Science Cafe: European green crabs, an invasive species

Another invasive species threatens Washington’s shores: Washington’s diverse and productive salt marshes and pocket estuaries, already threatened by shoreline development and pollution, now face another potential invader, the European green crab. Learn about this invasive threat at a free talk on Tuesday, June 14, from 7:00 – 8:00 p.m. at Orca Books, 509 E 4th Avenue. Guest speaker from the University of Washington, Emily Grason, Ph.D candidate will discuss the life history of the European green crab, how to identify them and the potential threats to Washington's coastal habitats.

Our April Topic Is: Another threat to Washington’s shores: Green Crab Science Café Awareness

The European green crab (Carcinus maenas), considered one of the world’s worst invasive species, is poised to enter Washington’s inland shoreline ecosystems.  Washington Sea Grant, Washington Department of Fish & Wildlife, and partners at the University of Washington have joined to launch Crab Team, a volunteer-based early detection and monitoring program to improve the understanding of native salt marsh and pocket estuary organisms, and how they could be affected by green crabs. 

Due to strong, warm ocean currents the European green crab has been established along the coastline of Oregon, Washington, and Vancouver Island. In 2012, a population of green crabs was discovered in Sooke Inlet, west of Victoria. Favorable conditions mean that the robust population of green crabs in Sooke could send the floating larvae our way negatively affecting native habitats and species.

Biologists and trained volunteers are monitoring beaches for the early detection of green crab when it is easiest to eradicate or control populations. How can you help? Everyone can help in the effort to spot European green crabs. On your next beach walk, pay close attention to the crab shells you find washed up on the beach. Most invasions are detected from the shed crab shells rather than live individuals. The best way to identify European green crabs is that they have 5 spines on the back shell to the outside of each eye. Color is not an accurate way to identify the crab as its color varies and can be mistaken for several of our native “green” colored crab species. To learn more about the threat of invasion, how to identify green crabs and a link to the reporting form, visit the Crab Team website:   

To register for this workshop, visit and click on “register” . Drop ins welcome!

Unable to attend? Learn how to identify green crabs and where to report sightings at the Crab Team website:



Event date: 
Tuesday, June 14, 2016 - 7:00pm
Event address: 
509 E 4th Ave
Olympia, WA 98501
Event Terms: