• The Early Life of Brown Trout (Salmo Trutta L.)

      Kennedy, M.; Fitzmaurice, P. (Department of Agriculture and Fisheries [Fisheries Division], 1968)
      The programme of research included field and laboratory studies of certain aspects of the early life history of the trout that are considered below.
    • Early warning of microbiological contamination of water

      Shakalisava, Yuliya; Diamond, Dermot (2011)
    • East Coast Queen Fishery 1970

      Bhatnagar, K M (Department of Agriculture and Fisheries (Fisheries Division), 1972)
      During July and August, 1970, two Isle of Man boats, equipped for fishing queen escallops (Clamys opercularis), were each licensed for one week by the Department of Agriculture and Fisheries to fish experimentally under the supervision of a scientist from the Department with a view to locating queen beds along the east coast. In August, a few Irish boats also fished for queens. As a result, large quantities of queens were located off the Bray Bank along the east coast and substantial landings of queens were made in Ireland for the first time. This report is in two parts giving the results of (1) a Queen Survey carried out by the Department of Agriculture and Fisheries on the east coast from 12th to 18th November, 1970 and (2) an Analysis of samples taken from fishing boats during the 1970 fishing season.
    • Ecological Changes over 21 Years Caused by Drainage of a salmonid stream, the Trimblestown River

      O'Grady, M. F. (Department of Agriculture and Fisheries [Fisheries Division], 1991)
      A site on the Trimblestown River (Boyne Catchment) studied by McCarthy (1977 and 1983), pre- and post-drainage (1968 to 1974), was re-examined by the author in 1989. Changes in the nature of the stream bed, in-stream and bank flora and fish stocks over the entire period (1968 to 1989) are reviewed. Data indicate a general ecological recovery of the site 17 years after drainage works.
    • Ecological Changes over 30 Years caused by drainage of a salmonid stream, the Bunree River

      O'Grady, M. F.; King, J. J. (Department of Agriculture and Fisheries [Fisheries Division], 1992)
      The general ecology of two sites in the Bunree River, May catchment are described for 1990 and compared with the observations of Toner, O'Riordan and Twomey, (1965) at the same sites 30 years ago when parts of this catchment were subjected to arterial drainage. Differences observed are discussed with particular reference to salmonid populations.
    • The Ecology of Brown Trout and Juvenile Salmon in the River Owena, Co. Donegal

      McCarthy, D .T. (Department of Agriculture and Fisheries [Fisheries Division], 1972)
      The growth rate and population structure of brown trout and juvenile salmon in two oligotrophic nursery streams in County Donegal in the North west of Ireland are compared, as well as data on sex ratios and sexual maturity. Details of the food of brown trout and salmon and the smolt run in 1967 are discussed. Estimates of fish population density and biomass for these rivers have been made and related to estimates made in two other rivers of similar terrain, one oligotrophic and the other eutrophic. Pre-migratory mortality rates in the salmon populations are discussed.
    • The Economic Significance of Ford Cork Week 1996 International Sailing Regatta

      Shields, Y; Deane, B; McDowell, N (Marine Institute, 1997)
      Ford Cork Week, held biannually, represents the highlight of the Irish sailing calendar and has, since its inception, in 1978 built up a formidable reputation as a world class sailing event. Over the period 1978 - 1996, entries to the event have grown from 40 boats to 486 boats: a level of participation that facilitates exciting and competitive racing in a number of varied fleets and classes. The 486 boats that participated in 1996 brought an influx of 3,360 participants (boat owners and crew) from all over Ireland, the UK and Europe to the local Cork area. Ford Cork Week is not, however, an event which appeals merely to boat owners and their crew. The event on the water is complimented by an extensive entertainment programme which, combined with the general ambiance created by the conglomeration of a large number of yachts and their crews, attracts a significant number of non-participating revellers. Given the high level of dependence of Crosshaven on the tourism and leisure side of sailing it is to be anticipated that an event on the scale of Ford Cork Week has a significant impact on the local economy. The event focuses the spending power of 3,360 boat owners and crew and a large number of accompanying visitors in the immediate vicinity of Crosshaven. This report, undertaken by the Marine Institute, estimates the revenue generated by the event and investigates its impact on the local economy. The report quantifies the level of expenditure by visitors vis a vis entertainment, accommodation and transport. It also gives a useful breakdown of the age of the attendees, their country of origin, the level of previous attendance, their source of hearing about the event, and an insight into the general organisational issues to be considered in staging an event of this scale. The report reveals that participants (boat owners and crew) at the event in 1996 spent a total of £1,387,000. In addition, the expenditure of non-participating overseas visitors attending the event was significantly higher than the average spend of overseas visitors to Ireland during the same year.
    • An ecosystem-based approach and management framework for the integrated evaluation of bivalve aquaculture impacts

