NOAA Working With Environmental DNA Samples To Combat Invasive Crabs
Really interesting piece from NOAA Fisheries Alaska on a rather pesky species invasive of crab that’s a bit of a pest in waters not far from Alaska. Here’s more on the study involving European green crabs:
Natural resource managers in British Columbia discovered several adult male and female European green crabs on Haida Gwaii this past July. Alarm bells immediately went off for biologists in Alaska.
The archipelago of Haida Gwaii, off the coast of Prince Rupert in British Columbia, is very close to Alaska. The July discovery is the closest confirmed finding of the invasive crustacean since it was first detected in the San Francisco Bay area in 1989.
European green crabs were first introduced to North America in the 1800s, likely hitching a ride in the ballast water of merchant ships from Europe. Experts believe the invasive crab was transported to the West Coast in ballast water as well.
The green crab is considered one of the most invasive species in the marine environment. It has few predators, aggressively hunts and eats its prey, destroys seagrass, and outcompetes local species for food and habitat. It has been documented that European green crab devour juvenile king crab as well as juvenile salmon. They also destroy eelgrass habitat that larval fish use to hide from predators, and outcompete Dungeness crabs for food and habitat. The European green crab could potentially damage Alaska’s multi-billion dollar fisheries, especially for salmon, crab, and mariculture operations. Resource managers in Alaska have been keeping an eye on the invasive crab’s northward movement for years. …
Shaw and Alaska Sea Grant Fellow Meredith Pochardt wanted to use a powerful tool called environmental DNA, or eDNA, to detect the possible presence of the European green crab in Alaskan waters. Deoxyribonucleic acid (DNA) is the molecule that contains the genetic code of organisms. The cellular material shed by organisms into the environment is eDNA. They would collect seawater from various locations around Alaska and test it for European green crab genetic material. This data would allow scientists to detect if the invasive species has moved into Alaska’s waters.
Shaw and Pochardt facilitated several meetings in the spring to plan for an eDNA European green crab monitoring project that would occur during the summer. They coordinated with invasive species researchers from Washington State and British Columbia on a monitoring design for trapping combined with eDNA water sampling.
The full piece is worth a read.