• Socio-Economic Evaluation of the Impact of the Aquaculture Industry in Counties Donegal, Galway, Kerry and Cork

      White, F; Costelloe, J (Marine Institute, 1999)
      As set out in the Terms of Reference of this study the aim at the outset was to put together a clear picture of how the development of the aquaculture industry in Ireland has socially and economically shaped the coastal communities in Counties Donegal, Galway, Kerry and Cork and where this development is likely to lead these communities in the future. Specifically the aquaculture industry was examined in the context of other influencing factors of economic and social wealth in each of the study regions to establish its role within the community. The hinterland of Kilkieran Bay, in southwest Co. Galway, was chosen as a suitable area in which to conduct a detailed case study of the impact of the industry in peripheral coastal areas. The 3 principal phases of the project comprised; 1. A comprehensive literature review and data collation exercise 2. An extensive consultation process involving representatives of the aquaculture industry, relevant government and semi-state departments, community development bodies, tourism operators, and aquaculture operators in each of the regions. 3. A detailed series of questionnaire surveys in the case study area.
    • A Socio-economic Study of Fisheries in Counties Cork, Donegal, Kerry and Galway

      Ó Donnchadha, G; Callaghan, T; Niland, C (Marine Institute, 2000)
      Ireland has an extensive continental shelf within its 200-mile Economic Zone and has contributed enormously to EU Common Fishery Resources. Irish access to these fisheries was decided under previous fishery agreements and it is felt that Irish coastal communities have been seriously disadvantaged under EU fishery policy. This report hopes to advance arguments that will persuade the EU that Irish fishing communities should have a more equitable share of contiguous fish stocks under the 2002 review of the CFP. Project No. 97.IR.MR.008 was undertaken by The Institute of Technology, Tralee and Aqua-Fact International Services Limited (Galway) to provide a Socio- Economic Evaluation of the impact of fisheries and aquaculture in Counties Donegal, Galway, Kerry and Cork. This report deals with sea fisheries. It covers Counties Donegal and Kerry in their entirety, County Galway excluding Galway City and the Coastal Rural and Urban Districts of County Cork. These districts of County Cork comprise the Rural Districts of Bandon, Bantry, Castletownbere, Clonakilty, Dunmanway, Kinsale, Midleton, Skibereen, Schull and Youghal No.1 and the Urban Districts of Clonakilty, Cobh, Kinsale, Midleton, Skibereen and Youghal. Galway City is included in the maps, not in the tables, figures or appendices. The study of aquaculture is published separately. The two studies share the secondary socio-economic data and complement each other.
    • Some comments on the management of the Irish mackerel fishery

      Molloy, J (Department of Fisheries and Forestry (Trade and Information Section), 1981)
      The total Irish catch of mackerel has increased dramatically in recent years and has risen from about 1000 tonnes in 1970/71 to approximately 50 000 tonnes in 1980/81. The total international catch taken by all countries in the ICES division VI, VII and VIII has also increased dramatically in the same period and has risen from 104,000 tonnes in 1970 to 604,000 tonnes in 1980. In 1980 mackerel contributed 40% of the total weight of the Irish wetfish catch and about 18% of the total value (based on the official statistics). Fishermen and processors have, in recent years, invested heavily in new vessels and in processing facilities, on the assumption of a continuation or even possible expansion of the recent high levels of mackerel catches. At the same time it is realized that pelagic fisheries such as herring and mackerel are liable to produce extremely erratic yields when intensively fished and there is always the danger of a sudden collapse of the fishery as has happened in many of our herring stocks. It is therefore important that those engaged in the mackerel fishery should be aware of the latest information relating to the assessment of the mackerel stock and also of the objectives as to how the stock should be managed.
    • Some Direct Gillnet Selectivity Tests for Brown Trout Populations

      O'Grady, M. F. (Department of Agriculture and Fisheries [Fisheries Division], 1981)
      Direct gillnet selectivity tests for introduced brown trout populations in three Irish lakes are outlined. The net gangs and netting procedure utilised are described. Data indicates that the gear used was capable of capturing a random cross section of a trout stock in the length frequency range 19.8 to 47.7 centimetres.
    • Some notes on crab fishing

      Gibson, F A (Department of Agriculture and Fisheries (Fisheries Division), 1957)
      Specific fishing on a commercial scale for the edible crab is practised only to a limited extent in this country and, although fairly substantial quantities of edible crabs are landed annually, these are largely the by-product of creel fishing for lobsters and crawfish. These notes give a short account of certain crab fishing methods and record the results of some experimental fishing undertaken by the Fisheries Division.
    • Some Problems and Methods in Dublin Bay Prawn (Nephrops norvegicus) Research