      Cranford, P.J.; Kamermans, P.; Krause, G.; Mazurié, J.; Buck, B.H.; Dolmer, P.; Fraser, D.; Van Nieuwenhove, K.; O'Beirn, F.X.; Sanchez-Mata, A.; Thorarinsdóttir, G.G.; Strand, O. (Inter Research, 2012)
      An ecosystem-based approach to bivalve aquaculture management is a strategy for the integration of aquaculture within the wider ecosystem, including human aspects, in such a way that it promotes sustainable development, equity, and resilience of ecosystems. Given the linkage between social and ecological systems, marine regulators require an ecosystem-based decision framework that structures and integrates the relationships between these systems and facilitates communication of aquaculture–environment interactions and policy-related developments and decisions. The Drivers-Pressures-State Change-Impact-Response (DPSIR) management framework incorporates the connectivity between human and ecological issues and would permit available performance indicators to be identified and organized in a manner that facilitates different regulatory needs. Suitable performance indicators and modeling approaches, which are used to assess DPSIR framework components, are reviewed with a focus on the key environmental issues associated with bivalve farming. Indicator selection criteria are provided to facilitate constraining the number of indicators within the management framework. It is recommended that an ecosystem-based approach for bivalve aquaculture be based on a tiered indicator monitoring system that is structured on the principle that increased environmental risk requires increased monitoring effort. More than 1 threshold for each indicator would permit implementation of predetermined impact prevention and mitigation measures prior to reaching an unacceptable ecological state. We provide an example of a tiered monitoring program that would communicate knowledge to decision-makers on ecosystem State Change and Impact components of the DPSIR framework.
    • Ecosystems

      Marine Institute (Marine Institute, 2006)
      Ecosystems are composed of living animals, plants and non living structures that exist together and ‘interact’ with each other. Ecosystems can be very small (the area around a boulder), they can be medium sized (the area around a coral reef) or they can be very large (the Irish Sea or even the eastern Atlantic). One of the first tasks marine scientists must decide on is to define the boundaries of the ecosystem they want to look at (e.g. is it Dublin Bay? the Irish Sea? the north east Atlantic?). Once the ecosystem we are interested in is defined then we can think about how this part of the ocean should be managed. This must be agreed by consensus with all the stakeholders (users of the ecosystem).The idea here is that we are managing an ecosystem with many users not just a fish stock exploited by fishermen.
    • The edible mussel (Mytilus edulis)

      Crowley, M (Department of Agriculture and Fisheries (Fisheries Division), 1970)
      The mussel is one of the commonest bivalve molluscs around the Irish coast but quantity and quality vary greatly from place to place. Ideal conditions for the natural or farmed production of mussels are as follows:- (i) Sheltered bays or inlets; (ii) Firm shingly substrata; (iii) Good food supplies in the water; (iv) Absence of parasites and predators. Mussels on exposed shores subject to excessive water movement are usually slow growing and of poor quality. In other areas, although there is shelter from the action of wave and weather, the bottom may consist of soft mud or sand, neither of which is suitable for the settlement, survival and growth of mussels. Similarly areas may have the necessary shelter and firm substrata for the attachment of mussels, but, because the water does not produce an adequate supply of food material, the mussels do not flourish. Even in areas where there is shelter, firm substrata and plenty of feeding there may be many predators (e.g. crabs, starfish etc.) or parasites (e.g. redworm (Mytilicola intestinalis) and pea-crabs) which often render mussels unsuitable for marketing. Because of these limitations, it is not surprising that many areas of our coast produce mussels which are of poor quality. At present the five centres at which good quality mussels are produced are (a) Carlingford Lough (b) Dundalk Bay (c) River Boyne estuary (d) Wexford Harbour (e) Castlemaine Harbour (Cromane), Co Kerry.
    • Eel Research 1965-1971

