Fully protected Marine Protected Areas do not displace fisheries

A recurring obstacle to the conservation of marine biodiversity is its perceived conflict with fisheries. Claims of fully protected Marine Protected Areas (MPA) closing and forcing out (displacing) fisheries are made so often that people may think they are true and lead to estimates of fishery loss proportional to MPA area. If MPA displace fishing then fishing effort may increase outside the MPA, worsening impacts on marine biodiversity. However, Ballantine (1) argued that this is an “invented problem” because fishermen are as dynamic in how, when, and where they fish as are the fishery resources, and these resources proliferate due to MPA. Whether MPA actually displace fishing has now been tested at a global scale, using historic data on industrial fishing effort and expansion of MPA (2). The study observed decreasing fishing effort in and around MPA and predicted continued decreasing effort as more MPA are established. This is not expected by fishery displacement.

Although McDonald et al. (2) did not analyze catch data, fishery catches have not been increasing for decades and can be considered exploited to the maximum (e.g., refs. 3–5). Thus, decreasing fishing effort in areas with MPA suggests that there has been a recovery of stocks associated with past expansion of MPA so that less effort is needed to maintain catch, as expected from previous studies on the recovery of fished populations in MPA (e.g., ref. 6). McDonald et al. found that their business-as-usual scenario predicted increased fishing effort. Continued increase in effort, often subsidized by governments (7), without increasing catch, will lead to fishery collapse (Fig. 1). Thus, without MPA, we will not see fisheries recovering and becoming more profitable (i.e., more catch for the same or less effort), as concluded by an analysis of Australian coastal fisheries (8).

Fig. 1.

A diagram of the trajectory of fishing effort from initial stages of increasing effort as a fishery develops to a point (circled) where either (a) effort increases to maintain catch, indicating overfishing, or (b) the establishment of fully protected MPA acting as permanent spatial closures or other fishery regulations that limit effort and lead to a sustained fishery catch.

A limitation of global studies such as this is that there may be local situations which contradict the general trend, and/or the results based on larger fishing vessels (above 24 m in length) may not apply to smaller vessels in coastal seas (2). However, there is no evidence of losses in catch to any fishery due to MPA establishment. In fact, there are at least 46 examples of benefits to fisheries from 25 countries, including increased catch and/or body size of diverse finfish and invertebrates (including spiny and clawed lobsters, crabs, clams, mussels, snails, scallops), following MPA establishment (9). Of these examples, 91% were from fully protected MPA and 98% were coastal. It seems that fish stock recovery and spillover from such MPA to adjacent fisheries outbalances any short-term local reduced catch due to MPA establishment. Together, these studies provide a compelling case that more fully protected MPA will benefit fisheries as a general rule. The rarity of examples of fishery benefits from partly protected MPA is notable.

Through a detailed global analysis, McDonald et al. found that multiple scenarios of MPA expansion led to declining fishery effort, not increased effort outside MPA (fishery displacement). These findings mean that economic models of the effects of MPA on fisheries need to account for stock recovery, spillover, and prior mobility of fishing (i.e., not everywhere being fished all the time). There is no evidence to assume a fishery loss due to MPA establishment; in fact, fisheries may profit from MPA.

Through a detailed global analysis, McDonald et al. found that multiple scenarios of MPA expansion led to declining fishery effort, not increased effort outside MPA (fishery displacement).

Four other misconceptions regarding MPA deserve similar scrutiny. First, claims that MPA do not work for pelagic fish, because it is assumed pelagic fish roam more widely than benthic fish, are also without evidence; but evidence to the contrary does exist (10). Pelagic species are even more sensitive to overfishing than demersal species (11), and so MPA should be located and large enough for their protection. Even if individuals of a species only spend part of their life in an MPA, they may gain some protection, and suitably located protected areas have long been established for migratory birds.

