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[troutbreath]

Sea lice jump from prey to predator
Young pink salmon infect bigger fish as they are consumed, new research shows
 
Kris Schumacher
Prince Rupert Daily News


Monday, July 07, 2008


PRINCE RUPERT - Sea lice are surprisingly acrobatic and can leap from juvenile salmon to larger fish that prey on them, new research has found.

In the study, published in the peer-reviewed science journal Biology Letters, Simon Fraser University doctoral candidate Brendan Connors and researchers from the University of Alberta focused on young pink salmon infected with sea lice that were eaten by predatory cutthroat trout and coho salmon.

Their findings show that in approximately 70 per cent of the trials, sea lice from the small pink salmon also infected the predators.

This represents the first time that scientists have documented lice moving up from prey to predator species.

"Sea lice on pinks that are about to be eaten by a coho or cutthroat literally do a backflip off the fish they were on and land right between the eyes of the predator," said Connors, a behavioural ecologist.

Connors also found that sometimes when sea lice on a pink salmon were eaten, they would crawl from the mouth of the predator fish through the gills and survive, further evidence of their ability to find ways onto a new host. It's still not entirely clear to researchers just how lice are able to sense the impending doom of their current host, but Craig Orr, executive director of the Watershed Watch Salmon Society, said it appears that male sea lice in particular are extremely mobile and able to "jump ship" very readily.

It appears the lice pick up cues from their hosts, Orr said.

"Whether it's vibration or visual or some kind of pheromone, it's not really known. But there are some cues they are picking up on that cause them to abandon ship. They're really quite tricky, and of course we never knew that they could do this. We've never seen it in any of the European literature at all."

Connors found the behaviour occurring naturally in the Broughton Archipelago, off northern Vancouver Island, but quantified the findings through experiments carried out in salt-water enclosures at a research station in the watershed.

Orr said it is clear that species such as cutthroat trout are susceptible to lice, which raises the ecological stakes in the sea lice debate.

Previous research by Watershed Watch, a co-sponsor of the new SFU research, has shown that farmed salmon in the Broughton area annually produce billions of infectious lice larvae, which pose a threat to wild salmon. Although a set threshold for how many lice are fatal to salmon has not been determined or widely agreed upon, Orr said current research in the watershed is finding that as few as one or two sea lice on a young pink salmon can prove fatal.

© The Vancouver Sun 2008

[troutbreath]

Sea lice infestations need to be dealt with
 
Steve Strand
Special to the Sun


Tuesday, July 08, 2008


After 25 years as a marine biologist at the University of California at Los Angeles, I decided to retire to British Columbia, where the combination of people with a similar life philosophy and a remarkably rich and interesting marine environment is very appealing.

Since my specialty was and is the ecology of marine fishes, salmon and the controversies surrounding farmed salmon inevitably captured my attention. I quickly realized the issues were more complex than I had thought. The salmon farming industry stresses the jobs created and the politicians appreciate the tax base. This is understandable, and potentially wonderful.

However, environmental concerns about the overall effects of salmon farms on the marine ecosystems of B.C., especially in light of the scientific literature that has proliferated in the past several years, has been ignored by both the scientific/regulatory branch of the government (Department of Fisheries and Oceans), and most of the politicians.

Last week I took a group of first nations elders and others on a trip to observe the research about the relationship of the fish farms to sea lice infestations in juvenile salmon.

What we witnessed was horrific. Juvenile salmon, pink and sockeye, were collected. Virtually every fish was carrying gravid female sea lice. Many were carrying five to 15 lice. These fish were all collected near the fish farms in Okisollo Channel. This infestation could only be possible if the salmon farms are acting as incubators for the lice.

In more than 30 years of research into fish biology, I have never seen such high levels of parasitism. Not only are all of these little fish going to die, before dying they are going to spread the infestation to other fish.

There is a catastrophe happening right now. It needs to be dealt with right now.

While the salmon farms do provide jobs, the wild salmon provide even more jobs to both the commercial salmon fishing industry and to the recreational fishing industry, the latter being an important draw for B.C. tourism. In addition, wild salmon are a major component of the entire Pacific Northwest ecosystem, both marine and terrestrial.

However, the tourism industry, commercial and sport fishers do not have the political savvy or lobbying ability of the multinational fish-farm corporations. Guess who the politicians listen to.

I do not know what has happened to the scientists at the DFO, their silence about the issues or worse, their easy acquiescence to the whims of the fish-farm industry.

Last year there was a government report stating that all salmon farming in B.C. should be switched to closed containment in the next five years.

When I mentioned this to an executive in the ministry of the environment I was told that this was "only a minority report." If the government commissions a study and then appoints members who can be dismissed as "minority" if the findings do not conform to the wishes of the party in power, what sort of an Orwellian system has erupted?

Despite what you may have read, there is no longer a real scientific controversy about the relationship of fish farms to sea lice infestations. The farms breed lice, and the lice infect and kill wild salmon.

It is time for the ordinary citizens of British Columbia to stand up and be counted.

If you consider yourself a supporter of the fish farms, ask yourself if you are really willing to give up wild salmon and the entire ecosystem they support in return for jobs that do not equal those offered by wild salmon.

I hope the answer is no.

Steve Strand lives on Quadra Island.

© The Vancouver Sun 2008