      Hillis, J P (Department of Agriculture and Fisheries (Fisheries Division), 1972)
      Much is in the process of being learned about the Dublin Bay Prawn or Norway Lobster Nephrops norvegicus (referred to simply as the prawn hereafter) but compared with many other commercially fished species much still remains a mystery. This paper describes methods of examination of its biology and ecology designed to yield information on habits, movements and especially growth and death-rates, these being the two most important factors in the prosperity of the fishery.
    • Some thick shelled whelk Buccinum undatum characteristics and fisheries in Ireland

      Fahy, E.; Grogan, S.; Byrne, J.; Carroll, J. (Marine Institute, 2006)
      Observations are presented on two whelk populations from the Cape grounds in Co. Donegal and the vicinity of Helvic Head Co. Waterford. Both co-exist with large populations of brown crab (Cancer pagurus) which is the likely explanation for their thick shells. In the south west Irish Sea (with which comparison is made) and in the Cape stocks, 83-88% of individuals were easily aged by reference to the operculum. Heavy calcification obscured structure in the case of Helvic animals and only 6% of these could be confidently aged. Helvic and south west Irish Sea whelk have similar L∞, but both Helvic and Cape whelk have more rapid early growth than in the Irish Sea. The density of whelk in the Helvic vicinity is insufficient to support a commercial fishery. The yield of whelk from other areas of the Celtic Sea is sporadic and slow to recover from exploitation. The Cape fishery shows signs of rapid depletion since most recent exploitation began there in 2003. The centrally situated sectors of the south west Irish Sea fishery are highly resilient and recover rapidly from heavy removals of biomass which can exceed 50% per annum. Maturation appears to take place at a lower size and age in the Irish Sea than in the other two whelk stocks and this is tentatively proposed as the explanation for their lower productivity.
    • South Coast (Waterford and Cork) Herring Fishery 1968-1969

      Molloy, J P (Department of Agriculture and Fisheries (Fisheries Division), 1969)
      The 1968/69 herring season proper commenced on November 27, 1968 and terminated on February 17, 1969. Prior to November 27, however, some small quantities of herrings had been taken by boats over a large area extending from Hook Head to the Daunt Rock. Fifty nine Irish boats made catches throughout the season and a total of 70,781 crans of herrings were landed which was an increase of 7,438 crans (11%o)n the figure for the previous season. Landings were made on 60 days out of a possible 70. The season, which began later than usual, was very disappointing before Christmas, due mainly to adverse weather conditions and the absence of shoals in inshore waters, After Christmas, however, landings of herrings increased substantially and fishing during January and February was exceptionally heavy, with the result that the total landings for the 1968/69 season were the greatest on record. As in the 1967/68 season, fishing was restricted after Christmas at times due to marketing problems which caused the closure of the ports on a number of occasions. The overall catch would otherwise have been considerably higher. Almost all landings of herrings were made at Dunmore East and Cobh.
    • South Coast (Waterford and Cork) Herring Fishery 1969-1970

      Molloy, J P (Department of Agriculture and Fisheries (Fisheries Division), 1970)
      The 1969/70 herring fishery began on the south coast in the week ending 15th November, 1969, and ended on the 25th February, 1970. Some small amounts of herrings had, however, been taken prior to the middle of November. Seventy three boats took part in the fishery, compared with fifty nine during the 1968/69 season. A total of 96,936 crans was landed, which was the highest on record and an increase of 26,155 crans on the figure for the previous season. Landings were made on 69 days out of a possible 81. The weather which, prior to Christmas, had been very favourable to fishing , deteriorated during January and thereafter caused many interruptions. As in the two previous seasons, marketing problems caused fishing to be suspended on a number of occasions and this restricted catches for considerable periods. All herrings taken throughout the season were auctioned at either Dunmore East or Cobh.
    • The south eastern ray Raja spp. fishery, with observations on the growth of rays in Irish waters and their commercial grading.

