Unalaska is getting ready to begin the process of monitoring European green crabs. This is after the invading species first was first discovered in Alaska in month in July.
The crabs can cause major issue. They can destroy habitats and compete with the native animals.
Biologists from The Alaska Department of Fish and Game explain that this monitoring system is essential for the country’s biggest ports for fishing. They’re planning to set traps in the coming summer.
“We do not have any reason to think that European green crab are in the area or have established themselves in the region However, we’re not yet conducting any surveillance,” said Ethan Nichols who is the assistant manager of shellfish at ADF&G within Dutch Harbor. “With European green crab steadily moving towards through the West Coast, through British Columbia and finally into the southern part of Southeast Alaska as of last year, I believe it’s imperative that we begin monitoring in Dutch Harbor. Port of Dutch Harbor, due to the volume of international vessel traffic we experience.”
In the majority in the entire state researchers have been keeping an eye on the species for a long time. In the communities surrounding Kachemak Bay and Prince William Sound They’ve been putting up traps for more than two decades.
Tammy Davis is the invasive species coordinator for Tammy Davis, the invasive species program coordinator with Department of Fish and Game in Juneau. She explains European green crabswhich are that are native to the coast of Europe as well as North Africa, and were introduced to the Atlantic coast by ballast water as early as the 1800s They are very alarming because, although they’re small, they’re extremely destructive.
They decrease the amount of eelgrass (important nursery area for young fish) as well as the population of oysters, clams, Mollusks, and other invertebrates that are found on or within the seafloor. They also prey on native crabs that are juvenile, such as Dungeness which could have a negative impact on Aleutian Island fisheries down the time, particularly if their habitats cross.
“Green crabs are regarded as to be among the top 100 species of invasiveness worldwide,” Davis said.
As with all other places, Davis said, they will have impacts on the environment near shore which could put species that depend on the subtidal or intertidal area at risk.
“They react differently depending on conditions,” she said. “There’s obviously certain general reproductive triggers at temperatures and tolerance to temperatures and so on. However, they’re extremely robust organisms We don’t know what the possible impacts could be in a situation similar to Dutch Harbor at this point.”
Davis added that biologists are concerned that the species may get introduced to Dutch Harbor through ballast water discharge, or through currents that transport larvae from through the Aleutian Chain.
She stated that they plan to find coastal areas that have significant commercial, recreational and subsistence harvests. They will then use trapping intensively as a method to control and monitor the green crab populations as they begin to expand across the state.
The traps are also helpful to know what species are using these areas and is susceptible to green crab predation according to Davis.
“Whatever is caught in our traps also makes use of this portion in the area of nearshore. They are the species in danger from the green crabs,” she said.
Davis admitted that, while it’s likely that they’ll remove green crabs in the event that they are established in the Aleutians the early detection of them is vital.
“You’re keeping the population of green crabs at a level that their negative impact on native species as well as the habitat they inhabit is not more than native species is able to handle,” she said.
ADF&G is planning to begin the monitoring program for the Port of Dutch Harbor this summer. Five traps are being shipped to the island today.
If you find what you think might be a European green crab, you can call ADF&G’s invasive species hotline at 1-877-INVASIV or visit their website.
