Trophic Plasticity of Fishes within the Tonlé Sap of Cambodia

The Tonlé Sap system of Cambodia is home to several hundred fish species, more than a hundred of which are intensively fished commercially or for subsistence. Despite recognition of the crucial importance of this fishery for sustaining people’s livelihoods within the region, very little is known about the Tonlé Sap’s food web structure and resiliency to a rapidly changing environmental landscape. In our study, we analyzed fish tissue stable isotope data (δ ¹³C, δ ¹⁵N, and δ³⁴S) from 18 sites over 5 years to explore trophic variability in the fish community.  More specifically, we assessed overlap in isotopic niche space among species to evaluate the degree to which species fill the same “trophic roles” across space and time.  We found that most, but not all, fish had a fairly plastic isotope niche with a high degree of overlap among key fishery species.  This suggests that the current community structure of numerous trophically redundant species could potentially provide resiliency to future environmental changes within the basin.