Tag Archives: Washington Sea Grant

Green crabs entrenched at Dungeness Spit, but new issues are emerging

Dungeness Spit on the Strait of Juan de Fuca near Sequim remains a hot spot for the invasive European green crab, which first showed up in Puget Sound during the fall of 2016.

This small male crab is one of the European green crabs caught last year in traps at Dungeness Spit.
Photo: Allen Pleus

The green crab, one of the most dreaded invasive species in the world, brings with it the potential to destroy shellfish beds and disrupt key habitats essential to native species in Puget Sound.

Thankfully, except for the Dungeness Spit, new findings of green crabs have been almost zero since a massive volunteer trapping effort resumed in April throughout most of Puget Sound.

I do have some additional news about green crabs to share, so please read on for a discussion of these topics:

  • Green crabs on Dungeness Spit
  • New findings on Whidbey Island
  • Where the crabs are NOT coming from
  • New efforts with Canada
  • First scientific paper on the green crab program
  • New assessment tool on the horizon

Green crabs on Dungeness Spit

So far this year, 42 of the invasive crabs have been found on Dungeness Spit, compared to 96 for all of last year, according to Lorenz Sollman, deputy project leader for the Washington Maritime National Wildlife Refuge Complex.

European green crabs have been found on Graveyard Spit, the small spit that juts off the main Dungeness Spit.

So far, nobody knows if the first crabs to arrive on the spit are reproducing or if the young ones being found there are new arrivals. Crabs can travel great distances through the water in larval form before they settle down and take on the familiar appearance of a full-grown crab.

“We don’t have any reason to think that they are not reproducing (at Dungeness),” said Emily Grason, Crab Team coordinator for Washington Sea Grant. The Crab Team is a group of volunteers and experts who monitor 54 trapping sites in the region.

Just this morning, Crab Team members found a new green crab at Dungeness Landing County Park, west of the Dungeness River and just outside the Dungeness National Wildlife Refuge.

“We’ve had our eye on that site, since it’s so close to the Dungeness Spit and assumed it was only a matter of time before one showed up there,” Emilly wrote me in an email.

Meanwhile, in Makah Bay just outside the Strait of Juan de Fuca in the Pacific Ocean, nearly 400 crabs have been captured in an intensive trapping effort this year alone. The first crab was spotted in the bay last fall. Matthew Nash of the Olympic Peninsula News Group updated the situation this week — although it is Makah Bay, not Neah Bay. The latter, which is technically inside Puget Sound, has not been found to have any green crabs.

New findings on Whidbey Island

At the beginning of this month, one of the most intensive trapping programs yet in Puget Sound was conducted over three days at Lagoon Point on Whidbey Island, where two green crabs were caught on different days last year. Working in deep sticky mud, only one green crab was caught in the enclosed lagoon during the latest effort.

Crab Team leaders Sean McDonald, Kelly Martin and Emily Grason following their three-day trapping effort on Whidbey Island.

“While we might have been happier not to catch any green crab, we are certainly glad that we only found one,” wrote Kelly Martin for the Crab Team Blog. Kelly, the newest member of the Crab Team management group, goes on to talk about the trapping adventure — including her accidental sit-down in the mud.

In a previous blog post, Kelly, who is a graduate student at the University of Washington, introduced herself to readers and talked about her background.

Where the crabs are NOT coming from

It has been suspected that the European green crabs found at Dungeness Spit as well as those on San Juan Island and Padilla Bay may have originated from Sooke Inlet at the southern tip of Vancouver Island, where a large infestation of green crabs has become well established.

After all, Sooke Inlet is physically close to areas in Puget Sound where green crabs have been found, at least when compared to infested areas along the coast. Although a large channel separates the U.S. from Canada, that might not be much of an obstacle for crab larvae, which drift with the currents.

To the surprise of many, a research project involving crab DNA showed that the green crabs in Puget Sound were NOT closely related to those in Sooke. Instead, the crabs at Dungeness Spit came from coastal populations, according to genomics work by Carolyn Tepolt of Woods Hole Oceanographic Institution. The Sooke population is considered genetically isolated and very different, probably because it started some time ago by a small number of crabs that did not mix with others.

