• A preliminary account of fisheries for the surf clam Spisula solida (L) (Mactracea) in Ireland

      Fahy, E.; Carroll, J.; O'Toole, M.; Hickey, J. (Marine Institute, 2003)
      Surf clams from seven stocklets on the west and south coasts are examined to provide a preliminary account of the fishery in Ireland. Spisula solida is the species harvested in every case. Most of the material was collected by commercial (box or hydraulic) dredge. A quantitative account of a surf clam bed is based on sampling by Day grab in Waterford Harbour. Ageing was by external shell sculpture. A limited comparison of this method with ageing by internal shell structure confirmed the method was usable and the results are presented on this basis with, however, reservations on the reliability of the approach. S. solida in Ireland had Linf of c 43 cm. Material gathered in Clifden, Co Galway, had an Linf of 35 mm. The Clifden stocklet was heavily fished when the material was gathered and a low value for Linf is attributed to the Lee phenomenon. A growth curve is constructed for only one stocklet, that in Waterford Harbour. Growth was slower than for S. solida in the North Sea, a possible consequence of heavy fishing also. The clam bed in Waterford Harbour was a low elevation bank of coarse (Spisula) sand. The area of the bed had become reduced during the preceding year by the invasion of silt grades displaced by earthworks upstream; these were injected into the coarse material to form a perimeter of the clam patch. Within the bed, the highest biomass of S. solida was 600 g/sq.m. Representation of age frequencies within samples suggests that heavy spatfalls of S. solida occur at irregular intervals and this complicates the calculation of F values from a catch curve. A yield per recruit curve is prepared for the clam patch in Waterford Harbour.
    • The status of the inshore component of the northern brown crab Cancer pagurus fishery, assessed from a time series of LPUE constructed from historical sources

      Meredith, D.; Fahy, E. (Marine Institute, 2005)
      A 27 year LPUE series was compiled from daily landings and creel numbers fished, as reported by a processor and by personnel participating in the activities of a small inshore fleet at Malin Head, Co. Donegal. The fleet targeted brown crab in the late summer and autumn months and the series was compared with two other series of LPUE constructed from data obtained from two fleet sources fishing the same stock. The most significant event to have taken place since records commenced in the late 1970s was the introduction in the 1990s of a small vivier offshore crabbing fleet. Competition between the inshore and offshore components intensified and the inshore fleet responded by further capitalising and increasing its seaward range. Since the mid-1980s the number of boats in the Malin Head inshore fleet pursuing the autumn fishery halved while the total amount of gear increased by 29%. The number of pots set by a vessel in a day averaged 600 in 2004 but in 2000 the practice of fishing two sets of gear simultaneously became established. The vivier boats also moved inshore and the ranges of the two fleets now overlap. In the past 15 years there was a loss of between 37 and 57% LPUE, according to the data assembled in this work. Schaefer analyses carried out on the inshore Malin Head fleet’s results and extended to cover the estimated landings of the Donegal inshore fleet, indicate that maximum sustainable yield was almost reached and that the F0.1 point was exceeded by both fleets. Any additional increase in F is likely to further accelerate decline in LPUE. The stock is regarded as being close to over-fished in a regime without effective effort controls. The problems associated with managing a fishery of this kind are briefly discussed.
    • National Survey of Sea Lice (Lepeophtheirus salmonis Krøyer and Caligus elongatus Nordmann) on Fish Farms in Ireland – 2004

      O'Donohoe, P.; Kennedy, S.; Kane, F.; Naughton, O.; Tierney, D.; Jackson, D. (Marine Institute, 2005)
      This bulletin reports on the National Sea Lice Monitoring Programme carried out by the Marine Institute in 2004. Results presented in this report are mean ovigerous sea lice levels and mean mobile sea lice levels for Lepeophtheirus salmonis and Caligus elongatus
    • Gutted to round-weight conversion factors for anglerfish (Lophius poscatorius and Lophius budegassa)

