• Performance of the EU Harmonised Mouse Bioassay for Lipophilic Toxins for the Detection of Azaspiracids in Naturally Contaminated Mussel (Mytilus edulis) Hepatopancreas Tissue Homogenates Characterised by Liquid Chromatography coupled to Tandem Mass Spectrometry

      Hess, P.; Butter, T.; Petersen, A.; Silke, J.; McMahon, T. (Elsevier, 2009)
      Azaspiracids (AZAs) are a group of lipophilic polyether toxins that were discovered in shellfish from Ireland in 1995, following a food poisoning incident. Both the limited availability of pure AZAs and the co-occurrence in shellfish of other toxins in combination with AZAs have so far prevented an in-depth evaluation of the performance of the EU reference test, the mouse bioassay (MBA), for this toxin group at the regulatory limit. The present study evaluated the performance of the mouse bioassay at the example of a mussel tissue homogenate, naturally contaminated with AZAs, diluted with uncontaminated tissues to appropriate concentration levels. Concentrations were determined using liquid chromatography coupled to tandem mass spectrometry (LC-MS-MS) (7 levels ranging from levels less than the limit of quantification to a maximum of ca. 2.24 mg/kg in hepatopancreas, which corresponds to a maximum whole flesh AZA1-equivalent of ca. 0.34 mg/kg). Replicate homogenates of each concentration level were analysed by MBA on 7 independent occasions over 6 weeks. Inhomogeneity between replicate aliquot portions was evaluated using LC-MS-MS and ranged from 1.8 to 6.6% RSD for the six levels contaminated above quantification limits. This variation was similar to the variability of the LC-MS-MS method within a batch, and the difference between replicate aliquots could thus be considered negligible. Other uncertainties considered in the study included the short- and long-term variability of the LC-MS-MS method, toxic equivalence factors, relative response factors in mass spectrometric detection, additional analogues and matrix effects. A concentration-response curve was modelled as a 4-parametric logistic fit to a sigmoidal function, with an LC50 of 0.70 mg AZA1-equivalent/kg hepatopancreas tissue. Furthermore, the mathematical model of the lethality data from this study suggests that occasional negative mouse assays at high concentrations, previously observed in the Irish statutory monitoring, are at least partly due to the biological variation of mice and can be understood on a statistical basis. The mathematical model of the concentration-response curve also describes the probability of a positive mouse bioassay at the current regulatory limit of 0.16 mg/kg to be ca. 95%. Therefore, it appears that the mouse bioassay performs very well in the implementation of this limit. Hence, the present study very strongly suggests that the MBA and LC-MS-MS techniques can be considered equivalent in the implementation of the current regulatory limit of 0.16 mg/kg for Azaspiracids in shellfish.
    • Phase II: Strain hybridisation field experiments and genetic fingerprinting of the edible brown seaweed Alaria esculenta

      Kraan, S; Guiry, M D (Marine Institute, 2001)
      Under phase II of the Marine Research Measure several field trials were performed with five biogeographical dispersed North Atlantic strains and their hybrids of the edible brown alga Alaria esculenta at Ard Bay, Carna, Co. Galway. The weight, length, width, biomass per meter rope, growth rate and protein level were measured. The fastest-growing crosses were produced with female Norway gametophytes together with male gametophytes of other strains. The Canadian selfcross produced most biomass of over 45 kg per meter rope. The female Iceland x male Ireland crossing produced the second highest biomass figure of 13.75 kg wet weight per meter rope, while the Irish self cross using a strain from the Aran Islands produced 7.4 kg wet weight per meter. The Canadian selfcross expressed the highest protein level followed by the female Newfoundland x male Norway hybrid. These strains and hybrids are well suited to be included in a protein rich macro-herbivore diet. The Irish native strain showed a lower protein level of 8% of the wet weight. Genetic fingerprinting using RFLPs did not show any genetic differences amongst the strains in respect of the DNA examined. A detailed sequencing study on the Rubisco spacer region showed a negligible 3 bp difference between the Irish and Canadian strains In conclusion, the Canadian strain or hybrids derived from female Canada gametophytes or female Iceland gametophytes produce more biomass per meter rope and grow larger and wider in size compared to the native Irish strain. They Canadian strain also showed the highest protein values in the field trials and hence are most suited to be applied in Irish aquaculture of the brown seaweed Alaria esculenta.
    • Phosphorus release from forest harvesting on an upland blanket peat catchment

