• The rise and fall of autumn-spawning herring (Clupea harengus L.) in the Celtic Sea between 1959 and 2009: Temporal trends in spawning component diversity

      Harma, Clémentine; Brophy, Deirdre; Minto, Cóilín; Clarke, Maurice (Elsevier, 2012)
      Sub-stock components of highly exploited migratory fish species exhibit different life-history traits and can thus show variation in productivity and vulnerability to fishing pressure. Celtic Sea herring comprises both autumn and winter-spawners that are targeted by the same fishery. The current study investigated if the relative abundances of the two components in the Celtic Sea have changed over time, and whether this could explain marked long-term trends in size-at-age. The study utilized a remarkably long time-series of biological data from commercial landings (1959–2009). Based on the maturity state of the gonads at the time of sampling, herring were assigned to seasonal spawning components. Significant temporal variations in spawning component dominance were found, even after potential bias due to fishing history patterns were accounted for. Strong directional changes in the relative proportion of spawning components consisted of autumn spawning herring proportions reaching a peak in the 1990s before drastically declining. Winter spawning herring had lower mean lengths- and weights-at-age than autumn spawning herring. The recent decline in the autumn spawning component did not fully explain the observed decline in size-at-age in the catches, with both spawning components showing similar decreases in mean-size parameters over time. Response of spawning components to environmental changes may have consequences for the fishery, especially in light of the observed influence of temperature on spawning components. Life-cycle diversity in herring stocks may confer resilience to potential climate-induced changes. Therefore, it is suggested that the relative proportions of spawning components should be monitored and diversity should be preserved as part of the management of fisheries for this species, which is characterized by stock complexity.
    • Risk factors associated with increased mortality of farmed Pacific oysters in Ireland during 2011

      Clegg, T.A.; Morrissey, T.; Geoghegan, F.; Martin, S.W.; Lyons, K.; Ashe, S.; More, S.J. (Elsevier, 2014)
      The Pacific oyster, Crassostrea gigas, plays a significant role in the aquaculture industry in Ireland. Episodes of increased mortality in C. gigas have been described in many countries, and in Ireland since 2008. The cause of mortality events in C. gigas spat and larvae is suspected to be multifactorial, with ostreid herpesvirus 1 (OsHV-1, in particular OsHV-1 μvar) considered a necessary, but not sufficient, cause. The objectives of the current study were to describe mortality events that occurred in C. gigas in Ireland during the summer of 2011 and to identify any associated environmental, husbandry and oyster endogenous factors. A prospective cohort study was conducted during 2010–2012, involving 80 study batches, located at 24 sites within 17 bays. All 17 bays had previously tested positive for OsHV-1 μvar. All study farmers were initially surveyed to gather relevant data on each study batch, which was then tracked from placement in the bay to first grading. The outcome of interest was cumulative batch-level mortality (%). Environmental data at high and low mortality sites were compared, and a risk factor analysis, using a multiple linear regression mixed effects model, was conducted. Cumulative batch mortality ranged from 2% to 100% (median = 16%, interquartile range: 10–34%). The final multivariable risk factor model indicated that batches imported from French hatcheries had significantly lower mortalities than non-French hatcheries; sites which tested negative for OsHV-1 μvar during the study had significantly lower mortalities than sites which tested positive and mortalities increased with temperature until a peak was reached. There were several differences between the seed stocks from French and non-French hatcheries, including prior OsHV-1 μvar exposure and ploidy. A range of risk factors relating to farm management were also considered, but were not found significant. The relative importance of prior OsHV-1 μvar infection and ploidy will become clearer with ongoing selection towards OsHV-1 μvar resistant oysters. Work is currently underway in Ireland to investigate these factors further, by tracking seed from various hatchery sources which were put to sea in 2012 under similar husbandry and environmental conditions.
    • The rocky shore biology of Bantry Bay: a re-survey

