Invasive species: 'The floating dock can be considered a wakeup call'

NEWPORT, Ore. – Scientists continue identifying the organisms attached to a floating dock from the 2011 Japanese tsunami that came ashore at Agate Beach just north of Newport, Ore., earlier this month.

They are also are casting a wary eye to the future and what other potential invasive species may arrive.

“The floating dock can be considered a wakeup call that conveniently arrived on the beach within five miles of a leading marine science center,” said Jessica Miller, an Oregon State University marine ecologist who was one of the first scientists to examine the organisms. “This provides us with a spectacular opportunity to understand the overall invasion process and the risks associated with tsunami debris fields to come.”

The Oregon Department of Fish and Wildlife is leading the state’s response to the invasive species threat and coordinating with OSU, state and federal agencies and other partners.

ODFW has established a website http://www.dfw.state.or.us/conservationstrategy/invasive_species.asp that keeps the public, scientists and the media informed about best practices for disposing of debris with organisms on it.

The Oregon Invasive Species Council has a hotline for reporting suspected invasive species at 1-866-INVADER.
Miller and colleague John Chapman, who work out of OSU’s Hatfield Marine Science Center, have identified as many as 50 different organisms from the dock, which has definitively been linked to Japan. They are still trying to identify and catalog some of the remaining species.

The fear, researchers say, is the species that arrive on debris from Japan may colonize along the West Coast, which has been most vulnerable to invasive species brought here in the ballast water of ships, as well as by other mechanisms. Tsunami debris is an undocumented, if not new threat for invasives.

“Among the living organisms that we have identified from the dock are some that could aggressively invade local marine environments and threaten native species,” said Chapman, an OSU aquatic invasive species specialist from the university’s Department of Fisheries and Wildlife. “The real question is how many of these organisms may have left the dock before it was beached.”

Chapman said some of the species that have the most potential for successful invasion are the Northern Pacific seastar (Asterias amurensis), the Japanese shore crab (Hemigrapsus sanguineus), and a species of brown algae (Undaria pinnatifida), which had covered the dock, which was 66 feet long, 19 feet wide and seven feet high.

Gayle Hansen, an OSU botany and plant pathology specialist, is working with Hiroshi Kawai from Kobe University in Japan on further identification of algal species, and the OSU scientists are also working with Jim Carlton of Williams College to find taxonomic experts to help with identification.

Other organisms aboard the dock include at least eight species of mollusk, an anemone, a sponge, an oyster, a solitary sea squirt, a granular claw crab, three or more species of flea-like amphipods, four or more species of barnacles and worms, bryozoans, a European blue mussel known as Mytilus galloprovincialis, and a sea urchin.

OSU’s Hatfield Marine Science Center has created a website that has photos of some of the identified species, It can be found at http://blogs.oregonstate.edu/floatingdock

Jack Barth, an OSU oceanographer who specializes in currents, says the dock that arrived at Agate Beach could have landed elsewhere if it had reached nearshore waters a few weeks earlier or later. The key, he said, is how seasonal winds create currents.

“Summertime winds come from the north and push currents south,” Barth said. “Because the Earth is rotating, that pushes things away from the shore and may keep some debris out at sea for a while. But when these northerly winds reverse and become southerly – or just relax and weaken – the surface flow is back on shore and that will bring debris with it.

“After about mid-October, coastal currents will reverse and flow to the north,” Barth added, “so at that point, we can expect more debris to land in Washington and British Columbia.”

Barth said there are some areas of the coast – including near Coos Bay and Winchester Bay – where currents sweep close to shore and may attract more debris.

Conversely, he said, debris can get caught in an offshore “convergence zone” and drift hundreds of miles up the coastline before beaching.