Now showing items 21-40 of 181

    • Have Hatcheries a Role in Sea-Trout Management?

      Fahy, E (Department of Fisheries and Forestry (Trade and Information Section), 1983)
      The artificial propagation of sea trout in Ireland has a long history but the fish were never produced in large numbers and they were disposed of at an early stage in development. The evidence suggests that artificial propagation was undertaken as a by-product of salmon management. The circumstances in which artificial propagation of sea trout may be justified are examined and some general reservations are expressed. For the future it seems likely that sea trout will be exploited in wild rather than in put-and-take fisheries. The emphasis should remain on providing the most suitable nursery conditions for the fish to reproduce naturally. Further investigations should however be undertaken on devising suitable methods of propagating sea trout and consideration might be given to re-establishing some of the long lived strains which are now believed to be extinct.
    • The Sea Trout Year, 1982

      Fahy, E (Department of Fisheries and Forestry (Trade and Information Section), 1983)
      The large juvenile trout exodus from fresh water to the sea which occurred in 1981 was not repeated in 1982. Climatic indicators suggest alternately good and poor years in the output of juvenile fish with a reduced recruitment to the fishery in the immediate future. The mean smolt age is likely to rise and the consequences of this will most likely be a reasonable post-smolt (or finnock) run and a diminution in the contribution of larger sea trout to the catch. Added to the poor run of exploitable fish in 1982, the angling season was curtailed by very dry weather which reduced effective fishing effort. In spite of this, yield per rod licence was almost identical to that in the previous year. However figures for the fishery districts suggest that fewer sea trout were captured. Draft net catches were up on those of 1981 by 68%. This had been anticipated in Fisheries Leaflet number 116 which suggested that trout from the larger juvenile exodus of 1981 would become exploited as one sea winter fish by this method: the recorded increase in the catch was almost certainly promoted by dry summer weather which confined sea trout to the estuaries. Both draft and drift net sea trout catches constituted a higher proportion of the salmon net catch in. 1982 than in 1981. The latter showed a marked reduction on the previous year but this evaluation of the data does not include returns from the Western and particularly the Northern fisheries regions where the salmon catch was said to be high.
    • Surveys for Herring Larvae Off the Northwest and West Coasts of Ireland in 1981

      Grainger, R; McArdle, E (Department of Fisheries and Forestry (Trade and Information Section), 1982)
      This Leaflet describes the methods used in sampling and gives the results of the 1981 survey in a series of maps showing the distribution of the young larvae. Sampling took place at fortnightly intervals and recorded the numbers of larvae in three size groups. The area of operation extended from Lough Foyle to Galway Bay. This region has been chosen because it is believed to include the entire spawning stock of a new assessment area for the herring. The survey has shown that spawning moves progressively southwards during the season in October and November and that there are three main spawning areas: north of Fanad Head, west of Aranmore and between Erris Head and Inishbofin. When the survey has been in progress for a few years it will be possible to make an improved annual assessment of the herring stock in the region which can be used by management to ensure that the fishery is exploited to the fullest extent without risk of damage to the stocks in the future.
    • The Sea trout Year 1981

      Fahy, E (Department of Fisheries and Forestry (Trade and Information Section), 1982)
      1981 was not a great year for sea trout landings. Rods which account for a large proportion of the total catch took fish of lower mean weight than in 1980 and various estimates suggest that fewer sea trout were caught in 1981. Numbers of "specimen" sea trout however were high and they are expected to remain so in 1982 after which it is thought they will decline. The draft net catch was also down on 1980; estimates of the drift net catch are inconclusive. In 1981 climatic factors favourable to trout production continued to improve from 1919 but indicators of growth still fell Short of those prevailing in the mid 1970s. The migration of juvenile trout to sea was good but the run seemed to consist largely of slow growing individuals whose development was arrested in 1979. A recovery of sorts would appear to be underway in the stocks and this is the explanation for the low mean weight of individuals caught in 1981. However the extended occupation of nursery areas by parr between 1919 and 1981 may well have inhibited the development of prospective migrants in 1982 and 1983.
    • Population estimates of juvenile salmonids in the Corrib system 1981

      Browne, J; Gallagher, P (Department of Fisheries and Forestry (Trade and Information Section), 1982)
      This is the third in a series of reports regarding the stocks of juvenile salmonids in the Corrib system. During the 1981 season fourteen tributaries were surveyed and in two cases upstream and downstream reaches were examined. These included three which had not been studied previously: the Failmore, Letterfore and Black. The methods were identical to those used in 1979 and 1980. As in the previous years the rivers were selected because they were known salmon holding tributaries and do not reflect trout numbers in the system. The population numbers are assessed by electrically fishing a selected area. The fish caught are marked by fin clipping and allowed to re-mix with the fish in the stream. The next day fishing is repeated in the same place and the proportion of marked to unmarked fish gives an estimate of the population. While it is not essential that river conditions remain the same on both days it does help the accuracy of the estimate. There is a tendency for fish to move out of their home territories during floods. Population surveys yield the best results when a large proportion of the tagged fish are recovered. Ideal electro fishing conditions are low water, overcast sky and similar river conditions on both days.
    • List of Fishery Leaflets Nos. 1 (1938) to 111 (1981)

