In today’s fast-paced, increasingly crowded world, we often view our conservation goals as directly in conflict with our economic ones. Save a forest, or cut it down for lumber? Preserve a wetland, or drain it for human habitation?
Marine reserves, parts of the ocean where commercial fishing is prohibited, are usually seen as embodying that conflict. On the one hand, they provide great conservation benefits by acting as safe zones for overfished species. On the other hand, they remove a portion of the fish stock from harvest and, in so doing, seem to remove money from fishermen’s pockets.
Fortunately, a growing body of literature is showing that marine reserves may be part of an economic best-case management strategy. That is, sometimes, you want to protect a portion of your fish stock, so that you can make more money when you fish the rest.
In a new paper out this month in Natural Resource Modeling, Mike Neubert and I highlight the economic benefits of marine reserves when fishing damages habitat. There are many cases in which habitat damage occurs: here on Cape Cod, the long history of bottom trawling for cod and haddock is just one example.
Using a very simple model in which we divide habitat into two portions, we show that profits are maximized when one of those two portions is closed to fishing. The reason for this is that the closed “patch” provides undamaged habitat that houses a healthy fish stock. The spillover from that patch (i.e., the fish that leave the reserve and swim into the fished habitat) can then be caught and brought to market.
Want to know even more? Check out our 2013 paper, which uses a more complicated model (partial differential equations to model continuous space) to show the emergence of marine reserve networks protecting >80% of habitat as part of the economically optimal management strategy. [pdf]