A Survey of Nursery Grounds for Celtic Sea and VIIj Herring

Abstract

The need for a recruit index for the herring stock in the Celtic Sea and Division VIIj has long been recognised. In order to develop a survey for recruits and pre-recruits, good information on the distribution of these fish is required. This study is based on a pair trawl survey, conducted in February 2008. The area covered was from central-east Irish coast (Dundalk Bay) to central west Irish coast (Galway Bay), with special attention paid to the bays and inlets of the south and southwest coast. The overall aim was to map out the distribution of 0- and 1-ring herring so that decisions could be made on the design of a future survey for young fish. The catch was quantified and sorted according to species. Herring were sampled for length, weight, sex, maturity and age. Young herring appeared as a light dust on the 38 kHz frequency. The east coast of Ireland, from Dundalk Bay to Howth was identified as an important nursery area, though it was not possible to ascertain what proportion of these juveniles were of Celtic Sea origin. Within the Celtic Sea the main nursery grounds identified were Dungarvan Bay, Cork and Kinsale Harbours. All the bays surveyed in VIIj contained juvenile herring. Overall this survey was a success. It provided updated information on the occurrence of young herring along the coast. Along with information from fishermen, and literature sources it allows for the development of recruit surveys for herring of this stock. Further work remains to be done on discriminating the juveniles by season of spawning.