Size Distribution, Length-Weight Relationship and Condition Index of Tagelus adansonii Bosc 1801 (Mollusca: Bivalvia, Solecurtidae) in the Joal-Fadiouth Lagoon (Senegal)

Abstract

Size distribution, length-weight relationship and condition index are some of the many parameters that contribute to the study of the growth, environmental conditions and reproduction of an aquatic species. For Tagelus adansonii, only a few studies were carried out on these parameters. This species is a bivalve of the solecurtidae family only found on the East Atlantic Coast between Mauritania and Angola. The objective of this study was to examine the biometric relationships as well as size and condition index variations, within the perspective of resource management. In this study, the average size obtained (47.78mm) from the monthly sampling in Joal Fadiouth lagoon was smaller compared to sizes obtained in other countries for the same genus and species. The size frequency distribution is unimodal, the most abundant class is 45-50mm. The mean condition index is 18.41±16.47 using the formula by Beninger and Lucas (1984). The values of the condition indices varied throughout the duration of the study. In the period of cold-to-warm transition (June) the maximum values of the condition indices were observed, while in the period of warm-to-cold transition (November to December), the minimum values were registered. The allometry is positive (3.07) in Joal as in most studies on this genus.