Professional Assessment of Seaweed (Macroalgae) Resources and Biotechnological Potential in Nigerian Coastal Waters

Nigerian coastal waters along the Gulf of Guinea support diverse macroalgal communities with significant but underexploited biotechnological and nutritional potential, and a professional resource assessment is a prerequisite for sustainable utilisation planning. This study conducted a professional assessment of macroalgal species diversity, biomass distribution, and biotechnological potential along 180 km of the Nigerian coastline, covering sites in Lagos (South West), Ondo (South West coast), and Cross River (South South) States. Surveys were conducted at rocky intertidal, sandy beach, and mangrove creek zones using belt transects during spring tides. All macroalgal species were collected, identified, and their wet biomass measured per unit area. Selected high-abundance species were subjected to proximate analysis, agar yield determination, and preliminary screening for antimicrobial activity and antioxidant capacity using standard methods. Forty-four macroalgal species from 28 genera were documented, comprising 19 Rhodophyta, 14 Chlorophyta, and 11 Ochrophyta. Biomass density was highest at rocky intertidal sites in Badagry, Lagos (3.8 kg wet weight/m2). Hypnea musciformis had the highest agar yield (18.7% dry weight). Methanol extracts of Sargassum species showed significant antioxidant capacity (DPPH inhibition: 71.4%). Caulerpa racemosa showed broad-spectrum antimicrobial activity against bacterial test strains. The study concludes that Nigerian coastal macroalgal resources are commercially underutilised and recommends a national seaweed cultivation feasibility study incorporating these biotechnological findings.

Keywords: macroalgae, seaweed, coastal resources, biotechnological potential, Nigeria