Lagoon Point, Whidbey Island: Blue dots are minnow traps; orange dots are larger fukui traps; large orange circles are where two European green crabs were found last year; and the yellow circle is where the one crab was found this year. // Map: Crab Team

At the same time, studies of the tidal currents in the area showed that Sooke was no more likely to be a source of crab larvae than coastal areas. Crab larvae coming from Sooke are likely to be swept toward the ocean, whereas rare conditions called “reversals” can bring larvae from the Washington Coast along the southern shore of the Strait of Juan de Fuca, according to a study by Elizabeth Brasseale, a graduate student in oceanography at the University of Washington. See the Crab Blog from April 25.

New efforts with Canada

Knowing that Sooke is not the source of the green crabs in Puget Sound changes the dynamic with Canada.

“It was a relief to find out that crabs (from British Columbia) were not inundating our shores,” Emily Grason told me. “If that had been the case, the necessary management action would be to throw everything at Sooke Basin.”

The cost of eradicating green crabs from Sooke would be enormous and probably would not help the situation in the U.S. On the other hand, the Canadians may learn some things from the extensive trapping program taking place in Puget Sound, which seems to be keeping the crab population in check. Sooke may be somewhat of a lost cause, but there could be hope for other B.C. inlets at risk of being invaded.

A cross-boundary task force has been discussing the green crab problem on both sides of the border. Meanwhile, an expert panel at April’s Salish Sea Ecosystem Conference discussed the pros and cons of international cooperation as well as political realities of dealing with the problem. Kelly Martin summarized that session for the Crab Blog on April 27.

First scientific paper on the green crab effort

The first publication addressing Puget Sound’s European green crab invasion documents the early stages of a horrific invasive species while celebrating the collaborations of hundreds of people making detection and control possible, according to Emily. Allen Pleus, coordinator of Washington’s Aquatic Invasive Species Program.

“If you are familiar with Crab Team, you might wonder why this scientific paper, which only covers the findings through the end of 2016, is important,” Emily Allen wrote in the Crab Team Blog. “We have certainly been sharing news about findings through our blog, the media and other outlets.

“So, what does this publication add?” she asked. “This paper will help scientists track how European green crab has spread across the globe. Because of the rigorous review conducted on the paper by multiple experts – and believe me, it was rigorous – the information can be used to inform policy and management of this species, both here, and in other locations.”

As with most scientific papers, the information shared with the world lags behind current events, yet it reaches a depth of information that will be most helpful for those working with European green crabs, invasive species and related subjects.

Here’s the paper: “Citizen science program detects range expansion of the globallyinvasive European green crab in Washington State (USA)” (PDF 1.4 mb) in the publication “Management of Biological Invasions”

New assessment tool on the horizon

Although trapping European green crabs has been effective at locating the early stages of an invasion in Puget Sound, imagine instead taking a water sample and sending it to a lab. After a short wait, a technician using DNA techniques would tell you the likelihood of finding crabs in that location.

This is the ultimate test that I’m imagining as a new effort gets underway to identify invasive species by looking for DNA floating in the water. The technique is known as environmental DNA testing, or simply eDNA, and it is increasingly being used in freshwater to look for the presence of species of interest.

Developing a technique for saltwater adds the complexity of tides and currents moving DNA around, chemical breakdown of DNA, and determining if the DNA signal is coming from the larval form of a species or reproductive adults.

Alison Watts, an environmental engineer at the University of New Hampshire, has received a two-year, $500,000 grant to study eDNA in marine estuaries. She is collaborating with researchers at sample sites in Oregon, Maine and New Hampshire. The idea is to use eDNA techniques alongside traditional methods of biological sampling, such as seining, trapping and electrofishing.

The eDNA samples undergo both “meta-barcoding,” which can identify DNA from multiple species in a single sample, and single-species PCR amplification, which is designed to test for the presence or absence of a target species, Alison told me.

The eDNA techniques might provide an early warning of green crabs — say in South Puget Sound, where they have not been found before — but it would not provide information about the number of crabs or their physical conditions.

“We are developing and testing the methods this summer, then will validate and develop guidance materials next summer,” she said in an email. “Once the initial methods are developed, it is our hope that they will be useful for a range of applications, including early detection of green crabs or identifying their range within a system.”

For information about the grant, check out:

Become a witness for ‘king tides’ in Puget Sound now and later

Witnessing Puget Sound’s “king tides” could return as a more popular outdoor activity this year, as Washington Sea Grant takes the lead in promoting the event.