      Baker, J M; Hiscock, S; Hiscock, K; Levell, D; Bishop, G; Precious, M; Collinson, R; Kingsbury, R; O'Sullivan, A J (Department of Fisheries and Forestry, 1981)
      A survey of the distribution and abundance of intertidal rocky shore animals and plants of Bantry Bay was carried out in 1970 and 1971 by G. B. Crapp and published in 1973. A re-survey was carried out during 1975 and early 1976 and a number of changes were noted. In an attempt to explain these the possible effects of changing weather conditions, the occurrence of oil spillages and the use of dispersants were examined. In most cases, the changes were not obviously attributable to visible oil pollution and seem more likely to result from a variety of natural factors. The re-survey highlighted a number of problems associated with this type of biological monitoring. The problems are discussed and some alternative approaches suggested.
    • Roe Yield of Irish Herring

      Barnwall, E (Department of the Marine, 1989-08)
      This Leaflet provides the detailed information on the spawning condition of herring required to develop the trade in the roe fishery. It is based on the laboratory examination of two thousand individual specimens supplied by the Industry.
    • The role of Azadinium spinosum (Dinophyceae) in the production of azaspiracid shellfish poisoning in mussels

      Salas, Rafael; Tillmann, Urban; John, Uwe; Kilcoyne, Jane; Burson, Amanda; Cantwell, Caoimhe; Hess, Philipp; Jauffrais, Thierry; Silke, Joe (Elsevier, 2011)
      Azaspiracids (AZAs) are a group of lipophilic polyether compounds first detected in Ireland which have been implicated in shellfish poisoning incidents around Europe. These toxins regularly effect shellfish mariculture operations including protracted closures of shellfish harvesting areas for human consumption. The armoured dinoflagellate Azadinium spinosum Elbrächter et Tillmann gen. et sp. nov. (Dinophyceae) has been described as the de novo azaspiracid toxin producer; nonetheless the link between this organism and AZA toxin accumulation in shellfish has not yet been established. In August 2009, shellfish samples of blue mussel (Mytilus edulis) from the Southwest of Ireland were analysed using liquid chromatography–tandem-mass spectrometry (LC–MS/MS) and were found to be above the regulatory limit (0.16 μg g−1 AZA-equiv.) for AZAs. Water samples from this area were collected and one algal isolate was identified as A. spinosum and was shown to produce azaspiracid toxins. This is the first strain of A. spinosum isolated from Irish waters. The Irish A. spinosum is identical with the other two available A. spinosum strains from Scotland (3D9) and from Denmark (UTHE2) in its sequence of the D1–D2 regions of the LSU rDNA. A 24 h feeding trial of blue mussels (M. edulis) using an algal suspension of the Irish A. spinosum culture at different cell densities demonstrated that A. spinosum is filtered, consumed and digested directly by mussels. Also, LC–MS/MS analysis had shown that AZAs were accumulating in the shellfish hepatopancreas. The toxins AZA1 and -2 were detected in the shellfish together with the AZA analogues AZA3, AZA6, AZA17 and -19 suggesting that AZA1 and -2 are metabolised in the shellfish within the first 24 h after ingestion of the algae. The levels of AZA17 detected in the shellfish hepatopancreas (HP) were equivalent to the levels of AZA1 but in the remainder tissues the levels of AZA17 were four to five times higher than that of AZA1, only small quantities of AZA3 and -19 were present with negligible amounts of AZA6 detected after the 24 h period. This could have implications in the future monitoring of these toxins given that at present according to EU legislation only AZA1–AZA3 is regulated for. This is the first report of blue mussels’ (M. edulis) feeding on the azaspiracid producing algae A. spinosum from Irish waters.
    • Roseate Terns - The Natural Connection