      Fahy, E (Department of the Marine, 1991)
      Five species contribute to the landings of the south eastern ray fishery, Raja microocellata being additional to the four more generally encountered in the Irish Sea. Fishing logs from 17 vessels were examined; they described more than 26,000 hours of fishing effort, most of it in division Vllg. Auction records contained a higher than expected proportion of small grades. The fishery is assessed as being more heavily exploited than the ray fisheries of division Vila. As far as possible, growth curves of rays in Irish waters were calculated on the fully recruited age groups. Values for L∞ were greater for females than males of all species; those for R. montagui and R. naevus are less than in other published accounts. Values of K range between 0.19 and 0.33 while values of to are between -3.009 and +0.49. In general, there is more variability in the values of to than is warranted by life cycles which are basically similar. Fishermen sort rays primarily on their size and secondarily on their external appearance, certain species having greater values than others. The supply of fish influences the outcome, insufficient quantities requiring that fish which would normally be segregated are bulked. Another Influence is the local occurrence of certain species. Statistical associations among species differ with grade, the smaller growing species rarely gaining access to the larger grades; when they do they are usually associated with species of lesser value. Rays are probably most effectively sampled by working on size grades within which samples are chosen at random.
    • Spatial and seasonal variation of peatland-fed riverine macroinvertebrate and benthic diatom assemblages and implications for assessment: a case study from Ireland

      O’Driscoll, C.; de Eyto, E.; Rodgers, M.; O’Connor, M.; Asam, Z-u-Z; Kelly, M.; Xiao, L. (Springer, 2014)
      Blanket peat catchments are important biodiversity refugia. Key pressures on peatland catchment water bodies include artificial drainage, forestry, over-grazing, wind farm development and climate change, and assessment of these pressures requires sensitive monitoring programmes. This study, undertaken in two neighbouring blanket peat catchments, examined the variability in macroinvertebrate and diatom assemblages and related indices in response to spatial and seasonal variability. Multivariate analysis revealed significant trends in the taxa distribution of both groups and the indices downstream and away from the constraining influence of the peat. However, the ecological quality ratios and status assessments for the associated water bodies were consistent irrespective of spatial variability in assemblages and raw indices. Significant seasonal trends emerged only in the macroinvertebrate assemblages and indices. This study contributes to the understanding of sources of uncertainty in ecological assessment and thus provides valuable information for the calibration of assessment protocols for sensitive peatland catchments.
    • Spatial Heterogeneity in Fishing Creates de facto Refugia for Endangered Celtic Sea Elasmobranchs

      Shephard, Samuel; Gerritsen, H.D.; Kaiser, Michel J.; Reid, David G. (PLOS, 2012)
      The life history characteristics of some elasmobranchs make them particularly vulnerable to fishing mortality; about a third of all species are listed by the IUCN as Threatened or Near Threatened. Marine Protected Areas (MPAs) have been suggested as a tool for conservation of elasmobranchs, but they are likely to be effective only if such populations respond to fishing impacts at spatial-scales corresponding to MPA size. Using the example of the Celtic Sea, we modelled elasmobranch biomass (kg h21) in fisheries-independent survey hauls as a function of environmental variables and ‘local’ (within 20 km radius) fishing effort (h y21) recorded from Vessel Monitoring Systems data. Model selection using AIC suggested strongest support for linear mixed effects models in which the variables (i) fishing effort, (ii) geographic location and (iii) demersal fish assemblage had approximately equal importance in explaining elasmobranch biomass. In the eastern Celtic Sea, sampling sites that occurred in the lowest 10% of the observed fishing effort range recorded 10 species of elasmobranch including the critically endangered Dipturus spp. The most intensely fished 10% of sites had only three elasmobranch species, with two IUCN listed as Least Concern. Our results suggest that stable spatial heterogeneity in fishing effort creates de facto refugia for elasmobranchs in the Celtic Sea. However, changes in the present fisheries management regime could impair the refuge effect by changing fisher’s behaviour and displacing effort into these areas.
    • Spatial patterns in the retained catch composition of Irish demersal otter trawlers: high-resolution fisheries data as a management tool

      Gerritsen, H.D.; Lordan, C.; Minto, C.; Kraak, S.B.M. (Elsevier, 2012)
      High-resolution fisheries data from integrated logbook and Vessel Monitoring Systems (VMS) records have revealed a detailed spatial structure in the species composition of the retained catches of the Irish demersal otter trawl fleets. Hierarchical cluster analysis was used to define 8 clusters with relatively homogenous species compositions. These clusters formed 34 distinct spatial regions in the waters around Ireland. Identification of these regions can be useful for a number applications, including spatial stratification of commercial or survey data, defining and characterising fishing grounds for marine spatial planning, evaluation of closed areas and prediction of how fishing effort might be re-allocated following a closure. A casestudy is presented that explores options to reduce cod (Gadus morhua) catches by implementing seasonal closures in two of the 34 regions. Cod are caught by demersal trawlers in a mixed fishery and the catches often exceed the quota, resulting in discarding of marketable fish. Two regions were identified that had relatively low effort and high cod landings. The effects of closing these regions during the first quarter of the year were explored. Cod catches were likely to be reduced by 8-22% while only 3-9% of the annual demersal otter trawl effort would be displaced. Whiting catches were also likely to be reduced, the change in catches of some other species depended on the assumed effort displacement.
    • Spatial Segregation within the Spawning Migration of North Eastern Atlantic Mackerel (Scomber scombrus) as Indicated by Juvenile Growth Patterns