      Rodgers, Michael; O’Connor, Mark; Healy, Mark Gerard; O’Driscoll, Connie; Asam, Zaki-ul-Zaman; Nieminen, Mika; Poole, Russell; Müller, Markus; Xiao, Liwen (Elsevier, 2010)
      The aim of this study was to investigate the release of phosphorus (P) to receiving waters resulting from harvesting 34-year-old lodgepole pine trees in an upland peat catchment. The study site was within a 25.3-hectare (ha) area, and was drained by a stream that received flows from ploughed furrows, mainly, via collector drains, and discharged directly to the salmonid Shrahrevagh River, Burrishoole, Co. Mayo, Ireland. The study site was divided in two parts: the upstream part was left intact and the downstream part was harvested in early Autumn 2005 following implementation of forest guidelines. Good management practices such as proper use of brash mats and harvesting only in dry weather were implemented. Two instrumented stations were established – one just upstream (US) and the other just downstream (DS) of the clearfelled area. The measurement of P concentrations at the two stations commenced in May 2005, two months before the harvesting started. The daily mean P concentration at the DS station increased from about 6 μg L-1 of total reactive phosphorus (TRP) during pre-clearfelling to 429μg L-1 in August 2006. By October 2009, four years after clearfelling, the P concentrations at the DS station had returned to pre-clearfelling levels. In the first three years after harvesting, up to 5.15 kg ha-1 of TRP were released from the harvested catchment to the receiving water; in the second year alone, 2.3 kg ha-1 of TRP were released. Linear regression can be used to describe the relationship between TRP load and water discharge. About 80 % of the total phosphorus (TP) in the study stream was soluble and more than 70 % of the P release occurred in storm events, indicating that traditional buffer strips with widths of 15-20 m might not be efficient for P immobilization. The P concentrations were affected by antecedent weather conditions and highest concentrations occurred during storm events following prolonged drought periods. The water extractable phosphorus (WEP) contents in the soil were significantly higher below windrow/brash material than in brash-free areas, and whole-tree harvesting should be studied as one of the means to decrease P export from blanket peats.
    • Phylogenetic analysis of infectious pancreatic necrosis virus in Ireland reveals the spread of a virulent genogroup 5 subtype previously associated with imports

      Ruane, N.M.; McCleary, S.J.; McCarthy, L.J.; Henshilwood, K. (Springer Verlag, 2015)
      Infectious pancreatic necrosis is a significant disease of farmed salmonids resulting in direct economic losses due to high mortality and disease-management costs. Significant outbreaks of the disease occurred in farmed Atlantic salmon in Ireland between 2003 and 2007, associated with imported ova and smolts. As the virus was known to occur in the country since the development of aquaculture in the 1980s, this study examined archived samples to determine whether these older isolates were associated with virulent forms. The study showed that two genotypes of IPNV were present in the 1990s, genotype 3 and genotype 5. A more virulent subtype of the virus first appeared in 2003 associated with clinical outbreaks of IPN, and this subtype is now the most prevalent form of IPNV found in the country. The data also indicated that IPNV in Ireland is more closely related to Scottish and continental European isolates than to Norwegian, Chilean and Australasian genogroup 5 isolates.
    • Phytoplankton and microbial plankton of the Northeast Atlantic Shelf

