Now showing items 21-40 of 176

    • Dunmore East Herring Investigations, 1965/66

      Molloy, J. (Department of Lands, 1966)
    • Herring Investigations at Dunmore East - 1962/63

      Bracken, J. J. (Department of Lands, 1963)
    • The Dunmore East Herring Fishery, 1958-59

      Bracken, J. J. (Department of Lands, 1959)
    • Racial analyses of Dunmore East Herring stocks by means of the Otoliths

      Foster, M. (Fisheries Division, Department of Lands., 1963)
      Einarsson (1951) has shown that it is possible to separate in a mixed fishery the winter/spring spawned fish from summer/autumn spawned fish on the basis of the appearance of the nuclei of the otoliths. In general, the winter/spring spawned fish have small hyaline and opaque nuclei, whereas the summer/autumn spawned fish have large hyaline nuclei. Otoliths from herrings taken at Dunmore East in the period 1960 to 1964 were examined and classified using Einarsson's method.
    • The Herring Fisheries off the North coast of Donegal

      Farran, G. (Department of Agriculture, 1937)
      The herring fishery which takes place every spring and early summer off the North Coast of Donegal is one of the most regular and uniform on the coast of Ireland, and, as it has been under close observation from a scientific point of view since 1921, a short account of it will serve to illustrate the aims of modern methods of research and the extent to which these methods can lead to results of practical value.
    • Herring larval surveys in the Celtic Sea in 1981/82

      Barnwall, E.; Cullen, A.; Grainger, R. J. (International Council for the Exploration of the Sea, 1982)
      The distributions of herring larvae sampled on ten cruises off the south coast of Ireland during the 1981/82 spawning season are described. A new larval abundance index, which is based on the abundances of <10mm larvae prior to 15 December and on <11mm larvae afterwards,has been calculated for the last four seasons. This index shows an increase each year since 1978/79 indicating that the spawning stock biomass has also increased.
    • Reports from the FSS mini-symposia 2004-2005

      Codling, E.; Kelly, C.; (eds) (Marine Institute, 2006)
      The mini symposia documented in this publication were meetings organised in October 2004 and August 2005 by the 'Modelling and Simulation' team in Fisheries Science Services (FSS) of the Marine Institute, Ireland. Both symposia took place at the Harbour Hotel in Galway, Ireland. Each meeting consisted of a number of presentations (given as talks or posters) followed by a round-table informal discussion session. The two meetings were attended by participants from FSS and the Marine Institute, BIM (Bord Iascaigh Mara - Irish Sea Fisheries Board), FRS (Fisheries Research Services) Aberdeen, and universities in both Ireland and UK. The Appendix contains a full list of the participants at each meeting, while contact details for those who gave presentations are given at the start of each summary paper.
    • Irish Sea Young Herring Survey

      Molloy, J. (An Roinn Iascaigh agus Foraoiseachta, 1979)
      Corrected proof
    • Fecundity studies on herring from the north west of Ireland

      McArdle, E. (International Council for the Exploration of the Sea, 1982)
      For some time past studies have been performed on herring fecundities by various scientists. Farren (1938) was the first to suggest that stocks could be separated by studying the different fecundity/length relationship of winter and autumn spawing populations from the Irish coast. Burd and Howlett (1974) calculated a fecundity index by length cubed and as a result clearly separated the spawning populations of Banks and Downs herring in the North Sea. Molloy (1979) regressed fecundity on length cubed for Celtic sea samples and was able to distinguish between the autumn spawning component and the winter spawning component in the Celtic Sea. This paper describes fecundity studies carried out on autumn spawning herring from the newly established management unit (V1a Lower and V11b) off the North west of Ireland. The results are compared with fecundity data from other Irish stocks and with the results obtained by Farran on the same stock over 40 years ago. It may be possible to use these results to calculate the spawning potential of the herring and those spawning off the Scottish coast. The spawning grounds from which these herring were taken are situated a few miles off the North West coast.
    • Mean weights at age in Celtic Sea Herrings

