INITIAL OBSERVATIONS ON FEEDING JUVENILE SEA LAMPREY (PETROMYZON MARINUS L.) IN IRISH LAKES

Reports of feeding on host fish by juvenile sea lamprey have been known from a number of Irish freshwater lakes since the 1950s.This review confirms the continued presence of juvenile feeding sea lamprey in some these lakes, with additional recent records from other waters. Juvenile sea lamprey out-migrating in winter (January) had a modal peak of 160mm. In-lake feeding fish were recorded in many months of the season, between January and September, and ranged in size from 140 to 410mm. The majority of records were compiled in the May June period during the brown trout 'mayfly' angling season. Feeding juvenile fish were also recorded attached to pike and bream. Information compiled indicated a low rate of attachment on host fish. No records of spawning by 'dwarf' sea lamprey in streams discharging to the host lakes have been recorded to date.