Fish fauna as an indicator of environmental quality in an urbanised region of the Amazon estuary

This study describes the biological importance of Guajara Bay (Belem, Para, Brazil) for fish fauna and presents a diagnosis of water quality in the main channel and creeks, using the icthyofauna as an ecological indicator. A total of 567 individuals from 40 species were identified. About 58% of these use Guajara Bay as a nursery ground, 49 and 81% use the bay as a breeding and feeding ground, respectively. There were no significant differences between environments as measured by the diversity index; however, fish relative abundance (catch per unit of effort) was greater in the creeks than in the main channel. A significant difference was detected in the fish fauna inhabiting the main channel compared with the creeks. In the main channel, icthyofauna significantly differed during December relative to other months.