      Lordan, C.; Gerritsen, H.D. (Marine Institute, 2006)
      In response to a request from the Department of Communications Marine and Natural Resources and fishing industry, the conversion factors used to estimate round or live weights from gutted anglerfish were re-examined. A number of data sources was available from survey data, port sampling and observer trips. In some cases, the liver is left in place when the fish are gutted. For these landings a separate conversion factor is necessary. The conversion factors were found to be independent of fish size, however, some significant differences between the data sources were found. Significant differences between the conversion factors of the two species of anglerfish (Lophius piscatorius and L. budegassa) were also found. As commercial landings of anglerfish are not usually speciated, a generic conversion factor was estimated for Lophius spp. by combining the data for both species after weighting by the estimated proportions of the two species in the Irish landings. The resultant conversion factor for fully gutted fish is 1.23 and 1.17 when the liver is left in place; both estimates are lower than the current Irish factor of 1.28.
    • National Survey of Sea Lice (Lepeophtheirus salmonis Krøyer and Caligus elongatus Nordmann) on Fish Farms in Ireland – 2005

      O'Donohoe, P.; Kane, F.; Kennedy, S.; Naughton, O.; Nixon, P.; Power, A.; Jackson, D. (Marine Institute, 2006)
      This bulletin reports on the National Sea Lice Monitoring Programme carried out by the Marine Institute in 2005. Results presented in this report are mean ovigerous sea lice levels and mean mobile sea lice levels for Lepeophtheirus salmonis and Caligus elongatus
    • 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.
    • Evaluation of the Benefits to Sustainable Management of Seasonal Closure of the Greencastle Codling (Gadus morhua) Fishery

      Ó Cuaig, M.; Officer, R. (Marine Institute, 2007)
      The project examined whether the seasonal closure of the traditional cod fishing grounds off Greencastle, Co. Donegal, could be an effective alternative management measure. The project was instigated by the local fishing industry and operated in cooperation between industry, the Marine Institute and Bord Iascaigh Mhara. The main objectives of the project were to demonstrate the change in yield likely to result from seasonal closure, and, to determine the pattern of movement of cod from the Greencastle fishery. Each winter from 2003 to 2005 the fishery was closed by Statutory Instrument. This was achieved with the voluntary commitment of the local industry. During this period over 13,000 cod were tagged and released by Marine Institute and BIM staff working aboard chartered fishing vessels. The closure itself provided a significant conservation benefit. During 2000-2002 50% of the Irish catch weight of cod in Division VIa (> 60% by number) was taken in the winter. The closure will therefore have markedly reduced the fishing mortality on cod that would otherwise have occurred from 2003 to 2005. As the Greencastle codling fishery is a mixed whitefish fishery, any benefits flowing from the closure are likely to have extended to other whitefish stocks. Growth was extremely variable but averaged around 17 cm per annum for cod at liberty for extended periods. During the winter tagging surveys the repeated recapture of recently tagged cod on the grounds indicated the retention of cod on the grounds during winter. Tagged cod at liberty for extended periods were subsequently recaptured on, or near the Cape grounds. This strong fidelity towards the Cape grounds during winter coupled with high growth rates may mean that a short winter fishing season, with a delayed opening, may yield a similar total weight of codling than the traditional fishery but with the catch of a reduced number of cod. Such schemes may reduce current fishing mortality rates. However, the stock status of Division VIa cod is so poor that a complete closure of the fishery is warranted. It is recommended that continuation of the project be considered as a mechanism for maintaining a closure of most of the Irish fishery, whilst simultaneously improving the quality of data available for stock assessment.
    • National Survey of Sea lice (L. salmonis Krøyer and C. elongatus Nordmann) on Fish Farms in Ireland – 2006

      O'Donohoe, P.; Kane, F.; Kennedy, S.; Nixon, P.; Power, A.; Naughton, O.; Jackson, D. (Marine Institute, 2007)
      This bulletin reports on the National Sea Lice Monitoring Programme carried out by the Marine Institute in 2006. Results presented in this report are mean ovigerous sea lice levels and mean mobile sea lice levels for Lepeophtheirus salmonis and Caligus elongatus
    • Validation of Standard Weights and Raising Coefficients for Discard Estimation: Report of a Survey Aboard MFV Roisin Bairbre

