New Zealand mud snails move into Great Lakes

A new invasive species of snail is threatening waterways in the Great Lakes region, according to researchers.
The Globe and Mail reported that a Penn State research team has found that New Zealand mud snails have moved east. The snails have long been a problem in the western U.S., but have now been found in all the Great Lakes except Lake Huron.
Edward Levri, an associate professor of biology at Penn State’s Altoona campus presented his research in Milwaukee on August 8.
Levri told the Globe and Mail that while the New Zealand mud snails haven’t spread too rapidly yet, “The problem is there’s potential.” He said that in some streams in Yellowstone National Park the snails have reached a population density of 323 per square inch.
The snails grow to 6.5 millimetres and reproduce asexually or sexually. They appeared in Idaho in 1987, and in Lake Ontario first in 1991. In New Zealand they are not a problem because parasites help kill them off.
The infestation of zebra mussels, another foreign invasive species, into the Great Lakes region began in the 1980s and became a huge problem, clogging up water intake pipes. Zebra mussels grow to 3 cm in length, considerably larger than the latest invaders.
According to Environment Canada, over 150 non-native aquatic species have been introduced into the Great Lakes over the last 200 years. Close to 60% of these are plants, while the remainder are fish and invertebrates.
Invasive species often arrive in the ballasts of ships from other continents, like Asia and Europe.