What is in this article?:
- Coastal fish farm waste a growing concern
- Future fish farms
- One of the fastest-growing segments of livestock farming in the United States is aquaculture, according to Roz Naylor, a Stanford professor of environmental Earth system science. And like any other form of livestock, fish generate waste.
- But just what happens to the waste produced by coastal aquaculture has largely been a matter of conjecture.
Future fish farms
Naylor said the model will likely show that some locations previously thought appropriate for fish farms are actually not suitable, but she doesn't think the aquaculture industry will necessarily see that as a bad thing. Having clearly defined boundaries of where aquaculture is acceptable will help the industry avoid conflict with other users of coastal waters.
"A lot of the industry people that I have talked to are not working against the environment, they are really trying to make aquaculture work, and this would provide a useful tool for them," Naylor said.
Naylor, Koseff and their colleagues will be publishing their findings in an upcoming issue of Environmental Fluid Mechanics. The paper is online now.
Naylor said their findings are quite timely, in light of legislation in the works at both the state and federal levels.
In 2006, California passed the Sustainable Oceans Act, aimed at protecting the biologically rich waters off the coast while also recognizing the importance and economic value of providing fresh seafood.
Naylor said that a draft of the regulations to implement that legislation is currently under review and this new modeling tool should help in setting guidelines for locating and monitoring aquaculture.
At the federal level, the National Oceanic and Atmospheric Administration is taking public comments through April 11 on a draft of a national aquaculture policy.
"After the bill is passed, rules and regulations will have to be written around it and what we are providing now is a tool to help with that," she said.
Koseff acknowledged that some people might balk at relying on a computer model to guide regulations.
"We understand and recognize the limitations of the simulations," he said. "But we have confidence that the physics that we are representing in the model are realistic and our results are very representative of what happens in a near-coastal environment."
Naylor said that for an aquaculture operation to be economically feasible, a lot of pens will likely have to be concentrated in one area, making waste a significant concern.
"I also work a lot in terrestrial livestock, and I think the dissolved wastes that come out are one of the worst aspects of intensive animal raising," she said.
"If we are really thinking about getting our animal protein from fish in the future, and it is coming from net pens that are in the ocean, one of the big fears is, are we going to have feedlots of the sea?
"We would really like to completely avoid the problems we have seen in terrestrial livestock. That would be the ultimate goal and this model can help achieve that."
Naylor is the director of Stanford's Program on Food Security and the Environment and a senior fellow at the university's Woods Institute for the Environment. Koseff is co-director of the Woods Institute and a senior fellow at the Freeman Spogli Institute for International Studies.