Chapter Phytoplankton assemblage Characterization along the Mediterranean coast of Morocco during autumn

The present study aimed to assess the composition, abundance and diversity of phytoplankton assemblage along the Moroccan Mediterranean Coast. Phytoplankton samples were collected in October 2018 at 48 stations from M’diq bay in the West to Saïdia in the East. 92 taxa have been inventoried, belonging to five groups. Diatoms dominate qualitatively and quantitatively (85.5%), followed by dinoflagellates (12%). Phytoplanktonic diversity and abundance was pronounced in the western part of Moroccan Mediterranean Sea, especially (from Jebha to M’diq) because of the influence of the Atlantic flow

Mortality of early life stages of European pilchard Sardina pilchardus along the Atlantic Coast of Northwest Africa (22°30'N-26°N)

The purpose of this study was to estimate the natural mortality of embryonic and larval stages of European pilchard Sardina pilchardus along the Atlantic Coast of Northwest Africa between Cape Barbas (22°30'N) and Cape Bojador (26°N) during November 2007. Using planktonic data that were fitted to an exponential model, sardine eggs hourly mortality rate (Z) was estimated in 0.07 (per hour) corresponding to 83.5% of daily mortality rate. On the other hand, for sardine larvae, Z was estimated in 0.01 (per hour), corresponding to a daily mortality rate of 21.4%. Southward and offshore transport can be considered as causes of variability in drifting scenario and survival condition of sardine larvae. Additional analyses of time series of the early life history data of sardines and future adaptive monitoring should be conducted to better manage sardine fisheries in Morocco.El objetivo de este estudio fue estimar la mortalidad natural en los estados embrionarios y larvales de la sardina europea Sardina pilchardus a largo de la Costa Atlántica del Noroeste de África entre el Cabo Barbas (22°30'N) y el Cabo Bojador (26°N) durante noviembre de 2007. Se utilizaron datos planctónicos seleccionados de un estudio realizado en noviembre 2007 y ajustados a un modelo exponencial; el índice de mortalidad de huevos de sardina (Z) fue estimado en 0,07 (por hora), siendo el índice de mortalidad diario del 83,5%. Por otra parte, para larvas de sardina, Z fue estimada en 0,1 (por hora), correspondiente a un índice de mortalidad diario igual al 21,4%. Migraciones hacia el sur y costa afuera pueden ser consideradas como una causa de la variabilidad en la deriva y condiciones de sobrevivencia de larvas de sardina. Análisis adicionales de serie de tiempo de las primeras etapas del ciclo vital de las sardinas y la futura supervisión con programas de monitoreo adaptativo deberían ser conducidos para un mejor manejo de la industria pesquera de esta especie en Marruecos

Chapter Phytoplankton assemblage Characterization along the Mediterranean coast of Morocco during autumn

The present study aimed to assess the composition, abundance and diversity of phytoplankton assemblage along the Moroccan Mediterranean Coast. Phytoplankton samples were collected in October 2018 at 48 stations from M’diq bay in the West to Saïdia in the East. 92 taxa have been inventoried, belonging to five groups. Diatoms dominate qualitatively and quantitatively (85.5%), followed by dinoflagellates (12%). Phytoplanktonic diversity and abundance was pronounced in the western part of Moroccan Mediterranean Sea, especially (from Jebha to M’diq) because of the influence of the Atlantic flow

Taxonomic diversity and structure of the molluscan fauna in Oualidia lagoon (Moroccan Atlantic coast)

International audienc

Community Structure and Spatial Patterns of Soft-Bottom Macrozoobenthos in Oualidia Lagoon, Moroccan Atlantic

International audienceThe paper analyses the composition, structure and spatial organization of the soft-bottom macrozoobenthos inhabiting Oualidia lagoon (Moroccan Atlantic coasts), as well as their relationships with the main environmental variables. Material for the study was collected from 43 stations in winter 2013. A total of 56 taxa belonging to 6 phyla were recorded. Species diversity showed the highest values for molluscs, crustaceans and polychaetes. We used a Hierarchical Ascending Classification and a non-Metric Multidimensional Scaling to characterize the macrozoobenthos of the lagoon. We identified three groups of stations according to the outer, middle and inner part of the lagoon, hosting arranged from the outer -most to inner-most areas of the lagoon. The trophic structure of the macrozoobenthos was dominated in density by deposit-feeders (88.1%) and species richness by carnivores (20%) and detritivorous (20%). The BIO-ENV analysis showed that the combination of granulometry, salinity and temperature were the major factors controlling the spatial distribution of the macrozoobenthos in the Oualidia Lagoon

Composition and spatiotemporal variations in the diet of Atlantic horse mackerel Trachurus trachurus from the Atlantic coast of Southern Morocco

WOS:000358394300004International audienceA study of the diet of the Atlantic horse mackerel Trachurus trachurus (Linnaeus, 1758) was carried out on the Atlantic coast of Southern Morocco, located from Cap Boujdour to Cap Blanc (26 degrees 30'N-21 degrees N latitude). This area is characterized by a permanent upwelling and is among the highly productive ecosystems of the worldwide ocean. The diet of T. trachurus was studied through qualitative and quantitative analysis of stomach contents. Samples were collected during the warm (June-July-August) and the cold seasons (November-December) in 2007 and 2008. Acoustic surveys were carried out on board of the Moroccan Amir Moulay Abdellah and the Russian Atlantida oceanographic vessels. A total of 456 stomachs were analyzed, exhibiting a diversified food spectrum. According to the results of the index of relative importance (%IRI), which takes into account weight, number and frequency of occurrence, the pelagic crustaceans (%IRI = 80.15%), mainly Copepoda, are considered the preferential prey for T. trachurus. Molluscs (%IRI = 16.76%) are secondary prey and fishes (%IRI = 2.91%) are complementary prey while Siphonophora, Chaetognatha, Appendicularian and Annelids polycheata are accidental prey (%IRI \textless 1%). A Principal Component Analysis combined with a permutation test highlighted a significant difference in diet according to the sampling periods. A MANOVA test applied to the survey periods, the latitudinal position of the stations, the depth of trawling and size of individuals highlighted the determinant factors of this variation. It appears that T. trachurus exhibits significant diet variability with high thresholds for season and space factors

Macroinvertebrate structure and trophic-functional organization in relation to environmental conditions in Dakhla Bay (southeast Morocco)

International audienceBenthic macroinvertebrate assemblages and environmental conditions were studied in Dakhla Bay (Morocco) to (1) characterize the macroinvertebrate composition and spatial distribution, (2) provide a species inventory, and (3) to assess the key environmental variables driving the observed patterns. We identified 9,288 individuals from 67 species. The most dominant taxa were molluscs, polychaetes and crustaceans. The most abundant species were (in this order) Peringia ulvae, Bittium reticulatum, Ophelia rathkei, Mesalia mesal and Maldane sarsi, while the most frequent were (in this order) M. sarsi, Ampelisca sp., Cyathura carinata, Naineris laevigata and Chondrochelia savignyi. The spatial distribution pattern was mainly driven by sediment grain-size and Chlorophyll-a, with hydrodynamics playing also a key role. This gives rise to a structure characterized by three different station clusters, well identified in the Hierarchical Ascending Classification analysis based on abundances, which correspond to a large moderately disturbed assemblage in the centre of the bay, a more disturbed assemblage in the extremes and a transition assemblage in between

Analysis of the structural characteristics and spatial organization of macrobenthic fauna in Oualidia lagoon, Morocco

Este artículo contiene 13 páginas, 9 figuras, 3 tablas.Morocco is a very rich country in terms of wetlands, including bays, estuaries, lagoons, lakes, and rivers, among others. However, many of them need to be well managed and better exploited, thus requiring baseline descriptive studies to assess faunal patterns and trends. Oualidia lagoon is not an exception. In fact, the studies conducted to date in the lagoon mainly focused on its oceanographic features and aquaculture capacities. The present paper presents the first study on the whole macrofaunal assemblages of Oualidia lagoon, having as main objectives analyze the composition and structure of the assemblages, as well as their relationships with the main environmental variables explaining their spatial distribution variability in the enclosed ecosystem of the Oualidia coastal lagoon. The benthic macroinvertebrates of Oualidia lagoon were studied in summer 2013 based on 43 stations spread over the whole lagoon by using a Van Veen grab. Two replicate samples were collected for macrobenthos and one additional replicate for sediment analyses at each station. Also, single water salinity and temperature measurements were recorded at each station. Fifty-one species from seven different taxa were recorded, among which mollusks (37%), polychaetes (25%) and crustaceans (25%) dominated in terms of species number. Peringia ulvae, Abra alba, Sphaeroma serratum, Cerastoderma edule and Corophium sp. accounted for 88% of total abundance. The benthos was structured along a downstream–upstream gradient, showing three assemblages, named according to the IndVal index: (1) Diopatra cf. marocensis, (2) Peringia ulvae, and (3) Cerastoderma edule, while the main factors driving their distribution were granulometry and salinity. The Biotic and Environmental analysis showed that the combination of granulometry and salinity was the major factors controlling the spatial distribution of the macrozoobenthos in the Oualidia Lagoon.FE, AE, MT, MM, HZ were partly funded by a research program on coastal resources of the LERL/DRH-Casablanca (National Fisheries Research Institute). DM received funding from the Consolidated Research Group on Marine Benthic Ecology, Generalitat de Catalunya (http:// agaur. gencat. cat), grant 2017SGR378, and the Agencia Estatal de Investigación (AEI) (http:// www. cienc ia. gob. es/ portal/ site/ MICINN/ aei), European Regional Development Funds (FEDER) (https:// ec. europa. eu/ regio nal_ policy/ en/ fundi ng/ erdf/), grant CTM2017–88080 / PopCOmics.Peer reviewe