OutdoorNebraska

Fishing the Sandhills • NEBRASKAland Magazine T he common carp has been making a mess of lakes, reservoirs, rivers and streams since it was first brought to the Unites States and later Nebraska from Europe in the late 1800s. Once established, they can ruin a fishery, and have done just that to many in the Sandhills. Carp are bottom feeders that stir up sediments and cloud the water. The aquatic vegetation that is the base of the food web doesn't grow well, if at all, in muddy water. And sight-feeding gamefish like pike, bass, bluegill and perch, unable to find what little food is left, grow slow and stay skinny. Eventually, there will be few gamefish left. Some Sandhills lakes have been infested with carp for so long that not even cattails grow in the shallows. Without vegetation, the lakes are also of little value to waterfowl and other wildlife. For decades, the Game and Parks Commission's fisheries division has been using rotenone to remove carp from lakes. This chemical kills gill-breathing organisms, including gamefish, but by the time biologists choose that route, few gamefish remain. With carp removed, waters clear quickly, aquatic vegetation rebounds and the gamefish stocked into the "new" lakes grow fast and fat. Unfortunately, it can be hard to kill carp in the Sandhills. These natural lakes are fed by groundwater, and springs bubbling up from a lake bottom can provide a refuge from the chemical for carp. It is also difficult to get the chemical mixed into every ounce of water that permeates the cattails and marshy areas around the lakeshore. Also, many of these lakes are connected by small streams and man-made ditches that run out of one lake, through a wet meadow or marsh and into another lake and eventually a river. Carp first found their way into some lakes by swimming up or down these streams during times of high water, and often do so again following a renovation. Biologists have understood this fact of life in managing Sandhills lakes, but feel that even if they have to re-treat a lake in 10 or 15 years, the good fishing in the interim makes the effort and expense worthwhile. Often, they stock lakes with predators like northern pike, muskellunge or walleye, which have been shown to help control carp populations, extending that timeline. In recent years, however, biologists have brought engineering to the battle in hopes of making the next renovation of a lake the last. Barriers that allow water but not carp to pass are being installed on streams below lakes to keep carp from swimming back up. And when lakes are renovated, so are their watersheds, ensuring that carp won't come downstream. Water control structures built to keep water in lakes often allow managers to let water out, or can be modified to do so. With lower lake levels, water and carp are drawn out of the shoreline vegetation, ensuring none escape the rotenone and allowing biologists to use less of it. Where structures aren't present, managers use high-capacity pumps to lower a lake prior to a renovation, or wait until drought lowers the levels naturally. Work is underway on several of these types of projects in the Sandhills, the largest of which is at the Valentine National Wildlife Refuge. Nine of the 36 lakes on the refuge are open to fishing. Six of them, along with another lake not open to fishing, are connected, including the five largest fishing lakes, covering nearly 3,500 surface acres combined. A joint project between the Commission, its Aquatic Habitat Program and the U.S. Fish and Wildlife Service is underway to improve existing or build new water control structures between the lakes to prevent movement of carp between them. A major piece of the puzzle – a new fish barrier below Willow Lake, the last in the system – is in place. When other barriers are completed, the partners plan to perform a systematic top-down renovation of the lakes, timing it so anglers will always have several lakes to fish. Another major project is installing barriers to keep carp out of Twin Lakes WMA in Rock County, which were renovated in March 2016. There is no guarantee any of these extra steps will work. Historic rainfalls sent water over the barriers installed at Goose Lake WMA prior to a 2003 renovation, allowing carp to re-enter the lake. It is tentatively set to be renovated again in 2016. And unbeknownst to some anglers, that bucket of crappie minnows they buy at the bait-shop often includes young carp, which is why the use of live baitfish is prohibited at newly renovated lakes. Even without guaranteed success, the return on investment for fish and anglers, as well as hunters and fowl, is high enough that biologists will continue to do whatever they can to get carp out of Sandhills lakes and keep them out. Down with Carp While carp are bad news for gamefish and some anglers search for lakes without them, others, including Joe Rydell of Alliance, appreciate the fight carp put up when they hook one while fishing for other species, as he did at Blue Lake. Still, other anglers target carp with their fly rods or with bow and arrow, and a growing number are making trips to the Sandhills in search of the non-native fish. PHOTO BY JUSTIN HAAG

• Cover