FERTILIZATION RATE IN A NATURAL-POPULATION OF THE COMMON SOLE (SOLEA-SOLEA L)

An assessment of fertilization rate in a natural population of Dover sole, Solea solea (L.), is described. A preliminary study of the morphological changes of fertilized and unfertilized eggs from a captive stock was carried out to aid identification of sea-caught eggs. In addition, changes in specific gravity were measured to determine whether, and for how long, unfertilized eggs would be expected to be distributed similarly to their fertilized counterparts. During the field assessment, in which over 16 000 live eggs were examined, only 38 were judged to be unfertilized. This was estimated to represent a fertilization rate of over 99%. The paper also presents results from similar experiments on the eggs of plaice (Pleuronectesplatessa L.). © 1991 Conseil International pour l'Exploration de la Mer.