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Monday, April 9 • 4:45pm - 5:00pm
SYMPOSIA-04: Reefscapes of Fear: Effects of Habitat Quality and Predation Risk on Coral Reef Fish

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AUTHORS: Margaret A. Malone, Christopher J. Whelan, & Joel S. Brown - Ecology & Evolution, University of Illinois at Chicago

ABSTRACT: Predators have both consumptive and non-consumptive effects on their prey. Non-consumptive effects are observable through an organism’s ecology of fear, or the combination of their population ecology and behavior. Coral reefs and their fishes are facing anthropogenic impacts through habitat degradation and intensive fishing, causing shifts in communities. These shifts may impact a fish’s perception of its habitat, including how it perceives predation risk. In this study we investigate the ecology of fear and spatio-temporal habitat use (commonly referred to as a “land(reef)scape of fear”) through the foraging behavior of a common Hawaiian coral reef fish. We ask: Does predation risk change across reefs of varying quality? To address this question we used experimental food patches to quantify the giving-up density (GUD) of generalist saddle wrasse (Thalassoma duperrey) on patch reefs of Kane’ohe Bay, Hawaii. When deployed at small spatial and temporal scales the GUD reveals costs of predation associated with foraging. Common predators on Hawaiian patch reefs include transitory predators like whitetip sharks and bluefin trevally, and reef-associated predators such as the yellowmargin eel. Using a randomized-block design, we deployed experimental food patches across 10m × 20m plots along the leeward side of 5 patch reefs of varying quality within Kane’ohe Bay. Coral cover and structure were quantified using photogrammetry and structure-from-motion (sfm) within the experimental plot, as well as along random transects throughout the reef. Saddle wrasse foraging was higher on reefs of high coral cover and structure, while fish on reefs with low cover and structure had lower foraging. Within reefs, fish did not have microhabitat foraging preferences. This suggests that predation risk is independent of microhabitat properties, and is instead a macro-phenomenon of overall patch reef properties.

Monday April 9, 2018 4:45pm - 5:00pm CDT
Adams Room