Increased Disease Calls for a Cost-Benefits Review of Marine Reserves

Emma C Wootton,Edward C Pope,Claire L Vogan,Andrew P Woolmer,Andrew F Rowley,Kristina M Hamilton

doi:10.1371/journal.pone.0051615

Abstract

Marine reserves (or No-Take Zones) are implemented to protect species and habitats, with the aim of restoring a balanced ecosystem. Although the benefits of marine reserves are commonly monitored, there is a lack of insight into the potential detriments of such highly protected waters. High population densities attained within reserves may induce negative impacts such as unfavourable trophic cascades and disease outbreaks. Hence, we investigated the health of lobster populations in the UK’s Marine Conservation Zone (MCZ) at Lundy Island. Comparisons were made between the fished, Refuge Zone (RZ) and the un-fished, No-Take Zone (NTZ; marine reserve). We show ostensibly positive effects such as increased lobster abundance and size within the NTZ; however, we also demonstrate apparent negative effects such as increased injury and shell disease. Our findings suggest that robust cost-benefit analyses of marine reserves could improve marine reserve efficacy and subsequent management strategies.

Highlights

The declining state of our marine environment is of global concern [1,2], there is a growing demand to increase the number of highly protected marine reserves
The catch data revealed that a greater number of lobsters were caught in the No-Take Zone (NTZ) than in the Refuge Zone (RZ) (NTZ = 514, RZ = 152; Figure 3a and Table S1), with the Catch Per Unit of fishing Effort (CPUE) being 7.71 times greater in the NTZ (1.364 v. 0.177; unpaired T-test, P,0.0001)
A previous survey at Lundy Island in 2007 [27]; which used very similar sampling locations, revealed a 5.0-fold increase in lobster abundance in the NTZ compared with the RZ, the 7.71-fold increase in CPUE observed during our current study suggests the lobster population in the NTZ continued to increase between 2007–2010

Summary

Introduction

The declining state of our marine environment is of global concern [1,2], there is a growing demand to increase the number of highly protected marine reserves These reserves are No-Take Zones (NTZs) designed to protect habitats of ecological importance; with the aim of restoring ecosystem function via increased species density and biodiversity [3,4]. Their conservation benefit is principally documented with respect to heavily fished species, where high increases in density have been observed [5,6,7]. High host abundance in marine reserves may, render animals vulnerable to disease [12,13], because infections can no longer be ‘fished out’ [14,15]

Methods

Results

Conclusion