Surveys of herring larvae in the North Sea and adjacent waters 1973/74
1. Report on the international surveys of herring larvae in the North Sea and adjacent waters 1973/74; R. J. Wood.
This report describes the results of the seventh international survey of herring larvae in the North Sea and adjacent waters. These surveys have been carried out annually since 1967 and they are intended to pro-vide measures of changes in the North Sea herring spawning stocks which are independent of catch per unit effort data.
Results of the previous surveys are published in Saville (1970), Boetius and McKay (1970), Wood (1971), Zijlstra (1972), Schnack (1973) and Saville and McKay (1974).
2. The distribution and abundance of herring larvae to the west of Scotland in 1973; D. W. McKay.
The results of herring larval surveys carried out to the west of Scotland in the autumn of 1973 are described. Larval densities were similar to those of corresponding surveys in 1972. The results are discussed in terms of numbers of larvae and in relation to the adult stock size in the area.
Comparisons have also been made between surveys carried out in early September by the RV "Corella" and RV "Scotia" and possible reasons for the differences are discussed.
3. Abundance and distribution of herring larvae in the North Sea and adjacent waters in 1973; E. Hahlbeck.
The investigations on herring larvae abundance which have been performed since 1962 were continued in 1973 during a cruise of FRV "Eisbär".
A research programme agreed upon with the People's Republic of Poland and the Soviet Union for investigation of the herring larvae abundance in the most important spawning areas along the east coasts of Scotland and England started in 1963 and has been continued with only a single interruption (we were unable to investigate the herring larvae abundance in 1972) until the present time.
The results of our work from 1962 to 1967 were published by Hyronimus in 1971, those for 1969 by Schultz and Hahlbeck in 1970 and those for 1970 and 1971 by Hahlbeck in 1973. These publications and the present paper deal exclusively with the results of our contribution to the joint programme.
The aim of the investigations is to clarify the problem of recruitment and to contribute towards assessment of the future year classes.
This paper deals with the abundance and distribution of herring larvae in 1973,