Locations where people have posted king tide photos on the Witness King Tides website

“King tides,” which are recognized in coastal areas across the country, is the name given to the highest tides of the year. These are times when people can observe what average tides might look like in the future, as sea levels continue to rise.

The highest tide of 2018 is forecast for this Friday around 8 a.m., although the exact time depends on the location in Puget Sound.

Activities include taking pictures of shoreline structures during these high-tide events and then sharing the photos with others. One can try to imagine what the landscape would look like in a given location if the water was a foot or more higher. King tide activities can be fun while adding a dose of reality to the uncertainty of climate change.

King tides by themselves have nothing to do with climate change, but these extremes will be seen more often in the future as new extremes are reached. As things are going now, experts say there is a 50 percent chance that sea levels in Puget Sound will rise by at least 7 inches in the next 22 years and keep going from there. They say there is a 99 percent chance that sea levels will be at least 2.4 inches higher by then. Check out the story I wrote in October for the Encyclopedia of Puget Sound.

Washington Department of Ecology, which had been promoting king tides each year, has backed away from the event in recent years. In the beginning, I thought the idea of king tides seemed kind of silly, because high tides are affected by weather conditions on a given day. But I came to embrace the idea that watching these high-tide events will help shoreline residents and others understand the challenges we are facing in the Puget Sound region.

Addressing sea level rise may not be easy, but some waterfront property owners are beginning to face the problem, as I described in another story in the Encyclopedia of Puget Sound.

During a king tide event in December 2012, the Kitsap Sun and other newspapers covered the resulting flooding by running photographs of high water in many places throughout Puget Sound. A low-pressure weather system that year made extreme high tides even more extreme. In fact, officials reported that the high tide came within 0.01 feet of breaking the all-time tidal record set for Seattle on Jan. 27, 1983. See Water Ways, Dec. 18, 2012.

Washington Sea Grant, associated with the University of Washington, has now taken over promotion of king tides, and we should soon see an improved website, according to Bridget Trosin, coastal policy specialist for Sea Grant. Bridget told me that she hopes to promote more local events, such as getting people together to share information during extreme high tides.

Sea Grant is sponsoring a King Tide Viewing Party this Friday at Washington Park boat launch in Anacortes, where Bridget will spell out what high tides may look like in the future. Warming refreshments will be provided, according to a news release about the event.

Wherever you live around Puget Sound, you can go down to the water to document the high tide, perhaps starting a new photo gallery to show how high tides change at one location during king tides in the future, as some folks are doing in Port Townsend.

For tips on preparing and posting photos, visit the “Witness King Tides — Washington State” website, then check out the page “Share Your Photos.” To see the locations where photographs have been taken, go to the map page. One can click on locations on the map to see the photographs taken from that spot.

King tides occur when the moon and sun are on the same side of the Earth at a time when the moon comes closest to the Earth. Their combined pull of gravity raises the sea level. The presence of a low-pressure system can raise the tides even higher than predictions published by the National Oceanic and Atmospheric Administration.

Friday’s high tide is predicted to be 13.2 feet in Seattle at 7:55 a.m. We won’t have a tide that high again until January of 2019, according to NOAA. Still, Feb. 2 will see a 13.1-foot tide in Seattle, and tides exceeding 12 feet are predicted for June 16, Nov. 27, Dec. 1, Dec. 10, and daily high tides from Dec. 26 through the end of this year.

Green crabs go wild near Sequim, but experts say control is still possible

Nearly 100 invasive European green crabs were trapped along Dungeness Spit near Sequim this past spring and summer — far more than anywhere else in Puget Sound since the dangerous invaders first showed up last year.

European green crabs started showing up in traps on Dungeness Spit in April.
Photo: Allen Pleus, WDFW

Despite the large number of crabs found in this one location, green crab experts remain undeterred in their effort to trap as many of the crabs as they can. And they still believe it is possible to keep the invasion under control.

“In a lot of ways, this program is functioning much as we had hoped,” said Emily Grason of Washington Sea Grant, who is coordinating volunteers who placed hundreds of traps in more than 50 locations throughout Puget Sound. “We look in places where we think the crabs are most detectable and try to keep the populations from getting too large, so that they are still possible to control.”

