Publication Abstract

Methods to assess female maturity and realised fecundity illustrated by studies on Solea solea.

P.R. Witthames

Studies on the development of potential fecundity during maturation, and its dispersal during spawning are described in Solea solea with reference to assessment of maturity at age and realised fecundity. Recruitment of fecundity was shown to be complete well before the start of spawning in older fish probably about to spawn for the second time or more. However the youngest group in the study (three year old fish) appeared to have a low spawning success indicated by many partially developed ovaries that appeared to abort maturation though follicular atresia. In view of this partial maturity it was considered that assessment of population maturity at age or length would be most accurate at the start of spawning and, if based on macroscopic assessment, the ovary should contain yolk oocytes visible (>0.5mm) to the unaided eye. The main obstacle to estimating realised fecundity was caused by high levels of follicular atresia in all age groups peaking around the start and end of spawning. The selection of methods and results were discussed with reference to other teleosts and the application of fisheries independent methods based on egg production.

Reference:

P.R. Witthames, 2003.Methods to assess maturity and realised fecundity illustrated by studies on Dover sole Sole solea Fisken og Havet, No. 12. 125-137.