Impact of Mariculture on the Macrobenthic Invertebrate Abundance and Distribution in Lagos Lagoon Nigeria

This study investigated the effect of a mariculture fish cage culture on the abundance, composition and distribution of macrobenthic invertebrates of Lagos lagoon from February 2011 through July 2011. A record of three animal Phyla – Mollusca, Arthropoda and Annelida was established with a total of 1469 macrobenthic taxa. The dominant species throughout the study were of the class Bivalvia - Aloidis trigona while the rarest species was the Polychaeta - Nereis succinea. - There was significant difference in the genera diversity (ANOVA test; p< 0.05). Generally, the diversity of macrobenthic invertebrate at the cageless site of the study area may have been influenced by the absence of fish cage because the highest fauna abundance was observed while the least diversity was at the cage downstream of the cageless site. Comparison of particle size showed a significant correlation between the three stations (p<0.01), at 99% mutual relationship between the three stations. Studies on the use of macrobenthic invertebrates to investigate the environmental impacts of anthropogenic activities such as fish cage culture system on the lagoon should include ecological impact to identify possible alteration in environmental conditions of benthic macro-invertebrates.