      Newton, S F; Crowe, O (Marine Institute, 2000-04)
      Prerequisites for successful seabird reproduction are secure nesting sites, reliable food supply and reasonable weather. In late 1996, Maritime Ireland / Wales INTERREG Programme agreed to fund a three year programme focussed on research and conservation action at Roseate Tern Sterna dougallii breeding colonies in the Irish Sea under Measure 1.3: “Protection of the Marine and Coastal Environment and Marine Emergency Planning”. All the colonies in the area were included: Rockabill, Lady’s Island Lake, the Dalkey Islands (all in Ireland) and Ynys Feurig, Skerries, Cemlyn Bay and Inland Sea (all on Anglesey in Wales). This report reviews progress at these colonies and gives more detail on the research carried out at the core breeding population at Rockabill and to a lesser extent at Lady's Island Lake.
    • Salmon and Trout: Natural and Artificial Propagation as Factors in the Maintenance of Stocks

      Anon. (Department of Agriculture, 1939)
      The object of fishery regulations whether statutory or departmental is, in the ultimate, conservation. That is to say, it is sought by the imposition of certain restrictions to ensure such a run of fish for breeding purposes as will increase or at least maintain the stocks. Many citizens profess dissatisfaction with the existing stocks of fish in our rivers and lakes and persistently urge that they should be enhanced by all practical means. Generally the method which suggests itself to such persons is the setting up of a hatchery, to be operated either by stripping fish captured locally or by procuring supplies of ova (eggs) from outside sources. There seems to be a rather widespread belief that such a procedure even on a modest scale is bound to produce immediately beneficial results for the waters concerned. In other words, the operation of a hatchery is expected to offset completely the evils of over-fishing, as well as the damage resulting from illegal activities (whether within or outside the fishing season) and the reduction in stocks caused by predatory birds, fish and mammals added to the pollution of waters by the entrance of deleterious matter. Such a belief is, however, fallacious as it cannot be accepted in any degree without serious reservation.
    • Salmon Mortalities at Inver Bay and McSwyne’s Bay Finfish farms, County Donegal, Ireland, during 2003

      Cronin, M.; Cusack, C.; Geoghegan, F.; Jackson, D.; McGovern, E.; McMahon, T.; O'Beirn, F.X.; Ó Cinneide, M.; Silke, J. (Marine Institute, 2004)
      This report details the investigations into a major mortality of farmed salmon at Inver Bay and McSwyne’s Bay, Co. Donegal in July 2003. Previous reports were provided on 29th July 2003 and on 11th August 2003. The information is based upon analysis and research by MI scientists, a review of environmental data, survey reports by external consultants, inputs from veterinary practitioners who visited the site, reports from DCMNR staff in Killybegs, and site visits made by DCMNR / MI inspectors. Following a review meeting of the principal investigators on the 9th October, 2003, MI proceeded to carry out further scientific investigations. DCMNR also commissioned Kirk McClure Morton Consulting Engineers (KMM) to carry out a parallel investigation of the mortalities at Inver Bay and McSwynes Bay salmon farms. MI provided support as required to the KMM study, the report for which was furnished to DCMNR and MI on 11 February 2004. (KMM, 2004) MI wishes to acknowledge the high level of co-operation and assistance that it received from the owners and staff of Creevin Fish Farm Ltd, Eany Fish Products Ltd and Ocean Farms Ltd. It also wishes to acknowledge the assistance of veterinary practitioners, DCMNR staff and others in the course of this investigation.
    • Salmon movements in Galway Bay in 1978 and 1979

