In 2002, the Convention on Biological Diversity asked for governments to protect at least 10% of all ocean areas. At present, 10 years after this convention, marine protected areas (MPAs) cover only just over 1% of all ocean area.
Some studies of MPAs (eg. Australia’s Great Barrier Reef protected area) show positive results – that the establishment of these areas have given real benefits to the ecosystem.
Others have had real problems that have led to inefficient protection of habitat and ecosystem function. These range from protecting the wrong habitats to insufficient regulation of fishing and other commercial activities within the protected area.
In the past decade there has been a large increase in the creation of ever-larger marine protected areas, spurred by the creation of the Papahānaumokuākea Marine National Monument in 2006 by the United States, the largest MPA at the time, covering 360,000km2. Marine protected areas size almost doubled between 2008 and 2010
Since then, Australia has plans for a 900,000km2 MPA, while Britain has established a 544,000km2MPA in the Indian Ocean.
There also seems to exist a culture of discouragement towards any critical studies of marine protected areas, making any inefficiencies into how MPAs are managed or established harder to identify and solve.
There is little debate whether or not a good MPA can be effective in protecting biodiversity. Studies collated across 124 reserves in 29 countries found that measures such as biomass and species richness increased inside the protected areas once they had been established.
However many MPAs are not effective due to improper enforcement or monitoring. A recent study of 20 protected areas found that 3 were not effective on any level while none were highly effective at meeting objectives such as making sure resources were used sustainably.
A reserve in south-western Australia was criticized by 173 scientists for protecting too few types of habitat.
There are solutions to this problem – computer programs have been made which minimize the cost of proposed marine protected areas while maximizing the number of habitat types covered by the protected area.
Studies of the cost-effectiveness of marine protected areas are few and far between, and the effectiveness of species conservation can be unexpected – take the case of the Hawaiian monk seal whose population has decreased within the marine protected area but increased outside of it.
However, the general benefits given by the establishment of MPAs tend to outweigh any inefficiency in zoning, and we should encourage governments to establish MPAs while we still have marine biodiversity left to protect.