      Molloy, J. (Marine Institute, 2000)
      Stock recruitment analysis for Celtic sea herring suggest that exploitation rates of F >0.4 carry a high probability of long term SSB decline. Fmed, which would carry a much lower risk of reducing the SSB, has been suggested as a candidate for Fpa and most recent analyses give this value at 0.29. However based on last years assessment only 4 of the 41 estimated fishing mortalaties were equal or less than 0.3 while 26 were higher or equal to 0.4 with the series average being F=0.50. This would indicate that F>0.4 does not seem carry a high probability of stock collapse. Thus there is an apparent discrepancy between the analyses and experience.
    • Report on the State of the Herring Fisheries North-West of Ireland and West of Scotland

      Molloy, J. (International Council for the Exploration of the Sea, 1970)
    • The Assessment of Irish Pelagic Species

      Molloy, J.; Mullins, E. (Marine Institute, 2001)
      The exploitation of pelagic species, particularly of herring and mackerel has for a long time been one of the most important components of the Irish fishing industry. Fisheries for both species have been responsible for the development of the very successful Irish pelagic fleet and also for the development of a very large processing industry in the Donegal area. The responsibility of assessing the stocks and providing management advice to the main Irish managing authority, The Department of the Marine and Natural Resources, lies with the Marine Fisheries Services Division (MFSD) of the Marine Institute. Both mackerel and herring have been continuously assessed since the 1960’s as a result of programmes carried out under the auspices of the International Council for the Exploration of the Sea (ICES) the international body that co-ordinates research and provides management advice to the EU. However, since the 1980’s both mackerel and herring stocks have been subjected to decreased total allowable catches (TACs) and decreased national quota and tighter management measures as a result of decreases in the stock sizes. This situation has forced the pelagic fleet, particularly that in the North west of Ireland to develop fisheries for alternative species so that it is not totally dependent on mackerel and herring. New fisheries have therefore developed for other pelagic species in recent years. Three species which are now exploited regularly are horse mackerel, (trachurus trachurus), also known as scad .or craig herring; blue whiting (Micromesistius poutassou) and Norwegian spring spawning herring (clupea harengus) also known as atlanto-scandian herring. When the fisheries for these species first developed there were no restrictions on catches for horse mackerel and blue whiting while catches on the Norwegian spring spawning herring were subject to an international agreement under which the EU was allowed a quota. None of these three species had previously been assessed by any Irish research project and the amount of scientific information was extremely limited. The international assessments carried out by ICES were based on poor data and had no input from Ireland. Ireland had for a number of years been taking significant catches of some species. The Processing Industry in Donegal were concerned that the lack of adequate biological sampling programmes could lead to inappropriate and inaccurate advice for the management of the stocks. This, it was felt, could have serious effects on the industry and would also demonstrate that Ireland had an irresponsible attitude to the development of these fisheries which was inconsistent with the Precautionary Approach to Fisheries Management. Therefore the Donegal Fish Merchants Association decided to co-operate with the Marine Institute to fund an initial biological sampling programmes on horse mackerel, blue whiting and Norwegian spring spawning herring and to make this data available to the relevant ICES Working Group. The objective of the sampling programme was to collect essential biological data necessary to expand the existing international programmes. In addition it was decided to provide an increased scientific input to existing MFSD assessment programmes such as the mackerel and horse mackerel tagging programmes, the international mackerel and horse mackerel egg surveys and the international blue whiting acoustic surveys. All the collected data has been submitted to the relevant ICES Assessment Working Groups from 1999 to 2001.
    • Surface Temperature Observations at Coninbeg Lightship on the South Coast of Ireland

      Farran, G. (Conseil International pour l'Exploration de la Mer (ICES), 1939)
    • The fat/water relationship in the mackerel Scomber scombrus L., pilchard, Sardina pilchardus (Walbaum) and sprat, Sprattus sprattus L., and the seasonal variation in fat content by size and maturity.

      Wallace, P. D.; Hulme, T. J. (Ministry of agriculture, fisheries and food Directorate of fisheries research., 1977)
      Mackerel, pilchard and sprat have the ability to store fat in their body tissues. During the spring and summer, when their main source of food, zooplankton, is abundant, fat reserves are accumulated. These reserves are utilized in the autumn and winter when zooplankton are scarce. Consequently, wide variations in fat content occur throughout a single year of life of these species. This report describes the relationship that exists between fat and water in these species and describes how the fat content varies with size, maturity stage and season.
    • Herring larval surveys in the Celtic Sea and division VIIj in 1982/83

      Grainger, R. J.; Barnwall, E.; Cullen, A. (International Council for the Exploration of the Sea, 1983)
      Surveys for herring larvae in the Celtic Sea were conducted between October 1982 ~ and February 1983 for the fifth successive season. To take account of the amalgamation of the Celtic Sea and Div VIIJ herring for assessment purposes and to ascertain if many larval drift into the Irish Sea, the survey grid of previous years was modified for the 1982/83 season. However, because of the nature of the larvae distribution it appears reasonable to compare the larvae index for 1982/83 with those of the previous seasons. The increase in indices since 1978/79 has continued up to 1982/83 indicating a steady, but slow, recovery of the spawning stock. Very few larvae appear to drift into the Irish Sea.
    • Biosensors for the monitoring of harmful algal blooms

      McPartlin, D. A.; Loftus, J. H.; Crawley, A. S.; Silke, J.; Murphy, C. S.; O’Kennedy, R. J. (Elsevier, 2017)
      Harmful algal blooms (HABs) are a major global concern due to their propensity to cause environmental damage, healthcare issues and economic losses. In particular, the presence of toxic phytoplankton is a cause for concern. Current HAB monitoring programs often involve laborious laboratory-based analysis at a high cost and with long turnaround times. The latter also hampers the potential to develop accurate and reliable models that can predict HAB occurrence. However, a promising solution for this issue may be in the form of remotely deployed biosensors, which can rapidly and continuously measure algal and toxin levels at the point-of-need (PON), at a low cost. This review summarises the issues HABs present, how they are difficult to monitor and recently developed biosensors that may improve HAB-monitoring challenges.
    • Gbm.auto: A software tool to simplify spatial modelling and Marine Protected Area planning

      Dedman, Simon; Officer, Rick; Clarke, Maurice; Reid, David G.; Brophy, Deirdre (Public Library of Science (PLoS), 2017)
      Boosted Regression Trees. Excellent for data-poor spatial management but hard to use Marine resource managers and scientists often advocate spatial approaches to manage data-poor species. Existing spatial prediction and management techniques are either insufficiently robust, struggle with sparse input data, or make suboptimal use of multiple explanatory variables. Boosted Regression Trees feature excellent performance and are well suited to modelling the distribution of data-limited species, but are extremely complicated and time-consuming to learn and use, hindering access for a wide potential user base and therefore limiting uptake and usage. BRTs automated and simplified for accessible general use with rich feature set We have built a software suite in R which integrates pre-existing functions with new tailor-made functions to automate the processing and predictive mapping of species abundance data: by automating and greatly simplifying Boosted Regression Tree spatial modelling, the gbm.auto R package suite makes this powerful statistical modelling technique more accessible to potential users in the ecological and modelling communities. The package and its documentation allow the user to generate maps of predicted abundance, visualise the representativeness of those abundance maps and to plot the relative influence of explanatory variables and their relationship to the response variables. Databases of the processed model objects and a report explaining all the steps taken within the model are also generated. The package includes a previously unavailable Decision Support Tool which combines estimated escapement biomass (the percentage of an exploited population which must be retained each year to conserve it) with the predicted abundance maps to generate maps showing the location and size of habitat that should be protected to conserve the target stocks (candidate MPAs), based on stakeholder priorities, such as the minimisation of fishing effort displacement. Gbm.auto for management in various settings By bridging the gap between advanced statistical methods for species distribution modelling and conservation science, management and policy, these tools can allow improved spatial abundance predictions, and therefore better management, decision-making, and conservation. Although this package was built to support spatial management of a data-limited marine elasmobranch fishery, it should be equally applicable to spatial abundance modelling, area protection, and stakeholder engagement in various scenarios.
    • Evaluation of Non-destructive Molecular Diagnostics for the Detection of Neoparamoeba perurans

