Infection Risk Prevents Sitka Research Project

By TOM HESSE
Sentinel Staff Writer
    An ongoing study of how an invasive marine organism affects herring eggs will have to press on without an on-site study of the tunicate-infested Whiting Harbor, the Alaska Department of Fish and Game has declared.
    State fisheries officials decided that even a controlled study of the invasive organism in Whiting Harbor by local and National Marine Fisheries scientists presented too much of a risk it could spread to other areas.
    The policy of the state, the federal researchers were told, is to focus all efforts on eradication of the biological threat, and to disturb it as little as possible in the meantime.
    An initial denial of the permit was made March 18 and a recent appeal to the decision was not granted.
    Whiting Harbor, the long inlet between the north end of the Sitka airport runway and the World War II causeway, island, is the only body of water in Alaska known to be infested with the tunicate.
    Didemnum vexillum (also known as D vex), is a carpet tunicate that can smother organisms on the sea floor. It appears as a slimy coating that adheres to any object or animal that comes into contact with it. The Whiting Harbor infestation was identified in June 2010, and since then no boats or human activity of any kind has been allowed in the area, which is bordered by the Japonski causeway.
     A research project on the effect of tunicate on the development and survival rate of herring eggs is already under way off the coast of San Francisco.
    Sarah Cohen, Ph.D., is an associate professor of biology at San Francisco State University and is one of the leads on the project. Cohen said the herring spawn in San Francisco takes place around January and her group of researchers is now analyzing the data they’ve found.
    “I’m excited about what we’ve found out so far with stuff down here,” Cohen said. “We did see interactions between the herring eggs and the D vex and I hope we can get that information out really fast.”
    Cohen added that it’s too early to say what the data will show about the invasive species’ effect on herring but that the early indication is it is “something to be concerned about.”
    San Francisco is pretty well blanketed with the tunicate, Cohen said. Alaska, on the other hand, has identified the problem only in Whiting Harbor.
    Katherine Miller, Ph.D., a research fishery biologist with the National Marine Fisheries Alaska Science Center, said the second part of the project was to find out how the tunicate interacted with herring eggs on the Alaska coast.         Alaskan coastlines differ greatly from those in the Bay Area and Miller said they were hoping to gather data from Whiting Harbor that may be used for future management of the tunicate before it is eradicated from the Sitka harbor.
    “We don’t know how it affects spawning species like herring,” Miller said. “We thought particularly this (the annual Sitka Sound herring spawn) was a good opportunity to see how it would affect spawning and development of the eggs.”
    The reason Miller wanted to gather the data during this year’s spawn is because the Alaska Department of Fish and Game doesn’t intend to let the tunicate get too comfortable in Alaska coasts.
    Tammy Davis, the head of the invasive species program for Fish and Game, said action is already being taken to eradicate the only known D vex in Alaska.
    “The department’s plan is not to manage the tunicate but to eradicate the tunicate,” Davis said in an email. “A request for proposals will be issued this week seeking a qualified contractor to complete the work.”
    Jim Seeland and Marnie Chapman, associate professors at UAS Sitka, filed the request for a fisheries resource permit to work in Whiting Harbor.
    Fish and Game Sport Fisheries Director Charles Swanton said in a letter to Seeland and Chapman that the request was denied because of concern about spreading the tunicate. D vex is spread by objects like boat hulls and floats, which is likely how it made it to Alaska in the first place.
    The project would have involved moving boats and herring pounds into Whiting Harbor to place eggs in infested areas for the purposes of the study. Davis said Fish and Game’s top priority was to avoid any spread of the tunicate and that the department thought the research project might present that risk.
    Miller said she was surprised that the request was turned down because she was hoping they could find a way to gather information that might be helpful in protecting Alaska’s herring populations in case the tunicate resurfaces.
    “We’ve got a gigantic coastline in Alaska ... There’s a lot of potential vectors for moving (D vex) up here, like  boat hulls,” Miller said. “It could easily get into other parts of Alaska. The potential for that is quite high and knowing impacts has a lot of value.”
    That’s not to say the research won’t find other ways to press on. Cohen said it’s “certainly not the first time” she’s had to alter a research project. She added that Fish and Game has handled the D vex infestation well by quarantining the area and moving quickly to eradicate it.
    “This is the first marine (infestation) of any concern ... where it really is possible to eradicate it, and that’s a really unique situation,” Cohen said.
    While the project no longer contains the Whiting Harbor study, the information being developed by the research project can still benefit Alaska.
    Cohen said a third part of the project involves mapping the coastline to get a better understanding of where the D vex may reappear, and the group is also sponsoring outreach to help protect the rest of Alaska’s coast.
    Cohen said Sitkans and the Game and Fish have been very proactive about handling the problem before it becomes too big to handle.
    “It was extremely impressive. It’s hard to mobilize people about something that mostly isn’t there yet,” Cohen said. “It’s a really dangerous invasive species. (How it’s been handled is) a model for how this should be done in a really pristine place.”
    Miller said invasive species in marine environments can be tricky, so it’s difficult to say where the tunicate could spread to. An important part of the process will be keeping fisherman and community members informed so they can spot the invasive organism if it should appear somewhere else.
    “One thing that I’ve found in coming up to Sitka and doing research there is how informed people are up there with the biology of the area,” Cohen added.
    Miller said the results of the herring egg test in San Francisco will be the first data available on how the species affects herring eggs. While the work will be done out of state, it will still provide some data relevant to Alaska, she said.
    Miller added that the Fisheries Science Center maintains a good relationship with Fish and Game and that the data will still be valuable.
    “If I was a herring fisherman then I would want to know this,” Miller said.
    Davis said the eradication of the tunicate will start this summer once Fish and Game has found a suitable contractor.

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