EASTSOUND, WA (MyBellinghamNow.com) – A middle school field trip on the San Juans turned into a real-life science lesson.

The Washington Sea Grant Crab Team said that a group from Orcas Middle School visited Crescent Beach in May for a mock invasive species hunt.

Science teacher Amy Sprenger said that she gave her students two minutes to collect as many crab shells that they could find. One of them returned with a molt that was distinctively different from the rest.

The class later determined it was an invasive European Green Crab shell, which had previously never been detected on Orcas Island.

Washington state Department of Fish and Wildlife was alerted to the discovery and set up hundreds of traps, leading to a live European Green Crab being captured.

The species is destructive to native marine habitats and can decimate other species if they’re not removed. WDFW highly encourages reporting possible sightings on their website for investigation.