Introduction

By contrast, under a SC framework, the NP approach is criticised for being too pessimistic about declining fish stocks and too optimistic about the value of MRs in reversing that decline. According to SC voices, the proposition that global fish stocks were crashing and that there was a danger of imminent species extinction, was misleading and exaggerated (Hilborn 2007b), not helped by sensationalistic science (Worm et al. 2006), sloppy journalism (Leake 2012), and endorsement by high profile conservationists². On declining fish stocks, as O’Sullivan and Emmerson (2011, p. 116) put it, “there is a real danger of overestimating threats and sensationalizing the process of extinction”. Many scientists are wary about making gross generalisations about fish-stock declines and of laying the blame for their alleged decline entirely on conventional fisheries science and management tools³. They acknowledge that there are many failed fisheries, but they also point to some successes (Hilborn 2007a, b). Hilborn and Ovando (2014, p. 1040, 1045) claimed that the real failure is not fisheries management but the lack of fisheries management: “Stocks that are managed are improving, while stocks that are not managed are not…The evidence is strong that where fisheries management has been applied, it has worked to both reduce fishing pressure and to rebuild stocks…it is not the failure but the lack of management that drives fishery depletion”. And SCs argue that “the apocalypse that many marine ecologists are warning of…has already been forestalled by improvements in CFMAs” (Jones 2014, p. 47).

On being too gung ho about MRs, Polunin et al. (2009, p. 6) stated that “the benefits of MPAs have too often been assumed despite being based on uncertain understanding of fish behaviour and ecology, and of fisheries themselves”. Agardy et al. (2003, p. 354, 359) warned of the danger of exaggerating the benefits of MRs, referring to “the tendency to decree as many MPAs as possible, an eagerness to do so without a clear understanding of many of the complexities or balanced framework required, and a zealous “one-size-fits-all” approach…[and an] assertive promotion of no-take MPAs as the best and only effective type of MPA”. Dunne et al. (2014, p. 24) pointed out that “direct evidence to support the creation of MPAs for fishing benefits is generally very limited and many arguments are in fact supported by nothing more than normative assumptions” (see also Stewart et al. 2008). Even in the case of coral reefs where the evidence for the role of MRs in mitigating impacts and aiding recovery within their borders is greatest, Sale et al. (2005, p. 74) held that “there are significant gaps in scientific knowledge that must be filled if no-take reserves are to be used effectively as fishery management tools. Unfortunately, these gaps are being glossed over by some uncritical advocacy”.

Some SCs ask whether an MR network is necessary at all, or whether other fisheries management measures would suffice. Sweeting and Polunin (2005, p. 55) claimed that “habitat protection can be achieved by exclusion of benthic gears, avoidance of conflict can be achieved by spatial segregation and sustainable exploitation of fish stock can occur within trawl exclusions, a fact that is recognised by most MPA practitioners”. Pajaro et al. (2010, p. 960) pointed out that “MPA establishment and management is a massive experiment in human environment relations”. Is the experiment worth it? It has huge opportunity costs: As Fraschetti et al. (2011, p. 13) noted, “the tendency to use MPAs as the preferred management tool may preclude consideration of other management options”. Hilborn (2013, p. 111) held that in “regulated fisheries that typify developed countries it is well ­demonstrated that overfishing can be controlled and good biological outcomes achieved without areas permanently closed to fishing”. Indeed, Suuronen et al. (2010, p. 243) stated that many modelling studies showed that “yields are maximised with effort regulation rather than by the introduction of closures” (see also Greenstreet et al. 2009). Likewise, Branch wrote that “numerous papers show that MPAs won’t improve fisheries yield unless the populations are already overfished. In such cases yield would also improve if overfishing was reversed and rebuilding allowed (‘traditional management’)” (Roberts and Hilborn 2013, p. 7). Similarly, Kaiser (2005, p. 1198) wrote that “the proper implementation of fishing effort reduction still has the potential to out-perform the use of MPAs in terms of increasing spawning stock biomass” (see also Jones 2007; Kaiser 2004; Metcalfe 2013).

SCs also criticise NPs for ignoring the socio-economic harm caused by MRs. For example, Christie (2004) pointed out that MPAs which are regarded as biological successes may be socio-economic failures by increasing social conflict between marine users, and causing economic dislocation in disadvantaged artisanal fishing communities. Hilborn added the suggestion that “the vast funds and energy going into MPA establishment in developed countries would better be applied to improving fisheries management in places that do not have good management systems” (Roberts and Hilborn 2013, p. 3).

Another SC criticism of MRs is that they are invariably poorly enforced—“paper parks” (Jones 2014; Marinesque et al. 2012; Pomeroy et al. 2005; Agardy et al. 2011). McClanahan et al. (2006, p. 1408) claimed that where there was ineffective management, MUMPAs fared better than MRs: “In cases where the resources for enforcement are lacking, management regimes that are designed to meet community goals can achieve greater compliance and subsequent conservation success than regimes designed primarily for biodiversity conservation”.

SCs also have doubts about MR networks. Roff (2014) claimed that there is no evidence that any MR networks have been implemented, and even when implemented, it will be extremely difficult to determine their effects, because there will be so many confounding factors. Moreover, SCs reject target percentages such as 30 % of the oceans as MRs are scientifically unjustified (Planes 2011). Hilborn drew attention to the wider issue of whether large MR networks have a net global environmental benefit, in particular because of their displacement of food production from the seas to the land:

Imagine we closed all the oceans to fishing. There is no doubt that fish abundance would rise and most measures of biodiversity status would improve in the oceans. But what else would happen?… If 80 million tons of lost fish production was made up by chopping down rain forest to grow cattle, I think the global environment would be worse off. Capture fisheries produce food at lower environmental cost than livestock and most forms of aquaculture. No water, pesticides, fertilizer or antibiotics are used, and greenhouse gas omissions are lower. These tradeoffs must be considered when large areas of the ocean are closed. (Roberts and Hilborn 2013, p. 1)