In recent years, ecologist Joachim Claudet has been at the forefront of MPA science. His studies of European marine reserves – which found that the older and larger a marine reserve is, the greater the density of large fish inside it is – have held important implications for MPA network design and fisheries management (“Older and larger reserves have more large fish” in Special Section, MPA News 10:11).

Now a new book edited by Claudet, with chapters contributed by researchers from around the world, gathers the latest scientific knowledge on MPAs, including on their use in biodiversity conservation and fisheries management. Applying findings from ecology, economics, sociology, and more, the bookMarine Protected Areas: A Multidisciplinary Approach (Cambridge University Press, 2011) walks readers through the effects of MPAs and how to measure sites’ effectiveness. It also discusses the development of representative MPA networks. Claudet, a researcher at the National Center for Scientific Research in Perpignan, France, talks below about the current state of MPA science.

MPA News: In your opinion, what have been the most important recent advances in MPA research?

Joachim Claudet: The most important advances lie at four different levels, each of which is presented in the book.

First, important discoveries or confirmation of theory was made on how MPA effects are driven by different factors such as MPA age, size, or level of enforcement. The implications are strong for MPA design and management. For example, even if young and small MPAs can be effective in increasing fish population density, old and large MPAs can show even greater positive responses. Meanwhile no positive responses should be expected from MPAs with low levels of enforcement.

Second, major advances were made on the numerous indirect ecological effects of protection, which are also time-dependent. These effects can involve trophic cascades and complex predator-prey relationships.

Third, the potential socio-economic benefits of MPAs are now becoming clearer. Studies show, for example, that MPAs can lead to jobs and/or revenue increases in activities linked to MPAs such as fishing and tourism, as well as to the maintenance of traditional activities.

Fourth, the general agreement among scientists that MPA networks can optimize conservation and fisheries benefits has led to significant advances in network design and evaluation.

MPA News: What are the most important MPA questions that still require answers?

Claudet: In my opinion, efforts are urgently needed to understand if MPAs can increase the resilience of protected ecosystems. Existing results are, for now, contradictory. Determining if healthier or more “pristine” ecosystems within MPAs can cope with higher regional or global pressures before shifting to alternate states is fundamental to mitigating regional and global change. (Along the same line, understanding how MPAs may help buffer against human-induced selection pressures and protect phenotypic and genetic diversity – to support adaptation to future environmental change – is of major importance.)

Understanding better patterns of connectivity among protected and unprotected areas of MPA networks is also needed, although recent advances have been made in this direction. This information is critical to designing effective ecological networks that can benefit multiple species at a time.

The recent emergence of large-scale pelagic MPAs also calls for new research to better understand how protection can be effective in these habitats and how regulations can be applied offshore over such large, remote areas.

Finally, MPA research publications still focus too often on a given discipline: ecology or economics or genetics or something else. MPAs are social-ecological systems. Future research needs to reflect this fact. Natural and social scientists in the MPA field need to collaborate more to make their work fully multidisciplinary.

For more information:

Joachim Claudet, National Center for Scientific Research, CRIOBE, Perpignan, France. E-mail:; Web: