No effect of anthropogenic food provisioning and population density on the aggressive behavior of a territorial Cichlid: a case study

Abstract

Food provisioning for fish is a very common leisure activity, especially in tourist attractions, causing impacts that are still poorly understood. There are many species of territorial fish to whom energy availability can limit aggressiveness and population growth. Our case study evaluated whether food provisioning and the resulting population density modify aggressive behavior in a territorial cichlid, the Congo tilapia (Tilapia rendalli). We compared the aggressiveness between a population that receives large amounts of food and has high density and an unfed and low-density population. Aggressiveness was the same between provisioned and non-provisioned treatments, except when we offered food, which stimulated aggression in the unprovisioned area. Food provisioning by humans and density reduced nest area, but did not increase aggressiveness, suggesting a possible habituation to the presence of conspecifics and a reduction in competitive aggression.