Nationally designated MPAs

The majority (estimated at more than 95%) of MPAs are nationally designated by governments using national legislation. The last major global review of MPAs was based on data from the early 1990s and assessed 1306 sites in 18 different regions, excluding those which were predominantly terrestrial or intertidal. The maximum number of MPAs (206) occurred in Australia/New Zealand and the minimum (15) in the central Indian Ocean. More tha half of all MPAs assessed occurred in just four regions: the Wider Caribbean, the Northeast Pacific, Northwest Pacific and Australia/New Zealand.

Data on the size of MPAs have to be interpreted carefully. Firstly there was no data available for 25% of the MPAs assessed, and secondly although the mean size was 100,000 ha this statistic is skewed by a small number of very large MPAs. The median size is much smaller, 1,500 ha. The smallest MPA in the survey was just 1 ha ' the Red Coral Reserve in Monaco and Doctor's Gully Fish Reserve in Australia. In total less than half a percent of the world's oceans lies within any MPA, few protect very much and 71% appear to have no active management. The past decade has seen a great expansion in the number of MPAs established and a new global survey is very much required.

In an assessment made in 1997 of Canada's 110 MPAs, 72 provided no protection to species or habitats. Furthermore most marine parks in the United States seem to positively encourage fishing: California has more than 100 MPAs, less than 0.2% of their combined area is protected from fishing, and little of that is effectively enforced.