Diversity of Fishery Resources in Mangrove Ecosystems: Case of Saloum Delta in Senegal

The objective of this study is to enhance the understanding of the diversity and structure of fishery resources. To achieve this, we conducted beach seine catches in two seasons from 2020 to 2022 at six sites within the Gandoule Marine Protected Area. All individuals captured were identified and counted, and their weight and size were measured. In total, 58 species from 46 genera and 31 families were recorded. Diversity, weight, and growth parameters of fishery resources showed variation across time and locations. Species richness and abundance varied significantly (p<0.05) between sites. Baradia (13.33±6.02) had significantly higher richness than Pass Fambine (5.66±4.27). The highest abundances were at Donakal (136.67±148.73), with the lowest at Pass Diamniadio (24.67±13.61). Over the study period, average richness declined from 10.83±6.63 to 7.33±2.87 species, and abundance decreased from 82.58±72.98 to 23.67±12.52 individuals from 2020 to 2022. There was no significant difference (p>0.05) in overall diversity among sites and years. Analysis of structural characteristics revealed significant spatio-temporal variation in biomass (P<0.05). Donakal (20.14±6.43kg) showed higher biomass than Pass Fambine (5.11±1.55kg). Biomass declined from 11.81±11.54kg in 2020 to 3.97±2.36kg in 2022, while the proportion of small fish rose from 69.47% to 72.73%. Fish length decreased significantly (p<0.05) over the study period, from 257.12±40.69cm to 157.48±16.71cm. Despite some contradictory data on the proportion of small fish (which rose then fell), the trends indicate a decline in fishery resources in the Saloum Delta, attributed to overexploitation, habitat degradation, and climate change.