Sea Lice Jump From Prey to Predator

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.

Read the full article in the Vancouver Sun.