Tag Archives: Crab Team

New facts and findings about the European green crab invasion

The ongoing story of the European green crab invasion offers us scientific, social and even psychological drama, which I would like to update by mentioning four new developments:

  1. The somewhat mysterious finding of a partially eaten green crab on the Bellingham waterfront,
  2. A “story map” that spells out much of what we know about European green crabs in Puget Sound, including maps, photos and videos.
  3. Information about Harper Estuary in South Kitsap and other areas where groups of citizen scientists are on the lookout for green crabs, and
  4. Reports of a new breed of European green crab in Maine that attacks people and may prove to be more destructive than the green crabs that have lived in the area for a very long time.
Green crab found in Bellingham

Since my last report on green crabs (Water Ways, May 9), a partially eaten carcass of an invasive crab was spotted along the Bellingham waterfront in Squalicum Harbor, where the crab was being eaten by a seagull.

Partially eaten European green crab found on the Bellingham waterfront
Photo: Angela Foster/WDFW

The big question, which might never be answered, is where did this crab come from? If it grew up locally, it would be the first sign of a green crab anywhere in Whatcom County. Since 2016, a trapping program designed specifically to catch green crabs — including two monitoring stations near Bellingham — has turned up no green crabs in the area.

The seagull could have caught the crab from the bay or nearby shorelines, or sport or commercial crab harvesters could have dumped the crab from their pots, according to Emily Grason, who manages the Crab Team volunteer trapping effort for Washington Sea Grant.

Casey Pruett, director of Marine Life Center in Bellingham, spotted the gull eating the crab at the boat ramp adjacent to the center in the busy Squalicum Harbor marina, Emily noted. Casey told her that green crabs have never been reported in crab pots in the harbor nor along the shoreline.

Marinas are often home to large Dungeness and rock crabs, which are good competitors and even predators of green crab, Emily wrote in the Crab Team Blog.

“In our region, green crab tend to do best in very muddy isolated habitats, such as saltwater lagoons, pocket estuaries and salt marshes,” she wrote. “If green crab become abundant enough elsewhere, however, some population spillover could occur into habitats like marinas where they have lower survivorship.”

The hunt for European green crabs throughout Puget Sound is meant to provide an early warning to hold the population in check wherever the invaders first show up. On the East Coast, where the crabs have become established, they have been known to eat large numbers of shellfish and destroy important habitat, such as eelgrass beds.

The single partially eaten crab in Bellingham has set off cautionary alarm bells, but since the discovery at the end of May, the monitoring traps have captured no other green crabs. Washington Department of Fish and Wildlife is planning a more extensive trapping effort next month, Emily told me.

Meanwhile, 44 green crabs have been trapped so far this season along Dungeness Bay near Sequim, which has turned out to be a hotbed of invaders. That number is fairly close to what was seen during the same time period the past two years, so we can hope that the population is not expanding. Another single crab was trapped in nearby Sequim Bay, but a more extensive trapping effort turned up no additional green crabs.

Green crab “story map”

In a new “story map” produced in a collaboration between Puget Sound Institute and Washington Sea Grant, the viewer is able to scroll through text, maps and video that explains what researchers know about the European green crab invasion.

An entertaining and instructive video from 2016 recounts the first sighting of a green crab in Puget Sound, following years of trapping that thankfully never caught a green crab. The video was produced by Katie Campbell of EarthFix, a partnership of public radio and television stations in the Northwest. A second video, produced in 2017 by the College of the Environment at the University of Washington, updates the story with images from Dungeness Spit.

The expansion of the green crab population is mapped on a worldwide,
West Coast and Puget Sound scale. The impacts of the crab and efforts to keep the population under control are described in the story map, along with a practical outlook for long-term success.

The production can be launched from this page. Be sure to click on the full-screen option. The project is housed on the UW’s ArcGIS online portal, where one can find other interesting projects.

Credit for the design of the story map goes to Kris Symer of Puget Sound Institute. Emily Grason provided scientific expertise and editing of the material.

Harper Estuary crab hunt

In many areas of Puget Sound, community volunteers get together regularly to participate in a ongoing hunt for green crabs in their local waters, a hunt they hope will not be successful. I first wrote about the Crab Team in 2016 for the Encyclopedia of Puget Sound. Coincidentally, my story, which featured volunteers at Zelatched Point on Hood Canal, was published just a month before the first green crab in Puget Sound was found in the San Juan Islands.

Earlier this year, I joined another team of volunteer scientists on Fidalgo Bay, where a single shell of a green crab was found last year. The story, also published in the Encyclopedia of Puget Sound, was mostly about the state’s aquatic reserves and how citizen scientists play a key role in studying the environmentally valuable areas. On the outing, I was able to see how the volunteers measured the spawning success of surf smelt in the bay.