      Smith, T.; Comerford, S.; Officer, R. (Marine Institute, 2007)
      This survey was carried out to verify the Marine Institute's discard sampling protocol and the standard weights and conversion factors used when calculating discard rates. The MFV Roisin Bairbre was chartered to fish as normal on the Aran Prawn Grounds using twin rig prawn gear. The entire bulk catch was weighed, as well as the entire retained catch, thereby getting an accurate rate of discarding for this trip, as well as accurate individual basket weights. Retained catch was also weighed by species prior to and after gutting, to check the raising factors used when changing gutted landings back to round. This survey showed that the rate of discarding for this trip was 62% of the total bulk catch. There was no significant difference between the measured bulk catch weighed and the estimated bulk catch derived from using the standard weights. This validates the standard weights used. There was no significant differences between the observed conversion factors (from gutted to whole weight) and those currently used routinely in weight conversions. A standard weight for big baskets of bulk catch on a fish directed trip of 34.5 kg, and 28kg for a Nephrops directed trip were achieved.
    • Activity patterns of some inshore fishing vessels in 2006-2007

      Fahy, E.; Fee, D.; O'Connor, S.; Smith, T. (Marine Institute, 2007)
      Observations of daily “absence-from-port” patterns and indications of gears used were carried out on 147 vessels ranging from 5 to 13 m overall length, between April 2006 and March 2007 at three ports in west, southwest and southern Ireland. The vessels numbered approximately 6% of the total national fleet and they were larger than the average length of boats observing a daily working “absence-from-port” pattern. Fishing gears belonged to one of five categories: shellfish dredges, nets, hook and line, pots and otter trawl. More than half of the vessels observed did not carry any indication of fishing gear; 46 % had evidence of using one gear and 3% showed signs of using two. Activity (absence) patterns were low, ranging between 14 and 42 % of week-days on which observations were made. The annual pattern of gear usage described by BIM in 1999 was not apparent in any of the three ports. Instead, the local availability of fishing opportunities was influential in deciding which methods predominated. In only one port was there a marked seasonal activity pattern. Visible signs of vessel registration were similar to the situation in 2002.
    • National Survey of Sea lice (L. salmonis Krøyer and C. elongatus Nordmann) on Fish Farms in Ireland – 2007

      O'Donohoe, P.; Kane, F.; Kelly, S.; Nixon, P.; Power, A.; Naughton, O.; Jackson, D. (Marine Institute, 2008)
      This bulletin reports on the National Sea Lice Monitoring Programme carried out by the Marine Institute in 2007. Results presented in this report are mean ovigerous sea lice levels and mean mobile sea lice levels for Lepeophtheirus salmonis and Caligus elongatus
    • National Survey of Sea lice (L. salmonis Krøyer and C. elongatus Nordmann) on Fish Farms in Ireland – 2008

      O'Donohoe, P.; Kane, F.; Kelly, S.; Nixon, P.; Power, A.; Naughton, O.; Tully, D.; Jackson, D. (Marine Institute, 2009)
      This bulletin reports on the National Sea Lice Monitoring Programme carried out by the Marine Institute in 2008. Results presented in this report are mean ovigerous sea lice levels and mean mobile sea lice levels for Lepeophtheirus salmonis and Caligus elongatus
    • National Survey of Sea Lice (Lepeophtheirus salmonis Kroyer and Caligus elongatus Nordmann) on Fish Farms in Ireland - 2009

      O'Donohoe, P.; Kane, F.; Kelly, S.; Nixon, P.; Power, A.; McDermott, T.; Drumm, A.; Jackson, D. (Marine Institute, 2010)
      This bulletin reports on the National Sea Lice Monitoring Programme carried out by the Marine Institute in 2009. Results presented in this report are mean ovigerous sea lice levels and mean mobile sea lice levels for Lepeophtheirus salmonis and Caligus elongatus
    • National Survey of Sea Lice (Lepeophtheirus salmonis Kroyer and Caligus elongatus Nordmann) on Fish Farms in Ireland - 2010

      O'Donohoe, P.; Kane, F.; Kelly, S.; McDermott, T.; Drumm, A.; Jackson, D. (Marine Institute, 2011)
      This bulletin reports on the National Sea Lice Monitoring Programme carried out by the Marine Institute in 2010. Results presented in this report are mean ovigerous sea lice levels and mean mobile sea lice levels for Lepeophtheirus salmonis and Caligus elongatus.
    • Irish fisheries-science research partnership trawl survey of the Porcupine Bank Nephrops Grounds July 2010

