Comparison between the opercular bones, the scales and the otoliths to investigate the growth of the brilliant pomfret (Eumegistus illustris) off the coast of Reunion Island (SW Indian Ocean)

The brilliant pomfret (Eumegistus illustris) occurs in the western part of the Indian Ocean and the western and central Pacific Ocean. To date, the biology of E. illustris has never been documented. The aim of the present study was to investigate age and growth of E. illustris along the coasts of Reunion Island, based on calcified structures analysis. One hundred thirty five individuals were sampled in the landings of the French local artisanal fisheries from March 2014 to March 2015. The relationships between two types of body length (Total and Standard lengths, cm) and Total weight (g) were significant (P<0.05). Total length-weight relationship was described by the following parameters: a=0.012 and b=3.015 without significant effect of sexual dimorphism. The oblong shape of the scales and the otoliths could explain the difficulty in using these calcified structures for ageing E. illustris. Consequently, the opercular bone is a good alternative calcified structure when the otoliths and scales are unsuitable especially for slowly growing fish.