Sea-trout and their fisheries from the Dublin Fishery District

Abstract

Age, length and weight data from 440 sea-run trout are described together with data from 339 parr from a small trout stream. Pre-migratory length at age was not influenced by calcium content of nursery streams. Relatively faster growth of certain year classes in particular years was observed. Mean smolt age (2.1 years) was low. Sea run fish averaged at 0.86 sea-winters, contrasting with longer lived sea-trout on the Welsh coast but early maturation was observed in both. The regression coefficient for percentage previous spawners on mean individual weight in the Irish/Celtic Seas was lower than for fish from the Atlantic. The four principal fishing centres are each supplied with sea-trout by two to four small to medium sized rivers. A proportion of the catch is likely to originate in non licensed mullet gear. The annual catch declined from a peak of four tonnes in the 1950s to stabilise at 1.5 tonnes since the 1960s. The decline coincided with an increase in the ratio of draft to drift nets.