SIZE AND AGE AT ONSET OF METAMORPHOSIS IN SOLE (SOLEA-SOLEA (L)) OF THE GULF OF GASCOGNE

This study describes seasonal, interannual and spatial variations of s ize and age at the onset of metamorphosis of sole, Solen solea. Length at the onset of metamorphosis was significantly less variable than ag e and weight: coefficient of variation CV length<CV age<CV weight (0.0 8, 0.2, 0.25, respectively). Length and age at the onset of metamorpho sis were not significantly correlated (r(2)=0.02). Sole larvae began m etamorphosis at a relatively constant length 8.5 +/- 1.3 mm and season al, interannual and spatial comparisons showed that length was not sig nificantly variable. Unlike length, seasonal and interannual variation s of age al the onset of metamorphosis were high, and resulted from di fferences in growth rates which were influenced by both temperature an d food availability. Analysis of otolith increment width suggest that these growth differences between slow-growing and fast-growing larvae occurred chiefly after the 10th day following the mouth-opening stage and seemed to diminish at the end of the larval period. These findings are discussed in terms of survival and recruitment variability.