Alassane Sarr

Resilience of Key Biological Parameters of the Senegalese Flat Sardinella to Overfishing and Climate Change.

The stock of the Senegalese flat sardinella, Sardinella maderensis, is highly exploited in Senegal, West Africa. Its growth and reproduction parameters are key biological indicators for improving fisheries management. This study reviewed these parameters using landing data from small-scale fisheries in Senegal and literature information dated back more than 25 years. Age was estimated using length-frequency data to calculate growth parameters and assess the growth performance index. With global climate change there has been an increase in the average sea surface temperature along the Senegalese coast but the length-weight parameters, sex ratio, size at first sexual maturity, period of reproduction and condition factor of S. maderensis have not changed significantly. The above parameters of S. maderensis have hardly changed, despite high exploitation and fluctuations in environmental conditions that affect the early development phases of small pelagic fish in West Africa. This lack of plasticity of the species regarding of the biological parameters studied should be considered when planning relevant fishery management plans.

Preliminary Study of Fish Assemblage Structure of the Marine Protected Area of Cayar in Senegal

Preliminary Study of Fish Assemblage Structure of the Marine Protected Area of Cayar in Senegal Since its establishment in 2004, Cayar Marine Protected area (North of Senegal) is characterized by a lack of information on its fish fauna. Therefore, it becomes necessary to characterize the fish fauna of this MPA and its dynamics in time and space for a sustainable management of this conservation area. This present study investigated seasonal and spatial structure of the fish assemblage of Cayar MPA. This study consisted of collaborative seasonal sampling with local communities from six stations within the four main fishing areas with two types of fishing gears, purse seine and long line between 2015 and 2016. Ecological and trophic classification was performed in order to determine the fish fauna nature of this MPA. Multivariate analysis like factorial correspondence analysis and hierarchical classification analysis were carried out to study spatial and seasonal structure of fish assemblage of Cayar MPA. A total of 103 fish species from 45 families were reported. The most abundant species and the richest family were Pagellus bellottii and Carangidae, respectively. The fish assemblage was dominated by species of marine affinity and predators. Spatial and seasonal fish assemblages differed both in terms species richness and fish abundance. The highest and lowest species richness and abundance were recorded during the cold season and cold to warm transition period, respectively. A clear separation was found between stations where purse seine and long line were applied, in species composition and abundance. Results from this study might serve as the reference point of the fish assemblage in Cayar MPA. However, further investigation on the environmental variability is needed for a better understanding of the observed fish assemblage organization in time and space.

Reproductive Biology of Round Sardinella (Sardinella Aurita) (Valenciennes, 1847) in Senegalese Coastal Waters

In this study, a total of 1068 specimens Sardinella aurita of which 553 females and 515 males were examined. The objectif of this study was to determine the reproductive parameters of Sardinella aurita . The sex ratio was significantly in favor of females (55%). The size at first sexual maturity was estimated at 18.9 cm for females and 18.0 cm for males. The monthly variation of sexual maturity stages and gonado-somatic index (GSI) allowed to locate the reproduction periods from February to June and from September to December. The mean absolute fecundity was estimated at 110.794 ± 7582 oocytes whereas relative fecundity was about 422 ± 26 oocytes per gram of female.