INTERVIEW TRANSCRIPT - Dr. Jurgene Primavera

Jurgene Primavera is Senior Scientist at the Aquaculture Department of the Southeast Asian Fisheries Development Center in Tigbauan, Philippines.


You’ve shown us a lot of different types of aquaculture. Could you tell us about each one?

Okay, first, with the milkfish, it’s the most important farmed fish in the Philippines—because it’s a local a food and mostly it’s growth depends on wild fry—which can be seasonal, which can be expensive. So, if you produce hatchery fry that will be a great help to the industry.

The grouper — this is a carnivore — it’s mostly aimed at the upscale restaurants, hotels, also the Chinese population in the Philippines which really likes grouper for sweet/sour fish. The problem with grouper is that it is a carnivore and it is fed trash fish, which in the Philippines can mean fish of people-food fish, so it competes with humans. So the big research challenge for grouper is to develop food substitutions that are not so dependent on fish, especially, fish meal or trash fish.

The mud crab or the mangrove crab — and again, this one can be grown either in open water but especially mangrove ponds and pens where you can integrate aquaculture with trees and it’s very environmentally friendly. But again, the problem with mud crab culture is the feeds because it’s a carnivore — needs fish meal in pellets of trash fish. So as with grouper, the research is to develop feed substitutes that are easily available and do not compete with for-human feeds.

Next was the abalone. Abalone is important for local communities in terms of gleaners. They are gleaned when the tide goes out, during low tide. The women and children harvest it even in the deeper parts. They harvest abalone also for its shell that’s used in making buttons and other items. So, the populations are in decline and if we can produce the seed in hatcheries and use these seeds for stock enhancement of natural populations, then we can give livelihood to coastal communities.

And this is the same rationale for sea horse research effort. Although there’s a specific cause for the decline of sea horses — the Chinese market that pays premium price for dried sea horses because they are considered aphrodisiacs. So they have declined in the wind and if we can produce seeds in captivity and develop some kind of grow-out or sea ranching, then this will relieve pressure on wild populations of sea horses.

It sounded like you had a lot of enthusiasm for milkfish, one reason being that it’s an herbivore. If aquaculture is going to feed the world, does herbivorous fish hold the most amount of hope?

I said that it’s true that milkfish are herbivores and it is when you have herbivores like milkfish, carps and filter feeding mollusks — bivalves — that aquaculture in creating new protein is realized. But in contrast when you grow carnivores — like shrimp, salmon, mud crabs, groupers — then it’s not totally new protein because it’s re-packaging fish meal that’s from captured fisheries into aquaculture protein.

And the ration is like two to four kilos of wild fish to produce one kilo of cultured fish — shrimp, salmon, whatever it is. So be that as it may, there is troubling science in the industry because there’s a trend towards intensification even of the omnivores and the herbivores like milkfish tilapia. So intensification means higher stocking densities, greater biomass, greater food requirements, so natural productivity can no longer sustain such high biomass and you need supplementary feeding and this means pellets. And because not much is known about the feed requirements of these herbivores and carnivores, the feed industry plays it safe and puts in a lot of fish meal exceeding what would be the required levels. So essentially you’re shifting the mode from creating new protein to the carnivore mode where you use fish meal. So the promise of aquaculture — maybe it’s a bit of a traitor, in a sense. You’re just taking away from captured fisheries and placing in aquaculture.

Now the literature in ecology is coming up with all these values in mangrove both in the tree products as well as the aquatic products — the fish, the crustaceans and the mollusks that you get. Both in mangroves and near shore or offshore, where the mangroves act as nurseries to these commercially important fish and invertebrates. So with the importance of mangroves, not just the products, but also as coastal buffers and filtration services and so many other non-valued services, mangroves are important in themselves and they should be conserved. So what is exciting about the project that you saw, the pens and the ponds, they give the option of conserving the mangrove. It’s really a major shift away from what at least the Philippino fish farmers have known for so long: that when you build a farm you have to do so at the expense of the mangrove forests. So we can integrate the trees together with the ponds. One way is physically integrating, in a single pond or pen, you have the water where you grow the crabs, the fish, whatever and you have the trees. But another way also is you can have open water ponds where you grow the fish or the shrimp and have a mangrove buffer zone around so that the mangrove zone can absorb the nutrients that are coming out of the fish or the shrimp pond. So that is also a sustainable blackfish aquaculture because you still keep a mangrove zone or a mangrove doing that.

Could you speak about unsustainable aquaculture again?

We all know about the decline of fisheries — wild fisheries — and we all know the reasons: illegal fishing practices, dynamite fishing, cyanide, fine mesh nets, the loss of mangrove nurseries, coral reefs and so many other factors. So, really to improve sustainability of fisheries, you have to address those issues. But the danger in promoting aquaculture as a panacea is that if you put enough support for aquaculture, then aquaculture will provide the loss in wild fisheries. We’ll solve all the problems and then you feel good. You’re not really solving the fisheries problems. So that is the danger.

Is aquaculture the answer?

Aquaculture can supplement the world food supply, but not completely replace our wild fisheries. Perhaps if focus were kept on the new protein species like the herbivores, the omnivores, the filter feeding mollusks, and keep the way they feed — like not feeding the herbivores high fish pellet — then the promise of aquaculture making new protein can really be maximized and the contribution world food supply would be maximized. But still, you need the fisheries component. And I don’t see it as a competition between the two sectors. I think they really should go hand in hand because there’s a lot of interfacing between capture-fishing and aquaculture. And this kind of thing should be maximized.

I think it’s the politicians and some agencies that prefer to polarize things, you know. That this is fishery and this is aquaculture, in an effort to maximize fundraising for their own territories. Which is a very sectoral way of cutting up things when in fact you have gradients and you have synergizing that are there, that get lost.