      McCarthy, D T (Department of Agriculture and Fisheries (Fisheries Division), 1980)
      In 1978 tagging investigations commenced into the origin of salmon caught in drift nets in Galway Bay. This fishery began in 1969 with a catch of 355 fish and, by 1975 had increased dramatically to 33,607. However the catch declined to less than half the maximum and in 1979 was down to 15,171. There are 76 drift net licences in the Bay which incorporates two fishery districts, Galway and Connemara. The vessels used vary from 5 metre currachs to 20 metre trawlers. The majority of the boats are half deckers of between 9 and 11 metres. The fishery starts in mid-May but the bulk of the catch is taken in June and July. The main component of the catch is grilse with an average weight of 3 kg. During the period fishing is carried on over 24 hours daily except for the weekly close season time. The fishery extends from west of a straight line from Spiddal Harbour to Blackhead, Co Clare in the east , and from Slyne Head to Hag's Head, Co. Clare in the west and also incorporates the Aran Islands. Drift nets are shot at right angles to the coastline in roughly a north-south direction, all vessels staying quite close to land, the furthest distance out being 2km. The maximum length of net permitted in the area is 730 metres or 800 yards. The majority of boats fished nets of this length; however some of the smaller craft used nets as short as 300 metres. All nets are 30 meshes deep. Throughout the programme fish were tagged using Lea's hydrostatic tags described by Went (1951). As in previous tagging programmes, recovery baths were used to ensure that only the fittest fish were released after tagging.
    • Salmon Tagging in the West of Ireland 1986 to 1988

      McDermott, T (Department of the Marine, 1990-07)
      The analysis of more than twenty-six thousand micro-tag recoveries has led to important discoveries for the management of Irish salmon stocks. This Leaflet gives details of the tagging over half a million young salmon and of the results of recovering 4,000 tags from 1986 to 1988. The most important conclusions are: Careful control of place and time of release of hatchery-reared smolts has a dramatic effect on their survival. In the Corrib system, transportation of smolts from Cong to Galway resulted in a substantial improvement in yield, with a tenfold increase on one occasion. This means that up to ten times as many salmon can be produced at no increase in the cost of rearing them. The returning adult salmon produced from smolts which were released at Galway tended to stay for a long time below the Galway weir and therefore made a major contribution to the rod fishery. Marine survival fluctuated yearly for hatchery and wild smolts released. For hatchery smolts those released later survived best. In contrast wild smolts which migrated in May had a lower survival than those which left in April. Marked differences in homing accuracy, timing and speed of migration were noted between wild and hatchery smolts within the Corrib system. Drift net fisheries depend mainly on the salmon which originate from rivers nearby. There is a distinct division between the catches north and south of Galway Bay: those to the south come mostly from the rivers Shannon and Corrib, those to the north from Connemara rivers. The drift net fishery continues to rely heavily on a self sustaining population of wild salmon despite improved hatchery performance and increasing catch of cage farm escapees. Hatchery smolts transferred to different rivers learned to recognise the new river within a remarkably short time. Two weeks were sufficient to achieve a degree of homing success approaching that of fish returning to their own rivers. This discovery is of major significance in the development of salmon ranching.
    • Salmonid carrying capacity of streams in the Connemara region, a resource appraisal

      Fahy, E.; Nixon, J. J.; Murphy, M.; Dempster, S. (Department of Fisheries and Forestry, 1984)
      Standing crops of salmonids in the Connemara region are described from 80 site fishings made between March 1982 and May of the following year. Trout were more widely distributed than salmon, being able to exploit isolated water bodies as resident populations. High salmonid densities were associated with salmon which during the dry summer months were caught in large numbers on riffles. The smallest streams in the region supported only trout presumably because there was insufficient depth of water to permit the entry of salmon. Trout biomass and density within the region were distributed within the lower range reported from a number of countries in which brown trout are endemic and naturalised. Low saimonid densities at 16% of sites were in some cases associated with the rooting of angiosperms, and possibly oligotrophic conditions resulting from geological structure. Length at age of salmon and trout was similar to measurements recorded in Britain. The streams were important only for the first year of the trout life cycle. Because trout move downstream as they grow, occupying lakes during the later parr phase, and the entire streambed area in Connemara is one fortieth of the lake area, space is unlikely to be a critical constraint on the later parr phase. The condition of the stream substratum may be a factor in the production of sea trout; where loose gravels do not occur in shallow nursery streams, the catchments tend towards producing "brown" or "resident" rather than sea trout.
    • Salmonid Stocks of the Cloonee Catchment in Co. Kerry

