The European Green Crab is considered one of the most invasive species in marine environments. This crab species has few natural predators, is aggressive in hunting and consuming prey, and causes damage to seagrass while outcompeting local species for resources. It has been observed to consume juvenile king crabs and salmon and destroy eelgrass habitats crucial for larval fish protection.

Jasmine Maurer, from the Kachemak Bay National Estuarine Research Reserve (KBNERR), explains the potential impacts of the European Green Crab migration as it moves up the coast of the Pacific Northwest and threatens Alaskan ecosystems and economies.

The green crab’s presence in Alaska raises concerns for the state’s multi-billion dollar fisheries industries, particularly salmon, crab, and mariculture operations.

This worldwide invader has already spread to both coasts of North America, South America, Asia, Australia and New Zealand. They were introduced to North America in the 1800s, likely through ballast water on merchant ships, and experts believe it was also similarly transported to the West Coast. Additionally, it may spread through aquaculture operations and ocean currents.

Efforts to combat the invasive crab include increased trapping, data collection for research, and expanded monitoring and outreach. Environmental and Marine Conservation Agencies such call for public assistance in identifying green crabs on local beaches and reporting sightings to relevant authorities. Addressing this issue is a collective responsibility that can lead to a more sustainable and resilient future for the region.

Through this documentary, I hope to raise awareness about the urgent need to control and prevent the spread of this invasive species before it’s too late.

HELP THE FIGHT AGAINST THE EUROPEAN GREEN CRAB

IDENTIFY IT
Look for the 5 spines! According to NOAA Fisheries, the most effective method to recognize a green crab is by counting these spines. You’ll find 5 spines situated behind the eye on both sides of the shell. Additionally, you can refer to the Crab Identification Guide provided by KBNERR.

It’s important to note that green crabs aren’t always green! The upper part of their shell can display a mix of dark brown and dark green, often with small yellow patches. When molting, the lower part of the shell may appear orange or red. The distinctive shape of their shell is another identifying feature. Fully grown shells can reach sizes of up to 4 inches in diameter.

REPORT IT
Capture multiple photos of the crab alongside a coin, key, or any commonly sized object for reference. Share your observations through either the ADF&G Invasive Species Reporter or by contacting the Invasive Species Hotline at (877) INVASIV (877) 468-2748). If you encounter the invasive green crab on Annette Islands Reserve, use the number (907) 886-FISH to file a report.

This video was produced by Marc Sherman for the Kachemak Bay National Estuarine Research Reserve (KBNERR) along with the support of students from UAA’s Journalism and Public Communications program, April 2023.

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