      Silke, J.; Kennington, K.; Bresnan, E.; Cusack, C. (ICES, 2012)
      The Northeast Atlantic Shelf region includes the sites from all coastal waters of Ireland, the Irish Sea, and western Scottish and Norwegian Sea waters. The region was defined by WGPME to include locations on the northern margin of Europe that were outside the North Sea/English Channel influence. The character of sites in the region are shallow, coastal-water sites ranging from sheltered bays on the south coast of Ireland and fjordic sea lochs of Scotland to fully exposed locations on the west coasts of Ireland and Scotland. Bathymetry of the region ranges from shallow embayments to regions of shallow, exposed continental-shelf waters. The topography of the shelf drops rapidly to 80–100 m within 20 km of the coast, where it extends to the shelf edge as a relatively flat plateau. Time-series of phytoplankton data from the Atlantic Shelf exhibit a typical seasonal pattern of temperate waters, with considerable geographical and temporal variation. The well-mixed winter conditions lead to a region-wide strong spring bloom observed at all sites. The ensuing decrease in nutrient levels lead to a variable summer period characterized by stratified conditions in coastal areas and periodic blooms of mixed or occasionally monospecific diatom and dinoflagellate composition. The growth period tails off in autumn, when a secondary bloom may occur in response to increased mixing and breakdown of the summer thermocline. The seasonal cycle returns to a quiescent winter phase, with generally mixed conditions, light limitation, and increased nutrients return. Seasonal stabilization and destabilization of the water column in this region accounts for most of the natural variation in both phytoplankton species composition and biomass.
    • Phytoplankton precision trials in the enumeration and identification of marine microalgae through the scheme "Biological Effects Quality Assurance in Monitoring Programmes (BEQUALM)"

      Salas, Rafael Gallardo (2011)
      Scientists are coming under increased pressure in recent years to show that results they obtain arising from their scientific work are quality assured and stand up to scrutiny by independent expert auditors. This has meant that the methodologies used by laboratories involved in making these measurements have to be validated and fit for purpose and has led to the adoption of internationally recognised standard protocols. These protocols must be underpinned by robust quality systems and must be accredited to an international standard. In order for laboratories to become accredited in particular methods, they have to fulfil a series of prerequisites but a compulsory one is the participation in a proficiency testing scheme. Proficiency testing schemes are independent assessor organisations which coordinate regular inter-calibration and intercomparative studies between laboratories with a common purpose. What happens, though when proficiency testing schemes do not exist for a particular scientific measurement? This study presents results from two inter-comparison exercises at European level between phytoplankton monitoring laboratories in the enumeration and identification of marine microalgae using the Utermöhl cell counting method. Microalgae are a very important ecological component of the marine ecosystem and have also become important ecological indicators of hydro-climatic change, ocean acidification and eutrophication. Member states of the European Union are obliged to monitor for toxic and harmful algae which can cause problems and devastation in the natural environment, have detrimental effects on human health if contaminated fish and shellfish are eaten, can cause huge economic losses to the aquaculture industry and impact directly in coastal communities. This study shows how an intercomparison of this kind is designed and organised, how samples are set up, materials homogenised and reference values obtained. It demonstrates the importance of using the right technique and best practice, based on experience, to analyse samples and how important it is to design the exercise to be statistically robust, both quantitatively and qualitatively. The taxonomy quiz in 2009 showed that there was no evidence that video clips were better audit trail tools than images or vice versa. The quantitative measure suggested that there was evidence of good agreement between virtually all the analysts and the reference value for all species except one (P.micans). However, there was evidence of lack of reproducibility between and within laboratories. The qualitative measure calculated indicated that analysts are more likely to identify a toxic organism as a non toxic organism than the other way around. The results from the enumeration data in the 2010 exercise showed that there was lack of reproducibility across laboratories using different counting strategies and volume sub-sampled and analysed. These results when compared to a set of hypothesised means used as reference values suggested that cell counts were potentially underestimated by as much as 30% and that this underestimation was most likely due to test method effects.
    • Pilot Water Quality Monitoring Station in Dublin Bay North Bank Monitoring Station (NBMS): MATSIS Project Part I