      Fahy, E (Department of Agriculture and Fisheries (Fisheries Division), 1978)
      An assessment of the status of the salmonids in the Cloonee system in Co Kerry is the objective of this work. The rivers and lakes make up a small coastal catchment, typical in many respects of those along the Western seaboard. The composition of its fish stocks is described; the strength of the salmonid species is evaluated and the factors which possibly affect their survival are listed. These estimates derive from observations made at a particular time but other details of the Cloonee system, its water chemistry, invertebrate community and nursery' areas of more lasting interest are also presented.
    • Sampling surveys for deep-water demersal fish in 1993

      Connolly, P L; Kelly, C J (Department of the Marine, 1994-09)
      Potential for new developments in deep water fishing have been identified by two sampling surveys carried out in April and September 1993, in the deep waters off the west coast of Ireland and Scotland. The primary objective of the two surveys was to secure samples of a variety of potentially commercial deep water fish species in order to examine aspects of their age, growth, reproduction and diet. These data will be essential in formulating management plans for the expanding deep water fisheries in the area. The surveys were conducted on a chartered fishing vessel using a commercial otter trawl, fitted with a small mesh cod-end liner. Fishing activity concentrated on the depth range 400m-1200m and a total of 81 trawling operations were carried out, of which 75 produced fish catches with limited gear damage. Fifteen species of cartilaginous and 50 species of teleost fish were recorded from the catches. These include the roundnose grenadier Coryphaenoides rupestris, black scabbard Aphanopus carbo, greater forkbeard Phycis blennoides, blue-mouth rockfish Helicolenus dactylopterus and Baird's smooth-head Alepocephalus bairdii. Length, weight, sex, maturity and catch data together with samples of otoliths, gonads and stomachs were secured. In general terms, the fishing ground off the north west of Ireland and west of Scotland caused little problems with gear damage and yielded good catches of deep water species. The two surveys have shown the areas have potential for commercial deep water fishing but the development of this fishery in the area will be contingent on the establishment of suitable markets. This initial report documents the surveys and presents some preliminary results. The data gathered from these surveys are currently under analysis at the FRC and the results will be published in the scientific literature.
    • Save the sea 3D poster

      Marine Institute (Marine Institute, 2013)
      The aim of the lesson plan is for students to develop drawings, paint and colour, as well as use fabric, fibre (including shells, seaweeds, flotsam and jetsam from the seashore) to create a 3D - poster showing how people can protect the marine environment and save the sea. This lesson plan should be delivered after the students have learned about the environment and the sea.
    • Scale Growth Analysis of Atlantic salmon (Salmo salar Linnaeus) Unlocking Environmental Histories

      Thomas, K. (Galway-Mayo Institute of Technology, 2018)
      Atlantic salmon (Salmo salar L.) populations have declined rapidly in recent years across all geographical ranges with populations becoming extinct within certain areas. Direct observation of the salmon’s life is difficult and costly; therefore, scales remain the most widely used material to indirectly assess and monitor the recent changes in growth. Growth marks (circuli) in scales of Atlantic salmon are used to estimate age and to reconstruct growth histories. This thesis investigated mechanisms of circuli formation and the causes of variation in scale growth measurements. Comparison of scales from multiple body locations (Chapter 2) showed that growth, size and shape measurements varied significantly between body locations. Scale measurements taken from the sampling location recommended by ICES were sufficiently correlated with measurements from two adjacent locations in the posterior body region to facilitate conversion; calibration equations are presented for this purpose. Scale measurements from the anterior body region were highly variable and their use is not recommended. Scale size measurements from the recommended sampling location and from the two adjacent locations in the posterior body region were sufficiently correlated with fish fork length. Differences in scale size could potentially be used to determine the body location from which a scale was most likely sampled if this information has not been recorded (e.g. in archived scale collections); regression equations are presented for this purpose. Analysis of scales from experimentally reared Atlantic salmon post-smolts (Chapters 3 and 4), showed that scale growth and circuli number was proportional to fish growth under a range of different water temperatures and feeding conditions, justifying the use of these measurements as a proxy for growth. The rate of circuli deposition varied between temperature and feeding treatments and circuli number was proportional to cumulative degree day. Narrow inter-circuli spacings were observed during periods of slow growth at low temperatures and during periods of fast growth at high temperatures; therefore, circuli spacing should not be used to infer growth rates. In Chapter 5, scales from Atlantic salmon collected from three Irish rivers (Burrishoole, Moy and the Shannon) between 1954 and 2008 were analysed to determine if marine growth has changed during that period and to establish if trends are consistent across populations. Scale growth measurements and their temporal trends varied between populations. Post-smolt scale growth and circuli number were negatively correlated with SST (Burrishoole and Moy), NAO (Burrishoole) and AMO Burrishoole and Shannon). The results indicate that trends observed in one national index river may not be representative of change across all populations. The new knowledge generated in this thesis supports more accurate interpretation of scale growth measurements, furthers our understanding of this important species and ultimately benefits the future management of this species.
    • Science - Creature Features and Chemosynthesis

