Spatio-temporal diet variation and movement decisions of Lake Erie yellow perch

Allison R Hrycik, Purdue University

Abstract

Yellow perch, Perca flavescens, are a native species to the Laurentian Great Lakes with high economic and ecological value, making them a useful model species to study ecosystem dynamics and species interactions. Here, we examined trophic connections and movement decisions of yellow perch in the Lake Erie’s Central Basin (LECB) at multiple spatial and temporal scales. We first examined stomach contents, fatty acids, and stable isotopes to determine spatio-temporal variability in diets and underlying production pathways across a sampling season at three distinct sites within LECB. Biochemical markers such as fatty acids and stable isotopes, quantified in conjunction with stomach contents analyses, provide information about not only prey consumption, but also underlying production pathways, which may change with seasonal succession of primary producer communities or spatio-temporal variation in riverine input or autochthonous production. Specifically, we demonstrated high temporal variation in biochemical trophic indicators and limited spatial variation. This high temporal variation in biochemical trophic indicators occurred despite relatively consistent stomach contents, demonstrating the importance of lake-wide seasonal effects on the underlying energy pathways that support yellow perch production. We then examined movement decisions by adult Lake Erie yellow perch at fine spatial and temporal scales using a spatially-explicit individual-based eco-genetic model with movement preferences set as heritable traits. Choice of appropriate movement rules is a central challenge in spatially-explicit ecological modeling due to the difficulty of understanding the relative influence of multiple proximate cues that result in movement and ultimate cues that influence fitness. Our framework allowed selection for appropriate combinations of movement rules in response to light, temperature, dissolved oxygen, predation risk, and prey availability that influenced individual growth and subsequent reproductive output. We found that yellow perch fitness was greatest when individuals weighted light and predation risk highly in conjunction with reduced weighting of temperature and prey availability. Additionally, we found little evidence of strong selection for dissolved oxygen preference. This high importance of light and predation risk evidently reflected their influence on survival, and therefore, fitness. Our selection-based modeling framework is applicable in a diversity of contexts with dynamic environmental resource gradients and interactive effects of proximate cues on individuals.

Degree

M.S.

Advisors

Collingsworth, Purdue University.

Subject Area

Ecology

COinS