Kelly said the organism is thought to like warm water and the cold fronts that have moved through the area this week may have forced it out of the bay. That's probably been to its advantage. So far, little is known about the organism. The big question is how the exotic species' presence will affect the Great Lakes. Studies of the organism began last month on Lake Ontario, MacIsaac said.
Scientists hope to know much more once experiments are completed.
What scientists do know is that the organism was first discovered in North American waters last summer in Lake Ontario and in New York state's Finger Lakes. The Inland Seas discovery is the first of its kind reported from Lake Michigan. A freighter can carry 3 million liters of ballast water, the equivalent to 50 family swimming pools of water. The organism also can be transplanted from one water system to another on fishing down rigger lines. It attaches itself to a fishing line by its spine, which is a tail on a right angle from its body.