Monitoring marine reserves

10 December 2013

Interview with

Josh Drew, Columbia University

Josh Drew

Josh -  Well, what we're interested in is seeing how reserves affect the whole reef ecosystem.  It's pretty obvious that if you go out and you eat fish and you get the fish by shooting them with the spear, then if you stop shooting with the spear, those populations are going to do fine.  That's a no brainer and that's an important conservation impact.  But what we're interested in is looking at what happens to the rest of the reef when suddenly those top predatory fish are being taken out.  And so, in order to do that, we're travelling to this place, Nagigi in Fiji where they're setting up a protected area.  And we're looking at what's happening before they've set it up, so that we have very, very solid baseline information.  And then we're going to track the effects of that protected area over the next 3 to 5, maybe 7 years and see how that protected area matures and what are the whole reef ecosystem effects from microbes to sharks.

Chris -   What is the natural structure of that marine reserve?

Josh -   It's one of the reasons why I went to Fiji in the first place, is that Fijians own their reefs.  So, just like you would own the land in your backyard and if somebody wanted to set up a tent there, they would have to ask your permission.  If somebody wants to do something on a coral reef in Fiji, they have to ask the permission of the people who own that reef.  And so, the Fijians have this custom called tambu - a period of rest for the reef where they let it go for 3 to 5 years where they don't fish on it.  What we're interested in is seeing if we can look at that traditional form of reef management and imagine it as a form of conservation.  So, instead of just having them not fish for a big fish or not fish during certain times of the day where they let it go completely on fish for 3 to 5 years so that the whole reef becomes a bit restored during that time period.

Chris -   Would the aim be, to create a comprehensively big reserve area or given the structure of Fiji which is lots of little islands, would it be to create lots of little marine areas, and hope that one can sort of cross pollinate into the other adjacent area?

Josh -   It's definitely the latter for a couple of reasons.  First and foremost, because the Fijians own their reef, that means each village only have a certain area that they can fish.  If that whole area was put into a protected area, then suddenly those villagers would be - they wouldn't have access to food and we don't want to unduly saddle any one village with too much of a conservation burden.  So, it's definitely important that we look at this as a system of small reserves, particularly in areas close to where there are villages.  There are parts of Fiji where there aren't a whole lot of people around and those might be areas where we would explore larger reserves.  But a reserve is not going to be effective if the local people aren't behind it.  If setting up that reserve means that they can't get their dinner then it's going to stay a reserve for too much longer.

Chris -   And is your hope then that if you have a preserved area which people cannot fish and they cannot damage then this will help to seed or support adjacent areas that are being exploited to maintain the diversity and to maintain the integrity of the adjacent areas?

Josh -   Absolutely.  The fish that are going to be inside the preserved area are going to grow bigger.  Bigger fish produce exponentially more eggs and sperm.  If you provide the chance for this fish to grow big then they're going to produce tons and tons and tons of babies.  Those babies are going to disperse and one of the major issues we're looking in my lab is tracking to see how closely related those different protected might be by looking at the population genetics or how the relatedness of fish from one reserve and fish in a different reserve.  And then we can figure out what's the best way to space those reserves so that it form a cohesive unit and that they seed each other as you were saying.

Chris -   Do we know what the anatomy of such a structure or network would have to be in order to make sure fish did transit from one place to the next to maintain the biodiversity?

Josh - Well, we're working on it.  It's definitely something that is a major research interest in our lab.  Some of the preliminary work I've done, the upstream areas definitely produce more export of larvae than the downstream areas.  And so, it's very simple.  If you look at the oceanography of the region, it makes sense to sort emphasise putting preserves in areas at the head of the stream so that the babies from those reserves are able to spread forth throughout the rest of the country.

Chris -  Do we know whether all fish can transit along these - I want to say corridors between these little isolated or enclaved areas that are the reservations or is that one of the big questions because if some fish can do it but others won't do it, then we still got a problem?

Josh - Yeah, and we're seeing that there's a lot of variability within it.  So, even fish that look pretty much the same in some of our preliminary results have shown to have very different patterns.  What that means is we kind of have to use what scientists call the precautionary principle and then that is, we play our safest hand.  And if there's several fish that have very limited dispersal or just really can't get that far out then we need to make sure that we setup protected areas that can incorporate that information so that we don't pass over them and we don't provide them an opportunity for those populations to be protected.

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