From 2020 to 2024, The Institut Mauritanien de Recherches Océanographiques et des Pêche (IMROP) and the Senckenberg Research Institute conducted five joint expeditions, exploring the marine biodiversity of the North-Mauritanian coastal habitats, primarily focusing on the Baie de l’Étoile north of Nouadhibou and to the Banc d’Arguin National Park. In order to establish a Mauritanian scientific reference collection of the marine fauna and to build up a DNA barcode library, macrozoobenthic invertebrates from all major groups were collected using various methods and gear. A total of 103 living marine macrozoobenthic invertebrate species were found and their key morphological features were described herein. This checklist gives an overview on the most common species of the Mauritanian coastal macroinvertebrates and provides a baseline for future biodiversity assessments along the Mauritanian coast.
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.
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.
The Cetaceans of Mauritania, West Africa: a concise zoogeographical review with two new species records
