PORTLAND, Maine - Hundreds of people from all over the world have come to Portland this week to talk about a tiny creature that poses a threat to salmon farming. "The sea louse is a crustacean," says Professor Ian Bricknell, of the University of Maine's Aquaculture Research Institute. "It's called a copepod crustacean - it's related to lobsters and crabs."
Bricknell says sea lice, though small, are global parasites that attach to salmon and greatly increase mortality rates in aquaculture operations. "It's about three-quarters of an inch long, and it's flattened so it sticks like a small frisbee onto the outside of the fish."
Bricknell is the organizer of the 10th International Sea Lice Conference, which is being held in the U.S. for the first time.
"We've got delegates from Australia, Mexico, South America, the Pacific Islands, Asia, and this really reflects the nature of sea lice," says Nell Halse, of Cooke Aquaculture. Halse is among those who traveled to Portland. "We're a salmon farming company that's based in New Brunswick, Canada. We're also the only salmon farming company in the state of Maine."
Halse says managing the threat of sea lice incurs significant cost to doing business. "Currently we have a limited number of chemical treatments, compared to, say, terrestrial farmers," Halse says, "and in North America we have very few treatments that are authorized, compared to our counterparts in other parts of the world, like Norway, Scotland and Chile."
The world's leading salmon country is Norway, which, two years ago, produced 1.2 million metric tons - about 100 times more than what Maine produces. And scientists say with increasing demand for protein sources from the sea, the effort to stem the damage of sea lice is significant.
"There's a lot of treatments that need to be done to keep it under control," says Simon Wadsorth, a research scientist based in Norway who is working for EWOS Innovation, which develops feed for the global aquaculture industry. Wadsorth says the cost of controlling sea lice is a major challenge.
"Some papers recently are showing sort of $300 million," he says, "but that's probably conservative. Globally it's probably a lot more than that."
One way to minimize the environmental impact of de-lousing salmon is to use so-called "well boats," which are becoming increasingly common in North American aquaculture. UMaine professor Ian Bricknell says fish are pumped aboard these vessels where they're treated with chemicals, such as hydrogen peroxide.
Each boat, he explains, has a large, swimming pool-sized aquarium in the center "where you put the drugs, you add the fish to it and then you take the fish out and put them back in the cage, so that water doesn't actually go in the ocean."
Bricknell says major research is also going on into more organic methods of controlling sea lice: for example using shellfish, which have been found to naturally filter sea lice larvae out of the water. He says shellfish could conceivably one day be used as a barrier against sea lice, if grown alongside cages where the salmon are kept.
In the meantime, industry representatives have come to Portland this week to compare notes on the sea lice problem. "Sea lice is always a concern for us - I mean as a farmer we have a stewardship responsibility for our farms and for our farm animals," says Sebastian Belle, executive director of the Maine Aquaculture Association.
Belle says efforts to safely control sea lice here in Maine could be improved by lessons learned in other countries. "The great thing about a conference like this is we can compare notes with our colleagues in other countries where they have slightly different environmental regulations, and we can see what has worked and what hasn't worked in terms of being able to control sea lice, but also reduce our environmental impact," Belle says.
Which is something that's on the mind of lobstermen in the Northeast, who, in the past, have expressed concern about the possible impact of pesticides on lobster populations.