      O'Donnell, G; Joyce, E; O'Boyle, S; McGovern, E (Marine Institute, 2008)
      The lack of short-term temporal resolution associated with traditional spot sampling for monitoring water quality of dynamic coastal and estuarine waters has meant that many organisations are interesting in autonomous monitoring technologies to provide near real-time semi-continuous data. Such approaches enable capturing short term episodic events (which may be missed or alternatively skew datasets when using spot samples) and provide early warning of water quality problems. New policy drivers such as the Water Framework Directive (WFD) provide added impetus to develop this field. Therefore, as part of the interreg IIIa funded MATSIS project the Marine Institute undertook to develop and pilot an autonomous monitoring station in Dublin Bay (North Bank Monitoring Station NBMS). This report presents the outcome for this pilot study.
    • Plant and animal life on the seashore

      Marine Institute (Marine Institute, 2013)
      Students will develop an understanding of the variety species and characteristics of the animals and plants that live on the seashore through scientific drawing and recording. The students will establish an understanding of the processes of life that takes place on the seashore due to environmental conditions and changes constantly taking place (e.g. tides & waves crashing on rocks, salinity of water, heat of the sun, predators) etc. Students will create their own seashore guidebook by recording information and drawing the details of species from the seashore that have been collected for the Explorers Aquarium. Students are to explore and learn about the species and plants through their own investigation and draw them in detail. Students should become familiar with the species and seaweeds names.
    • Polychlorinated Biphenyls and Organochlorines in By-Caught Harbour Porpoises Phocoena phocoena and Common Dolphins Delphinus delphis from Irish Coastal Waters

      Smyth, M.; Berrow, S.; Nixon, E.; Rogan, E. (Royal Irish Academy, 2000)
      Concentrations of 11 organochlorine (OC) pesticides and 10 individual polychlorinated biphenyls (PCB) in blubber and liver from 12 harbour porpoise Phocoena phocoena and eight common dolphins Delphinus delphis incidentally caught in fishing nets in Irish waters are presented. Female harbour porpoises had highest concentrations of OC in blubber and male common dolphins in liver. Harbour porpoises had higher mean concentrations of lindane (121-154 ng/g extractable lipid), dieldrin (116-121 ng/g) and  BHC (54-128 ng/g) but common dolphins had greater overall concentrations of DDT (9444-3998 ng/g). The predominant DDT metabolite was pp-DDE and for the chlordanes was t-nonachlor. Concentrations of ICES 7 PCB (liver-blubber) were similar in both species (4075-7999 ng/g in harbour porpoise and 4076-8945 in common dolphins). The sum of ICES 7 PCB in porpoises ranged from 3041-12270 ng/g extractable lipid in the blubber of females and from 2911-10429 ng/g in males and 798-11074 ng/g in the blubber of female common dolphins and 1555-15883 ng/g in males. Contaminant levels were generally similar to those reported from Scotland but lower than reported from Scandinavia. Ratios of DDT to DDE suggests that there are limited new sources of DDT into the Irish marine environment. These results provide a baseline for monitoring of persistent pollutants in the Irish marine environment.
    • Population dynamics, age, growth and maturity of lemon sole Microstomus kitt (Walbaum 1792) sampled between 2000-2002 off the west coast of Ireland.

      King, P. A.; Hannan, J. F.; McGrath, D.; Veldon, M. (Marine Institute, 2006)
      The age, growth, maturity and population dynamics of lemon sale (Microstomus kin), from commercial catches off the west coast of Ireland (ICES division Vllb), was determined for the period November 2000 to February 2002. The maximum age recorded was 14 years. Males of the population were dominated by 4 year olds, while females were dominated by 5 year olds. Females dominated the sex ratio in the overall sample, by month sampled, by age class and by size (from 22cm in total length onwards. when N > 20). Mature male and female lemon sale were encountered at age 2 and above. Von Bertalanffy growth parameters were estimated using the method of Rafail (1973). In recent years, the lemon sale has exhibited a smaller asymptotic length (L∞ = 34.47cm), faster growth rate (K = 0.1955) and younger age at first maturity than in the same area in 1978-1979. These changes are indicative of a decrease in population size following exploitation.
    • Population estimates of juvenile salmonids in the corrib system 1980

