Winter weather possible cause of fish kill on Black Earth Creek

CROSS PLAINS, Wis. - Fishery biologists doing routine population monitoring work on Black Earth Creek downstream of Cross Plains have documented a drop in fish populations from South Valley Road downstream about 0.8 miles. On-stream reports from early season trout anglers support this observation.

"We can't say with any certainty what the cause of the drop might be," said Scot Stewart, the Department of Natural Resources district fishery supervisor. "There are several possibilities including the very cold winter, an unknown runoff event of some kind or even last year's floods which greatly reduced the size of the 2013 year-class of fish in the creek. We simply don't have any solid evidence that points to any one clear cause.

"The good news is that this creek has high quality trout habitat, is very productive, and will recover naturally in two to three years. We can say this with confidence because we've experienced fish kills here before and the creek has recovered nicely within the two to three year timeframe."

Even some of the possible causes are somewhat lacking in probability say fishery experts. A sustained and very cold winter would make a runoff event less likely and there is no record of any such event taking place. A single reduced year class alone would not completely explain the preliminary estimate of a 70 percent drop in fish population in this stretch of stream.

"Winter is a stressful time of year for trout in streams, and this past winter was colder and longer than what we typically experience," said Matt Mitro, a DNR cold-water fish research scientist. "Our monitoring of water temperatures in nearby streams showed near-freezing temperatures from early December through March in areas of streams away from springs. Trout streams are usually not that cold for that length of time."

Biologists have already taken steps to ease the impact to the popular stream fishery by stocking 300 surplus wild brown trout from brood stock and additional rainbow trout into the affected stretch of stream.

Biologists will continue routine seasonal population monitoring in the area but will add some additional summertime monitoring as current work schedules allow.

"We've worked to build populations in this outstanding stream but something has happened," adds Stewart, "we don't know what, but we've taken action to soften the impact to anglers and we expect the stream to fully recover as it has done in the past."

QUESTION OF THE WEEK

Q: Once a lake gets winterkill, how do the fish repopulate?  Will they repopulate without DNR stocking?

A:  Winterkill is a natural process that happens with some regularity in the southern part of the state due to the type of lakes in the area. From the southern Minnesota lakes perspective, winterkill would be more appropriately termed “partial winterkill.” The Windom fisheries office has rarely seen a complete winterkill, meaning that all fish are dead in a lake. Often, a partial winterkill reduces a large portion of the population, but it varies greatly on the year, lake and fish community. 

Black bullhead is a species of fish that has a tendency to survive most winterkill scenarios.  Many times the general public sees large numbers of dead common carp and would describe the lake as “dead.” But ice out netting the spring after these winterkill events often reveals many species of fish are alive and well. In spite of the reduction of some of the fish populations, those surviving fish become the brood stock for the population to rebuild. In southern Minnesota, fish can quickly repopulate a lake following a winterkill naturally due to other connected bodies of water that haven’t experienced winterkill.

If a body of water does experience winterkill, then DNR fisheries can do an ice out netting survey to identify species that are present or absent. If the lake is managed for yellow perch and ice out netting reveals an absence of yellow perch and the lake has limited connected sources, DNR fisheries can stock pre-spawn adult yellow perch to reintroduce that species. Those fish then reproduce in the lake naturally.

In southern Minnesota, winter aeration is sometimes used in an effort to prevent partial winterkills but results with that strategy can vary. 

-Ryan Doorenbos, Windom area fisheries supervisor

Extended Wisconsin Ice Cover Expected to Cause More Fish Kills

MADISON - With ice 3 feet deep still covering many lakes in northern Wisconsin and yet more snow delivered last week, state fish biologists are expecting an increase in fish kills due to low oxygen levels in some shallower lakes.

As a result, anglers and lakeshore property owners could see an increased number of fish littering shorelines throughout Wisconsin this spring when the ice finally melts.

"We expect some winterkill every year, but we're likely to see more due to heavy snow and the long ice cover," says Paul Cunningham, Department of Natural Resources fisheries ecologist. "Shallow lakes with large amounts of aquatic vegetation and mucky bottoms are prone to this problem. They have much lower oxygen capacity to begin with, and that oxygen is consumed as the plants decay, leaving little for fish and other aquatic life as the ice cover prevents oxygen from the atmosphere from entering the lakes."

