June 10, 2024

Are you one of the millions of Washington residents living on or near the Salish Sea? Join the Salish Sea-wide Molt Blitz on June 20 to contribute to the largest-ever single-day dataset of crab molts collected in our state.

Invasive European green crab (Carcinus maenas). Photo by P. Sean McDonald.

Molts are the old shells crabs shed when they grow. Collecting and recording these molts provides valuable data on which species of crab are present in an area, including invasive European green crab (Carcinus maenas). The emerging invasion of green crab into Washington’s waters threatens marine resources. Early detection of small populations of green crab gives us the best chance to reduce the spread and impact of this globally damaging invasive species. Molt surveys also provide insight into native species of crab like Dungeness. For example, molts can help shed light on Dungeness crabs’ juvenile stage, an understudied period when the crab relies on many of the same habitats that green crab threaten.

In 2023, Washington Sea Grant and Washington State University Extension teamed up with local organizations around the state to launch Molt Search, giving local communities the ability to monitor their local shorelines so that new invasive green crab spread can be noticed quickly and responded to urgently. Community members can monitor local shorelines by performing systematic, timed searches for molts according to Molt Search protocols and submitting findings via the MyCoast smartphone app or website (mycoast.org/wa/crab).

You can help create the largest single-day dataset of crab molts by submitting a Molt Search report from your local shoreline on June 20. Not sure how? Attend one of many trainings offered in-person and online this month, or, on Blitz day, join a Molt Search trainer on a beach near you. All trainings and events associated with the June 20 Molt Blitz are listed at wsg.washington.edu/moltsearch. Happy searching!

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Washington Sea Grant, based at the University of Washington, helps people and marine life thrive through research, technical expertise and education supporting the responsible use and conservation of coastal ecosystems. The National Sea Grant College Program is part of the National Oceanic and Atmospheric Administration, U.S. Department of Commerce.
www.wsg.uw.edu.

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