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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.

This report provides the main results and findings of the 16th 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 2018 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 4.9 billion burrows. This was a similar result of that obtained in 2011, and 9% lower than the abundance in 2017. In contrast to 2017 the spatial distribution of burrows appears more homogenous across the survey area, with high densities in the SW of the ground in shallower water, and higher densities in the NW of the ground in deep water. Overall densities are high and abundance remains stable, well above MSY Btrigger. Reducing the number of stations compared to 2011 has not affected the accuracy of the survey estimate to date. 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 2018 implies a total catch option at Fmsy (=Fmax) of 11,107 tonnes which results in landings of no more than 8,959 tonnes. The sea-pen species observed in 2018 was predominantly Virgularia mirabilis, with one potential observation of Pennatula phosphorea (which requires verification). Sea-pens were observed at 20% of stations with high densities observed in the south-west of the ground. Trawl marks were noted at 26% of the UWTV stations.

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.

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.

This report provides the main results and findings of the 15th 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 2017 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 5.3 billion burrows. This was a similar result of that obtained in 2006, and 4% higher than the abundance in 2016. In contrast to 2016 the spatial distribution of burrows appears more homogenous across the survey area. Overall densities are high and abundance remains stable, well above MSY Btrigger. Reducing the number of stations compared to 2011 has not affected the accuracy of the survey estimate to date. 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 2017 implies a total catch option at Fmsy (=Fmax) of 11,807 tonnes which results in landings of no more than 9,630 tonnes. The only sea-pen species observed in 2017 was Virgularia mirabilis and this was found at 16% of stations ranging from occasional to common, with high densities observed in the south-west of the ground. Trawl marks were noted at 36% of the UWTV stations.

This report provides the main results of the 2017 underwater television survey on the ‘Labadie, Jones and Cockburn Banks’ ICES assessment area; Functional Unit 20-21. This was the fourth survey to achieve full coverage of the full area. The 2017 survey was multi-disciplinary in nature collecting UWTV, CTD and other ecosystem data. A total of 86 UWTV stations were completed at 6 nmi intervals over a randomised isometric grid design. The mean burrow density was 0.44 burrows/m2 compared with 0.18 burrows/m2 in 2016. The 2017 geostatistical abundance estimate was 4.4±0.01 billion a 236% increase on the abundance for 2016 with a CV of 4% which is well below the upper limit of 20% recommended by SGNEPS 2012. Highest densities were generally observed throughout the ground, and there were also high densities observed close to boundaries. Using the 2017 abundance estimate and updated stock data implies catch of 8,673 tonnes and landings of 6,553 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). One species of sea-pen were recorded as present at the stations surveyed Virgilaria mirabilis. Trawl marks were observed at 32% of the stations surveyed.

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.

This report provides the main results of the eighth underwater television survey of the various Nephrops patches in Functional Unit 19. The survey was multi-disciplinary in nature collecting UWTV, CTD, multi-beam and other ecosystem data. In 2017 a total 41 UWTV stations were successfully completed. The mean density estimates varied considerably across the different patches. The 2017 raised abundance estimate was a 25% increase from the 2016 estimate and at 499 million burrows is above the MSY Btrigger (430 million). Using the 2017 estimate of abundance and updated stock data implies catch of 1,192 tonnes and landings of 889 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). 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 10% of the stations surveyed.

This report provides the main results and findings of the twelfth 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 40 UWTV stations were surveyed successfully (good quality video footage) carried out over an isometric grid at 4.5nmi or 8.3km intervals. The precision, with a CV of 5%, was well below the upper limit of 20% recommended by SGNEPS 2012. The 2017 abundance estimate was 16% higher than in 2016 and at 1600 million is above the new MSY Btrigger (990 million). Using the 2017 estimate of abundance and updated stock data implies catch of 4,332 tonnes and landings of 3,784 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). Only one species of sea-pen Virgilaria mirabilis was recorded as present at the stations surveyed. Trawl marks were observed at 59% of the stations surveyed. Ten beam trawl tows were carried out providing important data on the benthic communities and size structure of the Nephrops population.

