Report of the Working Group on Herring Larval Surveys South of 62 N

The lCES Working Group on Herring Larval Surveys South of 62 N met for 5 days, 6-10 January 1986, in Hirtshals in accordance with C.Res. 1985/2:6 to produce a comprehensive review for full consideration by the North Sea Herring Assessment Working Group at its 1986 meeting, in order that it can evaluate the value of the her ring larval surveys tor assessment purposes. The terms of reference were:

(i) to review the causes of the continued difficulties in calculating the annual abundance indices using the present method based on abundance of only smaller larvae;

(ii) To evaluate the methods developed for calculating larval production, with confidence limits, from larval size distribution and estimates of larval growth and mortality rates;

(iii) to consider methodologies of calibrating larval production estimates to derive spawning stock biomasses independently of the use of VPA derived values.