MARSHALL - The Minnesota Department of Natural Resources Statewide Aquatic Invasive Species (AIS) Advisory Committee has released its annual report for 2013, detailing the environmental and economic threats posed by AIS along with recommendations for dealing with them.
Invasive species are defined as species not native to the region that do harm to the environment.
"Typically, most of them are Asian or European," said Ann Pierce, invasive species unit supervisor for the DNR. "They arrive in a variety of ways, depending on the species. Some in ballast water of ships, some in trade material."
In Minnesota, fishing alone supports 43,000 jobs. Outdoor recreation is a $4 billion a year industry and an important part of the tax base.
According to the report, aquatic invasive species, which have been identified in Minnesota, include aquatic plants such as curly leaf pondweed, flowering rush, round goby and Eurasian watermilfoil.
Aquatic invasive animal species include zebra and quagga mussels, spiny waterflea, rusty crayfish, silver carp and faucet snail.
"Zebra mussels come in through the Great Lakes via the St. Lawrence Seaway and up the Mississippi River," Pierce said.
Invasive plant species tend to grow explosively and choke lakes, such as the curly leaf pondweed infestation of Lake Benton, now under control after a few years of treatment.
Zebra and quagga mussels are filter feeders, which remove plankton that would otherwise feed fish fry.
"The small fry that rely on phytoplankton starve, and the starvation moves up the food chain," said Robert Olsen, Lincoln County environmental director and chairman of the AIS Advisory Committee.
Zebra mussels can cling to virtually any surface and reproduce rapidly. The shells wash up on beaches in large numbers and are sharp.
Once an AIS is established in an inland lake, the route of transmission is thought to be largely through recreational boats, in the bilges and live wells, or clinging to water plants stuck on the boat or trailer.
According to Olsen, though the life cycle of zebra mussels is not entirely understood, the same practices that control zebra mussels prevent 90 percent of everything else.
In March of 2013, the committee sent a letter to the state Legislature recommending the DNR actively seek out the participation of local government and voluntary groups, such as lake associations.
"The DNR has a lot of good programs," Olsen said. "We're just saying they don't have the resources; we have to work in tandem."
One recommendation is to provide long-term sustainable funding with a surcharge on boat registration and fishing licenses, or a boat sticker fee. But the most important efforts will focus on public education and participation. The report recommends improved signage at boat landings and points of sale for sports equipment and licenses.
"If the public buys into it and does what's necessary, they'll make a bigger impact than all the money we pour into it," Olsen said.
While the DNR maintains inspection and treatment points at popular landings, aware sportsmen can learn to take precautions that are simple and inexpensive.
Hot water washing of boat hulls and trailers is an effective preventive measure. Chlorine compounds for ballast tanks, bilges and live wells are being reviewed. And committee members are meeting with boat designers to try to design wells and tanks that drain completely with leaving any residual water.
"It's possible to prevent the spread of invasives in our water resources, and it's worthwhile," Olsen said. "It's in the interest of every Minnesotan who enjoys water sports and everyone who makes a living at them."