Search

Four algal species (Isochrysis galbana, Chaetoceros muelleri, Tetraselmis suecica and Nannochloropsis oculata) were tested experimentally as food for the calanoid copepod Gladioferens imparipes, which could be a potential food for marine fish larvae. Each of the algal species was used at four separate concentrations (5 × 104, 1 × 105, 2 × 105 and 4 × 105 cells/ml). The results illustrated that I. galbana and C. muelleri were the most suitable diets for the copepod species, promoting high survival of the adults and shortening the maturation time. With both algal species, intensive successful rearing of nauplii to mature adults was conducted at all concentrations of the algal species, resulting in high number of ovigerous females. Meanwhile, I. galbana was the best diet enhancing the production of egg sac in the cultivated copepod. In addition, the fatty acids in the copepod species were affected by the algal diets, resulting in variable amounts of the HUFA (DHA, EPA and ARA) in the copepod relative to the algal diets.

Spatio-temporal patterns of the distribution of crustaceans from shallow hard bottoms along the Alexandria coast (Egypt, Mediterranean Sea) were studied during a complete year cycle and also in relation to potential drivers of change (both biotic and abiotic), including variation in habitat-forming species. Overall, the crustacean assemblages appeared poor, including only 14 species belonging to Amphipoda (five species), Isopoda (five species), Tanaidacea (two species), Cirripedia and Decapoda (one species each). The distribution patterns of crustacean assemblages appeared significantly variable both in the spatial and in the temporal dimension on a rather unpredictable basis, albeit variation was related to changes in dominant algal and invertebrate habitat formers. High variability and low species richness observed suggest that the analyzed assemblages are selected by local unfavorable environmental conditions. In fact, the crustacean hard bottom fauna is composed by a bulk of tolerant forms, including the dominant Tanais dulongi, Apohyale perieri, Dynamene bidentata, Sphaeroma serratum, Elasmopus pectenicrus, and Jassa marmorata. Their spatio-temporal dynamics, as well as those of the remaining species, and correlations with the variation of habitat formers and environmental variables are reported. This is a baseline assessment of the crustacean diversity along the Mediterranean coast of Egypt, thus having paramount importance for understanding the predicted future changes of biodiversity for the area.