One thing I noticed in these and other citizen-science excursions is a high level of camaraderie among the folks working together, learning together, sharing laughs and enjoying nature. For those interested in science, there are plenty of opportunities in the Puget Sound region.

Restoration of Harper Estuary: Phase 1 restores the shoreline. Phase 2 is a future bridge to replace a portion of the causeway at #6. // Graphic converted from Kitsap County poster

I’m hoping to compile a list of all the citizen science projects taking place throughout Puget Sound. If you are involved in a group that could use more members, please send me a link to the program’s website or the email address of an organizer. I will try to keep the list updated for those who would like to join a group. It would be great if such a list already existed, but I have not found one with good contact information. One can search on the internet for the term “citizen science, Puget Sound” or a more specific location.

Meanwhile, Jeff Adams of Washington Sea Grant has posted a nice description of South Kitsap’s Harper Estuary, which is undergoing a major shoreline restoration. Community members are monitoring for marine life, including shoreline vegetation. Green crabs have not been found so far, but more than 5,000 hairy shore crabs were caught in traps there during the first two seasons, as shown in the graphic accompanying Jeff’s blog post.

I’ve written about Harper Estuary on several occasions, but I was intrigued by several bits of history from Jeff that I had never heard before.

For general information about joining the Crab Team or looking for green crabs on your own, check out “Get involved with Crab Team” on the Crab Team website.

Aggressive invaders in Maine

I’m waiting for someone to write a horror story about a new breed of aggressive European green crab that would rather attack people than run from them.

David Sharp, a reporter for the Associated Press, wrote about these new arrivals under the headline: “Canadian crabs with bad attitude threaten coastal ecosystem.”

The story tells us about an aggressive European green crab that has migrated to Maine form Nova Scotia in Canada.

“What we’re seeing is this insane level of aggressiveness,” said Markus Frederich, a professor at the University of New England who is studying the new invaders.

“Anytime I went down to grab one, they went to grab me instead,” he was quoted as saying. “They are the most aggressive crabs ever seen. We don’t understand yet why they are so aggressive.”

Frederich worries that the crabs may be more destructive than the green crabs that were introduced to the U.S. East Coast 200 years ago. “The crabs have a high potential for destroying soft-shell clams, eelgrass beds and who knows what else,” he said.

In a head-to-head test, subject crabs of both varieties were placed in an eelgrass bed. The Canadian invaders “shredded the eelgrass like Edward Scissorhands in their efforts to scarf down marine organisms seeking refuge,” Sharp wrote in his story.

The two strains of green crab are believed to originate from different parts of Europe, arriving at different times and in different parts of North America. One theory is that the aggression is gene-related, perhaps a result of hybridization of the two varieties of the same species.

The first green crab was discovered in Long Island Sound in 1817, according to Emily Grason, who provided some background information in response to questions from Crab Team members curious about the aggressive crabs. They wanted to know if we should be worried about them in the Pacific Northwest.

Once the invasion started, the population spread mostly northward along the East Coast, with southward movements apparently limited by warm temperatures and native blue crabs, she said.

The second strain of crabs arrived in the 1980s. Genetic evidence suggests it came from a more northern region of Europe and established themselves in a more northern part of the East Coast. Though some news stories have mentioned “mutant” crabs, Emily says the two types of European green crabs are simply distinct “haplotypes” of the same species, because they remained genetically isolated from each other.

Studies linking behavior to genetics is underway in Frederich’s lab at the University of New England. He has even placed green crabs on a treadmill, but results of his work have not yet been published. As a result, we don’t know what temperature range and other habitat conditions are favorable to the northern variety. Review the UNE news release.

If interstate and international shipping companies are careful about their practices involving invasive species — such as treating ballast water in ships — we might not see a second wave of green crabs on the West Coast.

Can volunteer trappers halt the green crab invasion in Puget Sound?

The war against the invasive European green crab continues in Puget Sound, as this year’s Legislature offers financial support, while the Puget Sound Crab Team responds to crabs being caught for the first time in Samish Bay in North Puget Sound and at Kala Point near Port Townsend.

In other parts of the country where green crabs have become established, the invaders have destroyed native shoreline habitat, diminished native species and cost shellfish growers millions of dollars in damages. See Environmental Protection Agency report (PDF 1.3 mb).

European green crab trapping sites in Puget Sound.
Map: Washington Sea Grant

In Puget Sound, it’s hard to know whether the crabs are being trapped and removed rapidly enough to defeat the invasion, but so far humans seem to be holding their own, according to Emily Grason, who manages the Crab Team volunteer trapping effort for Washington Sea Grant.

