Citizen BioBlitz Uncovers Unwanted Alaskan Guest

Using an NSF-funded facility, a research team has discovered a new invader off the Alaskan coast: the filter feeder Didemnum vexillum. Commonly referred to as a sea squirt, this rapid reproducer takes over habitats by smothering native species. The discovery was made during a citizen bioblitz in which the researchers engaged volunteers to systematically search for the non-native species.

Didemnum vexillum threatens one of the most pristine, yet little investigated areas of American coastline. The researchers' discovery represents a 1000 km northward journey for the sea squirt. By crowding out Alaskan flora and fauna, the species may disrupt the food web that sustains critical US fisheries. Knowing the location of sea squirt colonies allows researchers to develop ways to eradicate them.

The invertebrate's cryptic structure has made identification challenging over the last 15 years. In this study, researchers at the Romberg Tiburon Center of San Francisco State University used the NSF Field Stations and Marine Laboratories-funded DNA analysis facility to definitively identify specimens from Alaska and other global locations, providing information on possible source locations as well as species identification. Investigators from San Francisco State University, the Smithsonian, the National Oceanographic and Atmospheric Administration, Alaska Fish and Game partnering with the Sitka Tribe of Alaska, the University of Alaska Southeast, the Sitka Sound Science Center and many volunteers made the discovery possible. The findings show the key role a citizen bioblitz can play in identifying invasive species.