• The age Distribution of the Herring Stocks around the Irish Coast during 1993

      Barnwall, E.; Molloy, J. (1994)
      The age distribution of stocks is usually considered as an indication of how healthy a stock may be. In general stocks which are lightly exploited will contain a much larger proportion of older fish than a stock which is heavily exploited. A stock which is heavily exploited will probably be dependent on one year class which will recruit to the fishery and which will immediately be subjected to fishing effort. Obviously in such a fishery failure of recruitment or poor recruitment will have drastic effect on the catches. Herrings can be aged accurately until are about 10 years old and generally recruit to the adult stocks during their third year. During this year, the majority of fish will spawn for the first time.
    • 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.
    • Balancing selection on MHC class I in wild brown trout Salmo trutta

      O'Farrell, B; Dennis, C; Benzie, JA; McGinnity, P; Carlsson, J; De Eyto, E; Coughlan, J; Igoe, F; Meehan, R; Cross, T (Wiley, 2012-09)
      Evidence is reported for balancing selection acting on variation at major histocompatibility complex (MHC) in wild populations of brown trout Salmo trutta. First, variation at an MHC class I (satr-uba)–linked microsatellite locus (mhc1) is retained in small S. trutta populations isolated above waterfalls although variation is lost at neutral microsatellite markers. Second, populations across several catchments are less differentiated at mhc1 than at neutral markers, as predicted by theory. The population structure of these fish was also elucidated.
    • Biotic response to forest harvesting in acidic blanket peat fed streams: a case study from Ireland

      O'Driscoll, Connie; de Eyto, Elvira; Rodgers, Michael; O'Connor, Mark; Asam, Zaki-ul-Zaman; Xiao, Liwen (Elsevier, 2013)
      Blanket peat catchments are important biodiversity refugia and are increasingly recognised for their role in regional carbon and water balances. A key pressure on these catchments is forest clearfelling which increases stream phosphorus potentially leading to eutrophication. However, these unique systems are underrepresented in the development of bioassessment monitoring programmes and so are at risk to impacts. In this study, a multiple before-after-control-impact (MBACI) study was designed in three neighbouring peatland catchments and provided a unique opportunity to assess the impact of forest clearfelling events on macroinvertebrate and phytobenthic assemblages. Statistical analysis revealed substantial differences in the macroinvertebrate assemblages after clearfelling with higher abundances of chironomids. Macroinvertebrate derived indices EPT, diversity and species richness were significantly reduced. This was accompanied by a shift in functional feeding group representation away from shredders and collector–filterers to a dominance of collector–gatherers after clearfelling. In contrast, forest clearfelling did not significantly impact the diatom assemblages and diatom derived indices remained static for the duration of the study period.
    • Boarfish (Capros aper) target strength modelled from magnetic resonance imaging (MRI) scans of its swimbladder

      Fassler, S.; O'Donnell, C.; Jech, J. (International Council for the Exploration of the Sea (ICES), 2013)
      Boarfish (Capros aper) abundance has increased dramatically in the Northeast Atlantic from the early 1970s after successive years of good recruitment attributed to an increase in sea surface temperature. Due to increased commercial fishing over recent years, an acoustic boarfish survey funded by the Killybegs Fishermen's Organisation was initiated by the Marine Institute to establish a baseline for the future management of this stock. In the absence of any species-specific boarfish target strength (TS), acoustic backscatter was estimated by a Kirchhoff-ray mode model using reconstructed three-dimensional swimbladder shapes which were computed from magnetic resonance imaging scans of whole fish. The model predicted TS as a function of size, fish tilt angle, and operating frequency. Standardized directivity patterns revealed the increasing importance of changes in the inclination of the dorsal swimbladder surface at higher frequencies (120 and 200 kHz) and a less directive response at lower frequencies (18 and 38 kHz). The model predicted a TS-to-total fish length relationship of TS = 20 log10(L) − 66.2. The intercept is ∼1 dB higher than in the general physoclist relationship, potentially reflecting the bulky nature of the boarfish swimbladder with its relatively large circumference.
    • Certified Reference Materials for Marine Monitoring

      Pellizzato, Francesca; McGovern, Evin; Quevauviller, Philippe (J. Wiley & Sons, Chichester, West Sussex, 2011)
    • Contrasting responses to selection in class I and class IIα major histocompatibility-linked markers in salmon

