A study by McDonald et al. published in July 2024, challenged the notion that fully protected MPA (places with no fishing or other human activities that kill marine wildlife or damage their habitats) displace fisheries and cause increased fishing effort outside protected zones. Using global data on industrial fishing and MPA expansion, the authors found that fishing effort actually decreased in and around MPA, suggesting that fish stocks are recovering, allowing for sustained catches with less effort. 

Building up on this, plus the evidence from 46 more local scale studies that MPA can benefit fisheries published a few months previously, Mark Costello commented on this and on other four misleading ideas concerning the establishment of fully protected MPA, namely that (1) MPA do not work for pelagic fish, (2) establishing fully protected MPA is a radical idea, (3) Only commercial or industrial fishing should be excluded from MPA, and (4) MPA are expensive and can only be afforded by wealthy countries. 

In fact:  

• Studies show that pelagic species population can recover in MPA and spillover into adjacent fisheries. Because pelagic species are even more sensitive to overfishing than demersal species, MPA should consider the protection of these fish, even if for only a part of their life;  

• The idea of fully protected MPA is ancient and well-established. Indigenous cultures have established no-fishing areas and the first fully protected MPA were established over 50 years ago. Moreover, public access to certain areas of the ocean is already restricted (e.g., marinas, fish farms, pipelines, military areas) and considerable land is set asside for public use (e.g., hospitals, schools, sports, transport, parks); 

• It does not matter who fishes or why they do so. The ecological effects of recreational fishing is as harmful to biodiversity as commercial fishing, and why should killing marine wildlife for sport in a so-called “protected” area take precedence over fishing for food? 

• The costs of establishing and managing MPA need to be placed in the context of previous marine spatial and fishery management costs (if any) and the cost of doing nothing. Economic studies show that fully protected MPA cost less to manage than partly protected MPA due to its simplicity and clarity between what is and is not allowed. Moreover, thousands of MPA are established in developing countries, including some of the largest MPA in the world.  

Overall, the issue is that over 90% of MPA allow fishing and thus their potential benefits to fisheries are less likely to be realized. Most importantly, and as stated in the paper, the public is being misled about progress in marine conservation.