Roy L Hales/ Cortes Currents - Sea lice are a serious problem for the fish farm sector, but a new study from the University of British Columbia has found there are viruses that prey upon them.
“In theory viruses might be deployed in a way in which they might be able to help control sea ice densities in aquaculture. I certainly wouldn't be a proponent of that at this stage, and would strongly advise against that because we just don't know enough about it,” explained senior author Dr. Curtis Suttle.
“I'm a professor at the University of British Columbia, and my group works primarily on different kinds of microbes and different kinds of pathogens. One of the exciting things that we found recently is that there's a lot of viruses which infect sea lice, which were previously completely unknown.”
His team found 30 previously unknown RNA viruses in sea lice.
“What we also know is that these viruses do appear to be replicating and infecting the sea lice. We could see that the sea lice were mounting a very specific immune response to the individual viruses infecting them.”
“We were only looking at wild salmon smolts, not at anything to do with fish farms per se, but we would assume that viruses might be prevalent within fish farms when population densities are high. Sea lice are a parasite, their populations will grow really fast because essentially they're unlimited in terms of the number of hosts that they can exploit. So in those kinds of situations, populations tend to get out of control. You would expect that viruses would be able to spread from sea lice to sea lice relatively quickly.”
His team collected the viruses found in sea lice on five sites, ranging from southern Quadra Island to the Broughton Archipelago. Cortes Currents was especially interested in their findings in the Discovery Islands, done in collaboration with the Hakai Institute.
“You can be sure that these viruses infecting sea lice are the same viruses that are swimming around Cortes,” he said.
CC: Are any of these RNA viruses that you were studying known to be fatal to sea lice, or is that unknown?
CS: “That’s a complete unknown, and a very difficult question to address because the only way that you could really do that would be to be able to culture and grow sea lice. The only way that I know to grow and culture sea lice is to infect a fish. It becomes a very complicated experiment. You would have to have large quarantine facilities, take salmon that have sea lice and put some in with viruses, some without viruses and see what those consequences are.”
