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Feature Article January 22

Feature Article January 22, 2003

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Invasive Species: Water Fleas The CBC reported last summer that it's estimated more than 1,400 alien species have landed in Canada. Many were likely introduced into the Great Lakes by shipping activity. Two of the invasive aquatic species that are appearing in the Great Lakes basin are the spiny water flea and the fishhook water flea. Like the zebra mussel, these were probably imported in the ballast water of ships from Europe or the Mediterranean. Both are tiny crustaceans. The spiny water flea is up to 1 cm in length with a long, sharp, barbed tail spine. It is a native of northern Europe east to the Caspian Sea and was first found in Lake Huron around 1984. The fishhook water flea is similar in size but has a notable kink or hook in its tail. It is native to the European waters as well. Canadian scientists discovered the fishhook water flea in Lake Ontario in 1998.Water fleas prey voraciously on small native aquatic animal life called zooplankton, and thus may deprive larval fish of food. Larger fish find them unpalatable because of their spiny and fishhook tails. The organisms they eat are also the preferred food of native plankton and fish, leading to concerns that they may be competing for food with native species. Thus they have the potential to affect the food chains of the Great Lakes. At this time, however, scientists believe it is still too early to determine conclusively if they will alter our aquatic ecosystems to the detriment of fish populations. Anglers have complained that gelatinous blobs comprising hundreds of water fleas were fouling their fishing lines. As a result they had to cut their lines because they couldnt reel them in. Another concern is that the water fleas, because of their quantity and significant appetite, may concentrate additional toxins and contaminants in the food chain, which may result in further restriction on human consumption of fish. That would impact both commercial and recreational fisheries. Many questions remain unanswered about the full impact of this species and the extent of its spread in Ontario's waters. In 2002 the Ontario Federation of Anglers and Hunters joined forces with York University and the Federation of Ontario Cottagers' Associations to initiate the project Spiny Water Who? The TD Friends of the Environment Foundation provided partial project funding of $25,000. The OFAH surveyed the spread of water fleas using volunteers from conservation groups across the province. They analyzed water samples taken from over 40 lakes. We await their findings. Foreign species can be transported to Ontario's inland waters by recreational watercraft, bait buckets, fishing gear and fish stocking. Anglers using minnows, crayfish and other live bait can spread these organisms by dumping their bait buckets into a body of water. Plant fragments, larval and adult invertebrates, and fish can be unknowingly transported in the live wells, motor intakes, and even on boat trailers. Thus, the way to limit their spread is to ensure that boats, trailers and all aquatic gear are thoroughly cleaned and that no water is transported from one water body to another.

With the participation of the Government of Canada