• Western Irish Sea Nephrops Grounds (FU15) 2014 UWTV Survey Report and catch options for 2015

      Ligas, A.; Doyle, J.; Lordan, C.; Brown, V.; Doran, S.; McArdle, J.; McCausland, I.; McCorriston, P.; Simpson, S.; Schon, J. (Marine Institute and Agri-Food and Bioscience Institute, 2014-10)
      This report provides the main results and findings of the 12th 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 2014 design consisted of a randomised isometric grid of 101 stations at 4.5 nautical mile intervals out over the full known extent the stock. The resulting krigged burrow abundance estimate was 4.6 billion burrows. This was a similar result of that obtained in 2009, and slightly higher than the abundance in 2013. The spatial distribution shows a decline in abundance in the south-eastern area compared to 2013 figure, while a slight increase is apparent in the North and in the middle of the area. Overall densities remain high and abundance remains relatively stable, well above MSY Btrigger. Reducing the number of stations compared to 2011 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 2015 implies a total catch option at Fmsy (=Fmax) of 9,922 tonnes which results in landings of no more than 8,223 tonnes. The only sea-pen species observed in 2014 was Virgularia mirabilis and the frequency of occurrence was lower than the average during the investigated period, but higher than in 2013. Trawl marks were noted at 24% of the UWTV stations.
    • Western Irish Sea Nephrops Grounds (FU15) 2015 UWTV Survey Report and catch options for 2016

      Clements, A.; Doyle, J.; Lordan, C.; Brown, V.; Doran, S.; McArdle, J.; McCausland, I.; McCorriston, P.; Simpson, S.; Schon, J. (Marine Institute and Agri-Food and Bioscience Institute, 2015)
      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.
    • Western Irish Sea Nephrops Grounds (FU15) 2017 UWTV Survey Report and catch options for 2018

      Clements, A.; Doyle, J.; Lordan, C.; Lundy, M.; McCorriston, P.; McArdle, J.; McCausland, I.; Burns, G.; Schön, P.J. (Marine Institute, 2017)
      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.
    • Western Irish Sea Nephrops Grounds (FU15) 2018 UWTV Survey Report and catch options for 2019

      Clements, A.; Butler, R.; Doyle, J.; Ourens, R.; Lordan, C.; McCorriston, P.; Burns, G.; McCausland, I.; Erskine, K.; Lilley, K.; et al. (Marine Institute, 2018)
      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.
    • Western Irish Sea Nephrops Grounds (FU15) 2019 UWTV Survey Report and catch options for 2020

      Lundy, M.; McCorriston, P.; McCausland, I.; Erskine, K.; Lilley, K.; Heaney, G.; McArdle, J.; Buick, A.; Graham, J.; Reeve, C.; et al. (Marine Institute, 2019)
      This report provides the main results and findings of the 17th 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 2019 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 4.4 billion burrows. This was a similar result of that obtained in 2015, but a 10% lower than the abundance in 2018. In contrast to 2017 the spatial distribution of burrows shows a high density band on the central western area of the survey ground. The abundance remains within previously observed ranges and is above MSY Btrigger. 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 2020 implies a total catch option at Fmsy (=Fmax) of 10,377 tonnes estimated to result in landings of no more than 8,546 tonnes. Sea-pens were observed at 21% of stations with high densities observed in the south-west of the ground. Trawl marks were noted at 15% of the UWTV stations.
    • The western spurdog Squalus acanthias L. fishery in 1989 and 1990, with observations on the further development of the gillnet fishery directed on the species

      Fahy, E. (Department of the Marine, 1992)
      Between 1987 and 1990 the western fisheries of spurdog briefly harvested heavy then progressively reduced landings. These were sampled in each year. The peak and post-peak fisheries have been described and this account is of the fishery in 1989 and 1990. Although the catch per effort has declined substantially from the peak fishery, spurdog remains an important target species. The fishery is assessed from 856 individuals captured in 1989 and 688 the following year. The following criteria of sampled fish classified according to method of capture were examined: sex ratio, weight, age and a growth index. Gillnet-caught females are regarded as indicators of the broodstock which shows signs of having made some recovery from its immediate post peak condition. The Carrigaholt gill net fishery, the index fishery which has been monitored for four years, exploits a range of species by gill net, spurdog and gadoids being the principal ones to date, and it has increased its fishing capacity over the period. In 1989 and 1990 effort was directed on hake; some characteristics of these landings are given and compared with gill net caught hake from other parts of the country.
    • The Wexford commercial sea bass Dicentrarchus labrax (L.) fishery

