June 1, 2011
Aliens in the Gulf of Maine
by Sarah Paquette, Dr. Heather Deese, and Catherine Schmitt
Do you know where the creatures you find on the beach come from? Many of them don't have origins in the Gulf of Maine, but have flourished here since they were introduced from other seas around the world. These invasive, or alien species, affect the native plants and animals and their local environments. In recent years, monitoring efforts have intensified to identify the intruders and to educate people on the dangers of introducing non-native plants and animals into our waters.
Take, for example, Didemnum vexillum. A type of colony-forming animal also known as sea squirts, Didemnum forms mats on rocks, piers and other hard surfaces. It is thought that Didemnum was introduced to Maine in the early 1970s and has been spreading ever since. Codium fragile is another invader believed to have found its way to the Gulf of Maine around the same time. This green seaweed, also known as oyster snatcher, is originally from Asia, but has been a very successful invader throughout the Gulf. There are many other non-native plants and animals in our waters that have unknown origins, and many more that have yet to be documented.
The way most non-native species are introduced is through ballast water from ships traveling between the United States and Europe. When ships take in ballast water for stabilization, they also take in sediments and any organisms that happen to be living in them. These invaders are introduced to new areas when ships let out their ballast. Regulations for ballast water have been in place since 1996 and are enforced by the U.S. Coast Guard under the National Invasive Species Act and by Transport Canada under the Canada Shipping Act.
Another, very different, but equally harmful way invasive species travel is on shellfish shipped for aquaculture. Shellfish provide a hard surface for seaweed and animals to attach to, and once the shellfish are in aquaculture pens, it is not difficult for hitchhikers to spread to native animals. While these invaders aren't typically brought to new homes intentionally, there are some cases where they are. Many people order live fish from international markets, either for pets or for consumption, and then release them back into the ocean, believing they are saving the animal. In reality, they may be harming the ecosystem already in place.
Vital Signs, a program of the Gulf of Maine Research Institute, works with schools, informal educators, watershed groups, the public and scientists to collect observations of invasive terrestrial and marine plants and animals. Citizen scientists and students collect data for scientists to use. "Vital Signs gives students a chance to learn science by doing science," said program manager Sarah Kirn. Because the students are generating data that are useful to scientists, they begin to "understand the value of data," according to Kirn.
Vital Signs has an interactive website that provides identification keys, instructions for looking for invasive plants and animals, and a database full of observations of invasive creatures that have been spotted throughout Maine. Citizen scientists can upload pictures and information about the animals or plants they discover to the website and have their findings verified by a Vital Signs expert reviewer and posted on the site. "We are working to have every species posted connected to a species expert," explained Kirn. Each species expert-a scientist interested in the distribution of a particular species-receives instant notification when new information about his or her species is posted, making it easy for the expert to see where in Maine this plant or animal is appearing.
In 2010 the Massachusetts Institute of Technology (MIT) Sea Grant college program conducted a rapid assessment survey in the Northeast in 20 locations from Rhode Island to Maine. Volunteers and taxonomic experts found a total of 29 invasive plants and animals and two new species-Heterosiphonia japonica, a seaweed, and Palaemon elegans, a rockpool shrimp native from South Africa to Norway. "Our goals are to identify the species and use this information to inform the public about species that are present and how to prevent new invasions," said Judy Pederson, MIT Sea Grant Advisory Leader and Regional Project Coordinator.
Efforts to identify aliens in the Gulf of Maine have certainly increased in recent years, but for now, there seems to be little that can be done to eliminate invaders. Our best bet is to stay informed and be conscious of activities in the Gulf that may help prevent new invasions from occurring. In Maine, there are several agencies doing just that. The Maine Department of Marine Resources and the Maine Department of Environmental Protection (DEP) both conduct surveys to keep track of invasive plants and animals present in the Gulf of Maine, and work to raise awareness of ways to prevent new invasions. The DEP conducts their programs in freshwater, but are looking for ways to expand their work to marine environments.
Since 2002, Maine's Action Plan for Managing Invasive Aquatic Species has been raising awareness and understanding of the ecology and impacts of introduced creatures. The plan includes U.S. Coast Guard and other groups working on ways to control ballast water, to find new packing materials for shipping live animals to prevent seaweed that might be traveling with them from making a home in a new environment, and to compose a list of companies and organizations that transport and trade non-native creatures. The Marine Invasive Species Working Group, composed of representatives from groups across the state, is also finding opportunities for education, research, monitoring and management programs.
This article is made possible in part by funds from Maine Sea Grant.
Sarah Paquette is the Maine Lobstermen's Association industry communications assistant and is a 2010 graduate of Maine Maritime Academy where she received her B.S. in Marine Biology. Heather Deese holds a doctorate in oceanography and is the Island Institute's director of marine programs. Catherine Schmitt is communications coordinator for Maine Sea Grant.
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