Empirical Evidence for Species-Specific Export of Fish Naïveté from a No-Take Marine Protected Area in a Coastal Recreational Hook and Line Fishery.

Josep Alós,Miquel Palmer,Robert Arlinghaus,Rosario Rosselló,Antoni Puiggrós,Carlos Díaz-Gil,Heather M Patterson

doi:10.1371/journal.pone.0135348

Abstract

No-take marine protected areas (MPAs) are assumed to enhance fisheries catch via the “spillover” effect, where biomass is exported to adjacent exploited areas. Recent studies in spearfishing fisheries suggest that the spillover of gear-naïve individuals from protected to unprotected sites increases catch rates outside the boundaries of MPAs. Whether this is a widespread phenomenon that also holds for other gear types and species is unknown. In this study, we tested if the distance to a Mediterranean MPA predicted the degree of vulnerability to hook and line in four small-bodied coastal fish species. With the assistance of underwater video recording, we investigated the interaction effect of the distance to the boundary of an MPA and species type relative to the latency time to ingest a natural bait, which was considered as a surrogate of fish naïveté or vulnerability to fishing. Vulnerability to angling increased (i.e., latency time decreased) within and near the boundary of an MPA for an intrinsically highly catchable species (Serranus scriba), while it remained constant for an intrinsically uncatchable control species (Chromis chromis). While all of the individuals of S. scriba observed within the MPA and surrounding areas were in essence captured by angling gear, only one fifth of individuals in the far locations were captured. This supports the potential for the spillover of gear-naïve and consequently more vulnerable fish from no-take MPAs. Two other species initially characterized as intermediately catchable (Coris julis and Diplodus annularis) also had a shorter latency time in the vicinity of an MPA, but for these two cases the trend was not statistically significant. Overall, our results suggest that an MPA-induced naïveté effect may not be universal and may be confined to only intrinsically highly catchable fish species. This fact emphasizes the importance of considering the behavioural dimension when predicting the outcomes of MPAs, otherwise the effective contribution may be smaller than predicted for certain highly catchable species such as S. scriba.

Highlights

The implementation of marine protected areas (MPAs) is a widespread management tool for the conservation of marine fisheries resources [1,2,3,4,5]
We found empirical evidence that fish naïveté to recreational angling gear decreases with increasing distance from the boundary outside of a fully protected MPA
We found a gradient from high naïveté at sites within and close to the MPA, to low naïveté at far sites

Summary

Introduction

The implementation of marine protected areas (MPAs) is a widespread management tool for the conservation of marine fisheries resources [1,2,3,4,5]. This is because the spatial protection of marine fauna from harvesting in an MPA is thought to have multiple desirable ecological effects. One of the most important effects is the “spillover” of larvae and adult biomass from inside an MPA to the unprotected areas outside [6,7,8,9,10]. Common wisdom suggests that a properly scaled and positioned MPA should result in biomass accumulation within the reserve, which could benefit the fisheries operating outside of the boundaries [19,20,21]

Methods

Results

Conclusion