Fear and Foraging on the Coral Reef

It’s a fish-eat-fish world! As a fish swims through lush coral gardens they must contend with the threat from predators patrolling open waters and those lurking in crevices of the reef, all while trying to find food for themselves. My dissertation research aims to understand the risks and rewards of life on the reef. My research begins in remote reefs, untouched by human impacts. In these pristine ecosystems, shark populations are often greater than their prey. I used ecological theory to understand how fish should behave when they are outnumbered by their big, fierce predators. Next, I put ecological theory into practice to understand how predation risk impacts the foraging behavior of a coral reef fish. I developed an experimental food patch, the krill burrito, and validated its use to measure giving-up densities of a common Hawaiian fish, the saddle wrasse (hīnālea lauwili, Thalassoma duperrey). I observed saddle wrasse behaviors as they foraged across Hawaiian reefs and from remote video at experimental food patches. I found behavior at the krill burrito reflects those of wrasse foraging from rich and transient resources. Unfortunately, reefs worldwide are facing threats from multiple stressors, resulting in habitat degradation. Therefore, I investigated how habitat degradation influences a fish’s perceived risk on reefs. Finally, I investigated wrasses as predators themselves using biological collections. The results from each of these dissertation chapters advances coral reef conservation, the appreciation for food-safety tradeoffs, and direct knowledge of the feeding behaviors and morphologies of an important group of reef fishes.