Feature Story                                                                June 2012 

Plate Watch – Volunteer Citizen Scientists Track Introduced Tunicates in Alaska

By Monaca noble and Linda McCann, Smithsonian Environmental Research Center

Volunteers in Alaska are taking action to protect their bays, estuaries, and harbors from introduced species through a Citizen Science Program called Plate Watch. Volunteer monitoring is critical to the early detection of invasive marine species, allowing scientists to monitor in areas they might not otherwise be able to reach. Alaska has thousands of miles of coastline to protect, and so far very few invasive marine species. Each volunteer has the opportunity to collect valuable scientific data used to protect the health of their local environment. Over the last 5 years volunteers have conducted surveys in 20 sites from the south in Prince Rupert, British Columbia to the Aleutians in Unalaska Bay, Dutch Harbor, Alaska to look for introduced species, primarily tunicates.

A settling plate submitted by Plate Watch volunteer David Decker from Bartlett Cove/Glacier Bay, Alaska 2010 covered with barnacles, encrusting bryozoans and a native tunicate, Corella inflata.
There are 30 introduced tunicates in the United States. Many of these introduced tunicates are causing ecological and economic harm. A recent example from the news is the colonial tunicate Didemnum vexillum (D. vex or rock vomit). This species is a major concern in much of its introduced range, including Alaska, where it’s known to completely cover aquaculture nets, shellfish beds, and sensitive marine environments. Another example is the solitary tunicate Ciona intestinalis (sea vase). It can overgrow mussels and aquaculture equipment, causing economic harm to the shellfish aquaculture industry. In San Francisco Bay, CA it was found to outcompete native species for space. 

Volunteers in Alaska are taking action to protect their bays, estuaries, and harbors from introduced species through a Citizen Science Program called Plate Watch. Volunteer monitoring is critical to the early detection of invasive marine species, allowing scientists to monitor in areas they might not otherwise be able to reach. Alaska has thousands of miles of coastline to protect, and so far very few invasive marine species. Each volunteer has the opportunity to collect valuable scientific data used to protect the health of their local environment. Over the last 5 years volunteers have conducted surveys in 20 sites from the south in Prince Rupert, British Columbia to the Aleutians in Unalaska Bay, Dutch Harbor, Alaska to look for introduced species, primarily tunicates.

With direction and equipment provided by the Environmental Research Center’s (SERC) Marine Invasions Research Lab, small groups of volunteers survey the fouling community by setting out passive collectors called settling plates. The fouling community is made up of sessile (attached) organisms, such as tunicates, bryozoans, mussels, tube building worms, and sea anemones, found on the sides of docks, marinas, harbors, boats, and rocky shores. Settling plates are small PVC (polyvinyl chloride) panels that are attached to a brick and hung off the side of a pier or dock. At each site, 10 settling plates are deployed for 3 to 9 months between 1 and 4 times a year. Fouling species attach and grow on the settling plate during the months that the plates are in the water. When the plates are retrieved, volunteers take photographs and record the organisms they find, following a standard set of protocols. All of the volunteers are looking for invasive tunicate species on a 'target taxa' list. If they suspect that a target species has been found, a sample of the organism may be collected and sent to SERC for verification. 

Max Henshaw and Cole Somerville collecting water samples in Pertersburg, AK. Photo by Joni Johnson Petersburg High School.
Joni Johnson, a volunteer and teacher at Petersburg High School in Petersburg, AK, has incorporated invasive species monitoring into her curriculum. Two of her students, Cole Somerville and Max Henshaw, are participating in the Plate Watch project this semester. Joni and her students monitor their plates twice a year, once in the spring (~March) and again in the fall (~September) in North, South and Middle Harbors. Cole and Max have learned a lot about introduced species and tunicates during the course of this project. They’ve had a good mentor, Jeff Meucc from the Alaska Department of Fish and Game who has provided a lot of inspiration with his underwater video of D. vex in Sitka Harbor. Max says “it’s amazing that something that small can spread so fast and cause that much damage”. So far much of what they have seen on the plates is brown algae and barnacles, hardly the excitement that a new discovery brings but still important information for scientists.

If you’d like to join our Alaska Plate Watch volunteers, sign-up for our training workshop July 7-8, 2012 at the University of Alaska in Ketchikan. The workshop is free and open to current volunteers and interested citizens, but space is limited so register now online. More information on Plate Watch and the workshop can also be found on our website.