By: Erika Nava

I am a graduate student at California State University, Northridge working in a Fish Ecology Lab under Dr. Mark Steele. I am interested in evaluating if Marine Protected Areas (MPAs) can affect fish foraging behavior. MPAs are used to allow organisms and habitats to recover from anthropogenic impacts such as overfishing, which has significantly diminished populations of many exploited marine species. Protection provided by MPAs has allowed fish populations to recover and has increased their densities and size. But increased fish density may lead to unforeseen intraspecific competition for resources. Most studies on MPAs have focused on evaluating their performance in terms of recovery of targeted species, but few have evaluated how this protection can affect trophic interactions. Fish diet and behavior, for example, might change, and documenting such changes could improve our understanding of how MPAs affect protected species. My research intends to evaluate whether California sheephead is food limited within MPAs in southern California.

Male California sheephead at Santa Catalina Island

The foraging behavior of sheephead can influence ecosystem health. For example, previous studies showed that sheephead are capable of improving kelp forest health by controlling sea urchin (herbivore) populations.

Female sheephead searching for food

I did my research this summer at Catalina with the support of a Wrigley Institute Summer Fellowship. I started with SCUBA surveys of abundance of sheephead and invertebrates (food availability for sheephead). I also conducted time budget observations on sheephead foraging behavior. These observations will allow me to understand time spent searching for food and foraging rate within these time periods.

Sheephead foraging observations

I will also use Baited Remote Underwater Video (BRUVs) to observe fish foraging behavior, without the influence of divers. Since it can be difficult to observe diet with natural observations and impossible to control for prey availability, I will use BRUVs to introduce a standardized prey item and observe sheephead’s predation on it. By understanding if foraging interactions are changing within MPAs, my research can help inform future management strategies.