      Marine Institute; Tulca (Marine Institute, 2018)
      The Creature Features and Chemosynthesis Presentation is a simple PowerPoint presentation about life in the hydrothermal vent ecosystem. The presentation introduces students to some of the unique creatures that live there and how the vents provide energy for them to survive through the process of chemosynthesis.
    • Science and Fisheries Management

      Went, A E J (Department of Agriculture and Fisheries (Fisheries Division), 1977)
      The W.J.N. Menzies Memorial Lecture delivered at the Annual Course of the Institute of Fisheries Management at the University of East Anglia, Norwich, on 16 September, 1975.
    • Science Communication: Stakeholder perceptions of Real-time Incentive Fisheries Management

      Pedreschi, D.; Vigier, A.; Höffle, H.; Kraak, S.B.M.; Reid, D.G. (Marine Institute, 2021)
      In these changing times, with political and environmental uncertainty surrounding us, fisheries management needs to become more adaptive in order to respond to the changes in our natural environment and changing management frameworks. Based on close to real-time information updates, and harnessing modern technology, Real-Time Incentive (RTI) fisheries management is designed to evolve with the fish stocks, enabling managers to respond more quickly and efficiently to management issues as they arise. Through the use of a credit system that makes use of regularly updated fine-scale information, incentives can be incorporated as rewards to encourage desirable actions such as data collection or ‘fishing-for-litter’ activities. However, in order for a new system such as this to be useful and become accepted, stakeholders must be involved in the development and design process. This paper details the consultative process carried out with Irish demersal fishery stakeholders in an effort to identify their likes and dislikes of the system, and work towards tailoring the RTI system into a practical solution that works for them. In this process, we achieved a detailed understanding of the fishery, the complexity of the system, and the challenges faced by the stakeholders, all of which must be considered when attempting to implement a new management system such as RTI. A range of proposals were made by stakeholders, including new ideas for the future development of the RTI system. Most striking were the numerous ideas and approaches to tackling key issues currently facing the industry, many of which also have relevance to existing fisheries management. Given the freedom and support to do so, fishing industry stakeholders are eager to contribute to solving many of their own problems.
    • Science: 1st Class and 2nd Class: Beach Towels - What Material Works Best (Irish and English Version)

      Marine Institute (Marine Institute, 2014)
      The aim of the lesson plan is for the children to identify and investigate materials that absorb water.
    • Science: 1st Class and 2nd Class_ Exploring Materials which will protect Scuba Steve from Electric Fish (Irish and English Version)

      Marine Institute (Marine Institute, 2014)
      The aim of the lesson plan is for children to identify materials that allow electricity to pass through them. Experiments and demonstrations are to be conducted by the teacher. Students will become aware of the dangers of electricity as well as learn about animals in the ocean that conduct electricity.