      Fahy, E. (Department of Fisheries and Forestry, 1981)
      The Wexford sea bass fishery is operated during most months of the year with a high season from May to October. The fishery commenced in the 1950s but has shown a decline from the first years in which statistics became available. A proportion of the commercial catch comes from stake and ring nets with a mesh size of 18.4 cm in the round. Both take fish of similar fork length. Bass of 30-43 cm were the majority of those retained and they were mainly immatures. The smallest mature female examined in 1978 was a 6+ of 36.5 cm fork length. The greater part of the commercial catch is taken by line. Some details of the biology of bass in south east Ireland in 1978 are given: the fish fed mainly on shore crabs, sand shrimps and bait fishes. Sex ratios were approximately two females to each male. Growth in the mid 1970s differed little from other decades and it is concluded that bass in Irish waters conform to a single growth curve which is temporarily altered by good or bad growing years.
    • What floats, what sinks and why?

      Marine Institute (Marine Institute, 2013)
      Students will investigate floating and sinking with a range of materials and objects. Students should make and test predictions about objects that will sink or float and group objects based on these criteria. Students will also develop an understanding of how fish swim in the ocean.
    • What is Fisheries Science?

      Marine Institute (Marine Institute, 2006)
      Fisheries science is a branch of marine science that deals with studies on the life history and state of fish stocks. The term ‘life history’ refers to the general biology of a fish stock (e.g. when/where do the fish spawn? How fast do they grow?). The term ‘state of a fish stock’ refers to the number and weight of fish in the stock (i.e. current stock biomass in tonnes). The overall aim of fisheries science is to provide information to managers on the state and life history of the stocks. This information feeds into the decision making process. Fisheries science, economic, social and political considerations all have an impact on the final management decision.
    • What would you do with the Real Map of Ireland?

      Marine Institute (Marine Institute, 2015)
      The phrase “the Real Map of Ireland” is a statement established to highlight that the map of Ireland land area also includes our marine resource. In fact the area of our marine resource is ten times larger than our land area above the sea. This makes Ireland one of the largest maritime States in the European Union. Objective: Establish what an area is and how to measure it. Compare sizes of areas: e.g. the area of the classroom, school property, backyard at home, local park, farms, cities, counties, countries Identify what resources can we use that are on land in the “areas” … what would you find in a park, farm, etc
    • When good neighbours become good friends: observing small scale structures in fish aggregations using multibeam sonar

      Gerlotto, F; Jones, E; Bez, N; Reid, D G (EDP Sciences, 2010)
      Converging results in different scientific fields (behavioural ecology, fisheries biology, acoustic tagging, fisheries acoustics, behavioural modelling) suggest the existence of “micro-groups” inside fish schools. These would comprise a few (5–10) fish maintaining contact during a period long enough to allow individuals to recognise each other. It is hypothesised that they would prefer to share the space with familiar rather than anonymous conspecifics. To evaluate whether acoustic methods could be used to recognise “micro-structures” inside fish schools and help test the “micro-group” hypothesis we analysed acoustic data from anchovy schools off Peru, and gadoids in the North Sea. Data collection used a multibeam sonar (Reson SeaBat 6012). In the Peruvian case study, the sonar was mounted set horizontally on a drifting research vessel and the internal structure of the schools of anchovies was analysed, although individual fish could not be discriminated. In the North Sea case study, the sonar was orientated vertically above a demersal trawl to allow observation of individual fish entering the trawl. Geostatistical analyses were used to evaluate the existence of small spatial structures in anchovy schools. In these schools, “micro-structures” with a scale as small as 0.5 m were observed acoustically. For the gadoids nearest neighbour distance (NDD) measurements were carried out, suggesting that the fish aggregated in small groups (2 to 25 individuals, with an average of 3.7 fish per group) in the trawl catches. The perspectives and limitations of these results are discussed.
    • Where the lake meets the sea: strong reproductive isolation is associated with adaptive divergence between lake resident and anadromous three-spined sticklebacks

