JUVENILE RECRUITMENT AND SMOLT OUTPUT OF BROWN TROUT (SALMO-TRUTTA L)AND ATLANTIC SALMON (SALMO-SALAR L) FROM A LACUSTRINE SYSTEM IN WESTERN IRELAND

A combination of electrofishing of feeder streams and shore seine nett ing of two lakes in a salmonid fishery in Burrishoole, western ireland provided evidence of extensive use of lacustrine habitat by juvenile Atlantic salmon and brown trout. Mean densities of 0.024 trout and 0.0 02 salmon m(-2) were recorded in L. Bunaveela (46 ha), and 0.010 trout m(-2) and 0.010 salmon m(-2) in L. Feeagh (410 ha). Appearance of 0salmon and trout in summer seine net catches indicated early downstrea m movement of fry from inlet streams to lake inshore areas which also provided nursery habitat for older age classes. Total trap records of salmon and sea trout smelts migrating from Burrishoole catchment since 1970 were used to provide one of the first published estimates of sme lt production from a lacustrine catchment in temperate Europe. Trout a nd salmon smelt output from Burrishoole was shown to have declined by about 50% since records began. Current levels of production are estima ted at about 4 sea trout smolts ha(-1) (0.4 kg ha(-1)) and about 13 sa lmon smelts ha(-1) (0.3 kg ha(-1)). (C) 1997 Elsevier Science B.V.