      Browne, J; Gallagher, P (Department of Fisheries and Forestry, 1981)
      Population assessments of the juvenile salmonids in the Corrib System are being made as part of the overall management plan for the Galway Fishery. In 1980 the first of a series of reports which will be issued annually gave information on the juvenile stocks and on the state of the spawning and nursery tributaries during 1979. Details of the methods used and some background on each of the tributaries were presented. Chemical and biological data on water quality along with numbers, size, age and survival of both salmon and trout are given in Fishery Leaflet 103. During 1979 eight tributaries were surveyed and in two cases upstream and downstream reaches were examined. In 1980 the effort in terms of personnel and equipment was increased but the high rainfall during the period of work, from mid-July to mid-September, meant that only two further stations were studied, one on the Dalgan river and the other on the Balinbrack river. The methods used and the scope of the work were identical in 1979 and 1980. In these assessments the emphasis is on salmon type tributaries and salmon type habitats within these tributaries so that trout numbers could be expected to be low.
    • Population estimates of juvenile salmonids in the Corrib system 1981

      Browne, J; Gallagher, P (Department of Fisheries and Forestry (Trade and Information Section), 1982)
      This is the third in a series of reports regarding the stocks of juvenile salmonids in the Corrib system. During the 1981 season fourteen tributaries were surveyed and in two cases upstream and downstream reaches were examined. These included three which had not been studied previously: the Failmore, Letterfore and Black. The methods were identical to those used in 1979 and 1980. As in the previous years the rivers were selected because they were known salmon holding tributaries and do not reflect trout numbers in the system. The population numbers are assessed by electrically fishing a selected area. The fish caught are marked by fin clipping and allowed to re-mix with the fish in the stream. The next day fishing is repeated in the same place and the proportion of marked to unmarked fish gives an estimate of the population. While it is not essential that river conditions remain the same on both days it does help the accuracy of the estimate. There is a tendency for fish to move out of their home territories during floods. Population surveys yield the best results when a large proportion of the tagged fish are recovered. Ideal electro fishing conditions are low water, overcast sky and similar river conditions on both days.
    • Population specific smolt development, migration and maturity schedules in Atlantic salmon in a natural river environment

      McGinnity, P; deEyto, E; Cross, T F; Coughlan, J; Whelan, K; Ferguson, A (Elsevier, 2007)
      Identifying differences in quantitative life history traits between cultured and native or non-native wild populations is important in assessing the impact of accidental and deliberate introductions of hatchery-reared fish into the wild. As the ability to exploit the marine environment is the defining life history characteristic of anadromous salmonids, knowledge of variation in smoltification characteristics among populations is crucial in determining how these introductions affect fitness in recipient populations. Data are presented here describing the timing and extent of the autumn migration; the propensity for male parr maturation; the timing of the spring migration; and the size of autumn and spring migrants from Atlantic salmon (Salmo salar) populations from various genetic backgrounds. These experiments were carried out under common garden conditions over a decade in the Srahrevagh River in the west of Ireland. Population specific genetically determined differences in quantitative life history traits associated with smoltification were apparent. These differences may reflect smolt quality and therefore impact on marine survival and ultimately lifetime fitness. Both hatchery domestication and geography (different selective environments) were found to be important factors determining smolt phenotypes, although it was difficult to measure the relative contribution of each. These results indicate that farm, native hatchery, non-native wild salmon (even from a neighbouring catchment) and their hybrids with native wild fish, are likely to produce less well adapted and thus poorer quality smolts than native wild populations and, where wild populations are extant, such stocks should not be used for enhancement purposes.
    • A population study of the eel Anguilla anguilla in Meelick Bay, Lough Derg