After the first green crabs were found on Dungeness Spit in April, the numbers appeared to be tapering off by June, as I described using a graph in Water Ways on June 24. The numbers stayed relatively low, with three caught in July, two in August, three in September and two in October. But they never stopped coming.

The total so far at Dungeness Spit is 96 crabs, and more can be expected when trapping resumes next spring. The good news is that all the crabs caught so far appear to be just one or two years old — suggesting that they likely arrived as free-floating larvae. That doesn’t mean the crabs aren’t mating at Dungeness Spit, but the trapping effort has reduced the population to the point that males and females are probably having a tough time finding each other.

Officials with the U.S. Fish and Wildlife Service, which has taken charge of trapping at Dungeness Spit, will need to decide whether to attempt a complete eradication of the local green crab population, according to Allen Pleus, coordinator of Washington State’s Aquatic Invasive Species Program. That would involve managing a large number of traps until no more crabs are seen. The alternative, he said, would be to manage the crab population with fewer traps and make further decisions down the line.

During one three-day stretch last year, 126 traps were deployed in areas on and near Dungeness Spit, part of the Dungeness National Wildlife Refuge managed by the Fish and Wildlife Service.

Even with the most exhaustive trapping program, there is no guarantee that green crabs won’t be found again, Allen said. The likely source of the crab larvae is an established population of green crabs in Sooke Inlet on Vancouver Island, just across the Strait of Juan de Fuca from Dungeness Spit.

Allen said he is disappointed that crabs continued to be caught on or near Dungeness Spit — mainly in one small area near the connected Graveyard Spit. “But I am very impressed with the dedication of the U.S. Fish and Wildlife Service, which continued to trap throughout the summer,” he said.

While there is no evidence so far that the invading crabs have reproduced at Dungeness Spit, it is possible that mating took place. If so, everyone involved in the green crab effort could face a whole new group of young crabs next year.

I have to admit that I was worried last spring that funding for the essential volunteer effort would run out as officials scrambled to finance the start of trapping season. But the Environmental Protection Agency agreed to fund the project through next year under the Marine and Nearshore Grant Program.

Meanwhile, Allen said he is working with Canadian officials to see what can be done about reducing the population of green crabs in Sooke Inlet, which is likely to remain a source of the invasive crabs coming into Washington state. The Canadians have their own concerns about green crabs, which can severely damage commercial shellfish operations and disrupt critical eelgrass habitats.

“Sooke Inlet is the only known population established in the Salish Sea,” Allen said. “We are working with Canada and setting up meetings this winter to continue our discussions.”

Canadian officials are monitoring for green crabs on their side of the border, but the effort is much less than in Puget Sound. It appears that only limited efforts have been made so far to control the Sooke Inlet population and reduce the amount of invasive crab larvae heading to other areas in the Salish Sea.

Researchers are still investigating the conditions that allow green crab larvae to survive long enough to grow into adult crabs. It appears that larvae move up the coast from California during warm years and particularly during El Niño periods, Emily told me. That may explain why the Puget Sound traps began catching so many crabs the past two summers.

“The signal we are seeing does point to 2015 and ‘16 as being the first arrivals,” she said. “Our working hypothesis is that warm years are spreading larvae.”

That could offer renewed hope for the immediate future, since El Niño is over and we may be going into cooler La Niña conditions next year.

No new crabs have shown up in the San Juan Islands, where Puget Sound’s first green crab was discovered last year. But two more were found about 30 miles away in Padilla Bay, where four crabs were caught last fall.

New areas with green crabs this year are Lagoon Point on Whidbey Island, where two crabs were caught, and Sequim Bay, not far from Dungeness Spit, where one crab was caught.

The latest concern over green crabs is Makah Bay on the outer coast of Washington near the northwest tip of the Olympic Peninsula. In August, a beach walker spotted a single green crab on the Makah Tribe’s reservation and sent a picture to the Puget Sound Crab Team, which confirmed the finding. Tribal officials launched a three-day trapping effort last month and caught 34 crabs — 22 males and 12 females — in 79 traps.

