Distribution and Ecology of Mudskippers (Periophthalmus spp.) in the Intertidal Zone of Calabar, Cross River State

Mudskippers of the genus Periophthalmus are ecologically unique amphibious fish that occupy intertidal and mangrove habitats, making them valuable indicators of intertidal ecosystem health. This study investigated the distribution, population structure, and ecological preferences of mudskippers in the intertidal zone of Calabar, Cross River State, South South Nigeria. Surveys were conducted at four intertidal sites monthly over a five-month period. Visual counts within 10 by 10 metre plots were used to estimate population density. Fish were captured using hand nets for morphometric measurements including standard length, weight, and sex determination. Substrate characteristics, vegetation cover, burrowing site availability, and water quality were assessed at each station. A total of 213 individual mudskippers were recorded, dominated by Periophthalmus barbarus and Periophthalmus papilio. Population density was highest at sites with intact mangrove cover and muddy substrates with low tidal disturbance frequency. Periophthalmus barbarus preferred more open mudflat habitats, while P. papilio was more closely associated with the mangrove forest interior. Burrow density correlated positively with mudskipper population density, suggesting burrow availability as a key habitat requirement. Anthropogenic disturbance, particularly mangrove removal for urban expansion, was associated with significant reductions in population density at degraded sites. Sex ratio analysis showed female-biased distributions at all sites. This study provides foundational ecological data on mudskippers in Cross River and highlights the importance of intertidal habitat conservation. Keywords: Periophthalmus, mudskippers, intertidal zone, Calabar, mangrove.