Bumper bass crop one more reason to land spread manure carefully
EDITOR'S ADVISORY: This news release was previously issued to agricultural media.
MADISON – The bumper crop of smallmouth bass produced in southwestern Wisconsin in 2012 is one more reason for farmers to keep up their good work in carefully spreading manure on fields so that it doesn’t run off into streams and kill fish, state water resources officials say.
“Good manure management is good for the farmer and good for our water resources,” says Jim Amrhein, a Department of Natural Resources water quality biologist who covers streams in southwestern Wisconsin. “Our bass population has really improved since the 1970s and the 1980s, in part because of better land and water conservation practices. It’s important to be vigilant to keep the momentum going.”
March is typically among the riskiest times to spread manure because rain and melting snow can easily wash the manure off frozen fields and ground. Periodic fish kills caused by manure entering lakes and streams have been a problem in Wisconsin in past years, Amrhein says.
Pollutants in the manure can be toxic to fish and can use up the dissolved oxygen in the water, robbing fish of their oxygen supply. Some fish kills are immediate; others may occur months down the road in the summer when plants and algae growing in the water and fueled by the phosphorus associated with manure runoff demand more dissolved oxygen.
“2012 was a banner year for smallmouth bass reproduction,” said Dr. John Lyons, a longtime fisheries researcher in DNR’s science services bureau. “Smallmouth tend to pull off really good hatches during the hot and dry years, like we had in 2012. The hatch last year rivals that of 1988 and 1989, which also were dry years, in terms of their number and size.”
Amrhein also noticed a boom in bass population while conducting surveys. “We turned up bass hatched this year in just about every tributary to a major river,” he says. “The trick will be to get these young fish through to maturity so they can not only provide action for anglers, but also be able to spawn themselves.”
Smallmouth bass use these tributary waters as nursery streams. Periodic fish kills in tributary waters, sometimes caused by improper manure management can have a devastating effect on smallmouth bass populations, particularly if it kills the larger, mature fish that are necessary for spawning, Amrhein says.
“We saw a decline in the smallmouth fishery over the past 50-60 years from a variety of reasons, including fish kills caused by runoff of manure,” he says. “We’ve made progress in land and water conservation practices that have helped many rivers and streams rebound over the past 25 years.”
Farmers plowing along a contour, properly planning nutrient applications, creating vegetated buffers along stream banks and using other conservation practices have helped keep more soil and nutrients on the land. In addition, a greater awareness in the last five years of the potential dangers of spreading manure on snow-covered or frozen ground when it’s raining or snow is melting is helping reduce the number of runoff incidents and fish kills.
Amrhein and Lyons hope that greater awareness of the factors which influence smallmouth reproduction and survival can help return southwestern Wisconsin to the bass fishing heyday of the 1950s and 1960s, when Field & Stream magazine in 1968 highlighted the area as a draw for smallmouth bass anglers from all over the Midwest.
“We think we can again return southwestern Wisconsin to a destination for anglers who are interested in catching these hard fighting gamefish,” Amrhein says. “But we need to work together to keep manure on the land and out of the streams. Periodic fish kills caused by manure runoff are a major factor that could keep us from attaining our goal.”
Amrhein advises farmers to check the state’s online runoff risk advisory forecast – www.manureadvisorysystem.wi.gov (exit DNR) -- to plan when they will spread manure so to avoid conditions when the risk of runoff is high. That advisory also contains information about ways to reduce the risk of runoff if farmers must spread manure on fields on a day when soil, weather, and other conditions increase the risk of runoff.
He also encourages farmers to work with county Land Conservation Department staff to develop nutrient management plans. Such plans help keep nutrients on fields and out of lakes and rivers by properly balancing and timing applications of manure and other nutrients.
Resources to help farmers during times when runoff risk is high
New this year, DNR and partners have created a flier to help increase awareness of the runoff risk advisory forecast. DNR water quality officials encourage people to downloaded the flier, print it off and post it as a reminder. The flier, along with links to important resources including the Land Conservation Directory and an example emergency manure spill response plan, can be found on the Manure spills response, planning and prevention page of the DNR website.
FOR MORE INFORMATION CONTACT: Jim Amrhein, 608-516-5078 or John Lyons, 608- 221-6328