Seaweed and Associated Invertebrates at Iture Rocky Beach, Cape Coast, Ghana
Abstract
In this study, the various floral species of Iture beach were surveyed for seaweed composition, floral zonation and diversity of associated epifauna. No such study has been conducted for specific Ghanaian rocky shores such as Iture beach, although more generalized studies are available concerning the coastal ecology of Ghana as a whole. Iture beach has been the subject of ecological studies, however these have focused primarily on the mollusk and bivalve populations independent of the floral communities. Quadrat sampling was done to determine seaweed composition and distribution within three equally spaced shore zones. Floral zonation was studied to investigate a discernable gradient in ecological health from the upper shore neighboring Iture village to the lower shore bordering the ocean. Twelve distinct species of macro-algae in three phyla were recorded as Chaetomorpha anteninna, Chondria bernardii, Cladophora ruhengeri, Enteromorpha flexuosa, Galaxaura marginata, Gelidium arbuscula, Hypnea musciformis, Jania rubens, Padina durvillaei, Sargassum vulgare and Ulva fasciatta as well as one unidentified species. Additionally, at least twenty species of invertebrates in four phyla were found to inhabit the various algal species. They are Alaba culliereti, Littorina punctatta, Natica marochiensis. Nereis sp., Perna perna, Petricola pholadiformis, Polyapthalmus pictus, Semifusis morio, Sphaeroma rugirauda, Thais haemastoma, Amphitohoidae (family), Cirratulidae (family), Cumacea (family), Haustoriidae (family), Spionidae (family), Syllidae (family) and Ophiuroidae (Class) as well as juveniles of two unknown species. Zonation was distinct in species of green and red alga types and diversity and richness of algal species was found to decrease with shore height. Species of red alga were found to harbor a relatively more diverse and rich community of invertebrates compared to green and brown types of algae. Diversity and richness of epifauna were found to increase with shore height, a reverse of the trend shown by the algae. Further, a significant number of individuals found within the algal samples were in early stages of development, suggesting the importance of the seaweed of this isolated rocky beach as a nursery environment. These observations provide a basis for future studies in determining conservation strategies for Iture beach, which sits adjacent to a small community and between the two tourists centers of Elmina and Cape Coast.
