Here Come the Gobies
Hot on the heels of aquatic exotic invaders like zebra mussels and ruffe, yet another alien species is making waves in the Great Lakes: the round goby.
That's the word from David Jude, a researcher at University of Michigan's Center for Great Lakes and Aquatic Sciences.
Jude first discovered two species of gobies five years ago in the St. Clair River near Detroit. Since then the rare tubenose goby has not proliferated, but the aggressive round goby seems to be making a whirlwind Great Lakes tour.
"They're already in Lakes Erie, Huron and Michigan," Jude said. "They have tremendous range extension for a species that just got into the Great Lakes system a few years ago." Like the zebra mussel, the bottom-dwelling goby is native to the Black and Caspian seas, and probably came to North America in the ballast water of a transoceanic vessel.
Ironically, zebra mussels appear to be the main food source for round gobies, Jude said. While pressure from gobies might help eventually stabilize zebra mussel populations, he believes the goby-zebra mussel link is also potentially ominous. "Zebra mussels are known collectors of PCBs because they filter so much water and detritus in the water," Jude said. "The fact that the round gobies are eating so many zebra mussels - we're concerned there may be a transfer of PCBs through the zebra mussels, through the gobies and into top predator fish."
Those top predator fish include such popular sport and commercial species as walleye, smallmouth bass, rock bass and yellow perch.
Round gobies already are causing problems for other bottom-dwelling Great Lakes natives like mottled sculpin and log perch.
"We think round gobies are so abundant that they are occupying a lot of the optimal spawning and hiding places of native species," Jude said.
Where the gobies will ultimately fit in the Great Lakes ecosystem is still anybody's guess. It's even possible they could become popular fish. Easily caught by recreational fishers, they're commercially harvested as food fish in Russia, Jude said.
"We have not heard of anybody (in America) eating gobies yet," Jude admitted. "I guess I'll have to do that sometime so I can report back on how they taste!"
- Laurence Wiland
Door County Summer Programs Start
UW Sea Grant's "Programs in the Parks," directed by Education Specialist Bill Skadden, offer a series of summer slide shows highlighting topics of interest to Door County residents and visitors.
Following is the 1995 summer schedule:
The Geology of Door County: An aerial and ground-level overview of the Door County region, highlighting the area's unique glacier-carved features. July 7, 8 and 9; Aug. 4, 5 and 6; and Sep. 1, 2 and 3.
Door County Fishing - From Caviar to King Salmon: Explores the region's diverse fishing activity. July 14, 15 and 16; and Aug. 11, 12 and 13.
Unwelcome Guests in Door County: Features many of the nonnative aquatic species now inhabiting the Great Lakes. July 21, 22 and 23; and Aug. 18, 19 and 20.
Door County Weather - Play Safe: Tips to help fishers, hunters and outdoor enthusiasts predict and prepare for Wisconsin's changing weather conditions. July 28, 29 and 30; and Aug. 25, 26 and 27.
Friday programs will be held at 11 a.m. at Whitefish Dunes State Park.
Saturday programs will be held at 8:30 p.m. in July and 8 p.m. in August and September at Potawatomi State Park.
Sunday programs will be held at 8:30 p.m. in July and 8 p.m. in August and September at Peninsula State Park.
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This page created June 1995
Last updated 21 December 1995. T. Yao and J. Eischens
All contents copyright 1995 University of Wisconsin Sea Grant Institute
Designed by Tina Yao tlyao@seagrant.wisc.edu