Second, presenting fully protected MPA as a radical idea, or that it is somehow exceptional to exclude activities from a marine area, is disingenuous. It may seem radical where utilitarian ideologies prevail, but the idea of not fishing in certain marine areas is well established in indigenous cultures (e.g., rahui in Māori, tabu in Fiji, tengefus in Swahili), and the first fully protected marine reserves were established five decades ago (1). Public access is already restricted to parts of the ocean, including harbors, marinas, fish farms, pipelines, cable zones, and military areas; but generally public access is facilitated in MPA (1). Considerable land is set aside for public use, including hospitals, universities, schools, museums, art, sports, waste disposal, transport (including shipping lanes), and parks. Similarly, more of the ocean, already publicly owned, could be set aside for public benefits including conserving natural and cultural heritage. It should be normal that some places are left unfished, both to safeguard populations and act as a reference or control for the uncontrolled experiment of human impacts outside MPA (12).

A third problem in MPA establishment is the mistaken view that only commercial or industrial fishing should be excluded from MPA. Allowing recreational fishing in MPA has been counterproductive because the MPA then attracts more fishing with similar impacts on food webs and biodiversity; the opposite of intentions (1, 13). The idea that recreational fishing is somehow less harmful to biodiversity is false, because the ecological effects depend on how and how much not who or why the fishing takes place. This also raises questions about social equity because recreational fishing is a privilege of the rich, and ethical questions about why killing marine wildlife for sport in a “protected area” should take precedence over fishing for food; especially when there is no shortage of other places to go fishing. Moreover, people recognize the benefits of fully over partly protected MPA, which also have greater benefits to human well-being (14, 15). There is an emerging resetting of ocean governance that recognizes the rights of all people, including future generations, and not only industry, to benefit from marine biodiversity which is a public resource (1). Fully protected MPA can thus be a common sense, socially equitable solution to coastal fishery management that respects the rights of future generations.

A fourth criticism of MPA is that they are expensive and can only be afforded by wealthy countries. However, any management has costs, the costs are trivial compared to investments by governments in built infrastructure, and fully protected MPA are a lower cost to manage than partly protected (16). 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. The greatest MPA costs may be signage and facilities to support visitors (e.g., roads, toilets, waste disposal); which are more costs for tourism than conservation. The fact that thousands of MPA are established in developing countries, including some of the largest MPA in the world, shows that any country can have an MPA. Yet, most coastal countries do not have even one fully protected MPA (12). Establishing large MPA puts the precautionary principle into practice because permits can then be issued for ecologically sustainable harvesting of natural resources. Protecting marine biodiversity is common sense, and the people who depend on ocean resources realize this. However, they may have to compete with well-financed, politically influential, enterprises who profit from business-as-usual.

Throughout, this article considered MPA that were fully protected from fishing and other human impacts. However, almost all places called MPA by governments and UN bodies do not aim to protect “biodiversity” (i.e., diversity within and between species and of ecosystems) and over 90% allow fishing (12). As predicted by “Ballantine’s Law,” partly protected MPA do not return the benefits to biodiversity, fisheries, or human well-being making the unqualified use of term “MPA” meaningless (1, 7, 8, 12, 14, 15). It is disappointing that there is a widening gap between real and partly protected MPA (Fig. 2). This means the potential benefits of MPA to fisheries are less likely to be realized, and the public is being misled about progress in marine conservation. These half-measures are more an attempt at ecologically sustainable management, which should be the case in all of the ocean, as countries agreed to do in the United Nations Convention on the Law of the Sea in 1982, the UN Sustainable Development Goals, and the Convention on Biological Diversity targets.

Fig. 2.

The cumulative increase in the number of partly (dashed line) and fully (solid line) protected MPA. Data from the World Database on Protected Areas (17). These data overestimate actual protection (7).

Perhaps we should not be so surprised that setting aside areas for MPA can lead to restored fisheries and decreased fishing effort. There can be synergies of benefits when fisheries and biodiversity are conserved together (18, 19). Fishery management commonly closes fisheries in space and/or time to allow stocks to recover temporarily. MPA could provide fishery management with control areas for fish stock management, especially useful considering it is rare for a fishery to have baseline data prior to fishing. The establishment of MPA may also be accompanied by improved regional fishery management and enforcement, such as decommissioning and retiring of fishery overcapacity, removal of government subsidies, and/or incentives for fishermen to become fish farmers or provide tourism and recreational services. Going forward, the focus needs to be on developing a global network of fully protected MPA located in the areas where they are most likely to benefit biodiversity and/or fisheries based on the best available scientific data and analyses (e.g., refs. 19 and 20).