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.

This report provides the results of the fourth 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 2016, adjusted for edge effect, was 0.13 burrows/m². The final krigged abundance estimate was 958 million burrows with a relative standard error of 4% and an estimated stock area of 7,108km2. The 2016 abundance estimate was 32% higher than in 2014. There was no UWTV survey in 2015 due to vessel breakdown prior to survey. Using the 2016 estimate of abundance and updated stock data implies catch of 3,100 tonnes and landings of 3,100 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 30% of the stations surveyed

This report provides the main results and findings of the tenth 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 33 UWTV stations were surveyed successfully (good quality video footage) carried out over an isometric grid at 4.5nmi or 8.3km intervals. Of the planned stations 17% (7) could not be completed due to very poor or nil visibility conditions encountered at seabed. For these stations density estimates were filled-in using and average of historic values within 2nmi. The resulting krigged burrow abundance estimate for the Smalls ground decreased by 16% relative to 2014. The final abundance estimate was 1,363 million. The precision, with a CV of 7%, was well below the upper limit of 20% recommended by SGNEPS 2012. Using the 2015 estimate of abundance and updated stock data implies catch of 3,027 tonnes and landings of 2634 tonnes in 2016 fishing at Fmsy (assuming that all catch is landed). Only one species of sea pen Virgilaria mirabilis was recorded as present at the stations surveyed. Trawl marks were observed at 12% of the stations surveyed.

This report provides the main results of the sixth underwater television survey of the various Nephrops patches in Functional Unit 19. The survey was multi-disciplinary in nature collecting UWTV, CTD, multi-beam and other ecosystem data. In 2015 a total 39 UWTV stations were successfully completed. The mean density estimates varied considerably across the different patches. The 2015 raised abundance estimate of 482 million burrows was a 24% decrease from the 2014 estimate. Taking into account the uncertainty (CV of 13%) there is no significant difference in abundance estimates since 2011. Using the 2015 abundance estimate and recent mean weights and discard parameters would imply total catches of 793 t fishing at Fmsy in 2016. This stock will be subject to the landing obligation in 2016 and the calculation of catch options assume that all catches will be landed in 2016. The catch can be partitioned into landings of 543 t and discards of 250 t. The estimated discards rates in FU19 are relatively high and impact of this on the catch options is discussed. One species of sea pen was observed; Virgularia mirabilis which has been observed on previous surveys of FU19., Funder: Marine Institute

This report provides the main results and findings of the 13th annual underwater television survey on the ‘Irish sea west Nephrops grounds’ ICES assessment area, Functional Unit 15.

This report provides the main results of the 2015 underwater television survey on the ‘Labadie, Jones and Cockburn Banks’ ICES assessment area; Functional Unit 20-21. This was the second survey to achieve full coverage of the full area. The 2015 survey was multidisciplinary in nature collecting UWTV, CTD and other ecosystem data. A total of 96 UWTV stations were completed at 6 nmi intervals over a randomised isometric grid design. The mean burrow density was 0.20 burrows/m2 compared with 0.19 burrows/m2 in 2014. The 2015 geostatistical abundance estimate was 2.0±0.02 billion a 2% decrease on the abundance for 2014 with a CV of 3% which is well below the upper limit of 20% recommended by SGNEPS 2012. Highest densities were general observed towards the north and southwest of the ground, and there were also high densities observed close to boundaries. Using the 2015 abundance estimate and updated stock data implies catch of 3045 tonnes and landings of 2225 tonnes. Only one species of sea pen Virgilaria mirabilis was recorded as present at the stations surveyed. Trawl marks were observed at 30% of the stations surveyed.

