Long-term and spillover effects of a marine protected area on an exploited fish community

Abstract

ABSTRACT:We assessed the development of the exploited fish community inside and around the Columbretes Islands Marine Reserve (CIMR), a marine protected area (MPA), 8 to 16 yr after fishing ceased in the reserve. Sampling was by annual lobster trammel net fishing, an experimental technique used inside the CIMR, and on-board commercial operations in adjacent fishing grounds. We examined trends in combined fish abundance and biomass (catch per unit effort), species richness and diversity, size structure, trophic level and species composition of the community. Our results showed the CIMR fish community continued to change throughout the study period as (1) abundance and biomass increased, (2) mean body size and trophic level increased and (3) species composition changed according to a linear model. Relative to nearby fished areas the CIMR fish community had (1) higher abundance and biomass, (2) lower species diversity and higher taxonomic distinctness, (3) larger relative body size and (4) no difference in mean trophic level. We found clear evidence of spillover of fish from the CIMR to the adjacent fishery as commercial fish yields at the MPA border (< 0.5 km from the boundary) increased continuously during the study period, despite being locally depleted due to fishing effort concentration (fishing the line). Furthermore, fish size and diversity at the border were intermediate between the CIMR and other fished zones, suggesting that this is a transitional zone influenced by this MPA. Our results show that changes in community abundance, biomass, size structure and species composition provide a clear and interpretable view of MPA recovery. Diversity indices are also useful; however, their interpretation is more difficult. We conclude that the creation of the CIMR has had a positive effect on the exploitable fish community and that there is evidence of exportation of biomass to the surrounding fishery. We highlight the advantage of using multiple community metrics to study changes in fish communities, yet recommend the need for caution when interpreting them.

Simulation of the combined effects of artisanal and recreational fisheries on a Mediterranean MPA ecosystem using a trophic model

“…The evaluation of reserve effects usually relies on empirical results showing the gradients of species biomasses or catches (e.g. Russ & Alcala 1996, Stobart et al 2009). Such observations, although necessary, do not allow predictions for different scenarios and cannot provide insight into the mechanisms which cause the observed patterns.…”

The Relative Importance of the Sedge Island Marine Conservation Zone for Adult Blue Crabs in Barnegat Bay, New Jersey

“…The abundance of males is higher in the SIMCZ compared with other SAV-dominated locations, although not Blue Crabs within Marine Conservation Zonesignificantly, compared with the neighboring location, suggesting the SIMCZ does not significantly enhance the abundance of males in adjacent areas via a ''spill-over'' effect, as seen in other species protected by MPAs (Pillans et al, 2005;Russ, Alcala, and Maypa, 2003;Stobart et al, 2009). Additionally, the SIMCZ has a distinct size frequency distribution of males compared with all other locations, with more males greater than 115 mm carapace width.…”

Communicating marine reserve science to diverse audiences

“…In some regions, reserves do not yet exist, and thus there is concern that their effect on local fisheries and other resources cannot be accurately inferred. In other cases, reserves have had strong, positive effects inside their borders and augmented local fisheries over time through the spillover of adults (41,42), sometimes changing previously negative opinions of local stakeholders. The responses of human communities to reserves can change over time; for example, in some modeled scenarios, fishermen are more willing to pay, in both costs and missed opportunities, for the establishment of a reserve if it will benefit them in the long run (43).…”