“The numbers are still in line with what we saw the past two years,” Emily told me. “Since the numbers have not exploded, to me that is quite a victory. In other parts of the world, they have been known to increase exponentially.”

The largely volunteer Crab Team program is focused on placing baited traps at 56 sites in Puget Sound, as shown in the first map on this page. About 220 trained volunteers are involved in that work, with various federal, state and tribal agencies adding about 40 additional people.

Last year, 69 78 crabs were caught in the traps. All but eight of those were on or near Dungeness Spit, where officials with the U.S. Fish and Wildlife Service have increased their trapping in an effort to catch every crab willing to crawl into a trap. The agency manages the Dungeness National Wildlife Refuge.

In Samish Bay, east of the San Juan Islands in North Puget Sound, three green crabs — including a female bearing eggs — were captured in January while shellfish growers were tending to shellfish beds in the bay. This was the first time that green crabs have been caught in the winter, when they usually move offshore, according to Emily. For that reason, the overall trapping program begins in April and ends in September. But far out on the mudflats, during a low tide, the crabs might be found by those working the shellfish beds. See Emily’s Crab Team blog post from Jan. 23.

Staffers at Padilla Bay National Estuarine Research Reserve added a fifth trapping site in an extremely muddy area of Samish Bay, an area that would be tough for volunteers to monitor, Emily said.

A new Port Gamble site was added in an effort to detect any crabs that may have arrived during their larval stage and begun to grow. Port Gamble on the Kitsap Peninsula is considered to be in the proximity of Kala Point near Port Townsend, where a single green crab was found in September, just before the end of the trapping season. Further extensive trapping located another green crab in nearby Scow Bay between Indian and Marrowstone islands. See Emily’s Crab Team blog post from Sept. 25.

The monitoring at Point Julia in Port Gamble Bay will be managed by the Port Gamble S’Klallam Tribe, which may propose additional sites in the area.

Based on research since the Crab Team was formed in 2015, more crabs are caught in May than any other month, Emily told me, so everyone is waiting to see what shows up this month. As the waters warm and the crabs go out in search of food, they may become more vulnerable to trapping. So far this spring, 16 green crabs have been trapped along Dungeness Spit with one from nearby Sequim Bay.

Another big trapping month comes in August, before the crabs move offshore, she said.

The trapping effort is geared to catching as many crabs as possible at a young age, because a large population of breeding adults in any location could threaten to spread the infestation throughout Puget Sound. Having Crab Team volunteers putting out their traps in strategic locations increases the probability that green crabs will be found before they get established. If needed, larger eradication or control efforts can be launched with the help of other agencies.

As part of the effort, the Washington Department of Fish and Wildlife added a staffer last year to do spot checking in vulnerable areas not regularly trapped. That increases the chances of detecting an invasion.

For the first time this year, the Legislature funded the Crab Team’s operating budget, which allows Emily and other Crab Team leaders to focus on finding crabs, rather than spending their time searching for funding to keep the program going.

The hope, of course, is that fewer crabs will be caught this year, as an indication that the population is being held in check. It would be nice to think that all the major infestations have been found.

“We hope that this is going to be an easier year,” Emily said, “but we don’t get to determine that. We have to be responsive to whatever happens.”

Officials working along the Washington Coast, led by the Makah Tribe, have their hands full with an invasion that may have started as early as 2014 and has resulted in more than 1,000 green crabs being caught. Check out the story on the website of the Northwest Indian Fisheries Commission.

The interactive map below allows for selection of trapping sites, locations where crabs have been found and areas with suitable habitat for invaders. For those who would like to get involved in the Crab Team’s efforts, check out Sea Grant’s website and the “Get Involved” page.

This blog post was revised from an earlier version to correct changes in the total number of green crabs found last year and to clarify the overall effort.

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
  • Continue reading

New bridges provide improved habitat in two Kitsap County creeks

Contractors are putting the final touches on two new bridges in Kitsap County, both of which are expected to improve the local environment.

A new bridge over the Carpenter Creek Estuary near Kingston helps to restore the upper salt marsh.
Photo; Stillwaters Environmental Center

One is a 150-foot bridge that crosses the Carpenter Creek Estuary on West Kingston Road near Kingston. The other is a 50-foot bridge that crosses Big Anderson Creek on Seabeck-Holly Road near Holly.

Among local residents, the Carpenter Creek bridge may best be known as the bridge that blocked traffic and forced a detour near Kingston for more than a year — much longer than originally planned. (Recall reporter Nathan Pilling’s story in the Kitsap Sun.) While contract issues remain in dispute, the environmental benefits are clear, according to Joleen Palmer of the nearby Stillwaters Environmental Center.

Continue reading

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.”

Continue reading

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.

Continue reading