This report provides the main results and findings of the fourteenth 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 2015 a total of 44 UWTV stations were successfully completed, 34 on the Aran Grounds and 5 on each of the Slyne Head and Galway Bay patches. The mean burrow density observed in 2015, adjusted for edge effect, was medium at 0.38 burrows/m². The final krigged burrow abundance estimate for the Aran Grounds was 480 million burrows with a CV (or relative standard error) of 6 %. The final abundance estimate for Galway Bay and Slyne Head was 56 and 20 million burrows with CVs of 15% and 4% respectively. The total abundance estimates have fluctuated considerably over the time series. The 2015 abundance estimate was 42% higher than in 2014 and at 556 million and is just above to the new MSY Btrigger (540 million). Using the 2015 abundance estimate and updated stock data implies catch of 991 tonnes and landings of 915 tonnes in 2016 fishing at Fmsy (assuming all catch is landed). Virgilaria mirabilis was the most common of the two sea-pen species observed on the UWTV footage. Pennatula phosphorea was observed at one station on the Slyne Head Nephrops ground. Key words: Nephrops norvegicus, stock assessment, geostatistics, underwater television (UWTV), benthos, CTD. Suggested citation, Funder: Marine Institute

2015 ICES Advice on fishing opportunities, catch, and effort. Celtic Sea Nephrops Advice Drafting Group (ADGNEPH), ICES

This report provides the main results and findings of the fifth underwater television survey of the various Nephrops patches in Functional Unit 19. The survey was multi-disciplinary in nature collecting UWTV, CTD, multi-beam and other ecosystem data. In 2014 a total 40 UWTV stations were successfully completed. The mean density estimates varied considerably across the different patches. The 2014 raised abundance estimate of 636 million burrows was a 31% increase from the 2013 estimate. Taking into account the uncertainty (CV of 15%) this is not significantly different from abundance estimates since 2011. Using the 2014 abundance and recent mean weight and discard parameters would imply total catches of 1119 t fishing at Fmsy in 2015. Based on recent discard patterns which are high in this area; 715 t would be landings and 404 t would be discards. Two species of sea pen were observed; Virgularia mirabilis and Pennatula phosphorea, both species have been observed on previous surveys of FU19.

This report provides the main results of the 2014 underwater television survey on the ‘Labadie, Jones and Cockburn Banks’ ICES assessment area; Functional Unit 20-21. Some exploratory UWTV stations were carried out in 2006 and 2012. In 2013 ~60% of the ground was surveyed. This was the first survey to achieve full coverage of the newly defined area. The 2014 survey was multi-disciplinary in nature collecting UWTV, CTD and other ecosystem data. A randomised isometric grid design was employed with 98 UWTV stations at 6.0 nmi intervals. The mean burrow density was 0.19 burrows/m2 compared with 0.16 burrows/m2 in 2013. The 2014 geostatistical abundance estimate was 2.1±0.1 billion a 26% increase on the extrapolated abundance for 2013. Highest densities were general observed towards the middle of the ground, but there were also high densities observed close to boundaries. Using the 2014 abundance and recent fisheries data it is possible to estimate harvest ratios consistent with various landings options. These can be used by ICES to provide catch options for 2015. The occurrence of sea-pens and trawl marks on the UWTV footage and processed CTD is also presented.

This report provides the main results and findings of the ninth 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 52 stations UWTV stations were carried out over an isometric grid at 4.5nmi or 8.3km intervals. The krigged burrow abundance estimate for the Smalls ground increased by 22% relative to 2013 and was the highest in the 9 year time series. The final abundance estimate was 1,622 million with a CV of 8% which is well below the upper limit of 20% recommended by SGNEPS 2012. Using the 2014 estimate of abundance and recent mean weight and discard data would imply total catches at Fmsy in 2015 of 3,797t. This implies landings of 3,409 tonnes. Temperature on the seabed varied by 2oC over the Nephrops ground with coldest values around 9.4oC in the deepest part of the area. Only one species of sea pen Virgilaria mirabilis was recorded as present at 46% of the stations surveyed. Trawl marks were observed at 28% of the stations surveyed.

