There are currently nearly 17,000 Marine Protected Areas (MPAs) across the globe. Broadly defined, they are patches of ocean in which human activities, often including tourism and fishing, are managed to ensure sustainability. Though large in number they only cover 11 million square miles – about eight per cent of the world’s ocean, according to Protected Planet, an online interface for the World Database on Protected Areas.
Organisations such as the WWF are now calling for 30 per cent of the ocean to be protected by 2030, a target which it says will ensure the most complete benefits for marine ecosystems and people. It is the latter that have generally been left out of the picture. While the conservation effectiveness of MPAs has been demonstrated in several ecological studies, their impact on coastal communities is less clear. The research that has been carried out in this area largely focuses on an MPA’s economic impact for these people, something Dr Morena Mills, a senior lecturer in conservation science at Imperial College London, recently discovered.
Working as part of an international research team, she helped examine 118 previous studies – mainly covering tropical MPAs in Asia and Europe – and separated out the positive and negative impacts identified for local people. Favourable impacts came just out ahead at 51 per cent of the total.
The bulk of these positive effects related to community involvement, increased income and a measure known as CPUE, or ‘catch per unit effort’, which refers to the number of fish caught in surrounding areas. Though it might sound counter-intuitive that MPAs (which often limit or prohibit fishing) result in increased catch, there’s a simple reason why. ‘Fish are different to us because the more they grow, the more eggs they produce,’ says Mills. ‘So if fish in no-take zones are allowed to grow bigger and produce more eggs, they start to spill over to the adjacent areas.’
These findings tally with a recent report commissioned by the WWF that points to huge net benefits for humans if ocean protection is extended to cover 30 per cent of the world’s ocean waters. The report predicts benefits in the range of $490billion and 150,000 full-time jobs in MPA management, (in some cases numbers reached as high as $920billion and more than 180,000 jobs).
But while this is a positive sign, Mills notes that this field of research is still limited. ‘There are very few studies that look at impacts on cultural diversity or mental health or other areas that we know are really important,’ she says. In addition, there are also the negative impacts to deal with. In particular, conflict within communities increased in 79 per cent of MPA cases examined and, although it was only analysed in 13 studies, the cost of fishing increased in every one.
As a result of this mixed bag, Mills now believes there needs to be more experimental or quasi-experimental studies to ensure that MPAs help both marine animals and humans. ‘Before and after impact control experiments are so important because they show you the real impacts of management.’