Winterkill is a natural process occurring when fish don't have enough oxygen. In ice capped winters, most oxygen in the water comes from aquatic plants. However, when the ice and snow cover is thick, plants cannot get the sunlight needed, and instead of producing oxygen, they die back and decompose. Last year, DNR documented 18 fish kills caused by low dissolved oxygen levels in winter.

Cunningham says it's rare for lakes to experience total winterkill. Tributaries or springs where oxygen supplies are better are usually temporarily sought out by some fish.

"For some waters, partial winterkill is a natural, beneficial process that results in increased growth rates and improved size structure of the survivors and a better fishery all together," he says. "On more shallow lakes with excessive algae blooms, winterkill can have negative impacts to anglers because the majority of game fish die, and rough fish like black bullheads and carp survive, making it a challenge to restore and maintain game fish populations in these lakes."

Fortunately, usually enough fish survive, either in the lake or in connecting waters, to repopulate the lake in a couple of years. Only for extreme die-offs is fish restocking necessary, Cunningham says.

Rehabilitation of winterkill lakes typically involves restocking of species such as northern pike, largemouth bass, yellow perch, pumpkinseed and bluegill. After completing fish kill investigations, local fisheries biologists make the decision to request fish for restocking in the extreme cases of severe winterkill. DNR has contingency plans to increase production of largemouth bass and northern pike that may be needed for restocking lakes that are severely impacted by winterkill this year.

What to do if people see a fish kill

While the lack of oxygen normally kills fish in later winter, the fish may not be noticed until a month after the ice has melted from lakes. The dead fish are preserved by the cold water under the ice, but start decomposing as the water warms and the bloated fish float to the shore.

People witnessing a fish kill are asked to note the water body, fish species and approximate number of dead or dying fish and contact their local fisheries biologist or call the DNR TIP line at 1-800-TIP-WDNR, 1-800-847-9367. Do not collect fish samples from a suspected winterkill fish kill.

"They are several things we can look for to distinguish a winter kill," says Cunningham. "One sign is that the dead fish may appear fuzzy from a fungus infection, which is normal in winterkills. Another sign is the strong smell of sulfur dioxide, which smells like rotten eggs."

Other distinguishing factors include the species of fish affected and the rate of decomposition.

"With winterkills, fish may be partially decomposed, depending on when they died," says Sue Marcquenski, DNR fish health specialist. "And if the dead fish are comprised of all the different species in the lake at the time of ice out, winterkill is the likely cause."

If dying fish or fish in distress are observed this spring, the cause may be different than winterkill. If dying fish are observed, please contact local fisheries biologists or the DNR TIP line and indicate fish are actively dying (not a winterkill).

FOR MORE INFORMATION: Paul Cunningham, 608-267-7502, Sue Marcquenski 608-266-2871)

Fish habitat and water quality improvements expected from Chippewa Flowage drawdown

EAU CLAIRE - A drawdown of the Chippewa Flowage last fall should benefit local residents, property owners and other users of the Chippewa Flowage, according to a partners group that assists in management activities of the reservoir and surrounding lands to benefit the area's ecosystem.

The goal of the project is to reduce aquatic plants like the invasive Eurasian water-milfoil, which has grown to nuisance levels in some areas of the flowage, according to Max Wolter, Department of Natural Resources fisheries biologist. Wolter said biologists also expect changes in the aquatic habitat will benefit the walleye and musky fishery by improving their spawning habitat.

The late fall and early winter drawdown on the 15,300-acre reservoir, which has a current elevation of about 1,310 feet above sea level, slowly brought the water level down 8 feet. The main difference between this year's drawdown and previous years is that 5 feet was drawn down before ice-up. This is expected to minimize issues with low oxygen levels that can arise during later winter draw downs.

Wolter said the drawdown is intended to expose the bottom sediment to air as winter progresses, freezing out the roots of the Eurasian water-milfoil. During spring runoff, water levels will be restored to normal elevations. Precipitation and inflow from tributary rivers and streams will determine how quickly this happens. The reservoir is full at 1,313 feet.

