| USFWS Biologist Heidi Keuler Leaves Leaping Silver Carp in Her Wake. Credit: USFWS
Results are Mixed in Survey of Invasive Fish on Illinois Waterway
Illinois’s sunny skies and warm temperatures greeted biologists from the Fish and Wildlife Service and its partners during the week-long 2007 Goby Round-Up and Asian Carp Corral in June. One species of Asian carp, the silver carp, has gained notoriety from its dramatic leaping behavior around - and sometimes into - motorboats. Analysis of the results from four days of surveying fish along more than 180 miles of the Illinois Waterway yielded both good news and bad in the fight against invasive species.
During the 12th Goby Round-Up and 6th annual Carp Corral, 14 crews totaling 50 people monitored the Illinois Waterway from Blue Island to Havana. Participants represented federal agencies (Fish and Wildlife Service, U.S. Geological Survey and Army Corps of Engineers), state agencies (Illinois DNR and Natural History Survey, and Illinois and Indiana Sea Grant) and aquariums (Shedd Aquarium and Discovery World), as well as the Cook County Forest Preserve, the City of Chicago, the University of Wisconsin-Madison, the Field Museum of Natural History and The Nature Conservancy.
Objectives of this annual survey are to locate the downstream leading edge and relative abundance of round goby, and determine the relative abundance and upstream distribution of the invasive silver and bighead carp. In addition, crews collect round goby, bighead, silver, grass and common carp as part of the Fish and Wildlife Service’s Wild Fish Health Survey.
Results just in from this year’s surveys show that bighead carp have advanced to less than 50 miles from Lake Michigan, while round gobies have not advanced further downstream toward the Mississippi River.
Since 2002, an electrical fish barrier in the Chicago Ship and Sanitary Canal near Romeoville, Ill., has been in operation to slow or prevent the spread of nonindigenous aquatic species like gobies and Asian carp. The barrier was intended to prevent the round goby from advancing from Lake Michigan to the Mississippi River; biologists and fishermen hope it will prevent Asian carp from reaching Lake Michigan.
The pilot barrier’s electrodes are corroding; new barrier built just downstream can repel small fish more effectively than the pilot barrier and will have a longer lifespan. The new barrier is being tested for commercial barge and recreational boater safety before it becomes fully operational.
During this year’s surveys, biologists did not find round goby any farther downstream than where they were collected in July 2004 -- just below the Peoria Lock and Dam, nearly 170 miles from Lake Michigan and half the distance to the Mississippi River. Abundance of the round goby seemed to decrease from last year in one stretch of the river in Joliet downstream from the barrier.
This year, survey crews collected a bighead carp at River Mile 281.5. Previously, the most upstream record of a bighead was from a 2002 collection at River Mile 275. This now places bighead carp about 15 miles below the electrical barrier and 45 miles from Lake Michigan. Based on the survey collections and on observations by anglers, biologists say that the number of bighead and silver carp are increasing in several pools of the river.
Biologists working in the Peoria Pool--the stretch of the river from Starved Rock State Park to Illinois River Mile 223--for the past four years have observed a significant increase in the number of Asian carp netted. They collected 236 bighead and silver carp this year, more than double last year’s total. Some 60 silver “flying” carp jumped in the survey boat.
Although it seems populations of Asian carp are increasing, the encouraging news is that they have not been collected above the Brandon Road Lock and Dam, about 35 miles from Lake Michigan.
During the sampling, crews also checked carp for bacterial and viral pathogens including Viral Hemorrhagic Septicemia and Spring Viremia of Carp Virus (SVCV). In 2003, SVCV was found in common carp collected in the Calumet Sag Channel. Although it poses no threat to humans, it is highly contagious to carp, goldfish, koi, and minnows and could cause locally significant mortalities in these fish populations. The results from this year’s sampling are not yet available.
The Goby Round-up and Carp Corral garnered abundant media interest, due in no small part to a partnership with Chicago’s Shedd Aquarium. The public is becoming more aware of the impact aquatic nuisance species can have on the Great Lakes and Mississippi River ecosystems.
--Heidi Keuler, USFWS, La Crosse Fishery Resources Office
For more info visit:
U.S. Fish and Wildlife La Crosse, Fishery Resources Office
More about silver carp, round goby, aquatic invasive species and how the USFWS is working to stop them.