Date of Award
MS Marine Science
Environmental and Ocean Sciences
Andrew R. Thompson
David Checkley, Jr.
John R. Hyde
Steven S. Searcy
Marine protected areas (MPAs) are areas aimed at protecting natural and cultural resources that are often proposed as a way to alleviate the effects of overfishing on populations of targeted species; these areas have varying degrees of fishing and recreational use restrictions. In order to assess MPA efficacy, it is important to determine the mechanisms by which the presence of MPAs affect reproductive output within and potentially even beyond their boundaries. I attempted to address this through studying the responses of rockfish (Sebastes spp.) larval abundances to the presence of the Cowcod Conservation Areas (CCAs) located within the Southern California Bight region. Rockfish larvae were collected from mesozooplankton samples obtained during winter survey cruises by the California Cooperative Oceanic Fisheries Investigations (CalCOFI) program and identified by sequencing the cytochrome b gene. I constructed time-series of rockfish larval abundances within the Southern California Bight from 1998 to 2013.
I found that, not only have delta mean larval abundances of multiple rockfish species increased throughout the period, three historically-targeted species’ delta mean larval abundances—Bank Rockfish (S. rufus), Speckled Rockfish (S. ovalis), and Olive Rockfish (S. serranoides)—increased at a greater rate within the CCAs compared to locations with similar environmental parameters outside of the CCAs. This is the first decadal-scale study that explicitly demonstrates an increase in reproductive output from an MPA in the form of increased larval 2 abundances, thus contributing crucial information to the understanding of MPA efficacy.
Additionally, the dataset created during this study will become the basis for several future studies that will further elucidate the spatiotemporal dynamics of rockfish larvae within CCAs and in the Southern California Bight region as a whole. These studies will further contribute to understanding the efficacy of the CCAs in their facilitation of rockfish species recovery, as well as provide important information for rockfish fisheries management in the region.
Digital USD Citation
Chen, Dustin, "Larval rockfish diversity abundance dynamics in association with a marine protected area in the Southern California Bight" (2017). Theses. 21.