Use the URI link below to search the Marine Institute Data Discovery Catalogue for datasets relevant to this report., This report provides the main results and findings of the tenth annual underwater television on the ‘Irish sea west Nephrops grounds’ ICES assessment area; Functional Unit 15. The survey was multi-disciplinary in nature collecting UWTV, CTD and other ecosystem data. An analysis of the precision, accuracy and sampling intensity trade-offs showed that sampling intensity could be reduced without significantly reducing the precision and accuracy of the survey. Consequently, sampling intensity was reduced this year from ~150 stations in a 3.5 nautical mile grid to 99 stations (4.5nmi grid). Full coverage of the grid was achieved. The krigged burrow abundance estimate for the Irish Sea ground increased slightly (+3% relative to 2011). Abundance estimates have been fairly very stable over the time series. The 2012 randomised isometric grid design resulted in a CV (or relative standard error) of 3% which is in line with CVs observed previously and well below the upper limit of 20% recommended by SGNEPS 2012., Marine Institute; Agri-Food and Biosciences Institute

This article was originally published by ICES on their website http://www.ices.dk/., peer-reviewed, The Study Group on Nephrops Surveys (SGNEPS) met in Ancona, Italy from 6–8 March 2012. The group consisted of 12 scientists from Ireland, Scotland, England, Northern Ireland, Spain, Denmark, Portugal and Italy under the chairmanship of Colm Lordan, Ireland. SGNEPS has an important role as the international coordina-tion group for Nephrops UWTV surveys in the North Atlantic and Mediterranean. Heretofore SGNEPS has focused on planning, protocols, quality control, design and survey development issues. At the 2012 meeting group compiled a table summarizing the station densities and precision levels of most annual Nephrops UWTV surveys. Large variations in survey station densities occur across the grounds currently sur-veyed. Station density, accuracy and precision trade-offs were investigated and dis-cussed in detail for the two main survey design types (random stratifies and grids). The main outcome of these deliberation was that a minimum precision level of

Use the URI link below to search the Marine Institute Data Discovery Catalogue for datasets relevant to this report., This report provides the main results and findings of the fourth underwater television survey of the various Nephrops grounds in Functional Unit 19. The survey was multi-disciplinary in nature collecting UWTV, CTD, multi-beam and other ecosystem data. In 2013 a total 40 UWTV stations were successfully completed. Adjusted burrow density estimates varied considerably across the different grounds. The 2013 raised abundance estimate of 397 million burrows is a 20% decrease from the 2012 estimate. Taking into account the uncertainty (CV of 17%) this is not significantly different from abundance estimates in 2011 or 2012. Using the 2013 abundance and recent mean weight and discard implies 2014 total catch advice fishing at Fmsy (=F35%spr) of 618 tonnes which results in landings of no more than 521 tonnes.

Use the URI link to search the Marine Institute Data Discovery Catalogue for datasets relevant to this report., This report provides the main results and findings of the twelfth 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 total 31 UWTV stations were successfully completed in a randomised isometric grid design at 3.5nmi or 6.5km intervals over the known range of the stock on the Aran Grounds. The mean burrow density observed in 2013, adjusted for edge effect, was 0.32 burrows/m². The final krigged burrow abundance estimate was 317 million burrows with a CV (or relative standard error) of 4 %. Abundance estimates have fluctuated considerably over the time series. The abundance decreased significantly in 2012 and the 2013 estimate was 2% lower and the lowest estimate in the 12 year time series. Raised abundance estimates for Galway Bay and Slyne Head were also low for those areas. Using the 2013 abundance estimate together with updated parameters for mean weight and proportions of removals retained implies 2014 total catch advice fishing at Fmsy (=F35%spr) of 699 tonnes which results in landings of no more than 591 tonnes. Nephrops accounted for approximately 70% of the benthic catch by weight from 7 beam trawl tows. The observed length frequency and maturity of female Nephops caught was similar to previous years. Virgilaria mirabilis was the most common of the two sea-pen species observed on the UWTV footage (Pennatula phosphorea was also present).

