; Hehir, Imelda; Bentley, K.; Fitzgerald, Ross (Marine Institute, 2021)
      This report provides the results of the ninth 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 71 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 2021, adjusted for edge effect, was 0.14 burrows/m². The final krigged abundance estimate was 1018 million burrows with a CV of 5% and an estimated stock area of 7,130 km2. The 2021 abundance estimate was 19% lower than in 2020. Using the 2021 estimate of abundance and updated stock data imply that catches in 2022 should be no more than 2804 tonnes, according to the EU MAP and ICES MSY approach (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 38% of the stations surveyed.