Population Parameters and Exploitation Rate of the Heavy African Ark <i>Senilia</i> <i/> <i>senilis</i> in the Gandoul Marine Protected Area (MPA) (Sine-Saloum, Senegal) and Its Surroundings

Abstract

The Heavy African ark Senilia senilis is amongst the most harvested shellfish by local populations in the Gandoul MPA, located in the Sine-Saloum estuary, Senegal. It is accessible, and its harvesting does not require many financial means. This harvesting pressure, combined with the deterioration in environmental conditions in the MPA, is believed to be the cause of the decline in S. senilis stocks, with a reduction in the size of individuals and lower yields. The goal of this study was to estimate the population parameters and exploitation rate of Senilia senilis in the Gandoul MPA and its periphery to inform better resource management. The population parameters were estimated using the FiSAT II software. A total of 7.123 individuals were sampled, with a mean weight of 14.4 ± 7.4 g and a mean length of 29.1 ± 6 mm. The asymptotic length (L∞) is 53.55 mm and the theoretical age t 0 is estimated to be 0.08 yr -1 . The growth coefficient (K) and growth performance index (Φ’) are 1.70 yr -1 and 3.69, respectively. Total mortality (Z) is estimated at 6.51 yr -1 . Natural mortality (M) and fishing mortality (F) are 2.19 yr -1 and 4.30 yr -1 , respectively. Recruitment is continuous, with a first peak in March-April (21.80%) and another in September-October (15.09%). The exploitation rate (E) is 0.66 while the sustainable exploitation rate (E0.1) is 0.28, the optimum exploitation rate (E0.5) is 0.36 and the maximum exploitation rate (Emax) is 0.42. The results of the study show that Senilia senilis is overexploited in the Gandoul MPA and its periphery. Therefore, concrete management measures must be implemented to address this situation.