Report of the Working Group on Methods of Fish Stock Assessments

Terms of reference

It was decided at the Statutory Meeting in Copenhagen in 1990 (C. Res. 1990/2:5:24) that the Working Group on Methods of Fish Stock Assessments (Chairman: Dr G. Stefansson) would meet in St. John's, Newfoundland from 20-27 June 1991 to:

a) consider the effects of management measures on the interpretation of fishing effort data and, in particular, advise how best to cope with considerable changes in catchability in assessments using effort and CPUE data;

b) advise on the accuracy of prognoses derived from assessments based upon effort and CPUE data and corresponding to the classical management options (the evaluation should use simulated and real data sets);

c) advise on the validation or otherwise of the hypo­theses upon which stock estimation techniques are based (use of diagnostics, etc.);
d) advise on the appropriateness of using length cohort analysis for Nephrops stocks given the non-smooth growth of this species;
e) advise on the feasibility of extending time series on stock and recruitment for selected fish stocks to earlier years using cruder methods than virtual population analysis.