      Consuegra, S; De Eyto, E; McGinnity, P; Stet, R.J.M.; Jordan, W.C. (Nature Publishing Group, 2011-08)
      Comparison of levels and patterns of genetic variation in natural populations either across loci or against neutral expectation can yield insight into locus-specific differences in the strength and direction of evolutionary forces. We used both approaches to test the hypotheses on patterns of selection on major histocompatibility (MH)-linked markers. We performed temporal analyses of class I and class IIα MH-linked markers and eight microsatellite loci in two Atlantic salmon populations in Ireland on two temporal scales: over six decades and 9 years in the rivers Burrishoole and Delphi, respectively. We also compared contemporary Burrishoole and Delphi samples with nearby populations for the same loci. On comparing patterns of temporal and spatial differentiation among classes of loci, the class IIα MH-linked marker was consistently identified as an outlier compared with patterns at the other microsatellite loci or neutral expectation. We found higher levels of temporal and spatial heterogeneity in heterozygosity (but not in allelic richness) for the class IIα MH-linked marker compared with microsatellites. Tests on both within- and among-population differentiation are consistent with directional selection acting on the class IIα-linked marker in both temporal and spatial comparisons, but only in temporal comparisons for the class I-linked marker. Our results indicate a complex pattern of selection on MH-linked markers in natural populations of Atlantic salmon. These findings highlight the importance of considering selection on MH-linked markers when using these markers for management and conservation purposes.
    • Creation and functioning of a buffer zone in an upland peat forested catchment

      O'Driscoll, Connie; O'Connor, Mark; Asam, Zaki-ul-Zaman; de Eyto, Elvira; Rodgers, Michael; Xiao, Liwen (Elsevier, 2014)
      Buffer zones can be used to reduce nutrient and suspended sediment export following forest clearfelling by directing runoff over a vegetated area. This study demonstrates the achievability of constructing a buffer zone by initially clearfelling the standing forest, seeding with two native grass species and directing the water from a semi-natural stream draining an upstream 10 ha forested peatland site through it. Following the clearfelling of the upstream study site this study tested the efficacy of this management practice in reducing nutrient and suspended sediment concentration in the receiving water. The buffer zone reduced total reactive phosphorus (TRP) and suspended sediment (SS) loads by 18% and 33%, respectively. Phosphorus (P) retention efficiency was dependent on inlet concentrations, loading and hydraulic loading rates. In storm events with a loading rate of >28 g P ha-1, a flow rate higher than 88.5 L s-1 and an inlet concentration of <17 µg L-1 the buffer zone became a TRP release source. The maximum P concentration in the buffer zone did not exceed 40 µg L-1 during this study demonstrating that the buffer zone method could be used efficiently in peatland forestry to moderate the high P concentrations and assist in protecting salmonids and freshwater pearl mussels.
    • Donegal Bay Herring Investigations, 1967/68

      Bracken, J. J.; Phillips, D. (University College Dublin, 1968)
    • The Dunmore East Herring Fishery, 1958-59

      Bracken, J. J. (Department of Lands, 1959)
    • Dunmore East Herring Investigations, 1965/66

      Molloy, J. (Department of Lands, 1966)
    • 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.
    • 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.
    • Fluctuations in the Stock of Herrings on the North Coast of Donegal

      Farran, G. (Conseil International pour l'Exploration de la Mer (ICES), 1930)
    • A genetic marker for the maternal identification of Atlantic salmon × brown trout hybrids

      Karlsson, S.; Hagen, M.; Eriksen, L.; Hindar, K.; Jensen, A.; De Leaniz, C.; Cotter, D.; Guobergsson, G.; Kahilainen, K.; Guojonsson, S.; et al. (Springer Netherlands, 2013)
      Interspecific hybridization between Atlantic salmon and brown trout is well documented, but why it should vary so much among populations is not clear. Determining the maternal origin of hybrids can provide insights into the mechanisms underlying interspecific hybridization, but this information is lacking in many studies. Here we present a species-specific mitochondrial DNA marker for the identification of the maternal origin of hybrids. This marker involves only one PCR step followed by fragment analysis, can be integrated within PCR multiplexing for existing nuclear markers for hybrid identification, and is therefore faster and more cost-effective than previous methods.
    • 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.
    • The Herring Fishery in Éire, 1921 - 1941.

      Farran, G. (Department of Agriculture, 1944)
      In the following pages an attempt has been made to give a concise summary of the herring fishery in the years from 1921 to 1941, or approximately the period between the two European wars. The abnormal conditions in 1914-1918 were prolonged locally by abnormal transport and generally unsettled conditions until 1923 but, except for increased demand for herrings for export, higher prices and the absence of English and Scottish boats from our shores, the years 1940 and 1941 did not differ markedly from the preceding period.
    • Herring Investigations at Dunmore East - 1962/63

      Bracken, J. J. (Department of Lands, 1963)
    • 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.
    • Herring larval surveys in the Celtic Sea and division VIIj in 1983/1984

      Cullen, A.; Barnwall, E.; Grainger, R. J. (International Council for the Exploration of the Sea, 1984)
      Surveys for herring larvae in the Celtic Sea were conducted for the sixth ~ successive season between October 1983 and February 1984. The modifications made to the survey grid in the previous season to take account of the amalgamation of the Celtic Sea and Division VIIj for assessment purposes and to ascertain if larvae drift into the Irish Sea were also adopted for the 1983/84 surveys. A drift of larvae towards the Irish Sea was apparent in 1983/84. The larval abundance index for 1983/84 based on a standard survey area was almost three times higher than any previous value. A continuous increase in larval indices since 1978/79 indicates a recovery of the spawning stock.