Round goby were surveyed in near shore habitats throughout the study area, primarily with smelt-baited wire-mesh minnow traps set overnight. Meanwhile, sampling effort for Asian carp was more widely scattered in the study area and relied mostly upon trammel, gill, and fyke nets set overnight. As part of the Service's Wild Fish Health Survey, tissue samples were also collected from round goby and Asian carp to screen for certain viral and bacterial pathogens and parasites.

Results of the 2004 survey indicated the distribution and relative abundance of round goby increased substantially in many portions of the study area during the past year. The standardized catch of round goby in minnow traps set in each of the five sample regions located furthest upstream was more than double that of 2003 and was about 10-fold greater in portions of the lower Des Plaines River near Joliet. Round goby were also more widely distributed within these upstream sample regions in 2004 and were typically caught at more than 50 percent of the sample sites in each of these regions. In addition, several round goby were captured substantially further downstream than previously reported in past annual surveys by crews working in the Illinois River near the Marseilles Lock and Dam (river miles 246-249) and near Peru (river mile 222). Thus, round goby are more abundant than ever before in most reaches of the Illinois Waterway survey area and now range from one end of it to the other. Moreover, the capture earlier this summer of a round goby further downstream in the Illinois River at Peoria confirms that they have moved more than 160 miles inland from Chicago in the past decade and have passed the half-way point on their way from Lake Michigan to the Mississippi River. Meanwhile, no Asian carp were collected in the Chicago Sanitary and Ship Canal, nor in the Des Plaines River where a bighead carp was captured near Channohan in 2002. Therefore, Asian carp still appear to be about 21 miles below an electrical fish barrier and 50 miles from Lake Michigan. However, bighead carp, silver carp, and grass carp were frequently caught by crews in the Illinois River near La Salle and Peru, about 100 miles from Lake Michigan. Although the results of this years' fish health survey are not yet available, a common carp from the Calumet Sag Channel was found infected with the exotic spring viremia of carp virus during the 2003 survey. This virus, common to countries in Europe and the Middle East, does not pose a threat to humans who may handle or consume infected fish. However, the disease is highly contagious to carp, goldfish, koi, and minnows and may cause locally significant mortalities among them. This was only the third confirmed occurrence of the virus in the United States and the first in Illinois. Surveillance findings were reported to the Asian Carp Rapid Response Team and the Chicago Barrier Advisory Task Force to help guide upcoming actions to limit the continued dispersal of these invasive fishes and fish pathogens.