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

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

Classification of shell disease (SD) and exoskeletal injury in European lobsters, <i>Homarus gammarus</i>.

<p>These criteria were used to assess the health status of lobsters at Lundy Island in July and May 2010. Scale bar = 1 cm.</p

Population structures of Lundy Island lobsters.

<p>(A) Size-frequency distributions of lobsters surveyed from the Refuge Zone (RZ, coloured yellow) and the No-Take Zone (NTZ, coloured red); (B) Size-frequency distributions of ovigerous (‘berried’) female lobsters from the RZ and NTZ. MLS, Minimum Landing Size.</p