  |
|
|
Department of Ecology News Release - July 29, 2003
03-153
OLYMPIA- Goldfish gotten enormous? Plants too thick? Algae taking over?
When it gets to be too much trouble to keep up that fish tank, consider giving away the fish and tossing the rest.
But don't toss it near water: plants and animals in an aquarium can create havoc in a lake.
Most of the species are non-native. They didn't evolve here, so Washington doesn't have the predators and diseases that keep them under control in their native settings. In fact, some are quite aggressive.
"They get into the water and have a heyday, taking over everything in their path," said Kathy Hamel, aquatic-weed specialist for the Washington Department of Ecology (Ecology).
For example, Brazilian elodea, an attractive water plant, is easy to grow and fish like to nibble it. Although it's not for sale in Washington any more, it used to be extremely popular.
But once it gets into a lake, Brazilian elodea forms mats on the water surface; you can't boat or swim in a thick infestation. It also chokes out native plants and creates stagnant conditions that are bad for fish and good for mosquitoes.
"We're pretty sure it was spread by people dumping their aquariums because of the pattern in which it has shown up, although it certainly can be spread on boat trailers as well," said Hamel
Last year, Ecology researchers found an early infestation of parrot feather in eastern Washington. Parrot feather, a highly aggressive type of milfoil, is sold as an aquatic gardening and aquarium plant. It spreads easily through fragments and carpets the water with dense plant matter that makes it impossible for fish to thrive.
"It's a very pretty plant and I don't blame people for wanting it in their tanks," Hamel said. "But it's a bad idea to let it get out."
Even Eurasian water milfoil, a familiar noxious weed known for choking lakes and rivers all over Washington, used to be a popular aquarium plant. Evidence shows that infestations of milfoil in Lake Meridian in Seattle and Lake Osoyoos in north central Washington were probably caused by someone emptying an aquarium near by.
And aquarium plants are not the only concern. Aquarium fish or animals dumped into natural waters can bring disease and parasites, say fish and wildlife biologists.
An aquarium fish or wildlife species that can withstand water temperatures below 70 degrees may be able to survive-- and continue to cause problems-- in Washington waters, said Pamala Meacham, an aquatic invasive-species specialist for the Washington Department of Fish & Wildlife.
Non-native aquarium animals can have a devastating effect on the natural ecosystem by out-competing native species for food or water, or by preying upon them.
One example is the common goldfish, which is turning up in a number of Eastern Washington lakes.
"Goldfish totally alter the habitat and remove food and vegetation that other species need," Meacham said.
Members of the carp family, goldfish disturb lake bottoms as they forage. They also consume aquatic plants that native species use for shelter, and they are able to live over the winter, even in frozen lakes.
Other aquarium species that have been reported recently in Washington lakes include pacu --which resemble red-bellied piranha -- and Chinese mystery snails, Meacham said.
The best approach is to never dump an aquarium into natural waters. You just don't know when its contents will take over.
Once they do, it can be costly. For example, it's usually up to lake residents to get rid of aquatic weeds. Homeowners spend hundreds, even thousands of dollars a year to keep lakes in usable condition.
Trade unwanted aquarium fish or plants with friends or dispose of them in the trash; don't dump them into waterways. Some pet stores will accept unwanted fish. Plants can be composted as long as they can't get into natural waters. Put them on the compost heap or bury them in soil, far from any rivers or streams.
"It's such a shame when people can't swim or fish in a weed-infested lake. And so often we wouldn't have this problem if people would just not dump their aquariums in the water," Hamel said.
Media contacts: Leslie Thorpe, Washington Dept. of Ecology,
360-407-6848
Washington Dept. of Fish and Wildlife Public Affairs, 360-902-2250
Copyright © Washington State Department of Ecology. See http://www.ecy.wa.gov/copyright.html.