      Jansen, T.; Campbell, A.; Brunel, T.; Worsøe Clausen, L. (PLoS ONE, 2013)
      A comparison of growth data (fish length) with latitude shows that southern juvenile mackerel attain a greater length than those originating from further north before growth ceases during their first winter. A similar significant relationship was found between the growth in the first year (derived from the otolith inner winter ring) and latitude for adult mackerel spawning between 44uN (Bay of Biscay) and 54uN (west of Ireland). These observations are consistent with spatial segregation of the spawning migration; the further north that the fish were hatched, the further north they will tend to spawn. No such relationship was found in mackerel spawning at more northerly latitudes, possibly as a consequence of increased spatial mixing in a more energetic regime with stronger currents. This study provides previously lacking support for spawning segregation behaviour among North East Atlantic mackerel – an important step towards understanding the migratory behaviour of mackerel and hence the spatiotemporal distribution dynamics around spawning time.
    • Spawning Trout in Eastern Connemara

      Fahy, E.; Nixon, J. J. (Department of Fisheries and Forestry, 1982)
      Concentrations totalling 299 trout from nine spawning sites in eastern Connemara in 1981 were examined to elucidate the spawning biology of these stocks. Sea trout made up the majority. Brown liveried fish predominated among migratory males (75%) but were few among females (2.5%). Males were of younger sea and river age than females and the ratio of females to males was lowest among the younger age categories. Scars and marks were evenly distributed between the sexes and 51% of females showed signs of being spent. Spawning Connemara sea trout were similar to spawning Cummeragh, Co. Kerry, sea trout in a number of, respects as for example their length at age but the spawning behaviour of fish in the two places differed considerably: the density of spawning fish was greater in the Cummeragh than in Connemara where immature trout occurred in the vicinity of the redds. The ratio of females to males was lower in Connemara than in the Cummeragh and males appeared to be more heavily marked in Connemara. The relevance of these observations to some known genetic characteristics of the stocks is briefly discussed.
    • Spawning trout Salmo trutta L. populations in the Cummeragh System, Co. Kerry

      Fahy, E. (Department of Fisheries and Forestry, 1982)
      Concentrations totalling more than 300 spawning trout from five sites at three parts of the Cummeragh system were examined in 1980. The majority of the fish were sea trout but some brown trout and precocious males occurred at every site. Of the various physical characteristics of the sites, numbers of fish displayed the most consistent relationship with the volume of water in the pools where they occurred. Trout ranged from 22cm to 68cm fork length and maiden fish of two sea summers comprised the majority. Brown trout matured at a smaller size and younger age than sea trout. Males matured before females and older smolts before younger. Females outnumbered males in the entire collections although there were differences in this and other characteristics of the fish from one site to another, a result it is thought of the timing of sampling. The majority of male sea trout had a brown livery and more female than male trout displayed scars on the body behind the dorsal fin.
    • "Specimen" Brown Trout and Sea Trout From Irish Waters

      Went, A. E. J. (Department of the Marine, 1968)
      The present paper deals with all the material collected up to the end of the 1967 fishing season and relates to brown trout of 10 lb weight and upwards and sea trout of 6 lb and upwards.
    • Spring salmon enhancement on the Delphi Fishery, Ireland

