Program Notes from October 26, 2004 Meeting of LKWA

Chairman, Rick Persson, reported that we are now working on all three grants recently awarded to LKWA. Much of the field work has been completed on the Lowland Forest Grant. At least 4 members and several non-members put in many volunteer hours carrying equipment and helping to collect and record data. All the work is done under the supervision of biologists and ecologists from NRC, or their consultants. We are in the planning stages for the other 2 grants.

New Business:

1. Rick and Penny reported that LKWA received an award for the initial draft of our IBA nomination. We received 3rd place out of 85 applications. The prize was a pair of binoculars that our members can use. Rick and Gary Shackelford received the award in a ceremony at Horicon National Wildlife Refuge on October 16. It was part of a day long celebration of the National Wildlife Refuge system and Horicon Marsh was dedicated as Wisconsin's first IBA. Our nomination will require much more survey work to document that the area is indeed an important area for birds. Several of our members who are duck hunters are collecting survey data during the fall migration. Hundreds of ducks and geese have been seen, including green-winged teal, blue-winged teal, wood ducks, mallards, bufflehead, canvasback, gadwall, red head, greater scaup, lesser scaup, ruddy ducks, black ducks, Canada geese (both the large and smaller forms). In addition, tundra swans, great blue herons, cormorants, and many woodcock have been spotted. In addition, 2 mature bald eagles have been seen on the north side of the lake.

2. Penny reported on her correspondence regarding black tern nesting platforms with Jeff Pritzl, a wildlife manager for the DNR. She asked him if building and placing platforms for the black tern colonies on the eastern wetlands of Lake Koshkonong might aid them during times of high water. This June the birds had very few nests because their usual platforms of vegetation had been uprooted by the high water. Jeff responded that he did his master's research on the use of artificial platforms for Forsters terns and that he found that they did not contribute to the success of the tern population. They seemed to increase hatching success but not fledging success. He noted that there are no data regarding black terns. He concluded that the best thing for the terns would be "to influence the natural condition of the sites" where they nest.

Program:
Don Bush, Region Team Supervisor, WDNR, Division of Water, Fisheries Management and Habitat Protection

Don, the fish biologist for our region, presented data on the management and status of the fishery in Lake Koshkonong (LK) and the Rock River. He noted that over the years, 60 species of fish have been identified in LK. Presently there are 8 species of game fish, 15 of pan fish, 13 rough fish and 25 "other".

The objectives of fish management for LK are:

  1. Rough fish removal. By this is meant the undesirable rough fish, primarily carp. Some fish categorized as rough fish are actually desirable, such as Big mouth buffalo, and Red horse.
  2. Game fish enhancement.
  3. Habitat modification

Carp are detrimental to the lake. They cause high turbidity, low oxygen, decreased vegetation and increased algae. They are seined by private contractors who have removed about 2 million pounds of carp each year for 5 years. This has decreased the number of carp, but the best program for carp is to combine removal with an increased stocking of pan fish. The pan fish are major predators of small carp and can effectively reduce their numbers. The interest of contractors to seine the carp is dependent on the market. Presently, they get about 10 to 20 cents/ pound and sell primarily to a market for Gefilte fish ( an important food for Jewish holidays). The contract for the seiner is up for renewal this year.

For stocking with game fish and pan fish, the Bark River hatchery has been very important. This is actively supported by local sportsmen. There is an active program of stocking walleye, northern pike, yellow perch and muskie. Three million walleye fry and 500,000 fingerlings were stocked in LK last year.

Habitat modification has consisted of dam removal in the past. Small dams removed at Rockdale, Hebron and Waterloo have aided in the migration of game fish and have eliminated "carp pools" (the small impounded pools had created a haven for carp reproduction). Recently, carp barriers have been constructed to keep carp out of the wetlands contiguous with LK. Springs in these areas maintain warmer water temperatures relative to the lake (when it freezes). This attracts carp and provides them a refuge. The barrier can keep them out and protect small game fish introduced behind the barrier. A barrier placed across the entrance to Mud Lake was vandalized but it still worked because at the time it was destroyed the lake had already warmed up and the carp stayed in the lake.

Don noted that the recently introduced rock rip rap around the lake provides excellent spawning habitat.

Recent surveys of the fishery done using Fyke nets and shockers (to temporarily stun fish so they can be counted and weighed) have shown that the fishery is in excellent condition. Of fish counted, 12% were game fish, 37% pan fish and 51% rough fish. However, most of the rough fish were buffalo fish and drum. Only 8% of the fish in LK were carp!

Lake Koshkonong is now listed in the top 10 lakes for walleye in Wisconsin, having improved in recent years.

The overall "angling effort" (the amount of fishing going on) has increased in recent years and is in the average range for Wisconsin.

Hot news from recent shocking surveys:

  1. Large (35.5 inch flat head cat fish)
  2. Many big walleyes
  3. A huge hatch of young walleye were found off Thiebeau Point. They averaged 7 in., larger than usual. Probably due to food supply of late spring flood.
  4. Large northern pike and muskies
  5. World record bigmouth buffalo fish 73# 2 oz, 38 inches

In response to questions:

Fish from LK have traces of mercury, PCBs and other contaminants. None are at federal warning levels. PCBs are at advisory level.

Winter draw down was instituted to mimic natural conditions of the river and LK system. Normally, when less water flows into the lake during the winter, the ice becomes concave and pulls away from the shore. It benefits wetlands but effects on fishery are not apparent.

Oxygen levels: in many lakes, oxygen decreases with lower water levels. Fish need oxygen and will die of there is too little. However, Koshkonong receives a constant fresh water flow from the Rock River. Therefore, when the lake is lower, relatively more oxygen is infused by the river.

During recent winters, fish have been killed in Wisconsin lakes by too MUCH oxygen. This occurs when there is no snow cover and a lot of sunlight. This promote growth of algae under the ice. Algae produce oxygen is relatively large amounts, killing fish.