A first approach to unravel the jellyfish diversity and ecology of the Kribi coastal region (Cameroon, Gulf of Guinea)

Exploring the jellyfish diversity within the coastal region of Kribi in Cameroon was necessary, given its hydrological complexity and ecological significance—marked by five river systems, estuaries, and a dynamic land-sea interface—and its known understudied marine basin. In this study, a pioneer survey of jellyfish diversity was conducted using by-catch samples from artisanal beach seine fishing at two sampling stations along the Kribi coastal area from June 2017 to January 2018. The total catch of medusozoans (comprising 1688 specimens) consisted of 74.6% Scyphozoa and 25.4% Cubozoa, with no other gelatinous zooplankters. Four main jellyfish taxa were identified: Catostylus tagi (46.5%) with five colour morphotypes, Chimaerus palmatus (25.4%), Chrysaora sp. (20.6%), and Cyanea sp. (7.6%). Sea anemones, the soft coral Antillogorgia bipinnata, and a rhizostome jellyfish specimen with hexaradial symmetry (possibly an irregular Catostylus) were also documented. The sampled jellyfish specimens were frequent at both sampling sites, except for C. tagi, which was present in all samples. A positive and statistically significant correlation was observed between C. palmatus and Cyanea sp. abundance (rho = 0.75, p = 0.008). Analysing bell diameter proportions revealed evident homogeneity in C. palmatus, while C. tagi, and Chrysaora sp. exhibited more variability. Given the size structure, it is suggested that the identified jellyfish species could complete their entire life span within this environment, except for Cyanea sp., which appears to occupy a distinct niche. However, we recommend broader jellyfish population monitoring. The taxonomy of the Chrysaora and Cyanea specimens should be resolved, and further elucidation of the genetic identities of C. tagi and C. palmatus is necessary.