Research Technical Report

Contrasting Behavioral Responses of Marine Fishes to Scuba Diving, Fishing, and Environmental Change: Impacts on Predation Rates

Rhoades, O.K., S.I. Lonhart, J.J. Stachowicz (November 2016)

Oral presentation at the Western Society of Naturalists Annual Meeting, November 10-13, 2016, Monterey, CA

ABSTRACT

Behavioral traits of consumers vary broadly among species, with significant effects on the role that species play in ecosystems. However, few studies have considered how the sensitivity of behavioral traits to human activities and environmental change varies across species. Here, we employ data collected on flight and foraging of nearly 2000 individual fishes of 16 species during surveys and manipulations in central California kelp forests to estimate species-level values of behavioral traits across environmental contexts. Species vary in their flight and foraging traits, and flight initiation distance (FID) and prey consumption rate are negatively correlated across species. Species also vary in their sensitivity to human activities, with inversely correlated responses in FID to recreational fishing relative to the presence of SCUBA divers at sites. Additionally, species vary in their sensitivity to apparent threats, with inversely correlated responses in prey consumption to the presence of SCUBA divers versus natural predators. Finally, species exhibit distinct sensitivity to environmental conditions, with similar effect sizes of visibility, temperature, and depth on flight and foraging for each species. These results show that kelp forest fishes exhibit distinct behavioral traits and sensitivity, but that species change their behavior in a predictable manner across contexts. As a result, species-level variation in sensitivity to both extractive and non-extractive human activities and natural environmental conditions likely impacts fish predatory function in kelp forests.