Current Research and Research Interests

M.S. Thesis:
Effects Of Predator Accumulation On Community Structure Of Fishes In Marine Protected Areas

One of the main goals of community ecology is to understand how communities are structured and how they function. Marine protected areas (MPAs) are changing community structure. One change is that older, larger fish accumulate in MPAs. Predation pressure from these large piscivores may increase mortality in juveniles, smaller fishes, and conspecifics, potentially altering the community. My thesis work investigates whether predator accumulation in an MPA has altered the size structure of the fish assemblage. Replicated underwater visual transects are used to quantify the size structure of the fish assemblage inside and outside of three different MPAs in Southern California. All demersal species are surveyed at 8-week intervals over a 24-month period. Non-metric multidimensional scaling (nMDS) is used to evaluate whether the species and size structure of the assemblage inside the MPA differed from that found outside. Cohort analysis will be used to test whether mortality in young-of-year is greater inside vs. outside the MPA. Initial results indicate that fish assemblages inside the MPA are distinguished from those outside by the presence of both large predatory species and disproportionately few individuals of small species and size classes. This result implies that large predators in MPAs alter assemblage structure. This finding provides a basis for more realistic predictions of how MPAs may be expected to affect marine fish communities.