      Ravinet, M.; Hynes, R.; Poole, R.; Cross, T.F.; McGinnity, P.; Harrod, C.; Prodöhl, P.A. (PLoS ONE, 2015)
      Contact zones between divergent forms of the same species are often characterised by high levels of phenotypic diversity over small geographic distances. What processes are involved in generating such high phenotypic diversity? One possibility is that introgression and recombination between divergent forms in contact zones results in greater phenotypic and genetic polymorphism. Alternatively, strong reproductive isolation between forms may maintain distinct phenotypes, preventing homogenisation by gene flow. Contact zones between divergent freshwater-resident and anadromous stickleback (Gasterosteus aculeatus L.) forms are numerous and common throughout the species distribution, offering an opportunity to examine these contrasting hypotheses in greater detail. This study reports on an interesting new contact zone located in a tidally influenced lake catchment in western Ireland, characterised by high polymorphism for lateral plate phenotypes. Using neutral and QTL-linked microsatellite markers, we tested whether the high diversity observed in this contact zone arose as a result of introgression or reproductive isolation between divergent forms: we found strong support for the latter hypothesis. Three phenotypic and genetic clusters were identified, consistent with two divergent resident forms and a distinct anadromous completely plated population that migrates in and out of the system. Given the strong neutral differentiation detected between all three morphotypes (mean FST = 0.12), we hypothesised that divergent selection between forms maintains reproductive isolation. We found a correlation between neutral genetic and adaptive genetic differentiation that support this. While strong associations between QTL linked markers and phenotypes were also observed in this wild population, our results support the suggestion that such associations may be more complex in some Atlantic populations compared to those in the Pacific. These findings provide an important foundation for future work investigating the dynamics of gene flow and adaptive divergence in this newly discovered stickleback contact zone.
    • The Whiting Fishery Off Counties Dublin and Louth On the East Coast of Ireland

      Hillis, J P (Department of Agriculture and Fisheries (Fisheries Division), 1968)
      The whiting Merlangius merlangus (L) has for over 30 years been the leading demersal species by weight in the landings of commercial fisheries on the east coast of Ireland. The present study was commenced in the autumn of 1959, using samples of both the commercial fishery and the research vessel Cú Feasa. The present paper describes the commercial catch from port samples supplemented with research vessel material where extra detail is desirable.
    • The Whiting Fishery Off Counties Dublin and Louth On the East Coast of Ireland: Research Vessel Investigations

      Hillis, J P (Department of Agriculture and Fisheries (Fisheries Division), 1971)
      The stock of whiting (Merlangius merlangus L.) off Counties Dublin and Louth forms the basis of a commercial fishery (Hillis, 1968). This paper presents the result of research vessel investigations into the stock from July, 1962 to May, 1967. Hillis (1962, 1963) recorded the results from the early part of the period, which are also incorporated in the present work.
    • Who is John Philip Holland and what boats sink and float?

      Marine Institute (Marine Institute, 2013)
      The aim of the lesson is to introduce students to an Irish marine historical personality called John Phillip Holland, who was responsible for influencing the design of submarines. By designing their own DIY submarine, students will also learn about boats that can sink and float.
    • Whole-tree harvesting and grass seeding as potential mitigation methods for phosphorus export in peatland catchments

      O'Driscoll, Connie; O'Connor, Mark; Asam, Zaki-ul-Zaman; DeEyto, Elvira; Poole, Russell; Rodgers, Michael; Zhan, Xinmin; Nieminen, Mika; Xiao, Liwen (Elsevier, 2014)
      Forest clearfelling is potentially a major environmental problem with respect to the degradation of water quality in receiving water courses due to phosphorus (P) release from soil and clearfelling residue stocks. Recent studies have highlighted the need to investigate the performance and benefits of potential mitigation methods such as whole tree harvesting (WTH) and grass seeding. In this study, fifteen plots (0.014 ha each) were constructed in a standing coniferous forest and P concentrations in plot runoff were monitored for one year prior to clearfelling. Following clearfelling three replicates of five forest harvesting management practices/treatments were applied to the plots: brash with grass seeding (Treatment 1), brash (Treatment 2), brash mat/ tree extraction route (Treatment 3), WTH (Treatment 4) and WTH with grass seeding (Treatment 5). These treatments were designed to comparatively assess the benefits of WTH and grass seeding practices on mitigating P released from forested peatlands following clearfelling and to determine the sources and sinks of P following clearfelling operations. Annual average total reactive phosphorus (TRP) concentrations in the plot runoff were < 20 µg L-1 in all treatments before clearfelling, and increased to 79 µg L-1, 160 µg L-1, 335 µg L-1, 50 µg L-1 and 38 µg L-1 in Treatments 1, 2, 3, 4 and 5, respectively, after clearfelling. These results highlight that WTH and grass seeding can be used efficiently as methods to improve water quality, aiding in the protection of the biota residing in the aquatic systems draining peatland catchments.
    • The Winter Herring Fishery of the North-West of Ireland (1968-69)

