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Are Aquaculture Hatches, Growth and Methods Sustainable?

Aquaculture is growing so rapidly that it accounts for almost 50 per cent of all fish brought to the table. Rebecca Chappell, SDNN looks at leading fish farms in San Diego, US.

Two-thirds of the world’s wild fisheries are either depleted or severely overfished. In fact, in California waters alone, at least 20 kinds of fish are nearly extinct. Yet, world fish consumption soars to new highs.

“It’s no different than agriculture,” says Dennis Peterson, director of science for Carlsbad Aquafarm, which has been producing mussels, oysters, clams, abalone, and edible seaweed for over 50 years in both land- and sea-based growing areas. On shore, pumps and filters supply water to tanks for growing and processing. Across a 5-acre parcel of saltwater in the Agua Hedionda Lagoon, shellfish are suspended from the surface on ropes or trays. Mussels, for example, grow in 10-foot tubes of ropes that they latch onto while oysters proliferate in trays stacked by tens.

“It’s very much hands-on science,” adds Mr Peterson, who spends countless hours trying to mimic conditions for optimal species growth and spawning, from testing water and its food levels to monitoring weather temperatures.

And if you ask Mr Peterson’s colleague, Matt Steinke, who works on the engineering side of things, the sustainability factor is huge. “If you’re eating aquacultured shellfish, you are supporting an industry that is so sustainable it will feed your great-grandchildren. Every pound of aquacultured product is a pound that is not coming out of over-burdened and collapsing wild supplies.”

Just across the same lagoon is the Leon Raymond Hubbard, Jr., Marine Fish Hatchery. Built in 1995 on land donated by San Diego Gas & Electric, the 22,000-square-foot-hatchery is an expansion of the Ocean Resources Enhancement and Hatchery Programme (OREHP), which is overseen by Hubbs-SeaWorld Research Institute. According to the institute’s president Don Kent, the goal here is to replenish the hundreds of thousands of white sea bass adults that have been lost due to habitat changes in Southern California and to fishing pressure over the last 50 years.

“We’re replacing them artificially by increasing the survival of larvae in juveniles in a controlled environment, and then transferring those fish out into the wild,” says Mr Kent. “That is, we’re trying to bring the stock back up to its former levels so that it can be harvested at a higher level that’s sustainable over the long term.”

Twelve locations from Santa Barbara to San Diego receive the hatchery’s juveniles, in all 125,000-350,000 annually. Each site is run by volunteer fishermen who “grow out” the sea bass in near-shore net pens before releasing them into the wild. The idea behind that is that a larger fish is less likely to be eaten by something else. What’s more, by conditioning them, by putting them in the pens, they survive better after they’re released because they’re not starting stressed.

“They’ve already been swimming around in the same place for a couple of months and when you drop the net and let them swim out that’s a lot less invasive that scooping them out of a tank, putting them in truck, driving them 200 miles, then swooshing them down a boat ramp with a hose,” says Mr Kent. And because every fish that gets released has been tagged, Mr Kent’s team knows exactly what fish were released from what location, even the brood stock that the fish came from. “In that way, we manage what’s going on over 200 miles of coastline. And then the fishermen collaborate with us by bringing those fish back. We monitor not only the commercial catch but the recreational catch as well.”

Though US fish farms stretch from Hawaii to New England and generate about $1 billion annually, China accounts for 70 per cent of the world’s aquaculture products. As a result, the US imports about 80 per cent of its seafood, half of which is farmed. This contributes approximately $9 billion a year to our trade deficit, second only to oil, and to the loss of potential wages. Intending to spur America’s aquaculture industry, Hubbs aims to build a commercial-scale fish farm approximately five miles off the San Diego coast, west of Mission Beach. It would be the first of its kind in US federal waters.

The intent, explains Mr Kent, is to determine whether commercial scale, economically viable aquaculture is feasible in federal waters under US regulatory conditions with no significant environmental impact.

Aside from being far from boat-traffic zones, the site was chosen for its deep, clean, temperate water with good currents and a sandy bottom. In its initial phase, the farm would produce 1,000 metric tons a year of striped bass, grown from fingerling to market size, beginning with eight floating net pens anchored to the ocean floor. The farm ultimately would grow to 24 pens and produce 3,000 metric tons of fish a year, including other previously assimilated or native species such as Pacific halibut, white sea bass and yellowtail.

For the project to come to fruition, however, it first must gain the approval of numerous governing bodies, including the US Environmental Protection Agency, the US Army Corps of Engineers and the California Coastal Commission. That could take years. In the meantime, the California Department of Fish and Game (DFG) has already registered the offshore site as an approved facility.