"Drawdowns are frequently used to manage fish populations across the United States," Wolter said. "Significant drawdowns were a big part of the history of the Chippewa Flowage up until the mid-1990s, and during that period of time walleye recruitment was high. The current plan is conservative enough to allow access for fall and winter fishing, yet still have a beneficial impact on the select resources."

Throughout the 2013-2014 project, the group has been monitoring key areas for winter dissolved oxygen levels.

As the group expected -- based on the extended and harsh winter -- they have observed low dissolved oxygen levels in a few isolated areas, specifically Crane Lake and Blueberry Flats. These areas represent less than 3 percent of the flowage's acreage.

"While we won't know for sure about fish kills until after the ice melts, so far the main lake area look good, or even better than expected," Wolter said. After ice-out biologists will monitor the response of the aquatic plant and fish populations.

The Chippewa Flowage Partners Group -- which comprised of Xcel Energy, Department of Natural Resources, U.S. Forest Service, Chippewa Flowage Area Property Owners Association, Lake Chippewa Flowage Resort Association, Lac Courte Oreilles (LCO) Band of Lake Superior Chippewa Indians, Wisconsin Conservation Congress (Sawyer County) -- has been in existence since 2006 to assist in management activities of the reservoir and surrounding lands to benefit the whole ecosystem of the Chippewa Flowage.

Ohio DNR Warns of Possible Fish Winterkill

COLUMBUS, OH - The Ohio Department of Natural Resources (ODNR) is reminding people that fish kills may be common in ponds and small lakes as the ice and snow of the past few months gives way to spring.

Winter fish die-offs caused by long periods of heavy ice and snow cover on small waters are referred to as winterkills. Winterkill is caused when persistent ice forms a surface barrier between the water and air that prevents circulation of oxygen and blocks sunlight. If these conditions continue long enough, the oxygen fish need to survive may be depleted and result in some or all of the fish suffocating. Lacking sunlight, plants stop making oxygen and eventually start to use it as they die and decompose.

Winterkill is most common in shallow ponds and typically results in dead fish being seen along the shore. Ohio's northern counties are usually most susceptible to winterkill because of colder temperatures and more frequent snows, but this year winterkill of ponds is possible throughout Ohio.

Some fish die-offs are expected in Ohio's larger lakes as well this year, but for different reasons. Fish such as gizzard shad, which are less tolerant of long, cold winters, are commonly seen along the shorelines of reservoirs and even Lake Erie during moderate winters. However, in larger waters, the species that commonly die off following winter are resilient and return in great numbers following a single spawning season.

Unusual water coloration, strong odors or other unusual conditions may be indicative of non-natural causes and can be reported to the ODNR Division of Wildlife. Call 800-WILDLIFE to report a suspicious fish winterkill.

Go to wildohio.com to learn more about fish and preventing winterkills.

Drought conditions worsen in southern half of Wisconsin

50 counties now at increased fire danger levels

MADISON – The continued lack of significant rainfall in the southern half of Wisconsin has increased drought conditions and raised the fire danger to extreme, very high or high in 50 southern and central counties.

The lack of rain is lowering water levels on streams and rivers, making navigation more difficult and increasing the number of fish kills. There have been reports of private wells going dry, and some municipalities are placing restrictions on water use. The hot temperatures and low water levels are increasing the risk of blue-green algae outbreaks and concentrating waterfowl in areas that have been known to have outbreaks of botulism.

“The drought is affecting everyone – with farm crops in jeopardy, fire danger, and well impacts, and more,” said Department of Natural Resources Secretary Cathy Stepp. “DNR is doing everything it can to share information and expedite approvals for wells and pumping when we can without endangering the long term health of natural resources. Our hearts go out to people struggling with the dry conditions.”

The Department of Natural Resources has launched a new Web page intended to help the public find drought-related DNR information and assistance. People can go to dnr.wi.gov and search for the keyword “drought.”

