An otolithic image analysis method for ageing and estimating growth of larvae and juveniles of seabass (Dicentrarchus labrax (Linnaeus, 1758)): Preliminary results
Serge Planes, Philippe Laval, Raymonde Lecomte-Finiger
Age and growthof sea-bass (Dicentrarchus labrax) were studied by employing otolithincrement analysis. An objective automatized method has been developed forageing and growth estimation. An image analysis software on a personal computerwith a video camera allowed to obtain quick and precise measurements. Thisoffers an otolithic evaluation programm in Turbo-Pascal, a well appliedlanguage. It proved to be important to work on SEM (Scanning ElectronicMicroscope) photographs in order to have a more precise definition of theimage. To alleviate for small defects in the photographs, an integration of the4 radials made in the same sector realise a definitive radial showing theincrements. The analysis of the shape and the weight of the otolith showed apositive correlation to the environmental conditions.