Habitat Use by Fish in Mangroves of the Southern Arabian Gulf

Mangroves form an integral habitat component for species of the southern Arabian Gulf, yet their role in supporting fish remains limited. This study investigated habitat use by fish in mangroves to determine the diversity, abundance, size, and whether microhabitat complexity and environmental conditions influence fish assemblage. Fish were surveyed using an underwater visual census among mangrove habitat types across seasonal cycles. Results revealed 1137 individuals belonging to eleven families and fourteen species, a majority being juveniles with Gerres longirostris (44.59%) the most abundant. High-commercial-value species were documented, including Lutjanus ehrenbergii (dominance 18.65%) and Lutjanus argentimaculatus (dominance 15.48%). To date, this study reports the first evidence of Epinephelus coioides in the mangroves of this region. Results showed significant variation in fish assemblage among habitat types and seasons, with markedly higher abundance and diversity during the summer and in mangroves close to structural habitats. Seawater temperature emerged as the most influential environmental variable for fish. Together, structurally complex habitat settings and seawater temperatures were the key drivers shaping the fish assemblage in mangroves. Future investigations would benefit from diel and tidal sampling within multiple habitats near mangroves to better understand fish populations. Findings may guide research and conservation strategies by integrating coastal habitats and fish populations.