• 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.
    • Aran, Galway Bay and Slyne Head Nephrops Grounds (FU17) 2017 UWTV Survey Report and catch options for 2018

      Lordan, C.; Doyle, J.; Butler, R.; Sugrue, S.; Allsop, C.; O'Connor, S.; Vacherot, J.P. (Marine Institute, 2017)
      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 2017 a total of 40 UWTV stations were successfully completed, 31 on the Aran Grounds, 5 on Galway Bay and 4 on Slyne Head patches. The mean burrow density observed in 2017, 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 2017 abundance estimate and updated stock data implies catch of 551 tonnes and landings of 513 tonnes in 2018 when MSY approach is applied (assuming that discard rates and fishery selection patterns do not change from the average of 2014–2016). Virgilaria mirabilis was the only sea-pen species observed on the UWTV footage. Trawl marks were present at 20% of the Aran stations surveyed.
    • Aran, Galway Bay and Slyne Head Nephrops Grounds (FU17) 2018 UWTV Survey Report and catch scenarios for 2019

      Doyle, J.; O’ Brien, S.; Ryan, G.; Galligan, S.; Hernon, P.; Aristegui, M.; Vacherot, J.P. (Marine Institute, 2018)
      This report provides the main results and findings of the seventeenth 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 2018 a total of 43 UWTV stations were successfully completed, 33 on the Aran Grounds, 5 on Galway Bay and 5 on Slyne Head patches. The mean burrow density observed in 2018, adjusted for edge effect, was medium at 0.40 burrows/m². The final krigged burrow abundance estimate for the Aran Grounds was 488 million burrows with a CV (relative standard error) of 3%. The final abundance estimate for Galway Bay and Slyne Head was 33 million in both grounds with CVs of 17% and 12% respectively. The total abundance estimates have fluctuated considerably over the time series. The 2018 combined abundance estimate was a 37% increase compared to in 2017 and at 554 million burrows and is above the MSY Btrigger reference point (540 million burrows). Using the 2018 abundance estimate and updated stock data implies catch of 1002 tonnes and landings of 916 tonnes in 2019 when the MSY approach is applied (assuming that discard rates and fishery selection patterns do not change from the average of 2015–2017). Virgularia mirabilis was the only sea-pen species observed on the UWTV footage. Trawl marks were present at 9% of the Aran stations surveyed.
    • Aran, Galway Bay and Slyne Head Nephrops Grounds (FU17) 2019 UWTV Survey Report and catch scenarios for 2020.

      Aristegui, M.; Doyle, J.; O’ Brien, S.; Fitzgerald, R.; Vacherot, J.P.; Sugrue, S.; Quinn, M. (Marine Institute, 2019)
      This report provides the main results and findings of the seventeenth 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, CTD and other ecosystem data. In 2019 a total of 41 UWTV stations were successfully completed, 31 on the Aran Grounds, 5 on Galway Bay and 5 on Slyne Head patches. The mean burrow density observed in 2019, adjusted for edge effect, was medium at 0.38 burrows/m². The final krigged burrow abundance estimate for the Aran Grounds was 458 million burrows with a CV (relative standard error) of 4%. The final abundance estimate for Galway Bay was 23 million and for Slyne Head was 12 million, with CVs of 11% and 8% respectively. The total abundance estimates have fluctuated considerably over the time series. The 2019 combined abundance estimate (493 million burrows) is 11% lower than in 2018, and it is below the MSY Btrigger reference point (540 million burrows). Using the 2019 estimate of abundance and updated stock data implies catches between 696 and 800 tonnes in 2020 that correspond to the F ranges in the EU multi annual plan for Western Waters, assuming that discard rates and fishery selection patterns do not change from the average of 2016–2018. Virgularia mirabilis was the only sea-pen species observed on the UWTV footage. Trawl marks were present at 7% of the Aran stations surveyed.
    • 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) 2018 UWTV Survey Report and catch scenarios for 2019

      Doyle, J.; O'Brien, S.; Ryan, G.; Galligan, S.; Hernon, P.; Aristegui, M.; Vacherot, J.P.; Lordan, C. (Marine Institute, 2018)
      This report provides the results of the sixth 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 69 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 2018, adjusted for edge effect, was 0.16 burrows/m². The final krigged abundance estimate was 1117 million burrows with a relative standard error of 4% and an estimated stock area of 7,130 km2. The 2018 abundance estimate was 31% higher than in 2017. Using the 2018 estimate of abundance and updated stock data implies catch of 2,645 tonnes and landings of 2,645 tonnes in 2019 when MSY approach is applied (assuming that all catch is landed). The three species of sea-pen; Virgularia mirabilis, Funiculina quadrangularis and Pennatula phosphorea, were all observed during the survey. The deepwater sea-pen Kophobelemnon stelliferum was also observed and its presence/absence mapped from the available time-series. Trawl marks were also observed on 33% of the stations surveyed.
    • Porcupine Bank Nephrops Grounds (FU16) 2017 UWTV Survey Report and catch options for 2018

      Lordan, C.; Doyle, J.; Butler, R.; Sugrue, S.; Allsop, C.; O’Connor, S.; Vacherot, J.P. (Marine Institute, 2017)
      This report provides the results of the fifth 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 63 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 2017, adjusted for edge effect, was 0.12 burrows/m². The final krigged abundance estimate was 850 million burrows with a relative standard error of 5% and an estimated stock area of 7,134 km2. The 2017 abundance estimate was 11% lower than in 2016. Using the 2017 estimate of abundance and updated stock data implies catch of 2,734 tonnes and landings of 2,734 tonnes in 2017 when MSY approach is applied (assuming that all catch is landed). The three species of sea-pen; Virgularia mirabilis, Funiculina quadrangularis and Pennatula phosphorea, were all observed during the survey. The deepwater sea-pen Kophobelemnon stelliferum was also observed and its presence/absence mapped from the available time-series. Trawl marks were also observed on 43% of the stations surveyed.
    • The “Smalls” Nephrops Grounds (FU22) 2019 UWTV Survey Report and catch scenarios for 2020.

      Doyle, J.; O’ Brien, S.; Fitzgerald, R.; Vacherot, J.P.; Sugrue, S.; Quinn, M. (Marine Institute, 2019)
      This report provides the main results and findings of the fourteenth annual underwater television survey on the ‘Smalls grounds’ ICES assessment area; Functional Unit 22. The survey was multi-disciplinary in nature collecting UWTV, CTD and other ecosystem data. A total of 41 UWTV stations were surveyed successfully (high quality image data), carried out over an isometric grid at 4.5nmi or 8.3km intervals. The precision, with a CV of 9%, was well below the upper limit of 20% recommended by SGNEPS (ICES, 2012). The 2019 abundance estimate was 30% higher than in 2018 and at 1121 million is below the MSY Btrigger reference point (990 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 2247 and 2820 tonnes (assuming that discard rates and fishery selection patterns do not change from the average of 2016–2018). One species of sea pens were recorded as present at the stations surveyed: Virgularia mirabilis. Trawl marks were observed at 57% of the stations surveyed.