Seafood Diet: Linking Fish Feeding to Habitat, Prey Availability and Bioenergetics in a Pelagic Predator

The spatial dependence of predator and prey interactions is well known but often ignored in ecological models. Fish feeding rates are largely dependent on two key factors: 1) prey availability and 2) maximum consumption potential. In pelagic ecosystems, the prevailing physical/chemical (e.g. temperature, oxygen, light) environment helps define the degree of spatial overlap in predator and prey, encounter rates between predator and prey and the maximum consumption potential of the predator.  Most biological rates are nonlinear with respect to these environmental conditions and thus require a spatially-explicit modeling approach.  We modeled fish feeding rates of adult striped bass (Morone saxatilis) and bluefish (Pomatomus saltatrix) in the hypoxic area of the Northern Gulf of Mexico to explore these dependencies. Results show that 1) maximum consumption potential can restrict feeding rates even in the presence of high prey densities, 2) habitat gradients help define predator-prey overlap, and 3) fish feeding rate is highly sensitive to predator swimming speeds and reactive distance to prey. Spatial patterning and absolute scaling of the habitat drive the feeding rates and ultimately growth of fishes.