Global Marine Protected Area performance: looking under the hood

Over the last two decades, marine protected areas (MPAs) have become the most commonly used tool to conserve marine ecosystems globally, driven in part by international targets set to “effectively and equitably manage” 10 percent of coastal and marine areas by 2020. Despite substantial progress in reaching the associated 10% coverage target, key questions remain about the management of MPAs, including how management approaches can improve their conservation performance.

Go to the profile of David Gill
Mar 22, 2017
Upvote 1 Comment

The job

“I think you should apply for this post-doc, it’s perfect!”

“No, I’m still trying to finish my PhD, the start date is in November, and this job has been advertised around the world. It doesn’t make sense trying to apply.”

“Apply! Apply! Apply!”


This was a conversation between my officemate and me back in 2014. I was trying to finish up my Ph.D. at the Centre for Resource Management and Environmental Studies (CERMES) department at the University of the West Indies back home in Barbados. Who knew this conversation would result in me spending the next 2.5 years working with an incredible team of researchers on a project with implications for marine conservation globally.

The study was part of a National Socio-Environmental Synthesis Center (SESYNC) Pursuit and a portfolio of studies, aptly titled “Solving the mystery of MPA performance.” This work, initially conceptualized over a number of years (and a number of gin & tonics) by Helen Fox and Mike Mascia attempts to answer critical questions concerning MPA performance: are marine protected areas really meeting their social and ecological objectives? If not, why? How can we better design, implement, and manage MPAs so that they can produce positive benefits to both marine biodiversity and human societies?

Patrol boat and signage at two MPAs in the Meso-American Barrier Reef

Answering these questions required data — lots and lots of data. In addition to combining data from thousands of survey sites of MPAs worldwide, we had to employ theories and analytical approaches from across multiple disciplines. Not an easy job.

Some of the cast of the Solving the Mystery of MPA Performance research group at the National Socio-Environmental Synthesis Center (SESYNC)

The team

Fortunately, we had the right team to do it. With post-doc funding support from the Luc Hoffmann Institute, our interdisciplinary team of researchers and practitioners from across the globe brought their insights, data and networks together to tackle the research challenges. With the help of our co-author institutions, generous data providers, and significant computational support from SESYNC, we were able to assemble 750 management assessments for 433 MPAs in 70 countries. We focused on fish biomass as an indicator of ecological performance, and were able to assemble underwater fish survey data for around 16,000 sites globally (and painfully collect contextual data on each one!).

Location and sources of fish survey data used in the study

Measuring impacts

We drew on theories from common-pool resource governance to develop hypotheses of the relationship between management processes and subsequent conservation outcomes (Ostrom 1990; Mascia 2004; Cox et al. 2010; Scianna et al. 2015). To isolate the causal effect of MPAs from other confounding factors, we used impact evaluation: a powerful analytical approach used to identify the intended and unintended impacts of an intervention by comparing the observed outcomes against an estimate of what would have occurred in the absence of that intervention (Ferraro 2009). Why impact evaluation? Because MPAs are not randomly placed in the ocean, they are often placed where fishing and mining are less likely, or to protect special habitats (Devillers et al. 2015). This creates considerable bias when comparing fish populations at MPAs to non-MPA sites. The impact evaluation framework allowed us to use these same factors that bias the location of MPAs as attributes to match MPA to non-MPA site pairs (e.g. oceanographic conditions, proximate human pressures, etc. (Ahmadia et al. 2015; Ferraro 2009)). This process removes or minimizes the influence of these factors, and isolates the effect of the MPA itself.

The results

The results of the work were revealing. We found major weaknesses in MPA management processes globally: only 51 percent of MPAs said that stakeholders had direct involvement in decision-making, and a mere 9 percent of MPAs reported adequate staff to carry out critical management activities. When looking at ecological impacts, things were less surprising: Most MPAs (71 percent) had positive impacts on fish populations. However, these ecological impacts were highly variable.

Next came the big finale, linking the management assessment data to fish biomass data in locations where both types of monitoring data existed. Unfortunately this happened in fewer places than we’d like: 62 MPAs in 24 countries. Using a suite of statistical approaches, we found that staff capacity and budget were the most important factors in explaining the variation in ecological impacts. This result, and the strong correlative relationship between capacity and other key management activities (e.g. enforcement, monitoring), indicate that capacity shortfalls are likely to be limiting the potential of many MPAs around the world to achieve their targets/objectives. While the global community focuses on expanding the current MPA network, these results emphasize the importance of meeting capacity needs in current and future MPAs to ensure the effective conservation of marine species.

Relative importance of management and non-management factors in explaining MPA impacts on fish populations (from Gill et al. 2017 Nature).

The next phase of the journey

The decision to join this project 3 years ago was definitely worth it, even though it meant me defending my thesis on Thursday, packing my office on Friday, packing my life in a suitcase on Saturday, and flying on Sunday to another country to start a post-doc on Monday. While this research revealed important insights regarding the ecological impacts of MPAs, data limitations prevented us from understanding the social impacts of MPAs. To address this, my current David H. Smith post-doc research with Conservation International and George Mason University focuses on how MPAs are impacting the well-being of coastal communities around the world. Again, it isn’t going to be easy, but with the data and methods from this previous work, and another great team of collaborators, we hope to shed light on how we can better manage MPAs to deliver positive benefits to both marine biodiversity and coastal communities.

Our paper "Capacity shortfalls hinder the performance of marine protected areas globally" can be found here: or on Readcube here.


Ahmadia, G.N. et al., 2015. Integrating impact evaluation in the design and implementation of monitoring marine protected areas. Philosophical Transactions of the Royal Society B: Biological Sciences, 370(1681), p.20140275. Available at:

Cox, M., Arnold, G. & Villamayor Tomás, S., 2010. A Review of Design Principles for Community-based Natural Resource Management. Ecology and Society, 15(4), p.38.

Devillers, R. et al., 2015. Reinventing residual reserves in the sea: are we favouring ease of establishment over need for protection? Aquatic Conservation: Marine and Freshwater Ecosystems, 25(4), pp.480–504. Available at: [Accessed March 19, 2014].

Ferraro, P.J., 2009. Counterfactual thinking and impact evaluation in environmental policy M. Birnbaum & P. Mickwitz, eds. New Directions for Evaluation, 2009(122), pp.75–84. Available at: [Accessed December 16, 2014].

Mascia, M.B., 2004. Social Dimensions of Marine Reserves. In J. Sobel & C. Dahlgren, eds. Marine Reserves: A Guide to Science, Design, and Use. Washington D.C.: Island Press, pp. 164–186.

Ostrom, E., 1990. Governing the commons: the evolution of institutions for collective action, New York, NY: Cambridge University Press.

Scianna, C. et al., 2015. “Organization Science”: A new prospective to assess marine protected areas effectiveness. Ocean & Coastal Management, 116(2015), pp.443–448. Available at:

Go to the profile of David Gill

David Gill

Post-doctoral fellow, George Mason University/ Conservation International

No comments yet.