Category Archives: Invasive species

Green crab invaders settle in on Dungeness Spit, Olympic Peninsula

An invasion of the European green crab, which started last summer in northern Puget Sound, appears to be continuing this spring with 16 green crabs caught in traps at one location on Dungeness Spit near Sequim.

European green crab
Photo: Gregory C. Jensen, UW

The new findings are not entirely unexpected, given that invasive green crabs have established a viable population in Sooke Inlet at the southern end of Vancouver Island in Canada. From there, young crab larvae can move with the currents until they settle and grow into adult crabs. Last summer and fall, green crabs were found on San Juan Island and in Padilla Bay.

The big concern now is that a growing population of invasive crabs could spread quickly to other parts of Puget Sound, causing damage to commercial shellfish beds and disrupting the Puget Sound ecosystem.

“It knocks the wind out of your sails for sure,” said Emily Grason when I asked how she felt about the latest discovery. “You feel kind of powerless, and you want to get out there and start doing things.”

European green crabs were found on Graveyard Spit, the small spit that juts off the main Dungeness Spit. Google maps

Emily, a biologist with Washington Sea Grant, coordinates a group of trained volunteers known as the Crab Team. These folks place crab traps in dozens of locations where habitat is suitable for green crab survival. When invasive crabs are found, the volunteers put out many more traps in hopes of reducing the population before it grows out of control.

The hope is that invasions can be found early so that the extensive trapping makes it more difficult for the limited number of crabs to locate suitable mates and continue to expand the population. Each female can lay up to a million eggs at a time, and they are not limited to just one or two broods each year.

Officials with Washington Sea Grant are not only dealing with foreboding feelings about the green crab invasion but also concerns that the Crab Team may be shut down for lack of funding. At the federal level, President Trump has proposed eliminating the entire Sea Grant program nationwide, halting research and various types of assistance for marine projects across the country.

“We don’t like to think about a world where we have to stop this program in midstream,” said Kate Litle, assistant director of programs at Washington Sea Grant, “but that’s what will happen if we don’t get funding.”

At the same time, the state’s Aquatic Invasive Species Program may also have little or no money to battle the green crabs. Program officials requested increased funding from this year’s Legislature to support the Crab Team as well as address invasive zebra and quagga mussels. The budget proposed by the state Senate contains the full funding — including a portion of utility tax revenues that currently go into the state’s general fund. The House budget for the program includes a new fee on nonresident watercraft, but the amount of revenue is relatively small.

“If we lose the Sea Grant early detection program, we are going to be in a world of hurt,” said Allen Pleus, coordinator of the Aquatic Invasive Species Program at the Washington Department of Fish and Wildlife. Allen said it would be hard to get along without the trained Crab Team volunteers, who provide the first line of defense for all of Puget Sound.

Emily said she has about 150 volunteers putting out crab traps in every part of Puget Sound, and the number may grow. After last year’s discovery of green crabs in northern Puget Sound, officials from tribes have stepped up to help along with staff from state and federal agencies.

Trapping begins in April and continues into September if the funding holds up. So far this year, traps placed in Padilla Bay — where four crabs were caught last year — have come up empty, Emily said. That’s a good sign, she said, “but we definitely have a different story at Dungeness Spit.” To review last year’s findings, see Water Ways, Oct. 1, 2016.

Unlike Padilla Bay, where the four crabs were few and far between, the 17 crabs caught at Dungeness Spit were all in the same location. Of the first four crabs caught on April 13, two were caught in the same trap on Graveyard Spit, a small spit that juts out from the main Dungeness Spit.

More traps were placed in that general area — up to 52 traps at one time. Three more crabs were caught on April 18, then five more on April 19, one on April 20, and then three more yesterday, along with a discarded shell.

“If we can trap them down to make it harder for the males and females to find each other, that is the best we can do,” Allen told me.

The trapping at Dungeness Spit is being done with staff and volunteers from the U.S. Fish and Wildlife Service, which oversees the Dungeness National Wildlife Refuge.

Anyone can look for green crabs and help control their spread while visiting salt marshes and shallow pocket estuaries. People are asked to leave all crabs in place and follow the instructions to email a photograph of a suspect crab to the Crab Team. For identifying information, visit the Crab Team website.

Crab Team training will foster the upcoming hunt for green crab invaders

A European green crab invasion may be taking place in Puget Sound, and Washington Sea Grant intends to enhance its Crab Team this summer with more volunteers looking in more places than ever before.

The second European green crab identified in Puget Sound was found in Padilla Bay, where three others were later trapped.
Photo: Padilla Bay Reserve

Training is about to get underway, and anyone with an interest in furthering science while being exposed to the wonders of nature may participate. It’s not always good weather, but I’ve been inspired by the camaraderie I’ve witnessed among dedicated volunteers.

The work involves going out to one or more selected sites each month from April into September with a team of two to four other volunteers. It is helpful to have folks who can carry the crab traps, plastic bins and other equipment. For details, check out the Washington Sea Grant website.

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Ballast water bill could allow invasive species to enter Puget Sound

Invasive species from San Francisco Bay — known as the most infested waterway in the country — would have an open door for entry into Puget Sound under a bill moving through Congress.

Vessel Incidental Discharge Act invasive species
Ballast discharge from a ship
Photo: Coast Guard

You may have heard this line before. I posted the same warning last summer, when the Vessel Incidental Discharge Act, or VIDA, was attached to the “must-pass” National Defense Authorization Act. (Water Ways, July 16). Opponents fought back and were able to strip VIDA from the bill before final passage.

Now, with Republicans in control of both houses of Congress and an anti-regulatory atmosphere in place, the bill’s passage seems more likely this time — to the detriment of Puget Sound, the Great Lakes and other waterways.

If VIDA passes, ships coming up the coast from California will be able to take on infested ballast water in San Francisco Bay and discharge it without treatment into Puget Sound. Invasive species that hitched a ride in the ballast water would have a chance to populate Puget Sound.

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Invasive oyster drills react differently to predators than natives

Invasive saltwater snails, including dreaded oyster drills, seem to be far more leery of predators than native snails under certain conditions, according to a new study by Emily Grason, whose research earned her a doctoral degree from the University of Washington.

An invasive Atlantic oyster drill feeds on a young Pacific oyster. // Photo: Emily Grason

Why non-native snails in Puget Sound would run and hide while native species stand their ground remains an open question, but the difference in behavior might provide an opportunity to better control the invasive species.

Of course, snails don’t actually run, but I was surprised to learn that they can move quite rapidly to find hiding places when they believe they are under attack.

Like many marine animals, snails use chemical clues to figure out what is happening in their environment. For her experiments, Emily created a flow-through system with two plastic shoeboxes. Chemical clues were provided in the upstream bin, while the reaction of the snails was observed in the downstream bin.

The most dramatic difference between native and non-native snails seemed to be when ground-up snails were deposited in the upstream bin, simulating a chemical release caused by a crab or other predator breaking open snail shells and consuming the tender morsels inside.

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