Publication Abstract

An attempt to ascertain the spawning faction of female North Sea whiting based on visual staging of maturity

P. J. Bromley and J. Casey

This paper is based on the analysis of female whiting maturity data collected during North Sea International Bottom Trawl Surveys from 1991-1995. This provided an opportunity to investigate the sexual maturation of whiting throughout the North Sea on a seasonal basis. A standard protocol based on a 4-stage maturity key was used to sample the maturity stage of the whiting and the data were pooled into a common database. There was evidence that 1-group female whiting were predominantly non-spawning adolescents, or else spawned only occasionally. The whiting exhibited a protracted spawning season during the first half of the year. Because of this, and the relatively simple gonad grading key used to assess maturity, it proved difficult to obtain a reliable estimate of the spawning faction of the population as a whole. A more sophisticated gonad grading system appears to be required to achieve that objective.

Reference:

P. J. Bromley and J. Casey  (2003) An attempt to ascertain the spawning faction of female North Sea whiting based on visual staging of maturity. Fisken og Havet, No. 12.25-28