      Moriarty, C (Department of Agriculture and Fisheries (Fisheries Division), 1972)
      The catch of eels for the Republic of Ireland is very low. It averages 125 tons a year, thus comparing unfavourably with such figures as 800 tons for Northern Ireland and 1,500 tons for Holland. Since 1965 experiments have been in progress to find out whether there is any possibility of increasing the production of this valuable fish. A detailed report of the investigations was completed in March 1972 and this leaflet gives a summary of the most important conclusions. The approach to the problem was to make a study of some aspects of the life of the eel, concentrating on lakes where commercial eel fishing was well established. In addition to this some fishing trials were made in the estuaries of rivers such as the Munster Blackwater and the Shannon where no large-scale eel fishing had ever taken place.
    • Eel Research 1972

      Moriarty, C (Department of Agriculture and Fisheries (Fisheries Division), 1973)
      The national survey of eel stocks was continued in 1972. For the first time the eel population of a river, the Munster Blackwater, was studied. It proved to be the most densely stocked freshwater area sampled to date. It was calculated that between five and ten tons of eels must leave the river each year on migration. Unfortunately the eels were slow-growing and of rather low quality. The eel stocks of Lough Gill and Lough Conn were found t o be poor, heavily overfished and the eels were slow-growing. Two restricted areas which had been subjected to intense commercial fishing for several years, the South Sloblands Channel in County Wexford and the Broadmeadow Estuary, showed poor stocks and will take several years to recover, Unfortunately, eels grow so very slowly (rarely taking less than ten years to reach market size) that their stocks are highly susceptible to damage from overfishing.
    • Eel research 1973

      Moriarty, C (Department of Agriculture and Fisheries (Fisheries Division), 1974)
      Eel research broke new ground in 1973 by beginning a study of elvers and young eels. Elvers enter fresh water in spring and make their ways upriver. Precise information on when they arrive, in what numbers and how far they travel is very limited, although the subject was studied in the early years of the present century. Knowledge of the behaviour of eels in these early stages is essential because we have now proved that the scarcity of eels in many Irish waters is caused by the failure of the small eels to reach them. The situation could be improved by artificial transport of the young eels but first they must be caught and we must find out where and how best to catch them. In 1973 the arrival of elvers happened rather late and many were still on the move from the end of June right up to August. A study of the young eels at Parteen Weir on the River Shannon showed that there were virtually no elvers amongst them. This indicated that elvers took more than a year to travel distance of nine miles to Parteen from the top of the tide.
    • Eel Research 1978-1979

      Moriarty, C (Department of Agriculture and Fisheries (Fisheries Division), 1980)
      The good prices paid to fishermen for eels have led to an increased interest in eel capture in Ireland. In that regard the results of stock assessments examined in conjunction with records obtained from other European eel fisheries, have indicated that the present national catch could be increased by at least 100% and perhaps by several times as much. Such an improvement could be effected by the overland transport of elvers from collection points near the coast. An operation of this kind in already in progress on the Shannon river system undertaken by the Electricity Supply Board who own the entire fishery. Sampling of eels within that system have indicated that substantial increases in the numbers of growing eels in the lakes and in the numbers of male silver eels captured, have taken place. Since it takes between ten and twenty years from the beginning of a stocking programme for any results to be apparent it is essential to devise a system for making an accurate assessment of the developments. This is the principal aim of the routine sampling of yellow eels which forms the greater part of current research work.
    • Eel Research in 1968

      Moriarty, C (Department of Agriculture and Fisheries (Fisheries Division), 1969)
      Fyke nets for the capture of eels have been in use in some parts of the country since 1961. These are “summer” type nets, laid on the bottom in lakes and river estuaries and having, when set, a maximum height of about 60 cm (2 ft.). Experiments with these nets were made in a number of lakes from July to September. Five students were employed to operate the nets and examine the eels. Each student was supplied with a set of eight nets (sixteen traps with eight leaders arranged in a line) and the nets were fished daily except at weekends or in rough weather. The traps were 1.84 m (6 ft.) long with an opening diameter of 43 cm (16 ins.), the leaders were 4.7 m (18 ft.) long and the mesh size at the cod end was 1 cm (0.4 ins). The areas chosen were Lough Corrib (mainly in the vicinity of the Docros peninsula), Loughs Inchiquin and George, near Corofin, Co. Clare, Loughs Ecnish and Tullyguide, near Killeshandra and Town Lake, Dromore Lake and Dromloona Lake, near Cootehill, Co. Cavan, the latter three by kind permission of Brigadier Dorman O'Gowan. In all cases the lengths of the eels were measured and the stomachs and otoliths of as many as possible were collected. The Lough Corrib eels were also weighed, their weights were used subsequently to calculate the weights of the eels from the other lakes. Examination of the stomach contents and otoliths of the eels has not yet been completed. The indications are that the majority of the eels feed on invertebrates while a small proportion feed on fish. Loughs Corrib and George in the areas fished offer poor feeding while Inchiquin and the County Cavan lakes are rich.
    • Eel Research in 1969

