University of Windsor researchers have begun testing some elements of a “better trap,” hoping that round gobies – small, ravenous aquatic invaders introduced from Europe in the ballast water of transoceanic ships – will beat a path to their door.
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| University of Windsor researchers open a round goby trap. Photo: MNR-2007 COA-Jason Mortlock |
Researchers believe the urine of spawning male gobies contains certain chemical cues (pheromones) that when released into the water attract mature females to the males’ nests. They also think fertilized goby eggs give off another type of scent that attracts cannibalistic gobies searching for food.
That’s why researchers are setting traps baited with blends of male and egg pheromones at goby gathering spots in Lake Erie. If the “smells” can be re-created, they can be used in the field to reduce goby densities in areas where they are known to feed on the eggs of native fish species, and at river mouths to slow the spread of gobies.
Then there are the deep, alien “wub” sounds that male gobies emit. These eerie auditory signals may be used to attract females and discourage competing males. Researchers have discovered that round gobies respond to a speaker playing these goby sounds. This new knowledge will also be used to develop a trap.
Meanwhile, researchers are studying three river systems draining into Lake Erie, using genetic markers to find out what makes gobies move into new waters. Is an invasion an amoeba-like advance led by the gobies on the outer edges of a colony, or an aggressive expansion led by individual “conquering” gobies genetically predisposed to travel long distances to find new territories?
Click here to view a map of the project area
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About the Round Goby
• Round gobies are small, bottom-dwelling fish with frog-like eyes that can spawn several times each year and thus multiply rapidly. First reported by anglers in the St. Clair River (Lake Erie Basin) in 1990, round gobies have invaded all five Great Lakes.
• The goby feeds hungrily on the eggs and young or fry of many native Great Lakes fish species, including lake trout, lake sturgeon and smallmouth bass. It competes with native fishes for spawning habitat and alters aquatic food webs. The full impact of the invasion has yet to be determined, but the noticeable disappearance of many small, native, bottom-dwelling fish in the Great Lakes is not a good sign.
Project Partners:
- Canadian Aquatic Invasive Species Network
- National Science and Engineering Research Council
- Ontario Ministry of Natural Resources’ Aquatic Research & Development Branch
- University of Windsor, Department of Biological Sciences
For more information, contact:
- Jeff Brinsmead, Invasive Species Biologist, Biodiversity Branch, Ministry of Natural Resources, Peterborough (705) 755-5424