This report provides the main results and findings of the eighth 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. The sampling intensity was reduced this year from around 100 stations in the past to 51 stations this year. A randomised isometric grid design was employed with UWTV stations at 4.5nmi or 8.3km intervals. Previously a 3.0 nmi square grid was used. The krigged burrow abundance estimate for the Smalls ground has decreased by 19% relative to 2012 and was the fourth highest in the 8 year history of the survey. Abundance estimates have been fairly stable over the time series. The 2013 randomised isometric grid design result in a CV (or relative standard error) of 7% which is 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 2,937 tonnes which results in landings of no more than 2,674 tonnes., Funder: Marine Institute

Use the URI link below to search the Marine Institute Data Discovery Catalogue for datasets relevant to this report., This report provides the results of the second 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 68 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 2013, adjusted for edge effect, was 0.106 burrows/m². The final krigged abundance estimate was 768 million burrows with a relative standard error of 4% and an estimated stock area of 7,100km2. The abundance estimate was 2% lower than in 2012. Landings options at various different fishing mortalities were calculated in line with the recommendations of WKNEPH 2013. Fishing at Fmsy in 2014 implies a slight increase in the TAC from 1,800 t to 1,850 t. This increase is mainly due to an increase in average mean weight of the landings. The three species of sea-pen found on muddy habitat in Irish waters are Virgularia mirabilis, Funiculina quadrangularis and Pennatula phosphorea were all observed during the survey. Trawl marks were also observed on over half of the stations surveyed.

Use the URI link below to search the Marine Institute Data Discovery Catalogue for datasets relevant to this report., This report provides the main results of the 2013 underwater television survey on the ‘Labadie, Jones and Cockburn Banks’ ICES assessment area; Functional Unit 20-21. Some exploratory stations were carried out in 2006 and 2012. The survey was multi-disciplinary in nature collecting UWTV, CTD, Multibeam and other ecosystem data. A randomised isometric grid design was employed with UWTV stations at 6.0 nmi intervals. Due to weather and technical downtime only 58 out of the 95 planned stations were successfully completed. The adjusted mean density for 2013 was 0.18/m2 which can be classified as “low density”. Scientific knowledge of the heterogeneous habitat and spatial distribution of the Nephrops population in this area is developing. Survey design and burrow identification are particularly difficult in this area due to factors discussed. The occurrence of sea-pens and trawl marks on the UWTV footage is also presented.

Use the URI link below to search the Marine Institute Data Discovery Catalogue for datasets relevant to this report., 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.

The Nephrops fishery on the Porcupine Bank takes place on a large area, approximately 7000km2, of complex muddy habitat between depths of 300 to 470m. Irish effort has been increasing and Ireland is now responsible for the majority of the landings. The scientific advice has indicated that the stock has declined and fishing mortality should be reduced to the lowest possible level. This Irish Fisheries Science Research Partnership (IFSRP) survey was developed in 2010 to address the pressing need for data from the closed area established by the EC between 1st May to 31st July 2010. 46 hauls were carried out and the results indicate high CPUE for the survey relative to recent observations for the fleet. Strong patterns in size and sex ratio were observed spatially. The male biased sex ratio and size-at-maturity are similar to historical observation. The size distributions of the catches are very different to the Spanish survey in the area which took place two months later. The utility of the survey for monitoring the stock is discussed., Funder: Marine Institute

Use the URI link below to search the Marine Institute Data Discovery Catalogue for datasets relevant to this report., This is the fourth in a time series of UWTV surveys on the ‘Smalls grounds’. The 2006 survey covered the distinct mud patches of the Smalls Grounds and also indicator stations on the Labadie Bank, Nymphe Bank and Seven Heads, whereas the 2007 to 2009 survey covered the Smalls grounds only due to poor weather and time constraints. This report details the results of the 2009 survey for the Smalls ground Nephrops stock.