      Moriarty, C. (Department of Fisheries and Forestry, 1983)
      Monthly samples totalling 1,945 yellow eels were caught by fyke net in a small bay, area 100 hectares, of a large lake in 1981 and 1982. Catch per unit effort figures showed that population density varied between months and between specific areas of the bay. Most of the eels sampled (80%) measured between 34 cm and 54 cm. Ages of a sample of 168 specimens taken in 1979 ranged from 7 to 17 years, 80% from 8 to 13 years. Length frequencies were constant throughout the bay within months but showed changes between months. Recapture rate of 1,660 eels tagged was extremely low at 1.14%. The results showed that (1) when eel population density is being compared between years, it is necessary to define exactly the positions where sampling takes place and (2) the eel population in this bay was not resident but appeared to be undergoing constant change throughout the warm months of the year.
    • Populations Estimates of Juvenile Salmon in the Corrib System from 1982 to 1984

      Browne, J; Gallagher, P (Department of Tourism, Fisheries and Forestry, 1987)
      This leaflet gives the details of juvenile salmonid densities for the years 1982 to 1984 in the Corrib system. In general, since these investigations began in 1979, the Corrib tributaries have appeared to be adequately stocked with salmon. The salmon densities in the rivers to the west of Lough Corrib are much higher than in the rivers to the east. However, survival is higher in the latter. A detailed survey of juvenile salmon habitat revealed that there are 392,000 square metres of suitable habitat in the system. Of this 253,000 square metres are on the west side and 139,000 on the east side.
    • 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) 2012 UWTV Survey Report and catch options for 2013

      Lordan, Colm; Doyle, Jennifer; Dobby, Helen; Hehir, Imelda; Fee, Dermot; Allsop, Chris; O'Neill, Ross (Marine Institute, 2012)
      This report provides the results of the first 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. The UWTV results and a scientific basis for survey based catch advice in 2013 are presented. In total 47 UWTV stations were successfully completed. The mean burrow density was 0.19 burrows/m² (empirical 95% confidence intervals are from 0.17-0.21). The final krigged abundance estimate was 992 million burrows with a relative standard error of 5% and an estimated stock area of 7,100km2. This abundance estimate can be considered as a conservative estimate given that the spatial coverage of the southern part of the ground was not complete. A correction factor of 1.26 is proposed based on expert judgments of burrow size and potential detection and identification biases. A yield and spawner per recruit analysis was used to estimate a harvest rate of 5.0% for the combined sex F0.1 and other F reference points. This harvest rate is low compared to other FUs and can be considered very conservative. Applying this harvest rate to the abundance observed in the survey and using a mean weight in the landings of 45.0g implies landings in 2013 of 1,770 t. The results here could form the basis of the catch advice for 2013.
    • Porcupine Bank Nephrops Grounds (FU16) 2013 UWTV Survey Report and catch options for 2014

      Lordan, C.; Doyle, J.; O'Connor, S.; Hehir, I.; Fitzgerald, R.; Blaszkowski, M.; O'Sullivan, D.; O’Donovan, S.; Salaun, M.; Stewart4, P. (Marine Institute, 2013)
      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.
    • Porcupine Bank Nephrops Grounds (FU16) 2014 UWTV Survey Report and catch options for 2015

      Doyle, J.; Lordan, C.; O'Cuaig, M.; Hannify, O.; Murphy, Á.; Sheridan, M.; Vila, Y. (Marine Institute, 2014-10)
      This report provides the results of the third 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 67 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 2014, adjusted for edge effect, was 0.10 burrows/m². The final krigged abundance estimate was 722 million burrows with a relative standard error of 3% and an estimated stock area of 7,108km2. The abundance estimate was 6% lower than in 2013. Landings options at various different fishing mortalities were calculated in line with the recommendations of WKNEPH 2013. Fishing at Fmsy in 2015 implies catches of 1,850 t which close to the 2014 catch limit. This is because of an increase in average mean weight of the landings. The three species of sea-pen; 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.
    • Porcupine Bank Nephrops Grounds (FU16) 2016 UWTV Survey Report and catch options for 2017

      Doyle, J.; Lordan, C.; Fitzgerald, R.; O'Brien, S.; Allsop, C.; Kelly, C.; McArdle, J. (Marine Institute, 2016)
      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