Fire conditions

Fire danger levels as of July 17 were at extreme in 25 southern counties and very high or high in another 25 central counties. DNR fire control officials have been responding to 10 to 15 fires a day, and since June 1 there have been more than 275 fires. A 40-acre fire closed a westbound lane of Interstate 90-94 Monday. An Army National Guard helicopter assisted in fire suppressing the fire with water drops.

“With these tinder dry conditions, equipment caused fires have become the number one cause of fires, mostly with hot vehicle exhaust systems or farm equipment,” says Trent Marty, DNR fire prevention director.

Emergency burning restrictions remain in place in all or parts of 19 counties. The restrictions prohibit any outdoor burning -- outside of fire rings in campgrounds -- smoking outdoors or disposal of ash or charcoal. In addition, even campfires within fire rings have been banned at four state park and forest properties including Southern and Lapham Peak units of Kettle Moraine State Forest, Richard Bong State Recreation Area and Big Foot Beach State Park. Park officials caution that without rain soon, the fire prohibitions may be expanded to other properties.

Water concerns

DNR officials are receiving and reviewing applications for emergency permits to pump water for crop irrigation from lakes and rivers. DNR is approving permits for irrigation from lakes and rivers where the withdrawal will not have a negative impact on fisheries or other aquatic life or on other users of the waterway.

The agency has been receiving six to 10 applications a day for new high capacity wells for irrigating crops and is approving the applications where the new wells will not have a negative impact on other private wells. To date there have been numerous reports of private wells going dry, but as of yet no reports of municipal wells going dry.

State dam safety officials are notifying dam operators of their responsibility to maintain a minimal flow of water below dams, as some operators have reportedly begun to hold water back to maintain water levels on lakes, flowages and impoundments.

“Dam operators need to ensure they maintain minimal flow from their dams to ensure fish health and to ensure there is adequate flow for the dilution of wastewater from municipal treatment plants and other industries and operations downstream,” said Bill Sturtevant, state dam safety engineer.

Fish kills

State fisheries biologists have entered more than 31 verified fish kills since the beginning of June, with more being investigated.

“The earlier fish kills were primarily due to low water levels resulting in low dissolved oxygen levels,” says Paul Cunningham, DNR fisheries habitat coordinator, “but lately we’ve seen more thermal-related fish kills. The water has just gotten too hot for many of our cold-water species like northern pike.”

Fisheries biologists have started to deny some applications for chemical control of aquatic weeds, because of the additional stress the control may have on fish populations.

Beach and swimming concerns

The hot, dry weather is fueling excessive algae growth as the increased water temperature speeds up cell growth and division. Blue-green algae, which are found naturally in Wisconsin lakes and can produce toxins that pose a health threat to people, animal and pets, are becoming a problem in waters with a history of blooms, like Lake Winnebago and Tainter/Menomin lakes, but are in places where blooms are normally not a problem, DNR water leaders report.

DNR staff are fielding more calls on the algae Cladophora from property owners and beachgoers all along the Lake Michigan coast, says Steve Galarneau, who directs the DNR Office of the Great Lakes. The algae, naturally found in Lake Michigan, breaks off from the rocks on the lake bottom and washes ashore, where it smells and looks foul as the algae and aquatic life it carries decompose.

Zebra mussels and quagga mussels proliferating in Lake Michigan are helping create the conditions for more of the algae to grow, along with the warm water temperatures and sunny skies. “Cladophora has been a problem for decades. There are good blocks of time and bad blocks of time during a year, and this is a particularly bad period of time,” he says. “We empathize with people concerned about how it looks and smells. We encourage people to avoid swimming through cladophora or coming in contact with the algae that’s washed ashore because it may harbor harmful bacteria.”

Boating safety

With low water levels on lakes and rivers (USGS Wisconsint streamflow) (exit DNR), boaters need to be especially cautious of navigational hazards that may not have been apparent with higher water levels. Stumps and sand and rock bars may all be closer to the surface, especially on river systems. The Rock and Wisconsin rivers in particular are very low and navigation is difficult in some stretches.