NOTICE: this is the author’s version of a work that was accepted for publication in Journal of Sea Research. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Sea Research, [Volume 64, Issue 4, (November 2010)] doi:10.1016/j.seares.2010.01.011 http://www.sciencedirect.com/science/article/pii/S1385110110000237, peer-reviewed, The sex ratio in the catches of megrim (Lepidorhombus whiffiagonis, Walbaum) varied systematically with depth on three independent trawl survey series off the west coast of Ireland. Female megrim dominated the shallow catches, while males were more common in catches from deeper waters. The size difference between the sexes alone cannot explain this pattern because it remained evident when fish length was taken into account. Therefore size-specific habitat preferences or size-selective fishing mortality cannot fully explain the observed trend in the sex ratio of megrim. Female megrim grow to a larger size, at a faster rate than males and it is likely that their differences in habitat preferences are related to this. Shallower waters are warmer during the growing season and are likely to provide better conditions for fast growth. An understanding of the mechanisms behind these patterns is an important consideration in the management and conservation of this fish stock, which might be particularly vulnerable because the commercial landings are to a large extent dominated by female megrim

Use the URI link below to search the Marine Institute Data Discovery Catalogue for datasets relevant to this report., Since 2003 a joint UWTV survey has been carried out by the Marine Institute (Ireland) and AFBI (Northern Ireland). In 2009 this survey was used to develop catch options for the stock using a bias corrected survey estimate as an absolute measure of stock size and recent discard rates and mean weight to forecast catch (ICES, 2009a). This report details the results of the 2009 survey for the western Irish Sea Nephrops stock. We also update the catch option table using the most recent survey estimate.

Use the URI link below to search the Marine Institute Data Discovery Catalogue for datasets relevant to this report., The prawn (Nephrops norvegicus) are common around the Irish coast occurring in geographically distinct sandy/muddy areas were the sediment is suitable for them to construct their burrows. The Irish Nephrops fishery is extremely valuable with landings in recent years worth around €30m at first sale supporting an important indigenous processing industry. The Nephrops fishery “at the back of the Aran Islands” can be considered the mainstay of the Ros a Mhíl fleet. Without this Nephrops fishery the majority of vessels in the fleet would cease being economically viable (Meredith, 1999). Given these socio-economic realities, good scientific information on stock status to enable sustainable management of the resources are urgently required. This is the eight data point in a time series of UWTV surveys on the ‘Aran grounds’. The survey covers three distinct mud patches; the Aran Ground, Galway Bay and Slyne Head. These have approximate areas of 940, 41 and 26sq.km respectively. In 2009 this survey was used to develop catch options for the stock using a bias corrected survey estimate as an absolute measure of stock size and recent discard rates and mean weight to forecast catch (ICES, 2009a). This report details the results of the 2009 survey and updates the catch option table using the most recent survey estimate.

Use the URI link below to search the Marine Institute Data Discovery Catalogue for datasets relevant to this report., The Nephrops fishery “at the back of the Aran Islands” is the mainstay of the Ros a Mhíl fleet and sustaining this valuable fishery would be at the heart of any management plan for fisheries in the area. In 2006 the fifth in a series of annual UWTV survey was completed, and the results of that survey together with a synthesis and analysis of the results were published. The survey is multidisciplinary in nature collecting data on burrow abundances from UWTV, Nephrops biological data from beam trawls, oceanographic data from CTD, sediment data, multi-beam and other habitat data. A geostatistical analysis indicates that burrow densities and abundances have fluctuated considerably in space and time. Highest densities occurred in 2004 with the lowest densities in the 2006 survey. There may be a negative relationship between abundance in landings in the autumn and a positive relationship between observed densities and landings the following spring.

In response to a request from the Department of Communications Marine and Natural Resources and fishing industry, the conversion factors used to estimate round or live weights from gutted anglerfish were re-examined. A number of data sources was available from survey data, port sampling and observer trips. In some cases, the liver is left in place when the fish are gutted. For these landings a separate conversion factor is necessary. The conversion factors were found to be independent of fish size, however, some significant differences between the data sources were found. Significant differences between the conversion factors of the two species of anglerfish (Lophius piscatorius and L. budegassa) were also found. As commercial landings of anglerfish are not usually speciated, a generic conversion factor was estimated for Lophius spp. by combining the data for both species after weighting by the estimated proportions of the two species in the Irish landings. The resultant conversion factor for fully gutted fish is 1.23 and 1.17 when the liver is left in place; both estimates are lower than the current Irish factor of 1.28., Funder: Marine Institute