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PHOTOS: 91ƵOne of worst91Ƶ invasive crustaceans found on Lower Mainland shoreline

Management of European Green Crab a long-term project: biologist

An invasive crustacean described as one of the world91Ƶs top-10 unwanted species has made its way to Blackie Spit in South Surrey 91Ƶ as well as other nearby marine habitats 91Ƶ and efforts are underway to curtail its spread.

The European Green Crab 91Ƶwill eat anything that fits in its mouth,91Ƶ Lori Schlechtleitner 91Ƶ a biologist/ecologist contracted by Friends of Semiahmoo Bay Society to set up a local management program 91Ƶ said Sept. 25, during field work in Blackie Spit.

And that non-discriminating palate, along with a high resiliency to water temperatures and salinity and a distinct lack of predators to keep them in check, is bad news for native species.

91ƵYou91Ƶve got to respect it for being so incredibly adaptive,91Ƶ Schlechtleitner said of the spiny crab. 91ƵBut it does have the potential to decimate.91Ƶ

The crab, which can range in colour from dark mottled green to orange, is native to European and North African coastlines, and was first found in Canadian waters in 1951. It91Ƶs believed they arrived in B.C. between 1998 and 1999.

They are currently found along the entire west coast of Vancouver Island, and have an established population at the southern tip, in Sooke.

Lori Schlechtleitner (left) watches as volunteers check what was caught in the traps that were set Sept. 25. (Contributed photo)
Lori Schlechtleitner (left) watches as volunteers check what was caught in the traps that were set Sept. 25. (Contributed photo)

Schlechtleitner said a survey in early September just south of the border found 145 of the invasive crabs, while officials with DFO found 91Ƶjust one or two91Ƶ in Blackie Spit both last year and last month. She said the reason behind the discrepancy between the two sets of numbers is unclear.

What is clear is that their presence is a problem that can91Ƶt be ignored. They have done substantial damage on Canada91Ƶs East Coast, she said. Left unchecked here, they will predate everything from oysters to juvenile crabs to eelgrass beds 91Ƶ a critical home for juvenile salmon 91Ƶ and alter the local shoreline ecosystem and habitats.

91ƵOn the Pacific Coast, they will brood up and eat the eelgrass beds, which is why we91Ƶre really concerned,91Ƶ Schlechtleitner said.

91ƵOnce they start to take a leghold, that91Ƶs when the ecosystem might not, unfortunately, make it back.91Ƶ

Schlechtleitner and volunteer Dave Shorter91Ƶs mission on Sept. 25 was to set a dozen traps in two channels that run through Blackie Spit91Ƶs protected salt marsh. Baited with cat food and staked 10 metres apart, they were left overnight to see if any of the unwelcome, trapezoid-shaped creatures were present. None were found, Schlechtleitner told Peace Arch News in an emailed update on Sept. 30.

The results were the same for traps set in the Little Campbell River estuary, on Semiahmoo First Nation land, the week prior, as well as for traps set off the base of 64 Avenue on Sept. 29. More traps were set at Delta91Ƶs Centennial Beach on Sept. 30.

Dave Shorter and Lori Schlechtleitner prepare bait and tags for traps in Blackie Spit on Sept. 25 as part of the Invasive European Green Crab project. (Tracy Holmes photo)
Dave Shorter and Lori Schlechtleitner prepare bait and tags for traps in Blackie Spit on Sept. 25 as part of the Invasive European Green Crab project. (Tracy Holmes photo)

The four locations were identified by DFO as priority management sites and will remain under close eye 91Ƶfor the foreseeable future,91Ƶ Schlechtleitner said.

Schlechtleitner, who lives in Vancouver but grew up in Surrey, said for her, the effort is 91Ƶa passion project.91Ƶ It91Ƶs hoped that community groups will get involved, perhaps by adopting channels to monitor, or walking wrack lines 91Ƶ the line of debris left on the beach by high tide 91Ƶ after trapping season is over, to look for molts on the beaches.

91ƵThis is going to be a long-term management process,91Ƶ Schlechtleitner said.

Friends of Semiahmoo Bay Society has committed to the project for the long-term, society president Margaret Cuthbert noted.

Lori Schlechtleitner and Dave Shorter carry trapping equipment towards the Blackie Spit salt marsh. (Tracy Holmes photo)
Lori Schlechtleitner and Dave Shorter carry trapping equipment towards the Blackie Spit salt marsh. (Tracy Holmes photo)

91ƵSince we have mapped 86 hectares of eelgrass in Boundary Bay and conducted the DFO 3-5 year Shorekeepers (program) for over 15 years, our Marine Coordinator Matt Christensen and our Board of Directors agree we must now focus our volunteer activities and funds to this crucial concern,91Ƶ Cuthbert told PAN by email.

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The City of White Rock has contributed funding to the effort, Schlechtleitner noted, but more is needed.

The ultimate goal, she said, is for the management efforts to reap only native-species results.

91ƵThat91Ƶs the goal of this project, is to not find what we91Ƶre looking for.91Ƶ

Volunteers return to Blackie Spit Sept. 26 to check what was caught. (Contributed photo)
Volunteers return to Blackie Spit Sept. 26 to check what was caught. (Contributed photo)

Anyone who spots one of the crabs 91Ƶ they measure up to 10 cm across the back shell, and have three bumps between the eyes as well as five 91Ƶspines91Ƶ to the outside of each eye 91Ƶ is asked to leave it where it is, but email a photo and details of its exact location (ideally, GPS co-ordinates) and the date it was observed to aispacific@dfo-mpo.gc.ca



tholmes@peacearchnews.com

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Tracy Holmes

About the Author: Tracy Holmes

Tracy Holmes has been a reporter with Peace Arch News since 1997.
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