Managing a global network of MPAs in which 30% of each habitat type is protected would likely cost US$12-14 billion annually – less than what is spent on international subsidies for commercial fishing, according to researchers. In a study published in June in the Proceedings of the National Academy of Sciences, a team of UK scientists surveyed the management costs of 83 well-managed marine parks worldwide, then used the findings to model costs for a global MPA system.

“Our purpose was to find the price tag of good management and to explore how costs scale up when extensive networks of MPAs are contemplated,” says study co-author Callum Roberts of the University of York. “The message from the figures is that MPAs are a bargain and that we should be putting our money into them rather than propping up unsustainable fisheries with subsidies.” The authors say US$15-30 billion is spent each year on commercial fishing subsidies worldwide. If used for MPAs instead, they say, the funds would help fortify marine ecosystems, making them more productive and fisheries more sustainable.

The cost model in the study is principally based on MPA size: the researchers’ global survey of MPA costs found size to be the primary determinant of management expenses. In other words, larger MPAs cost less per unit area than smaller ones. (Editor’s note: The findings of this survey were described in “The costs of operating an MPA” in MPA News 5:5.) In the model, scenarios that essentially featured fewer but larger MPAs reduced the overall cost of the global network, accounting for variation in the final estimate.

At the World Parks Congress in September 2003, delegates recommended that MPA networks worldwide include at least 20-30% of each marine and coastal habitat in “strictly protected areas”, meaning these sites would be off-limits to fishing. The UK study used this recommendation as inspiration. The study model simplifies some factors. It does not account for the distribution of different habitats, assuming a homogeneous ocean. It also does not account for potentially higher management costs associated with the enforcement needs of no-take areas: the preliminary survey of management costs was conducted primarily on multiple-use MPAs. “But the evidence that no-take reserves cost more in our existing sample is only weak,” says co-author Andrew Balmford of the University of Cambridge.

The study appears in Vol. 101, issue 26, pp. 9694-9697 of the Proceedings of the National Academy of Sciences. Readers without access to the journal may e-mail Balmford for a copy of the paper at

For more information:

Andrew Balmford, Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK. Tel: +44 (0)1223 331770; E-mail:

Callum M. Roberts, Environment Department, University of York, York, YO10 5DD, UK. Tel: +44 (0)1904 434066; E-mail:

Pippa Gravestock (who conducted the global survey of MPA costs), 60 Howards Lane, Putney, London SW15 6QF, UK. Tel: +44 208 788 6946; E-mail: