Little is known about the diversity of Calanoida, Copepoda, in different habitats of the north-western Red Sea. In this study, biodiversity of Calanoida, Copepoda, during the cold and warm seasons of 2017, were observed at 12 stations belonging to four different habitats (coral reef (CR), sheltered shallow lagoons (SSL), seagrass (SG), and open deep-water (ODW) habitats) in the Hurghada shelf, north-western Red Sea. SSL habitats were the most affected by environmental conditions, especially temperature, salinity, and depth. Some calanoid species were restricted to certain habitats, others were adapted to live in more than one habitat, while some species showed a wide distribution in all habitats. ODW habitats showed maximum diversity and density of the calanoid species. The effects of temperature and salinity were distinct in the SG and SSL. The results clearly showed that different Red Sea habitats affected the biodiversity of calanoid copepods.

Solenocera crassicornis is a commercially important shrimp of the Solenoceridae family. The current study investigated the morphology, molecular identification, phylogenetic relationships, and population dynamics of S. crassicornis in Egypt. Samples were collected monthly (total, 1722; male = 40.19%, wet weight, 0.89–10.77 g; female = 59.81%, wet weight, 1.55–19.24 g) from Al-Attaka commercial catch in the Gulf of Suez in the Red Sea. Two barcode markers, 18S rRNA and cytochrome c oxidase subunit I (COI), were used for molecular identification. COI partial sequences were used to construct the phylogenetic relationships among different species of genus Solenocera and to infer the origin of the studied Solenocera crassicornis. The applied molecular markers successfully identified the studied species to the species level. The genetic distances among S. crassicornis sequences from different countries revealed the Indo-West Pacific origin of S. crassicornis. The relationship between total length (TL) and total weight (TW) was TW = 0.035TL^2.275 and r² = 0.805 for males and TW = 0.007TL^3.036 and r² = 0.883 for females, indicating that females were heavier than males. Despite its social and economic relevance in the area, information on the hatching, larval rearing, and farming of S. crassicornis is scarce and requires future studies under Egyptian conditions.

This work aimed to study the structure of the commercial fish communities at six coastal coral reef bays around Marsa Alam city on the southern coast of the Egyptian Red Sea. Fish communities were counted in Marsa Saifen, Marsa Shoni2, Marsa Shoni4, Marsa Fujiri, Marsa Nakari and Marsa Hamata using underwater visual census technique (UVC). A total of 2458 fish belonging to 16 families and 44 species of commercial fish were found. Five families (Scaridae, Serranidae, Mullidae, Lutjanidae and Lethrinidae) contained 27 species (61.4% of the total number of species). Four families (Mullidae, Siganidae, Scaridae and Lutjanidae) were the most abundant and they formed about 91.3% of the total number of recorded individuals. Mullidae was the most abundant constituting about 63.5% of the fish community). The most abundant species was Mulloidichthys flavolineatus, of the family Mullidae with 1390 individuals forming 56.5%, followed by Siganus rivulatus of the family Siganidae (251, 10.2%). The highest abundance of fish was recorded in Marsa Saifen (609 individuals) and the lowest abundance was recorded at Hamata (271 individuals). The highest number of species (23 species) was observed in Marsa Fujiri, whereas the lowest number of species (17 species (was recorded in Hamata. This study concluded that knowledge of the ecology of marine fish communities in the Red Sea is sparse and hence quantitative ecological studies are needed. Action plans and research programs must be developed to reduce early stages bycatch and initiate fisheries management strategies for commercially exploited species.