Giant otter diet differs between habitats and from fisheries offtake in a large Neotropical floodplain

Abstract

Giant otters Pteronura brasiliensis are semiaquatic mammals that mainly eat fish, the abundance of which is affected by seasonal flooding and habitat structure. The piscivorous habits of giant otters lead to negative human perception and conflicts with fisheries. We compared giant otter feeding habits between seasons and habitats in the Southern Pantanal, Brazil, by analyzing feces collected between September 2008 and June 2011.We investigated whether habitat and season affected P. brasiliensis diet composition and prey size. We calculated the frequency of occurrence, relative frequency, and overlap of fish species eaten by giant otters and caught by fishermen. The giant otters had a more diverse assemblage of fish prey than the offtake in the fisheries. We did not find strong seasonality in otter diets, but diet composition and prey size differed between rivers and lakes. The giant otter diet had higher overlap with the offtake of sport than with professional fishermen. Although the otters’ piscivorous diet often leads to negative perceptions by humans, the low overlap between otter diet and species taken in local fisheries suggests that otters have little effect on the commercial fishery. These results indicate that educational programs could be used to reduce perceived conflict between giant otters and fishermen.

Essential and non-essential elements levels in fish species highly consumed in the middle Miranda River, Brazilian Pantanal

“…was also well-represented in the giant otter's diet. The authors also found a variety of other fish genera in P. brasiliensis prey spectrum, in addition to reptiles, insects, mollusks, and crustaceans, the last two consumed in high frequencies (Leuchtenberger et al 2020). Thus, it is possible that Hg sources which resulted in moderate Hg levels in P. brasiliensis matrices (Fonseca et al 2005;Soresini et al 2021) may not correspond to the fish species herein analyzed, but to other prey items explored by the carnivoran.…”

“…Interestingly, a study conducted on P. brasiliensis diet in Miranda and Negro river basins (Leuchtenberger et al 2020) pointed out ‗Serrasalmus sp'.as the second most consumed fish, after only the trahira Hoplias sp.…”

Characterization of shelters of the giant otter (Pteronura brasiliensis, Mammalia, Carnivora, Mustelidae) in the pantanal wetlands, state of Mato Grosso, Brazil

“…Other aspects involve the spatiotemporal dynamics of the environment, such as complex hydrological interactions and characteristics that influence processes of flooding and erosion (Lima et al, 2012;Duplaix et al, 2015). However, the species faces several threats to its habitat Groenendijk et al, 2015), such as pollution and the difficulty in establishing conservation units for the protection of giant otter populations in the Pantanal wetlands (Groenendijk & Hajek, 2002;Tomas et al, 2015;Leuchtenberger et al, 2020).…”