Asian shore crab discovered by a middle school citizen scientist in Acadia National Park

Molted shell of an Asian shore crab (Hemigrapsus sanguineus)

NPS Photo by Alexa Pezzano

A middle school-aged citizen scientist made a grim, yet significant discovery in an intertidal area near the edge of Little Moose Island in Acadia National Park near Winter Harbor, Maine.

Peter Petraitis, professor emeritus at the University of Pennsylvania, has confirmed that the student's discovery is the molted shell of an Asian shore crab (Hemigrapsus sanguineus), an invasive species from East Asia spreading into North America and Europe. He said the white banding on the legs is characteristic of the species, although the body tends to be darker when it is part of a living creature.

This is believed to be among the first confirmed reports of the opportunistic omnivore within Acadia National Park. A molted shell means the animal that made it was likely still alive, scuttling around the area somewhere.

The discovery occurred on Sept 19, 2019 on a Marine Investigations program that the student was attending during a Schoodic Education Adventure program (SEA) for middle school students in grades 5-9. With continuing support from Friends of Acadia, the park has hosted residential education programming for more than 25 years.