Variation of the Condition Index and Sex-ratio of the Sea Urchin Paracentrotus lividus in the Southeast Mediterranean

Abstract

Objective: The objective of this study is to monitor the variation in the condition index at the level of two populations, male and female of the sea urchin Paracentrotus lividus (Lamarck, 1816) fished in the most Southeastern part of the Mediterranean (Gulf of Annaba) and the structure of the population through sex-ratio determination. Methodology: Sampling was done monthly from February, 2012 to January, 2013 at three stations (Gap de Garde, Lacaroube and Draouch) and the physico-chemical characterization of the water was performed by in situ measurements of temperature, pH, salinity and dissolved oxygen. In addition, the individuals harvested were dissected, sexed and weighed to determine their condition index and the sex-ratio. Results: The physico-chemical parameters revealed that the waters of the 3 sampling stations are favorable for the development of the sea urchin Paracentrotus lividus. Furthermore, the condition index indicated that the highest values were recorded in spring (March and April). However, the lowest values were found between July and November. Conclusion: Overall, the structure of the population of Paracentrotus lividus differed from one station to another, the sex-ratio of the population was estimated at 46.99% at station S1, 39.11% at station S2 and 48.31% at station S3.