Publication Abstract

Can groundfish surveys be improved without breaking the series?

A.J.R. Cotter

Time series of CPUE indices estimated for selected gadoids from North Sea groundfish surveys undertaken by different countries are compared by converting to series of total mortality, Z, for each survey. A reasonable degree of coherence is seen amongst the surveys, but not enough for complacency over designs. Reasons for divergences are discussed, and a case made for more randomisation, within practicable limits, of station positions, fishing times, and other survey procedures. With planning, design improvements could be incorporated without losing comparability between old and new time series.

Reference:

A.J.R. Cotter, 1997. Can groundfish surveys be improved without breaking the series? ICES Copenhagen, CM1997/Y:24, 8pp + figs.