Imagine a surreal waterway, filled with treacherous currents, flotillas of swift boats, surprise missile attacks, semi-automatic weapons fire, deadly microbes, and a lurking alligator.  Sweat pours from the brow of crew members who must wear uncomfortable protective equipment as they seek cover in a steamy, electrically charged atmosphere. Amid this setting, arguably more appropriate for another Indiana Jones film, what possible mission could an armada of U.S. Fish and Wildlife Service biologists be out to accomplish? They are working with partners and dedicated volunteers to safely conduct annual surveillance for round goby, Asian carps and fish-disease pathogens in the Illinois Waterway System.

The Service’s La Crosse National Fish and Wildlife Conservation Office organized and outfitted 40 individuals for the13th Annual Goby Round-Up and the 7th Annual Carp Corral. Those participating in the June 17 to June 20, 2008, event represented nine government (federal, state, and local) agencies; two educational institutions; and two private businesses.  This year’s effort spanned a distance of nearly 100 miles from Alsip, Ill., downstream to Peru, Ill. It included portions of the Calumet-Sag Channel, the Chicago Sanitary and Ship Canal, the Des Plaines River and the Illinois River. During the survey, biologists estimated the downstream leading edge and relative abundance of round goby and the upstream distribution and relative abundance of Asian carps. Biologists from Service’s La Crosse Fish Health Center also used survey samples to test several other species of fish for a variety of deadly fish-disease pathogens. This testing is part of the Service’s nationwide Wild Fish Health Survey (http://www.fws.gov/wildfishsurvey/), a collaborative effort it has undertaken since 1997.

As in recent years, the numbers of round goby that survey crews have captured near Chicago suggested a continued decline in the upstream relative abundance of this species since it peaked here . The species peaked here  nearly about a decade ago .  Meanwhile flood conditions in the lower Illinois River forced the postponement of surveillance efforts for round goby at sites downstream of Peoria until later this summer. Biologists currently believe the goby’s presence extends downstream from Lake Michigan to this area of the Upper Mississippi River basin  in central Illinois . Although results of all laboratory tests to detect fish-disease pathogens remain pending, heightened interest exists in the outcome of these latest tests. Earlier this year, biologists identified the often deadly viral hemorrhagic septicemia virus in round goby that washed ashore from Lake Michigan in Milwaukee. That fish kill occurred less than 100 miles from Chicago and the Great Lakes connection to the Mississippi River Basin.

Surveillance activities this year did not detect Asian carps any farther upstream than the Des Plaines River location (river-mile 281.5) where biologists collected a bighead carp in the Dresden Island Pool last year.  Biologists captured two bighead carp here this year and implanted one with an ultrasonic transmitter to closely monitor its movements. Thus far, according to the survey, the upstream range of bighead carp remains about 15 miles below an electrical fish barrier in Romeoville and 45 miles from Lake Michigan in Chicago.  Meanwhile the relative abundance of Asian carps increased markedly during the past year in adjoining navigation pools located downstream.  For example, a crew surveying the same portion of Marseilles Pool captured an annual total of five bighead carp during June in both 2006 and 2007.  Under similar circumstances this year, however, they caught a total of 41 bighead carp in this reach, as well as nine silver carp.  Likewise, a 150-foot trammel net crews setplaced further downstream for one night set a surveillance record: It captured a total of 57 Asian carps (32 silver, 17 grass, and 8 bighead) in the Starved Rock area of Peoria Pool. However the number of silver carp leaping into the boat, rocketing about like slimy missiles and pummeling the crew was unexplainably (and fortunately) reduced this year.  Biologists do not expect this apparent lull in activity to persist though. Floodwaters this summer have increased the size of shallow-water nursery habitats, which may eventually help produce a very large 2008-year class of Asian carps.

The Service reported surveillance findings to the Asian Carp Rapid Response Team and the Chicago Barrier Advisory Task Force. Those finding will help guide upcoming actions to limit the continual dispersal of these invasive fish and fish-disease pathogens.  Information from the survey also attracted the interest of reporters and photographers from many electronic- and print-media outlets. This was due in no small part to the successful outreach efforts of Shedd Aquarium, a partner in the annual surveillance program for several years now. Garnering other media attention at this time was local authorities’ capture of a 5-foot-long alligator. Authorities believe it could be a pet that someone discarded. These surveillance efforts and media reports have helped inform the public about the current distribution of these aquatic-nuisance species. They have also underlined the impacts these species are having on the Great Lakes and Mississippi River ecosystems.