Invasives make headway in Alaska

SITKA, ALASKA

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Sitka’s Bio Blitz was headquartered at the Sitka Sound Science Center, which acted as a hub for biologists and volunteers of all ages.

“This is one of the squirting tunicates and another part, another tunicate, the invasive tunicate was growing on this one.”

Small children and adults bustled in and out carrying buckets of sea water and ocean discoveries. One of them is Michelle Putz, she was looking for invasive species at Crescent Harbor.

“I got out there a little bit late, and they were looking for things, and when you are out surveying for kinda any animal or plant or whatever you are always excited when you actually find it, but when you are working on invasives you don’t really want to find it, so it was kinda funny we’re out there , we found some of these invasive species, and we’re like, “Wooo we found em!” Which is exciting, but it’s like wow, that’s not a good thing, we should be saying, “Woo we didn’t find them!”

While volunteers hit the docks and coastline, volunteer divers headed underwater. I met Patrick Fowler, with the Department of Fish and Game at A-N-B Dock where he was working with divers to document and collect invasive species.

“So we have a couple of bags of samples that we collected, our divers doing a great job identifying the invasive tunicates vesus the native tunicates,  and are simply just kinda throwing them up on the dock and we are bagging them up for definitive classification.”

Back at the Sitka Sound Science center scientists and volunteers alike were busy documenting their finds. John Stein is the Director of the Center and says the Blitz is part of a growing concern that invasives are making headway in Alaska’s waters.

“It’s part I think of a national concern about animals coming in on the bottoms of freighters from foreign lands. We wanna see what’s happening and see what the effect is on the local populations of intertidal animals.”

Linda Shaw is with the Habitat Conservation Division of the National Marine Fisheries Service in Juneau and says invasives are on the move.

 “In most of the lower 48 and many parts of the world invasives are there, they are already out of control they are at a point where it would be extremely expensive to do something about them. In Alaska we aren’t there yet, and we have a golden opportunity to get ahead of the curve, find infestations early, when we can do something about it, and it’s not too expensive.”

Alaska has had historically low numbers of alien species, but recent studies have shown a jump in their population. Sarah Cohen is an Associate Professor at the Romberg Center and says this jump might be because scientists have only recently started to document invasives in Alaskan waters. At this point, she says, there are probably invasive populations anywhere there is a high density of boats.

Tunicates, a relatively new species to Alaskan waters were the main target of last weekend’s Blitz.

These little gelatinous creatures are also called sea squirts, and come in many shapes and colors. Some are solitary tube shaped animals, and others are more gregarious, living in sponge-like colonies and carpeting the sea floor, boat hulls, ropes and, sometimes, crustaceans.

And it’s these colonies of tunicates that worry scientists. Linda Shaw says the fishing industry should also be on guard. An example in Georges Bank, off the coast of Maine tells the story of invasive tunicates all too well.

“There is a tunicate, Didendum, that is on Georges Bank, very famous fishing grounds on the North East, they were the cod fishing grounds, it’s covering huge areas there, like up to six miles in diameter, areas on the bottom.

And with all those tunicates carpeting the bottom, ground fish can’t eat off the sea floor and could starve to death. And, she says, Alaskans can’t count on cold waters to keep invasives at bay. Studies have shown many invasive species do just fine in colder water.

Tunicates already have made a stronghold in Sitka. But how are they getting here?

 Sarah Cohen from the Romberg Tiburon Center, part of San Francisco State University, wants to find out.

“They’re probably coming from boats moving north along the coast, it used to be that we thought a lot of invasives coming across ocean in ballast water, but these don’t have larva that last in ballast water so it’s probably hull fouling, and so they are moving in hops skips and jumps up the coast on all types of boats . And we are seeing them in boat hulls here and all types of different structures.

In other words, these little guys are hitching a ride and colonizing the coast as they go. Cohen hopes to use DNA samples from the Blitz to track their origins, which some scientists believe maybe as far south as Central America.

This information she says, could influence policies surrounding boat travel, and someday limit the spread of invasives.

Sitka’s BioBlitz was a combined effort among a host of different Universities and scientific bodies, including the Smithsonian, the Romberg Tiburon Center for Ecological Studies, and Alaska Fish and Game.