More Sea Lice news

[phearless]

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

[knotnot]

Good info, very scary.
The fish farms have to go. If they must stay perhaps only allow pools on land like above or inground. So if they escape they have to actually run for it.
Maybe the farmers should have to use old hot tubs or kiddy pools.
That way they are away from real fish and their habitat.

[slayin1993]

haha they arent going to run far