. Sick Bass Found in the Mississippi River
> 2. Four Men Pleaded Guilty in Deer Poaching Case
> 3. Early Ice, Best Fishing – by Joe Wilkinson
> 4. DNR to Continue Collecting Deer Tissue Samples
> > > SICK BASS FOUND IN THE MISSISSIPPI RIVER > > GUTTENBERG – Fisheries workers conducting routine autumn surveys have seen a number of largemouth bass with open wounds at over-wintering areas in Pools 10 and 11 on the Mississippi River. Overall, 22 percent of bass collected had skin lesions but infection rate was as high as 38 percent at some locations. Several diseased fish were sent to the U.S. Fish and Wildlife Service Fish Health Center in LaCrosse, Wis.
> > Preliminary laboratory tests indicated that these fish suffered from a variety of bacterial infections. The principle infectious agent was a bacterium called Aeromonas hydrophila but other bacteria were present (not all have been identified as of yet).
> > In addition, virus testing also detected the presence of largemouth bass virus (LMBV). This pathogen was detected earlier this summer on Pools 3 and 7 by the LaCrosse Center and it appears to be a new fish virus on the Mississippi River. LMBV has been previously detected in 17 states including Illinois, Indiana, Michigan, Minnesota and Wisconsin. > > For anglers, eating fish infected with these organisms does not pose a known threat to human health. Largemouth bass virus has only been reported from cold-blooded animals (fish, reptiles and amphibians). However, anglers should heed common sense by properly cooking all fish and not consuming dead or sick fish. In addition, they should wash their hands thoroughly with soap and water after fishing.
> > The primary reason for this disease outbreak is probably due to stress, said Scott Gritters, Iowa DNR fisheries biologist at Guttenberg. Stress can lower the fish’s natural defenses against disease. Bass living in the Mississippi River may encounter a variety of stressful conditions including poor water quality, repeated handling by anglers, long distance movements to overwintering areas and crowded conditions in backwater habitats. > > To survive the winter conditions in the Mississippi River, bass use lakes that are too deep to freeze to the bottom and have little or no water current flowing through th> em. This type of backwater habitat is becoming very limited on the river due to siltation. Bass have been found to move up to eight miles to get to these high quality overwintering areas. In addition, since these areas are so limited, thousands of fish crowd into them. Excessive crowding and movements elevate stress levels, weaken the immune system, and permit the rapid transmission of diseases among fish. > > Ice anglers who come across fish with lesions are asked to notify a local fisheries biologist. In this way, fisheries scientists can track this outbreak and document its impact on the Mississippi River fishery. Because diseased fish were collected within areas of the Upper Mississippi River National Wildlife and Fish Refuge, fishery biologists are also working with refuge staff to document and seek solutions to this problem. > > For further information, contact Scott Gritters with the Iowa DNR 563-252-1156, Pat Short with the Wisconsin DNR 608-326-8818, Pam Thiel with the Fish and Wildlife Service 608-783-8431, or John Lindell with the refuge office 563-873-3423.
December 19, 2002 at 1:00 am
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