A preliminary assessment of the health status of feral populations of Chrysichthys nigrodigitatus in Lagos lagoon complex, Nigeria, using a modified Health Assessment Index protocol

Abstract

A ‘snapshot' evaluation of the health status of feral populations of the brackish water catfish, Chrysichthys nigrodigitatus, was carried out in 2006 at four locations in the Lagos lagoon complex, with varying levels of anthropogenic impacts, using a modified Health Assessment Index (HAI) protocol. Fish health was assessed using condition-related indices including condition factor and a modified Health Assessment Index (HAI). Condition indices provided relatively simple and rapid indications of how well fish were coping in their environment. The HAI score varied across the four sample sites. The highest individual mean value was 76.57 at Badagry Lagoon, followed by a score of 49.87 at Ologe and 48.16 at Epe, while the lowest was 29.67 in the Lagos Lagoon. This investigation did not reveal widespread pathognomonic, truly specific, responses to contaminant exposure, but showed the existence of differences in the health status of fish populations in four different lagoons within the Lagos lagoon complex.

Keywords: Chrysichthys nigrodigitatus, Lagos lagoon complex, condition factor, fish health

African Journal of Aquatic Science 2008, 33(1): 77–82