Divers Work To Keep Invasive Tunicates From Spreading
OLYMPIA — For the third year in a row, divers are heading to several marinas in Puget Sound to remove colonies of invasive tunicates from boat hulls with the aim of preventing their spread to other area waters.
From the end of May through June 30, divers from the Washington Department of Fish and Wildlife (WDFW) and contract divers will work to remove the rapidly spreading species at six marinas. This is the third year WDFW has worked to contain the non-native siphon feeders that compete for food and smother native sea life including clams, mussels and oysters.
Since invasive tunicates or “sea squirts” were first discovered on a sunken boat in 2004 near Edmonds, more than a dozen colonies have spread throughout the Sound from Des Moines to Birch Bay. The tunicate problem is so severe that the state Legislature has provided emergency funding for WDFW to develop and carry out an eradication plan.
“These critters have a bad rap sheet,” said Allen Pleus, aquatic nuisance species coordinator for WDFW. “They have no natural predators and once they spread, they’re really tough to remove completely.”
Pleus and his crew of divers are targeting six marinas where the hulls of a number of recreational boats have become infested. The plan is to remove the invasive tunicate colonies before boating season gears up and people unwittingly spread the species to other waters. The marinas are located in Blaine, Semiahmoo, Elliot Bay, Des Moines, Dockton on Maury Island and Pleasant Harbor on Hood Canal.
“We’re trying to contain the problem while working on more long term eradication solutions,” Pleus said. “This is our third year in those marinas where numerous established colonies have been identified. This year, we’re attempting a full eradication at Dockton.”
The biggest problems come from rarely used or abandoned boats that are docked permanently at the marinas, Pleus said. “Boats that haven’t been moved in years are covered with these animals,” Pleus said. “This poses a much higher risk, especially if these boats are moved.”
To address the situation, Pleus said WDFW is informing boat owners about their liabilities and the potential fines they face if their boats are moved without being cleaned.
However, success with permanent removal from Puget Sound waters ultimately depends on the efforts of many people, Pleus said.
“We’re working closely with the Puget Sound Partnership, marina and boat owners and other agencies to not only contain tunicates, but eliminate them completely,” he said. “The timing is critical.”