      Moriarty, C (Department of Agriculture and Fisheries (Fisheries Division), 1970)
      Most of the research effort was concentrated on experiments with summer fyke nets on the lines of the 1968 work (leaflet No. 9). Three zoology students, Messrs. Dermot Douglas, Tommy Hayden and Martin O’Grady were employed on bursaries for the field work and the Electricity Supply Board co-operated on the Shannon System. The standard set of eight nets (sixteen traps with eight leaders, arranged in line) was used on the Corrib system. On account of losses and damage to nets only seven were available for the Shannon but it is unlikely that this made any material difference to the results. When possible fishing took place daily. The figures are based, with one exception, on the total number of days when the nets were fishing, including weekends and stormy weather when they were not lifted daily. The exception was Lough Mask where persistent rough weather made lifting the net impossible for a fortnight. It was found in this case that the smaller eels escaped and the catch was therefore not typical of normal conditions. The nets used had a mesh size at the cod end of 10 mm.
    • Eel Research in 1970

      Moriarty, C (Department of Agriculture and Fisheries (Fisheries Division), 1971)
      The summer of 1970 was the third in which a standard set of fyke nets was used to make a detailed study of the eel stocks in a particular lake. The lake chosen was Lough Key which lies on the Boyle River, a tributary near the source of the River Shannon. Miss Ann Fortune and Miss Christine Royle, zoology students, were employed on bursaries for the field and some of the laboratory work. The method of working has been described in previous Leaflets (Nos. 9 and 21). In brief it consists of fishing daily with a standard set of eight nets (sixteen traps with eight leaders arranged in line) which have a cod-end mesh size of 10 mm. The eels were measured, weighed and sexed and otoliths and stomachs were preserved for examination.
    • Eel research in 1974

      Moriarty, C (Department of Agriculture and Fisheries (Fisheries Division), 1975)
      The value of eels at present is about 50p per pound, placing them amongst the most highly priced fish. Our studies over the past few years have shown that most of the Irish eel-barfing waters are seriously under stocked. This situation can be greatly improved by artificial stocking.
    • Eel Research in 1975

      Moriarty, C (Department of Agriculture and Fisheries (Fisheries Division), 1976)
      The national survey of Irish eel stocks was completed in 1975. A definitive report is being prepared and will be published later. The work began eleven years ago and the final phase was a study of the eels in the River Barrow. We have now searched for eels in coastal locations, in river estuaries, rich lakes, poor lakes, mountain streams and lowland rivers rich and poor. This has provided a picture of how and where quantities of eels may be found, how they may best be fished for and managed and how the stocks may be improved for the benefit of the fishermen. The stocks are definitely low, although the annual output of eels is of the order of one hundred tons with a value of over £100,000. About two-thirds of this catch came from the Shannon fishery. In general, fishing is intensive and the scope for improvement in fishing methods is limited. Stocking with elvers however, can greatly increase the catch in the long term and at a value of £1,000 a ton it is clearly worthwhile to go to work on this. The Electricity Supply Board has in fact been engaged in restocking for many years and can expect an increased yield in the near future.
    • The Eel Stocks of the Shannon System and Prospects for Development of the Fishery

      Moriarty, C (Department of the Marine, 1987)
      Lough Neagh has long been known to yield the greatest quantities of eels of any water body in Ireland, the annual catch being in excess of 700 tonnes. The Shannon catchment on the other hand yields less than 100 tonnes per annum. This Leaflet describes work carried out in Lough Neagh and in the Shannon catchment in 1985 and 1986 which has indicated that eels are now more abundant in the Shannon System than in Lough Neagh. The implications are that the stocks in the Shannon System are sufficient to yield an annual catch of as much as 1,000 tonnes and value £2 million. The current capital cost of establishing a two-man crew capable of catching 3 tonnes of eel, value £6,000, is £2,500. Annual running costs per crew are less than £1,000. The large scale exploitation of the fishery would involve much more substantial investment by the owners. Arising from this paper, the Department has raised the matter with the ESB and the Shannon Regional Fisheries Board to agree on a strategy to maximise employment from the fishery.