The Economic Benefits of Marine Protected Areas
An interview with Dr. Mark Costello
Dr. Mark Costello, marine ecology expert, and Professor of Marine Ecology at Nord University in Norway, joined me on the Science4Parliament podcast to talk about marine protected areas (MPAs) and his recently published paper on the evidence of the economic benefits associated with them.
Click here for the full Science4Parliament episode
Dr. Costello began by discussing what the word “protected” actually means, in the context of MPAs, as this where we need to start, to consider why and where MPAs should be created. The first decision is what exactly you are trying to protect and what you want this protection to achieve. The biggest worry that people have when they hear “protected” is what limitations will be placed on them, but as Mark said when people see the benefits that MPAs bring, they actually campaign for them.
There are many definitions of protected areas. Some countries define them as areas that are completely wild, where humans don't have any deliberate impact, such as no-take areas where nothing is taken or extracted or mined. There are other countries which allow for some activities in some areas, or have internal zones where part of an area is fully protected. There are also a school of thought which says that people shouldn't be allowed into some of these areas at all.
The problem is that, in the sea, fishing has taken out the top predators, as pretty much all the fish and crustaceans that humans eat are carnivores. Compare this to human activity on land, where herbivores are hunted and quite a lot of deer, rabbits, hares and other herbivorous animals can be taken out without altering the food chain hugely. But if the top predators, such as the big fish and big lobsters in the oceans, are taken out, immediately, the whole marine food chain starts to change. What the predators used to eat become more abundant, and then the next level begins to be fished out and on and on. Some call this fishing down the food chain, where we keep taking out the biggest fish and then we end up just eating the little fish because that’s all that is left. There is a perception that taking a few fish is not going to have any effect, but it depends which fish are taken. And as this is usually, the biggest ones and there are fewer of them, it can have a huge impact.
An example Dr. Costello gives of the impact of MPAs is the sudden recovery of the kelp forests in fully protected areas in New Zealand and North America which was caused by the return of the predators of sea urchins. Sea urchins are little spiny shellfish, who love seaweed, and if nothing is eating them, like the big lobsters or big fish, then they just graze the seaweed forest completely bare down to the rock. When areas are protected, the sea urchins’ predators return, keep the population in check and allow the kelp to regrow. So even in areas which may not have been classified as being overfished, more protection allows the ecosystem to restore its natural order.
Dr. Costello said that when he began to research his new paper on the economics of MPAs, he compiled a list of 40 or 50 research papers which show their benefits. He also wanted to make a list of those papers showing the negative effects, but he couldn’t find any evidence, not even from fisheries, such as a reduction in fish catch. This may be due to the small size of the MPAs in relation to big fisheries and it could also be due to the “spillover effect”; an increased abundance of species within the protected area, with the fishermen lining up outside, waiting for the lobsters or fish to swim out to them.
MPAs can also have positive effects on attracting tourism to the area, but that this needs to be carefully managed or it can have devastating effects, such as allowing sports fishing in MPAs, which can be counter-productive and lead to overfishing, pollution and littering. If countries are going to look at tourism benefits, then they must put in the infrastructure, for example public toilets, to minimise its impact. A solution that was found in New Zealand was to have more marine reserves, so that if there was a problem in one MPA, tourists could go to a different one to reduce the pressure.
Finally, I asked Dr. Costello for any tips that he would give policymakers who want to engage with science or scientists and how they could go about reaching out to start that engagement. His advice was to keep asking the questions, looking for the evidence and don’t believe everything in popular discourse.
Dr Costello's recent paper on the economic effect of MPAs :