      Anon. (Department of Fisheries and Forestry (Trade and Information Section), 1981)
      These leaflets provide a medium for distributing information on various aspects of fishery research and development undertaken by Officers of the Department. 111 leaflets have been published to date (December, 1981). A list is attached.
    • The sea trout year 1980

      Fahy, E (Department of Fisheries and Forestry (Trade and Information Section), 1981)
      The fol1owing pages comprise the first of a brief and, hopefully, annual account of research in progress on sea trout, a summary of results recently available and a short account of stocks of this fish during the preceding fishing season with a tentative prognosis for the coming year. The purpose of the report is to inform user groups, anglers and netsmen, about the work and to promote an interchange of information with interested parties; a primary objective is the identification of priority research objectives and hence the promotion of better management of fisheries in which sea trout are an important or the only quarry.
    • 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.
    • Performance of the Crumlin sea-trout Fishery, Co. Galway

      Fahy, E (Department of Agriculture and Fisheries (Fisheries Division), 1979)
      The physical features of the Crumlin catchment, a small sea-trout fishery in Co. Galway, are described. Its sea-trout stock is examined and found to be typical of others in the region: the fish are slow growing in the sea, poorly conditioned, mortality in the stock is high and the fish have a low weight at capture. Fishery statistics date from 1896. The main influence on the numbers taken by anglers appears to have been the two wars. Individual catch weights do not show any inverse relationship with catch numbers of the kind that has been reported already in the vicinity. Catch per effort has not altered in keeping with any identifiable long-term trend but is within the range recently reported elsewhere in the region. Regulations designed for the protection of smolts in past years also protect about 20% of post-smolts (finnock) currently captured. Yield from Crumlin has most in common with output from a small neighbouring fishery. It is tentatively suggested that sea-trout production from the Connemara catchments is dependent primarily on the physical features of the systems concerned.
    • The fat content of Irish herring

      Molloy, J; Cullen, A (Department of Fisheries and Forestry (Trade and Information Section), 1981)
      The fat content in herrings determines the way in which these fish are presented for human consumption. For example, a high fat content is good for kippering, whilst low fat is suitable for marinating. The Department of Fisheries & Forestry has for many years provided the trade with the fat content data they require. The information is based on routine analyses of herring samples which are now made regularly at the Fisheries Research Centre. Sufficient data have been collected over the past ten years to prepare graphs of the mean monthly fat contents in our four main herring fisheries. These graphs may be used to estimate when herring of a particular fat content will be available. This Leaflet presents the essential data and gives an explanation of the biological background of the changes in fat content.
    • List of some historical papers etc. on Irish fish, fishing and fisheries 1940-1974

      Went, A E J (Department of Agriculture and Fisheries (Fisheries Division), 1978)
      Since 1940 I have had a keen interest in the history of fish, fishing and fisheries in Ireland and in my capacity as an inspector of fisheries I had an unrivalled opportunity, in my travels around the country, to acquire information on fishing methods, which were becoming, or even had became obsolete. For example, when I was preparing my second paper on the Galway Fishery (No. 6 on list below) I made inquiries at the National Museum, Dublin as to what Irish fishing spears were preserved in that museum. I was surprised to learn that very little material of this kind was available, although I knew that “hoards” of salmon spears, seized by the Boards of Fishery Conservators, were kept in various parts of Ireland. Fortunately I was able to have these, and other spears, mainly for eels, collected up and deposited in the National Museum, which can now claim to have a good representative collection of Irish traditional fishing spears for salmon and eels. My paper on Irish fishing spears (No. 29 on list below) resulted from the collection of the fishing spears referred to above. Articles in newspapers and other popular journals have generally been omitted from the list below, because they were usually based on information given in contributions to the journals etc. of learned and other societies. This list also does not include details of papers on the scientific aspects of Irish fisheries, details of which have already been published in Fishery Leaflet No. 25.
    • Mulroy Bay Scallop Research 1980

      Griffith, David de G (Department of Agriculture and Fisheries (Fisheries Division), 1981)
      Following a preliminary investigation in 1977, the Department of Fisheries & Forestry carried out an intensive multi-disciplinary survey of Mulroy Bay in the summer of 1978. The results of this "blitz" survey, when evaluated, formed the basis of more extensive research in the North Water during 1979. This North Water programme was expanded in 1980, as part of the Department's contribution to a co-operative research programme on Mulroy Bay organised in conjunction with the National Board for Science & Technology. This included a hydrographic survey, specially commissioned by the Department, to produce a detailed bathymetric chart of the North Water. This was made available free of charge to interested individuals and groups in the locality. The 1980 research results were presented at a seminar in January 1981 at the Department's Fisheries Research Centre, which was organised in order that the data obtained could be discussed and evaluated by the individuals and agencies involved in the field programme. This Fisheries Leaflet is a summary of the papers read at that seminar, by staff of the Fisheries Research Centre.
    • 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.
    • The herring fisheries on the South and South-West coasts 1977-78

