Effects of consecutive dredging on the fish community of a tropical estuary

Abstract

Dredging is a human activity that significantly alters aquatic habitats, potentially impacting ecosystem services such as artisanal fishing. This study aimed to evaluate changes in fish density in Buenaventura Bay in response to three dredging events that occurred between 2015 and 2021. Fish monitoring was conducted using artisanal trawl nets before, during, and after each dredging event, with annual sampling in two areas of the bay over the study period. The findings revealed species-specific responses: while species such as the catfish Cathorops multiradiatus and the sole Achirus kluzingeri benefited from dredging, the pygmy pufferfish Sphoeroides trichocephalus was negatively affected. Contrary to common assumptions in the literature, resident estuarine species were not necessarily the most negatively impacted but instead exhibited variable responses to dredging disturbances. The fish assemblage showed a shift towards species more tolerant to these impacts, highlighting a potential loss of ecosystem resilience. These changes could have long-term implications for the productivity of artisanal fisheries and the food security of local fishing communities.