An aggressive trapping effort is being planned by tribal officials for the coming spring. Interested volunteers should contact Adrianne Akmajian, marine ecologist for the Makah Tribe, at marine.ecologist@makah.com

The Makah effort is separate from the Puget Sound Crab Team, which encourages beach goers to learn to identify green crabs by looking at photos on its website. Anyone who believes he or she has found a green crab should leave it in place but send photographs to the crab team at crabteam@uw.edu

Emily said she is most proud of all the people and organizations that have come together as partners to quickly locate the invasive crabs and advance the science around the issue. Such cooperation, she said, makes the impact of the program much greater than it would be otherwise.

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.”

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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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More invasive crabs found; wider search will resume next spring

Padilla Bay, an extensive inlet east of Anacortes in North Puget Sound, could become known as an early stronghold of the invasive European Green crab, a species dreaded for the economic damage it has brought to other regions of the country.

Trapping sites for crabs (gray markers) during this week’s rapid assessment in Padilla Bay. The red markers show locations where invasive European green crabs were found.
Trapping sites for crabs (gray markers) during this week’s rapid assessment in Padilla Bay. Red markers show locations where three more invasive European green crabs were found.
Map: Washington Sea Grant

After one young green crab was found in Padilla Bay on Sept. 19 (Water Ways, Sept. 24), three more crabs were found during an extensive trapping effort this past week. All four crabs were captured at different locations in the bay. These four live crabs followed the finding of a single adult green crab in the San Juan Islands — the first-ever finding of green crabs anywhere in Puget Sound. (Water Ways, Sept. 15).

With these new findings in Padilla Bay, the goal of containing the crabs to one area has become a greater challenge. Emily Grason, who coordinates a volunteer crab-surveillance program for Washington Sea Grant, discusses the difficulty of putting out enough traps to cover the entire bay. Read her report on the fist day of trapping:

“Similar to our trip to San Juan Island, we are conducting extensive trapping in an effort to learn more about whether there are more green crabs in Padilla Bay. One difference, however, is scale. Padilla Bay is massive, and it’s hard to know exactly where to start. On San Juan Island, the muddy habitats where we thought crabs would do well are well-defined, and relatively limited. Padilla Bay, on the other hand, is one giant muddy habitat — well, not all of it, but certainly a huge portion. We could trap for weeks and still not cover all of the suitable habitat!”

In all, 192 traps were set up at 31 sites, covering about 20 miles of shoreline. The crab team was fortunate to work with the expert staff at the Padilla Bay National Estuarine Research Reserve, a group of folks who know the area well and had worked with shoreline owners to get approval for access.

Three of the four green crabs caught in Padilla Bay were young, probably washed into the bay during last winter’s warm currents, Emily said in her wrap-up report of the effort.

“All of the detections of European green crabs occurred on the east portion of the bay,” she wrote. “Though the sites varied somewhat in the type of habitat, all of the crabs were found relatively high on the shore, in high salt marsh pools, or within a few meters of the shore.

The first of four European green crabs found in Padilla Bay. Photo: Padilla Bay Reserve
The first of four European green crabs found in Padilla Bay.
Photo: Padilla Bay National Estuarine Reserve

“Padilla Bay has about 20 miles of shoreline, and, at last count in 2004, there were 143 acres of salt marsh habitat in the bay,” she continued.”These numbers suggest that there are a lot of places European green crabs could live in Padilla Bay, and protecting the bay from this global invader will undoubtedly require a cooperative effort.”

Yesterday, the response team held a conference call to discuss what to do next. Team members agreed that no more intensive trapping would take place this year, Sean McDonald of the University of Washington told me in an email.

Winter is a tough time to catch crabs. Low tides shift from daytime hours to nighttime hours, making trapping more difficult. Meanwhile, crabs tend to lose their appetite during winter months, so they are less likely to go into the traps to get food, experts say.

Researchers, shellfish growers and beach walkers are being asked to stay alert for the green crabs, not only in Padilla Bay but also in nearby Samish and Fidalgo bays.

The Legislature will need to provide funding to continue the citizen science volunteer monitoring program, which provided an early warning that green crabs had invaded Puget Sound. Whether the crabs will survive and in what numbers is something that demands more study and perhaps a major eradication effort.

Meanwhile, Washington Department of Fish and Wildlife would like to expand its overall Aquatic Invasive Species Program with additional efforts to prevent invaders from coming into Puget Sound. For information, check out my story on invasive species in the Encyclopedia of Puget Sound — specifically the section titled “Biofouling still mostly unregulated.”