Investigation on the Efficacy of the Traditional Depuration Method of Oysters (Crassostrea gasar) used in Lakeside Villages of Southern Benin

Abstract

Amongst fisheries products, oysters have an important role in the provision of need protein for populace. In Benin, there is beginning to be awareness in oyster as a protein resource. The present study aims to investigate the efficacy of the traditional purge method of oysters (Crassostrea gasar) used in lakeside villages of southern Benin. Thus, four lakeside villages characterized by high activity of collection and parking of oysters were chosen. There are Azizakouè, Djondji, Dègouè and Meko. In each lakeside village, a semi-structured survey was conducted and five parking stations were selected for the study. This survey was also coupled with the sampling of oysters before their parking. After three months of parking, sampling was again conducted to assess the efficacy of the parking on the quality of oysters. Results indicated that, before parking, microbial load of coliforms in oyster samples was high (24.106 - 3.109 ufc/g) with the presence of E. coli and Salmonella spp. However Vibrio spp was not detected in the analysed samples. Chemical pollution characterised by heavy metals such as copper and lead were also detected. After 3 months of parking, the results of microbiological analyzes indicated that the treatment was more effective in Azizakouè where the average microbial load has significantly decreased (p<5%) and at Djondji where the value rose from 107 cfu/g to 106 cfu/g. However, the results obtained on stations of Meko and Dégouè indicated that the treatment was ineffective. Results of chemical analyses after the parking of oysters, indicated that, this technique had reduced the lead content (15.96% in samples of Azizakouè, 60.30% in samples of Dégouè, 36.88% in samples of Djondji and 61.65% in samples of Meko), but was ineffective on copper content of oysters.