Browsing Scientific Papers by Subject "Celtic Sea"
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Herring larval surveys in the Celtic Sea and division VIIj in 1982/83Surveys for herring larvae in the Celtic Sea were conducted between October 1982 ~ and February 1983 for the fifth successive season. To take account of the amalgamation of the Celtic Sea and Div VIIJ herring for assessment purposes and to ascertain if many larval drift into the Irish Sea, the survey grid of previous years was modified for the 1982/83 season. However, because of the nature of the larvae distribution it appears reasonable to compare the larvae index for 1982/83 with those of the previous seasons. The increase in indices since 1978/79 has continued up to 1982/83 indicating a steady, but slow, recovery of the spawning stock. Very few larvae appear to drift into the Irish Sea.
Herring larval surveys in the Celtic Sea and division VIIj in 1983/1984Surveys for herring larvae in the Celtic Sea were conducted for the sixth ~ successive season between October 1983 and February 1984. The modifications made to the survey grid in the previous season to take account of the amalgamation of the Celtic Sea and Division VIIj for assessment purposes and to ascertain if larvae drift into the Irish Sea were also adopted for the 1983/84 surveys. A drift of larvae towards the Irish Sea was apparent in 1983/84. The larval abundance index for 1983/84 based on a standard survey area was almost three times higher than any previous value. A continuous increase in larval indices since 1978/79 indicates a recovery of the spawning stock.
Herring larval surveys in the Celtic Sea in 1981/82The distributions of herring larvae sampled on ten cruises off the south coast of Ireland during the 1981/82 spawning season are described. A new larval abundance index, which is based on the abundances of <10mm larvae prior to 15 December and on <11mm larvae afterwards,has been calculated for the last four seasons. This index shows an increase each year since 1978/79 indicating that the spawning stock biomass has also increased.