This study examines the geographic variability in otolith shape of round sardinella Sardinella aurita as a tool for stock discrimination. Fish were analysed from six sampling locations from Senegal to the Mediterranean coast of Morocco. A combination of otolith shape indices and elliptic Fourier descriptors was investigated by multivariate statistical procedures. Within the studied area, three distinct groups were identified with an overall correct classification of 78%. Group A: Nador (Alboran Sea), group B: Casablanca (northern Morocco) and group C: Senegalese-Mauritanian. The results of this study confirm the absence of an Atlantic Ocean-Mediterranean Sea transition for this species, the Gibraltar Strait acting as an efficient barrier for S. aurita population separation. Off north-west Africa, fish from northern Morocco form a single group which is clearly isolated from Senegalese-Mauritanian waters, confirming the existence of a distinct stock in this area. Among group C, some discontinuity exists and suggests the existence of a sedentary fraction of S. aurita in northern Mauritania (Arguin Bank). The results are discussed in relation to oceanographic features and physical barriers to dispersal and fish management strategy in the study area.

R. 2015. Fish assemblages of a shallow Mediterranean lagoon (Nador, Morocco): An analysis based on species and functional guilds. Acta Ichthyol. Piscat. 45 (2): 115-124.Background. Due to their location between the continent and the sea and their shallow depths, lagoons play an important ecological role in coastal ecosystems by providing a selection of habitat types for many species, functioning as nursery areas and feeding grounds for marine opportunistic fi shes. The fi sh fauna of the Nador Lagoon (NE Morocco), as in the majority of southern Mediterranean lagoons, has been insuffi ciently studied, even though the lagoon itself supports important commercial fi sheries. The presently reported study investigated the spatial and seasonal uses of shallow habitats for fi sh fauna in the Nador Lagoon. Materials and methods. Sampling was done using a beach seine net at six stations covering almost entire lagoon and representing habitats differing in many parameters such as the distance from the inlet, bottom sediment characteristics, presence of macroalgae, etc. The fi sh abundance was standardized as catch per unit effort (CPUE) and the fi sh community was analysed both in terms of its taxonomic and functional composition (by making use of both ecological and dietary preference guilds). Results. A total of 2872 individuals, representing 15 species from 12 families, was collected during the four seasons. Only six species were always present in all seasons. Fish abundance peaked in spring and the species diversity was higher in spring and summer. The fi sh assemblage was largely dominated in terms of ecological guild by the resident and benthivorous species. Spatial and seasonal fi sh assemblages differed both in terms of fi sh abundance and diversity and also in terms of functional guilds composition. In autumn, the fi sh assemblage was dominated by the marine juvenile migrants whereas in winter, spring, and summer, resident species were the most abundant. Conclusion. The combination of taxonomic and functional characteristics of the fi sh assemblages, determined in the presently reported study, may contribute to a better understanding of the ecological networks of the Nador Lagoon, thus providing useful data for its conservation and management. Keywords: fi sh, spatio-temporal assemblages, beach seine, lagoon, Nador, Morocco Jaafour et al. 116 or even restoring certain Mediterranean lagoons are being discussed. Hence, there is a need for more information on the role and functioning of coastal lagoons in terms of fi sh requirements.The Nador Lagoon, also known as the "Sebkha Bou-Areg" or "Mar Chica" (the small sea), is the second largest lagoon complex in northern Africa (115 km 2 ) and the broadest paralic environment of Morocco. Its importance consists not only in its ecological value (RAMSAR site) but also in its socio-economic role. The fi sh fauna of the Nador Lagoon is not well known (Bouchereau et al. 2000), although the lagoon itself maintains a diverse fi sh community and supports important commercial ...