Human-driven spatial and temporal shift in trophodynamics in the Gulf of Maine, USA

Abstract

Utilizing marine protected areas (MPAs) to isolate the ecological effects of human influence can help us understand our effect on systems and foster ecosystem-based approaches to management. Specifically, examining invertebrate prey community dynamics inside and outside an MPA may provide a measure of how altering human influence (i.e., certain fishing pressures) affects ecosystem interactions. We measured trophic interactions inside and outside a deep-water temperate MPA over 2 years. Predation rates on tethered, preferred groundfish prey (crabs) were initially identical inside and outside the MPA, but decreased outside the MPA after the commercial groundfish fishing season commenced. Predation trials using a ubiquitous prey species (brittle stars) and a less preferred prey species (urchins) served as controls, showing no MPA effect. Our experiments quantify differential predatory activity resulting from differences in human activity driven by an MPA, demonstrating important effects of fishing and regulations on the strength of trophic interactions.