So last post I wrote about some of the ways which MPAs work and some of the challenges faced in implementing and designing them. This time we’ll discuss some of the innovative ways that some of these challenges are being avoided.
One of the biggest problems in designing an MPA is that many fish have an annoying habit of having quite long planktonic larval stages. These planktonic stages have some control over where they go through vertical migrations and getting moved around ocean basins by major ocean currents. Even with this form of control over their destination the fish will often settle in destinations tens or even hundreds of kilometers from their point of origin, easily far outside of most MPAs.
There are two basic methods of countering this, using the age old premises of bigger is better and strength in numbers. You can either make a few massive protected areas, like the already implemented Phoenix Islands Protected Area in Kiribati, or by creating a network of often smaller reserves, such as those proposed in California. These approaches help to maximize the diversity of habitat protected (a key factor in promoting fish biodiversity) while also retaining greater levels of settling larvae so they can be protected from fishing practices during at least the earliest stages of life.
Now another issue faced when designing an MPA is the fact that many ocean going animals including many economically important ones such as tuna, and charismatic ones like whales also tend to be highly migratory. One proposed solution for this is to design MPAs with movable boundaries. This would basically involve having boundaries that move following migratory routes to protect these species that do travel great distances. Obviously saying the logistics of something like this in the high seas would be a nightmare is a massive understatement.
Source and Sink
In the Caribbean great efforts have been undertaken by the team in Dr. Mark Butler’s lab, Old Dominion University, to map out both where spiny lobster are coming from, as well as were they are predominantly settling. This is called source:sink dynamics and studying it will allow for the targeted placement of protected areas in locations where they will have the most positive effect on growth of lobster populations throughout the region. These sorts of techniques could be implemented for other commercially important species to help to more specifically target locations for MPA placement.
So those are some of the innovative ways that are being used to try and increase the effectiveness of marine protected areas to ensure these species are here for the future.
Have you heard of any other cool of interesting ways managers are trying to do to improve the efficacy of MPAs? If so share them here.