• 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.
    • Heavy Metals in Mussels and Sea-Water from the Irish Coast

      Crowley, M; Murphy, C (Department of Agriculture and Fisheries (Fisheries Division), 1976)
      Samples of mussels and sea-waters from various locations around the Irish coast were analysed for certain heavy metals using Atomic Absorption (AA) Spectroscopy. The results are presented and discussed below.
    • Irish Mussel Fishery 1971-1972

      Crowley, M (Department of Agriculture and Fisheries (Fisheries Division), 1972)
      Since 1966 the landings of mussels in Ireland have increased significantly. Almost all the mussels landed are exported either in the processed form or live in the shell to Britain and the continent; only a small quantity (only a few cwt.) of live mussels are sold weekly during the season in Dublin. The price of such mussels averages about 7½p per pound. The amount of mussels consumed in the rest of the country is negligible.
    • Making more money from Periwinkles

      Crowley, M (Department of Agriculture and Fisheries (Fisheries Division), 1975)
      Each year about £250,000 worth of periwinkles are picked on our shores. This makes them far and away the most valuable molluscs in our fishing industry. What is more, the value might be doubled if the catch were to be handled carefully. The fact is that, although they appear very tough, the periwinkle are in some ways delicate animals and rough treatment kills many of them. An important fact in the periwinkle industry is that the resource is a natural one which costs little to exploit. No equipment is required to harvest them because they are simply picked by hand when the tide is out.
    • Parasitology of Irish Mussels

      Crowley, M (Department of Agriculture and Fisheries (Fisheries Division), 1975)
      Investigations of the distribution of three parasites of mussels, an internal copepod parasite of the gut (Mytiliocola intestinalis), an external decapod parasite in the gill region (Pinnotheres pissum) and an annelid shell parasite (Pylodora ciliata) were carried out from September 1974 to May 1975. Samples from 28 locations around the Irish coast were investigated. One hundred mussels from each sample were weighed, measured in 5 mm groups, boiled and the following parameters were determined as percentages of the whole mussel:- a. Shell: b. Meat; c. "Loss"
    • The Parasitology of Irish Mussels

      Crowley, M (Department of Agriculture and Fisheries (Fisheries Division), 1972)
      Investigations of the distribution of three parasites of mussels, an internal copepod parasite of the gut (Mytilicola intestinalis), an external decapod parasite in the gill region (Pinnotheres pissum) and an analid shell parasite (Polydora ciliata) were carried out from October 1971 to April 1972. Samples from 26 locations around the Irish coast were investigated. One hundred mussels from each sample were weighed, measured in 5 mm groups, boiled and the following were estimated as percentages of the whole mussel:- a. Shell; b. Meat; and c. Loss.
    • Preliminary Survey of the Littorina littorea (the Periwinkle) in South-East and South Coasts of Ireland

      Crowley, M (Department of Agriculture and Fisheries (Fisheries Division), 1973)
      Of the three periwinkles Littorina littorea, Littorina saxatilis and Littorina littoralis only L. littorea, is of commercial value. The other two species are used mainly for decorative purposes and not for human consumption. Periwinkles are found on rocky shores and also on muddy intertidal zones which have a good cover of seaweed. They spend most of their existence in the intertidal zone below high water of neap tide and are found associated with the brown sea weeds such as bladderwrack (Ascophalium nodosum) and also the green sea weeds (Enteromorpha spp.). These weeds provide them with both shelter and food. Periwinkles browse on the sedentary animals which live on sea weed and on the weed itself. The investigations were confined to the size and quality of the periwinkles from Wexford, Waterford, Dungarvan, Youghal and Cork Harbours. The numbers per kilogram and the percentage meat yield were determined together with length frequency distribution.
    • Shellfish Survey of Castlemaine Harbour (Cromane)

      Crowley, M (Department of Agriculture and Fisheries (Fisheries Division), 1973)
      Castlemaine Harbour has the oldest mussel fishery in Ireland and the only mussel purification tank to date (capacity 360 tons per month built in 1941) is operated in that area. The monthly landings and their values since 1966 are given in. Recently Castlemaine Harbour has shown a sustained annual growth in mussel landings. In September 1972 a survey was carried out in Castlemains Harbour and the inner part of Dingle Bay to estimate the total quantity of available commercial shellfish. There are bout 6,840 acres in Castlemaine Harbour inside a straight line drawn from Inch Point to the old Coastguard Station at Cromane. About 2,000 of these are sub-littoral and the rest consist of about 1,800 acres of sand (which is less suitable for shellfish farming). A further 2,240 acres of mud and sandy mud at Banc Fluic are suitable for shellfish cultivation. There are a further 880 acres suitable for cockle cultivation outside these boundaries in Glenbeigh Straid known locally as the Cockle Strand.
    • Shellfish Survey of Estuaries and Bays of West Cork

      Crowley, M (Department of Agriculture and Fisheries (Fisheries Division), 1972)
      A survey was carried out in the summer of 1971 in the estuaries and bays of West Cork, by biologists from the Department of Agriculture and Fisheries. The purposes of the survey were to: (1) determine the potential of this area for possible shellfish farming; (2) discover any existing beds of edible mussels or other commercial shellfish species; and (3) describe the type of mussel found in each area.