      Stokes, D.; Lordan, C. (Marine Institute, 2011)
      The Nephrops fishery on the Porcupine Bank takes place on a large area, approximately 7000km2, of complex muddy habitat between depths of 300 to 470m. Irish effort has been increasing and Ireland is now responsible for the majority of the landings. The scientific advice has indicated that the stock has declined and fishing mortality should be reduced to the lowest possible level. This Irish Fisheries Science Research Partnership (IFSRP) survey was developed in 2010 to address the pressing need for data from the closed area established by the EC between 1st May to 31st July 2010. 46 hauls were carried out and the results indicate high CPUE for the survey relative to recent observations for the fleet. Strong patterns in size and sex ratio were observed spatially. The male biased sex ratio and size-at-maturity are similar to historical observation. The size distributions of the catches are very different to the Spanish survey in the area which took place two months later. The utility of the survey for monitoring the stock is discussed.
    • National Survey of Sea Lice (Lepeophtheirus salmonis Kroyer and Caligus elongatus Nordmann) on Fish Farms in Ireland - 2011

      O'Donohoe, P.; Kane, F.; Kelly, S.; McDermott, T.; Drumm, A.; Jackson, D. (Marine Institute, 2012)
      This bulletin reports on the National Sea Lice Monitoring Programme carried out by the Marine Institute in 2011. Results presented in this report are mean ovigerous sea lice levels and mean mobile sea lice levels for Lepeophtheirus salmonis and Caligus elongatus.
    • An Inventory of Irish Herring Spawning Grounds

      O’Sullivan, D.; O’Keefe, E.; Berry, A.; Tully, O.; Clarke, M. (Marine Institute, 2013)
      Herring, an important commercial and forage species in Irish waters, are benthic spawners and specifically rely on gravel and/or rock on which to lay their eggs. The present study collates information from both the fishing industry and seabed surveys (INFOMAR) to produce a detailed inventory of individual herring spawning beds, grounds and areas around the coast of the Republic of Ireland.
    • National Survey of Sea Lice (Lepeophtheirus salmonis Kroyer and Caligus elongatus Nordmann) on Fish Farms in Ireland - 2012

      O'Donohoe, P.; Kane, F.; Kelly, S.; McDermott, T.; Drumm, A.; Jackson, D. (Marine Institute, 2013)
      This bulletin reports on the National Sea Lice Monitoring Programme carried out by the Marine Institute in 2012. Results presented in this report are mean ovigerous sea lice levels and mean mobile sea lice levels for Lepeophtheirus salmonis and Caligus elongatus.
    • Report on Sea Lice Epidemiology and Management in Ireland with Particular Reference to Potential Interactions with Wild Salmon (Salmo salar) and Freshwater Pearl Mussel (Margaritifera margaritifera) Populations

      Jackson, D.; O’Donohoe, P.; McDermott, T.; Kane, F.; Kelly, S.; Drumm, A. (Marine Institute, 2013)
      In 2009 two Non-Governmental organizations (NGOs) submitted a legal complaint (Anon. 2009 a) against Ireland to the EU Commission (EU Pilot Case 764/09/ENV1). The substance of the complaint was that Ireland was failing to comply with the Habitats Directive and the Environmental Impact Assessment Directive in three named fisheries; the Delphi (Bundorragha River), the Newport Fishery (Newport River) and the Ballynahinch Fishery (Ballynahinch River). The complainants also cited a failure to protect both the salmon (Salmo salar) and the freshwater pearl mussel (Margaritifera margaritifera). In responding to the complaint a detailed scientific investigation was undertaken. Long term research and specifically commissioned studies were accessed and their data drawn on to ensure a comprehensive and accurate response based on the best available scientific data and information. This report sets out this information, together with the associated studies and data which formed the basis of the scientific response to the complaint. The complaint was closed in favour of the State on the 11th of October 2012.
    • National Survey of Sea Lice (Lepeophtheirus salmonis Kroyer and Caligus elongatus Nordmann) on Fish Farms in Ireland - 2013

      O'Donohoe, P; Kane, F; Kelly, S; McDermott, T; Drumm, A; Jackson, D (Marine Institute, 2014)
      This bulletin reports on the National Sea Lice Monitoring Programme carried out by the Marine Institute in 2013. Results presented in this report are mean ovigerous sea lice levels and mean mobile sea lice levels for Lepeophtheirus salmonis and Caligus elongatus.