      McDermott, T. J.; Willis, S. E.; Mantle, P. (Atlantic Salmon Trust, 1996)
      This paper summarises the results of an Atlantic salmon (Salmo salar) enhancement programme on the Delphi Fishery in the west of Ireland between 1991 and 1995. The aim of the programme was to increase salmon rod catches in the wake of a sea trout stock collapse. Smolts from two other Irish rivers, Burrishoole and Corrib, were released alongside Delphi fish and differentially tagged. Record angling catches were subsequently recorded. Catch rates varied from 0.6 to 12.7 per 1,000 smolts released. The comparative performance of the different stocks is assessed, with significant differences emerging between the stocks and between year classes In terms of survival/exploitation rates, run limes, sex ratios and homing patterns. The Delphi fish produced consistently lower overall returns than the Burrishoole groups, but consistently much higher numbers of early-running multi-sea-winter (MSW) salmon. These MSW salmon were predominantly female, while Delphi grilse were predominantly male. The Corrib fish performed relatively poorly. The smaller MSW salmon component of the non-indigenous groups ran later in the season than their Delphi counterparts. Important size differences in adult returns were noted and related to stock, sex, husbandry and selection by interceptory fisheries. It is suggested that the MSW salmon component of Delphi stocks is attributable to genetic factors, possibly linked to low freshwater temperature regimes. The programme has contributed to an increase in estuarine droll netting. Exploitation of grilse by all forms of coastal net ranged from 56% to 87%. Exploitation of MSW salmon by nets was lower, ranging from 0% to 54%, the lowest rates being achieved by the early-running Delphi MSW salmon. The programme is expensive and cannot be justified in terms of direct angling revenue. But when related accommodation income is taken into account, the financial results and the sustainment of the fishery's capital value broadly justify the programme to date.
    • The spurdog Squalus acanthias (L) fishery in south west Ireland

      Fahy, E (Department of the Marine, 1988)
      Spurdog landings are made on all parts of the Irish coastline but most heavily concentrated on the west of the country. The fishery expanded to a maximum catch of just under 8,000 tonnes in 1985. The species had been pursued most intensively in the north west but effort is shifting southwards. This account of the south west Ireland fishery is based on material collected between April 1987 and March 1988, inclusive; information was collected by questionnaire and 5,300 individual fish were examined. Ageing was undertaken using the posterior spine: ages in the commercial catches ranged between 5 and 40+ years. The growth characteristics of the south-west Ireland spurdogs resemble those of the Scottish-Norwegian fish, but the Irish populations have a lower L∞. Female maturation takes place at a shorter length than in other populations hitherto investigated from British or Irish waters; the length at 50% maturity is slightly more than 74cm which corresponds with an age of 14 years. The fecundity of the south west Ireland spurdogs is relatively high. Mortality coefficients (Z) of fully recruited spurdogs are calculated from age 17 as 0.24 for females and 0.30 for males. Two life tables are constructed. The first, which is intended to ascertain the numbers of female whelps required to maintain numbers, suggests that the stocks are close to being overfished. The second life table examines the age structure of the breeding female component of the population but its outcome is inconclusive. In terms of its organization the south west of Ireland spurdog fishery can be considered as two separate fisheries: a trawl and a gill net fishery, the latter being regarded as the more detrimental to the prospect of sustained yield.
    • Stable isotope analysis of baleen reveals resource partitioning among sympatric rorquals and population structure in fin whales

      Ryan, C.; McHugh, B.; Trueman, C.N.; Sabin, R.; Deaville, R.; Harrod, C.; Berrow, S.D.; O'Connor, I. (Inter-Research, 2013)
      Stable isotope analysis is a useful tool for investigating diet, migrations and niche in ecological communities by tracing energy through food-webs. In this study, the stable isotopic composition of carbon and nitrogen in keratin was measured at growth increments of baleen plates from 3 sympatric species of rorquals (Balaenoptera acutrostrata, B. physalus and Megaptera novaeangliae), which died between 1985 and 2010 in Irish and contiguous waters. Bivariate ellipses were used to plot isotopic niches and standard ellipse area parameters were estimated via Bayesian inference using the SIBER routine in the SIAR package in R. Evidence of resource partitioning was thus found among fin, humpback and minke whales using isotopic niches. Highest δ15N values were found in minke whales followed by humpback, and fin whales. Comparison between Northeast Atlantic (Irish/UK and Biscayan) and Mediterranean fin whale isotopic niches support the current International Whaling Commission stock assessment of an isolated Mediterranean population. Significantly larger niche area and higher overall δ 15N and δ 13C values found in fin whales from Irish/UK waters compared to those sampled in adjacent regions (Bay of Biscay and Mediterranean) suggest inshore foraging that may be unique to fin whales in Ireland and the UK. Isotopic profiles support spatial overlap but different foraging strategies between fin whales sampled in Ireland/UK and the Bay of Biscay. Stable isotope analysis of baleen could provide an additional means for identifying ecological units, thus supporting more effective management for the conservation of baleen whales.