From Prey Behavior to Predator Habitat Analysis: Predator Prey Interactions in North Temperate Lakes (and River/Estuary) (2024-04-05)

Abstract

The quantity and quality of information during predator-prey interactions is influenced by a variety of environmental factors such as light intensity and temperature, as well as sensory and locomotory abilities of both predator and prey. The vast majority of fish predator-prey studies have focused on interactions of a single predator/prey; however in the current study, to better recapitulate the sensory environment and recreate situational complexity, the interactions of multiple predators with multiple prey species in moderate concentrations were determined under natural relevant lighting conditions. Likewise, successful foraging of piscivores is often dependent on available light penetration. Thermal-optical habitat, the overlap of optimal temperature and optical conditions, is an important criterion for young of the year (YOY) walleye. In areas like Northern Minnesota, high tannin concentrations can limit the penetration of light into the water which may impact both foraging success and growth. The goal of these studies are to 1) link the importance of prey behavior on predator capture success while comparing native and invasive prey, 2) establish optimal optical habitat of YOY walleye by observing foraging behavior at eight different light intensities, 3) translate how foraging behavior over extended periods of time leads to growth rates, and the influence tannins have on growth rates of YOY walleye, and 4) combine the data from the ecophysiology experiments into an individual based model (IBM) to determine which parameters, light intensity, temperature, or prey density, are the most important to YOY walleye growth. Briefly, invasive round goby are more successful than native mottled sculpin at avoiding predators based on their flight initiation distance, escape angle, as well as the number of turns they make during an escape attempt. YOY walleye reaction distance increases as light increases, but the probability of an attack decreases with increasing light intensity. YOY walleye also have increased growth rates in stained water, although the IBM provides evidence that prey density is a strong determinant of growth rates in stained water. This disconnect between prey detection, attack probability, and ideal growth conditions indicates a complex set of foraging cues that select for low light success in YOY walleye.