      Molloy, J; Kennedy, T D (Department of Agriculture and Fisheries (Fisheries Division), 1969)
      The 1968/69 winter herring fishery off the Donegal, North Mayo and Sligo coasts began in mid October, 1968 and continued until the end of January, 1969. A total of 63,821 crans were landed during the season as compared with 55,193 crans landed during the 1967/68 season. The majority of the landings mere made at the ports of Killybegs, Sligo and Burtonport. A feature of the season was the increased landings made at Sligo by both local and Killybegs boats.
    • Winter measurements of biogeochemical parameters in the Rockall Trough (2009–2012)

      McGrath, T.; Kivimäe, C.; McGovern, E.; Cave, R.R.; Joyce, E. (Copernicus publications, 2013)
      This paper describes the sampling and analysis of biogeochemical parameters collected in the Rockall Trough in January/February of 2009, 2010, 2011 and 2012. Sampling was carried out across two transects, one southern and one northern transect each year. Samples for dissolved inorganic carbon (DIC) and total alkalinity (TA) were taken alongside salinity, dissolved oxygen and dissolved inorganic nutrients (total-oxidised nitrogen, nitrite, phosphate and silicate) to describe the chemical signatures of the various water masses in the region. These were taken at regular intervals through the water column. The 2009 and 2010 data are available on the CDIAC database.
    • Winter Nitrate and Phosphate levels in the Western Irish Sea in 1991

      Gillooly, M; Nixon, E; McMahon, T; O'Sullivan, G; Choiseul, V (Department of the Marine, 1992-02)
      This study of nitrate, phosphate and salinity levels in the western Irish Sea indicates that the distribution of nutrient levels can be explained by taking into account the known physical and hydrological features of the area. There is a clear inverse relationship between nitrate and salinity data with nitrate levels decreasing rapidly moving offshore. The distribution of phosphate levels is more complex and appears to be influenced by multiple point source inputs and inflows from the Celtic Sea.
    • Winter Nutrient Monitoring of the Western Irish Sea – 1990 to 2000

      McGovern, E; Monaghan, E; Bloxham, M; Rowe, A; Duffy, C; Quinn, A; McHugh, B; McMahon, T; Smyth, M; Naughton, M; et al. (Marine Institute, 2002)
      Winter nutrient concentrations in the western Irish Sea have been monitored annually from 1990 to 2000. Surface samples have been taken between Dundalk Bay and Carnsore Point and analysed for total oxidised nitrogen (TOxN), ortho-phosphate (ortho-P), silicate and salinity. More recently monitoring has been extended into the Celtic Sea. Data from this monitoring programme are presented in detail, along with comparisons to existing data sets. The spatial distribution of nutrients and salinity are presented for each year in contour or classed plots (depending on sample coverage for the particular year). Salinity values were representative of those expected in the Irish Sea and TOxN, ortho-P and silicate values were in general agreement with previous studies. A short summary of studies on nutrient levels in estuaries on the western Irish Sea is presented. In addition, riverine input data supplied by the Environmental Protection Agency (EPA) is used to evaluate the relative magnitude of nutrient inputs from riverine and oceanic sources. Nutrient concentrations are considered using an ecological quality objectives (EcoQOs) approach, proposed as part of the Oslo Paris Convention’s (OSPAR) ‘Common Procedure for Identification of the Eutrophication Status of the Maritime Area’, in partial consideration of the trophic status of the western Irish Sea. Although there is evidence for nutrient enrichment in some estuarine waters and possibly to a lesser extent in some coastal waters, there is little evidence for generally elevated nutrient levels in coastal and offshore waters in the western Irish Sea. Salinity regression curves were calculated for TOxN and ortho-P values in order to generate salinity-normalised concentrations for trend determinations. Regression and trend analysis were carried out on the sample area as a whole and also on regions defining the north, mid, and south western Irish Sea. Trend analysis has been performed, based on nutrient-salinity regressions, using Trend-Y-Tector. A decrease in TOxN over the study period (ranging from 4 to13%) is observed in all regions analysed with the exception of the south west Irish Sea, where a 5% increase was indicated. Analysis of trends in ortho-P concentration showing decreasing trends ranging from 20 to 33%. On visual examination, trends in TOxN are not as intuitively apparent as trends in ortho-P concentrations, therefore it may not be prudent to draw conclusions from them at this stage. Trend analysis of riverine inputs shows an increase in TOxN by 17% and no apparent trend in ortho-P levels. These trends are not consistent with trends observed in the Irish Sea. On the basis of this assessment, it is recommended that this monitoring be continued. The design of future nutrient monitoring surveys is considered, with a view to improving the efficacy of the monitoring regime.