La pêche continentale des petits pélagiques en Mauritanie

This study analyses certain socio-economic aspects of continental fishing in Mauritania. It shows that more than 367 pirogues are used for fishing and that more than 3117 people are employed. Of these, 2816 are fishermen, 144 are fishmongers and 157 are processors. Inland fishing, once considered a subsistence activity, with production intended for self-consumption, is increasingly moving towards commercial fishing. The value of landings is estimated at €19.2 million for landings, €729,564 for processing and €4.45 million for fish trade. The study shows that although inland fishing is carried out alongside and in addition to other activities (livestock farming, agriculture, trade), it is a highly profitable activity for fishermen. This profitability is explained by the low level of investment and the non-payment of taxes and royalties. However, fishermen face a number of constraints, including a lack of fishing equipment and funding

Quantitative mapping of effective habitats for the White grouper Epinephelus aeneus (Geoffroy Saint–Hilaire, 1817) in North West Africa

Within the Mauritania–Senegal maritime zone, we have identified and mapped habitats of the white grouper (Epinephelus aeneus). To this end, data collected since the 1980s through scientific sampling surveys along the coastline and on the continental shelf in the study zone have been analysed. On the basis of data collected in shallow coastal and estuarine environments, it has been shown that only the juvenile fraction of the E. aeneus population lives in the diverse habitats (mangroves, sea grass beds, salt marshes, etc.) of both the Banc d’Arguin and the estuaries. On the continental slope, habitat suitability of both juvenile and adult was modelled, using descriptors relating to environment (bathymetry, sediment) and landscape (proximity of estuaries and the Banc d’Arguin). Bathymetry is a major factor driving these distribution patterns, while other environmental descriptors also have significant influence, though to a lesser degree: juveniles of E. Aeneus live in nearshore zones and their density is higher near the Banc d’Arguin and the estuaries, unlike the adult populations found further offshore. The density of both populations has varied over time, falling significantly in 1990, and partly recovering since 2010. These habitat maps tell us the importance of the coastal fringe as essential habitat for juvenile E. aeneus and the usefulness of space-based management measures to enhance the population and allow for sustainable fishing exploitation

Chapitre 6. Bénéfices attendus et réels des AMP

Sous la pression de nombreuses organisations conservationnistes, le postulat de l’efficacité biologique des aires marines protégées s’est imposé : elles réduisent la mortalité des espèces cibles, améliorent l’abondance et la qualité des peuplements, favorisent la reproduction et le recrutement et vont même jusqu’à repeupler le milieu extérieur. Nombre de ces synthèses globales sur les AMP tendent à comparer des situations très hétérogènes et sans vouloir remettre en cause l’apport positif des AMP, le chapitre de Laë et al. vise, sur des bases scientifiques rigoureuses, à mieux décrire les processus de restauration, à les resituer dans le temps et dans l’espace

Identification of critical essential habitat for demersal fish in the Gulf of Guinea

Habitats of three marine fish species of major interest (Epinephelus aeneus, Pseudotolithus senegalensis, and Pagellus bellottii) at both juvenile and adult life stages were identified and mapped in the western part of the Gulf of Guinea. Habitat suitability models (HSMs) were designed to quantify species- and stage-specific fish densities from scientific survey data collected for the last 40 years according to two environmental descriptors (bathymetry, distance to river mouth) and accounting for temporal contrasts. Delta general linear models were selected to fit with the 0-inflated distribution of the fish density data. Despite their high residual deviance, both the prediction accuracy and robustness of these HSMs were satisfactory. HSMs showed a strong influence of bathymetry on stage-specific fish distribution and a lower and non systematic influence of proximity to river mouths. The spatial distribution of juveniles of E. aeneus and P. senegalensis evidenced their concentration in shallow coastal nurseries. The adults of P. senegalensis were also located in nearshore habitats under estuarine influence, whereas adults of E. aeneus were spread towards deeper waters. P. bellottii did not rely on coastal fringes at juvenile or adult stages. Finally, model outputs showed a decrease in abundance in recent decades for all species at both life stages. These HSMs and maps reveal the importance of the coastal fringe as a critical essential habitat for two of the three studied species and the usefulness of space-based management measures to maintain populations and ensure sustainable fishing exploitation