      Downes, Jamie K.; Rigby, Megan L.; Taylor, Richard S.; Maynard, Ben T.; MacCarthy, Eugene; O'Connor, Ian; Marcos-Lopez, Mar; Rodger, Hamish D.; Collins, Evelyn; Ruane, Neil M.; et al. (Frontiers Media SA, 2017)
      Amoebic gill disease (AGD) caused by Neoparamoeba perurans, has emerged in Europe as a significant problem for the Atlantic salmon farming industry. Gross gill score is the most widely used and practical method for determining AGD severity on farms and informing management decisions on disease mitigation strategies. As molecular diagnosis of AGD remains a high priority for much of the international salmon farming industry, there is a need to evaluate the suitability of currently available molecular assays in conjunction with the most appropriate non-destructive sampling methodology. The aims of this study were to assess a non-destructive sampling methodology (gill swabs) and to compare a range of currently available real-time polymerase chain-reaction (PCR) assays for the detection of N. perurans. Furthermore a comparison of the non-destructive molecular diagnostics with traditional screening methods of gill scoring and histopathology was also undertaken. The study found that all molecular protocols assessed performed well in cases of clinical AGD with high gill scores. A TaqMan based assay (protocol 1) was the optimal assay based on a range of parameters including % positive samples from a field trial performed on fish with gill scores ranging from 0 to 5. A higher proportion of gill swab samples tested positive by all protocols than gill filament biopsies and there was a strong correlation between gill swabs tested by protocol 1 and gross gill score and histology scores. Screening for N. perurans using protocol 1 in conjunction with non-destructive gill swab samples was shown to give the best results.
    • The GOSHIP A02 Survey 2017 Taking the Pulse and Temperature of the North Atlantic Ocean.

      McGovern, E.; Cusack, C.; Wallace, D.; Croot, P. (The Journal of Ocean Technology, 2017)
    • Fisher's preferences and trade-offs between management options

      Fitzpatrick, Mike; Maravelias, Christos D; Eigaard, Ole Ritzau; Hynes, Stephen; Reid, David (Wiley, 2017)
      Failure to understand the potential responses of fishers to management measures creates a significant risk of revisiting the familiar scenario of perverse and unintended consequences of those measures. This paper reports on a choice experiment survey to evaluate fisher's preferences for various management measures proposed under the EU Common Fisheries Policy (CFP) reform process, but the conclusions have wider relevance as similar measures are used by comparable fleets in fisheries globally. The survey was conducted with fishers involved in mixed pelagic and demersal fisheries in Ireland, pelagic fisheries in Denmark and demersal fisheries in Greece. Fisheries management policies were characterized by five attributes designed both to cover the principal CFP reform proposals and to integrate ecological, social, economic and institutional factors affecting fisher's decisions. The study uses a random utility modelling framework to reveal the preferences of the fishers across the alternative policy attributes. Results show that while there are generally preferences both for healthy stocks and for maintaining the importance of fishing to the local community, strong interfishery preference differences exist. These differences are most notable in relation to a discard ban and to the use of individual transferable fishing rights, favoured in Denmark, but not in Ireland for instance. The strength of these interfishery differences supports the assertion that there are no panaceas in fisheries management and that solutions should be tailored within the context of specific fisheries. Not doing so could create a significant risk of inappropriately managed fisheries that may lead to unsustainable outcomes.