“The Hubbs project would generate data to inform future debate on the efficacy and impacts of marine fin fish farming,” says Mr Jordan Traverso, DFG’s deputy director of communications, education and outreach. “There could be significant scope for increased sea food production and development of ancillary industries such as feed formulation from fish processing plants if the Hubbs project demonstrates that marine fin fish farming is environmentally sustainable and economically viable in the state.”

Not surprisingly, controversies abound regarding aquaculture’s role in the spread of diseases from farms to wild stocks as well as pollution, escapes of non-native species, habitat degradation and displacement of local fisheries.

“There probably aren’t too many concerns out there that as scientists we aren’t already addressing,” says Mr Kent. “We already understand those limitations. The big difference is we aren’t ever going to draw a line out there that says this shouldn’t be done. If people are concerned about sustainability, about growing a good product that’s affordable and non-invasive to the environment, then we have to go out and show them how that can be done.”

Mr Kent offers salmon farming as an example. “There’s a lot of reticence about salmon farming but, like anything, there are right ways and there are wrong ways of doing it. Back in the ‘70s there were a lot of things that were done wrong. Now, in the Pacific Northwest, British Columbia, Washington state, and also in Maine, there is a lot of effort going into growing these fish in a very sustainable way.”

The same holds true for shellfish farms. “We test the water every day to ensure our waters are safe,” says Mr Steinke. “Our testing is more rigorous than any other shellfish farm on the Pacific coast. All of the species we culture are already present in the lagoon, removing the risk of us introducing a new species.” Plus, shellfish are filter-feeders, which is to say they eat naturally-occurring plankton that grows on sunlight rather than fishmeal. In some cases, says Mr Steinke, farmed shellfish may actually improve the health of the environment by filtering water

Ocean Conservancy, a non-profit that champions policy change, is not against aquaculture but is critical of premature expansion. “I think aquaculture has to be part of the solution to where we’re going to get our future seafood,” says Mr George Leonard, director of the organisation’s aquaculture program. “But the real question becomes a question of not if, but how. We believe a national regulatory approach is needed to deal with what is currently happening, which is a case-by-case approach-which we don’t think is a way to develop an industry.”

Mr Russell Moll, director of California Sea Grant at Scripps Institution of Oceanography, feels the Hubbs project is first and foremost a research undertaking. “Until that research is conducted, we cannot determine if the operation of larger aquaculture installations would be environmentally sustainable and responsible,” he says. “We owe it to ourselves to let the research progress, to see what is the impact and outcome of the offshore farm and determine if we wish to proceed or not beyond the research stage.”

Mr Dave Rudie, a sport diver and long-time sea urchin diver, has mixed feelings. “There’s going to be aquaculture in the world because of the demand for fish,” says Mr Rudie, who also owns Catalina Offshore Products – a wholesaler that primarily offers local and wild-caught product. “I guess I’d rather see it happen in US waters where it is well-regulated and well-managed opposed to in other parts of the world where they’re likely not to have the rules and regulations, and likely to do more environmental damage. Given that, I wouldn’t want to see aquaculture negatively affect local sustainable fishermen.”

Mr Rudie’s concern is one that many anglers share, but at least one says there’s no reason to worry. “There’s room for everyone out there,” says Ted Dunn, a life-long commercial fisherman who has been involved in everything from research with Scripps and Monterey Bay Aquarium to monitoring wild tuna stock and managing net pens off the coast of Baja. “Aquaculture is not going to impact any fisherman that’s fishing now or wants to continue fishing.” If anything, aquaculture will help fishermen rather than harm them, he says, namely because fish pens are essentially aggregating devices that attract other fish.

There is also another option. “In light of decrease in some commercial fisheries, there would be the opportunity to retrain commercial fishermen/women to become fish farmers,” says Mr Traverso.

Does anyone have all the answers now? No, says Mr Kent. “What’s going to drive the answers is a vibrant, sustainable industry that has problems that need to get solved.”

Mr Dunn says: “I believe in conservation and I believe in a sustainable fishery. If the US wants to eat fish in the future we have do something other than take it [wild stock] out of the ocean and I think aquaculture is the way. I don’t know of anything else. Instead of environmental groups fighting it head on, I think people should come together and find out how to do it. When I was growing up-I’m 66 now-people used to say, ‘Don’t worry about the beef and all that so much; we always have the ocean to harvest.’ But that’s not true anymore. We can go out and harvest it today, but I’m not sure about tomorrow.”

November 2009

the Fish Site Editor

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