Trophic Ecology and Resource Partitioning of Common Snook and Mexican Snook in the Usumacinta River Delta

The study investigates how Common Snook and Mexican Snook, two carnivorous fish species, coexist by resource partitioning in the Usumacinta River delta in the southern Gulf of Mexico, a region significant for fisheries and the economy. Through analyzing spatial, temporal, and ontogenetic variability in their trophic dynamics and distribution, alongside stomach content and stable isotopes, the study identifies 51 prey items, with fish remains as the most abundant component. Significant dietary differences between the two species were found; Common Snook favored certain fish families while Mexican Snook consumed others. Size-classes also revealed dietary variations, with different sized fish within the species having varied reliance on certain prey types. Seasonal and site-based dietary differences were also noted. The study found varying degrees of trophic niche overlap between the two species across different systems, indicating spatial resource partitioning as a strategy aiding their coexistence in the region.