      Molloy, J (Department of Agriculture and Fisheries (Fisheries Division), 1978)
      Herring fishing off the south coast, in that area now commonly known as the Celtic Sea, was prohibited during most of the year commencing 1 April 1977. In spite of this, however, nearly 3,000 tans of adult herring are believed to have been taken, mainly by Irish and Dutch vessels. Scientific investigations and the results obtained from a trawling survey carried out from September 1977 to January 1978 indicated that the spawning stock is still in a very depleted condition. Recruitment of young herring to the adults stocks during the last three years has been critically low and because the adult stock size is now estimated to be only 10,000 tons a continuation of the existing ban on fishing must be envisaged for some time. The fishery off the south west coast in 1977, showed an increase in landings largely due to increased catches in November off Fenit, Co Kerry.
    • Herrring Investigations on the North-West and West coasts 1976

      Molloy, J; Kennedy, T D (Department of Agriculture and Fisheries (Fisheries Division), 1977)
      The herring fisheries off Donegal, Mayo and Galway in 1976 are reviewed. A serious decline in catches, particularly in the Donegal fishery, took place but this was compensated for by increased prices. The decline in catches is caused mainly by a decrease in stock size, because the recruitment of young herring in recent years has not compensated for the amounts removed by fishing. To minimise the dangers of poor recruitment it would be unwise to allow any fishing to develop on young immature herring in the area. The total international catch off Galway increased considerably in 1976, largely due to increased Dutch effort. International catch restrictions on the total catch are likely to be even more severe in future years.
    • Preliminary Investigations of the Sprat stocks off the South coast of Ireland

      Molloy, J; Bhatnagar, K (Department of Agriculture and Fisheries (Fisheries Division), 1977)
      The development of a new fishery for sprat off the south coast is reviewed. The fishery during 1976 and 1977 produced over 1,600 tons of sprat, valued at over £92,000. The quality of sprat landed was excellent throughout the fishing period. While it is difficult to estimate the size of the stock in the area, it would appear that landings could be substantially increased. This, together with the quality of the sprat, could make this fishery a valuable alternative to the Celtic Sea herring fishery.
    • The herring fisheries on the South and south West coats 1976-77

      Molloy, J (Department of Agriculture and Fisheries (Fisheries Division), 1977)
      The quantities and values of herring landed during the 1976/77 herring season off the south coast and during the July to November period off the south west coast are reviewed. In both areas there was a further serious decline in the catch - mainly due to a continuing very poor rate of recruitment of young herring to the adult stock. In the Celtic Sea the total international catch during 1976/77 was only 7,000 tonnes compared with 48,000 tonnes in 1969, while the total Irish catch of approximately 3,000 tonnes was the lowest since the mid-fifties. The immediate aim of any management policy for the Celtic Sea herring stock must be to rebuild it to a level of at least 40,000 tomes. It is, at present, estimated to be below 10,000 tonnes. This can only be done by having a complete ban on all herring fishing in the Celtic Sea until 1980 at least.
    • Herring investigations on the North West and West coasts 1975-76

      Molloy, J; Kennedy, T D (Department of Agriculture and Fisheries (Fisheries Division), 1976)
      The herring fisheries off the northwest and west coasts during 1975 and 1976 are reviewed. Details are given about value of the fishery off the Donegal, Mayo and Galway coasts in recent years. Scientific examinations show that there has been a decline in stock size in the area, chiefly due to poor recruitment of young herring. The question of management of the fishery is also discussed in view of the increased catches by continental fleets fishing in the area.
    • Movement of Salmon from the South Coast in 1975

      McCarthy, D T (Department of Agriculture and Fisheries (Fisheries Division), 1977)
      In 1973, tagging investigations commenced into the origin of the salmon stocks being exploited by drift nets along the south coast of Ireland (8º0’W - 10º0’W). The exploitation of these stocks commenced in 1968 with a catch of 1,500 fish and by 1975 the catch had increased to 90,400. The results of the 1973-1974 programme and a description of the fishing methods used have been published in Fishery Leaflet No. 67. Throughout the programme, fish were tagged using Lea’s hydrostatic tags described by Went (1951). A marked difference in returns was observed in 1975 between salmon revived in sea water tanks and those released directly after tagging, In the former, a 14.8% recapture rate was recorded, compared with 6% in the case of salmon released immediately after tagging.
    • 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.