Sustainable aquaculture pushes limits
Published: Wednesday, October 3, 2012
Updated: Wednesday, October 3, 2012 15:10
A question that has plagued chefs around is how do to keep fish on their menus?
For the last 50 years people have been fishing the seas like as they have been clear cutting forests.
Due to this fact, 90 percent of big fish populations, including tuna, halibut, salmon and swordfish, among others, have collapsed.
The world is hungry for fish.
Faced with declining wild stocks, the fishing industry is giving way to aquaculture, or fish farming, which produced close to 53 million tons of fish in 2006 alone, almost half of all fish consumed in the world.
The worldwide industry is growing at an average of 6.8 percent per year, making it the world’s fastest-growing food sector.
But this growth has come at a cost.
Chemicals and antibiotics used in fish farms seep into surrounding waters. The fecal contamination causes harmful algal blooms, causing sensitive coastal and wetland areas to be disrupted or destroyed.
So, what options are left to conscientious consumers? Choosing fish is like choosing a cut of meat. Consumers need to know their farms.
Some fish farms are able to maintain profitability and improve the quality of their products, yet still minimize their environmental impact.
Such is the reasoning behind Veta la Palma fish farm.
Veta la Palma is located in southern Spain and lies at the center of the Guadalquivir River’s estuary marshes.
In 1982, the family that owns the Spanish food conglomerate Hisaparroz bought wetlands that had been drained for cattle farming, and re-flooded them. The owners set out to develop an extensive close-to-nature aquaculture venture in a former wetland area.
The intent was to create economic value from land use, while at the same time improving the ecology of the area.
Hisaparroz used the same channels built originally to empty water into the Atlantic and just reversed the flow.
Today that neat little feat of engineering allows the tides to naturally sweep in estuary water, which a pumping station distributes throughout the farm’s 45 ponds.
Because it comes directly from the ocean, that water teems with microalgae and tiny translucent shrimp, which provide natural food for the fish that Veta la Palma raise. This distinguishes their aquaculture operation from many other operations, which feed their fish on wild catch.
To keep them healthy, fish are kept at a relatively low density of about 9 pounds of fish to every 35 cubic feet of water. The fish are not harvested until they weigh about 4 pounds each, unlike fish from intensive aquaculture or modern fish farms, which are harvested on average at about 1.5 pounds and are kept in crowded conditions.
One of the most fascinating aspects of the Veta la Palma estate is its key role as a migratory bird stopover.
For 250 different species, migrating from Africa to Europe and back, the ponds serve as a resting spot and feeding ground.
Estate staffers estimate the birds consume about 20 percent of the fish in the system.
Most would see this as bad for business, but they see it as indicative of success. They see it as positive sign that the ecosystem is functioning at a high level.
By working closely with the natural ecosystem, Veta la Palma avoids many of the pitfalls of most conventional intensive fish farming. This particular fish farm could be a useful model for future plans to regenerate the disrupted marshland areas and coastal wetlands of Spain and even in the U.S.
At Veta la Palma they are not only making consumption and conservation compatible, but they are moving toward a new outlook on conservation and development where the careful use of natural resources, such as water and land, can generate economic profits while enhancing a wide range of environmental values.