A stable isotopic study of the diet of Potamonautes sidneyi (Brachyura: Potamonautidae) in two coastal lakes of the iSimangaliso Wetland Park, South Africa

A stable isotopic analysis of the diet of Potamonautes sidneyi, a dominant freshwater crab in KwaZulu-Natal, South Africa, reveals its complex trophic role and dietary flexibility across seasons. The study found that juveniles from Mpophomeni Stream exhibit a more carnivorous diet and higher trophic position compared to adults, while both sites showed seasonal shifts—consuming aquatic invertebrates and sedimentary organic matter in wet summer months but shifting to detritus and microphytobenthos in autumn/winter. Despite abiotic variations between Lake Sibaya and Mpophomeni Stream, adult crab diets remained consistent, suggesting resilience to environmental changes. The species acts as an intermediate consumer, facilitating nutrient cycling by breaking down decomposing organic matter, highlighting its ecological significance in coastal wetland ecosystems.

Peer, N., Perissinotto, R., Miranda, N., & Raw, J. (2015). A stable isotopic study of the diet of Potamonautes sidneyi (Brachyura: Potamonautidae) in two coastal lakes of the iSimangaliso Wetland Park, South Africa. Water SA, 41(4), 549. https://doi.org/10.4314/wsa.v41i4.15