Dm. Mason et Ev. Patrick, A MODEL FOR THE SPACE-TIME DEPENDENCE OF FEEDING FOR PELAGIC FISH POPULATIONS, Transactions of the American Fisheries Society, 122(5), 1993, pp. 884-901
The time-varying spatial distribution of pelagic fish is an important
factor in the development of feeding rate estimates for input into bio
energetics growth models. Key issues are the degree to which fish and
prey distributions overlap, the frequency and duration of such overlap
s, and the effectiveness of foraging during overlaps. A model for the
space and time dependences of feeding by the pelagic planktivorous ale
wife Alosa pseudoharengus in the Great Lakes is presented. The model c
ombines two submodels: (1) a diffusion-taxis model of predator and pre
y dispersal and (2) a foraging rate model. Both models depend on envir
onmental variables. The diffusion-taxis model is based on directional
motion and random motion on the part of the fish. Directional motion i
s determined from a taxis function that relies on local cues for feedi
ng rate and encounter rate with predators. The foraging model expresse
s the feeding rate of a predator as a function of predator and prey si
zes, prey density, light level, and temperature. The diel movements, d
istribution, and feeding rates of alewives were simulated with these m
odels. The model simulations successfully represented the time-varying
spatial distribution of alewives and predicted peaks in their feeding
rate at dawn and dusk. The model simulations suggested a nighttime fe
eding rate that was less than what is known from the literature. These
results suggest that many of the known features of alewife distributi
on can be reproduced with this class of model. Given the typically pat
chy distribution of predator and prey, the nonhomogeneous character of
environmental conditions, and the dynamic nature of both the biologic
al and physical components of an ecosystem, a spatiotemporal approach
such as this may be necessary for modeling the feeding, growth, and pr
oduction dynamics of pelagic fishes.