Wildlife health concerns

U.S. Fish and Wildlife Service staff have collected approximately 50 dead birds, primarily mallards, wood ducks and teal as well as pelicans, shore birds, and great blue herons on the northern end of Horicon Marsh. Specimens have been submitted to the National Wildlife Heath Center for confirmation, but officials highly suspect that botulism is the cause. They will be conducting daily monitoring of other state and federal wildlife areas where botulism has caused waterfowl deaths in the past.

Record heat may be contributing to fish kills in Minnesota lakes

Record-setting heat may be contributing to fish kills in lakes across the state, according to the Minnesota Department of Natural Resources (DNR).

“Natural summer fish kills are not unusual,” according to Brian Schultz, DNR assistant regional fisheries manager. “In the past several days, however, we’re getting increased reports of dead and dying fish in many lakes from around the state.”

Unusually warm weather has raised water temperatures of many shallow lakes. Schultz has received reports from DNR field staff of surface water temperatures in some lakes reaching 90 degrees, with temps at the bottom only a few degrees cooler where maximum depths are less than 10 feet. “Those are some high readings and northern pike are especially vulnerable when the water gets this warm,” Schultz said. “They are a cool water species and just can’t adjust to the high temperatures when sustained for more than a few days.” Warm water temps can also impact other species such as walleye, yellow perch and bluegills.

Should the high heat continue, there may be die-offs of both northern cisco (tulibee) and lake whitefish in central and northern Minnesota lakes.

Oxygen depletion can be another factor contributing to fish kills of a broader range of fish species. Heavy rains earlier in the summer caused unusually high runoff from fertilized lawns, athletic fields, golf courses and farm fields, starting a chain reaction of high nutrient loads in some lakes.  

The runoff carries nutrients into the lakes, which combined with hot weather, can accelerate the growth of algae. Hot, dry, sunny and calm weather can cause algae growths to suddenly explode, according to Craig Soupir, DNR fisheries habitat specialist.

“Aquatic plants remain relatively stable over time, but algae have the ability to rapidly increase or decrease under various conditions,” Soupir said. 

Algae produces oxygen during the daylight hours, but it uses oxygen at night. This can create drastic daily changes in lake oxygen levels. These daily changes can result in complete saturation of oxygen during peak sunlight and a near complete loss of oxygen during the night.   “All of this can add up to stressful conditions for fish,” Soupir said, “and even summer kill events.” Fish don’t seem to sense when oxygen depletion occurs and may suffocate in isolated bays, even when another area of the lake contains higher levels of oxygen.

Disease may also be a contributing factor to some fish kills. Schultz explained that when lake temperatures rapidly change, fish can become more susceptible to bacteria and viruses that naturally occur in the water. Columnaris is one of the most common diseases. 

The bacterium is always present in fish populations but seems to affect fish when water temperatures are warming rapidly and fish are undergoing some stress due to spawning. Fish may die or be seen weakly swimming along shores. Species affected are usually sunfish, crappies and bullheads and occasionally, largemouth bass and northern pike.

“It is difficult to pin a summer kill on just one cause,” Schultz said, “and although it is a natural occurrence, it can be disturbing.” 

Fish kills are usually not serious in the long run.  Most lakes contain thousands of fish per acre and the fish kills represents a very small percent of that total. 

Some positive effects from partial fish kills is that it creates an open niche in the fish population, allowing the remaining fish species to grow faster with less competition.  

Minnesota lakes are resilient. The DNR has documented these conditions many times over and lake conditions and fish populations do return to managed expectations, either naturally or with the help of stocking if necessary.

If people see strange behavior, they should contact the local DNR fisheries office immediately. “If we can sample fish before they die, we may be able to learn what’s going on in the lake,” Schultz said.  “Once the fish are dead it can be difficult to determine what happened.”

Announcing the Great Lakes Restoration Initiative – Wildlife Health Event Reporter (GLRI-WHER)!

Calling all beachcombers! Get involved in an effort to improve the health of the Great Lakes!

 

If you are a concerned citizen who spends time near-shore around the Great Lakes in the US and in Canada, or if you are a coordinator with an established volunteer network that can expand their observational power, please consider sharing your observations of injured/dead animals or algal blooms using the Great Lakes Restoration Initiative – Wildlife Health Event Reporter (GLRI- WHER; http://glri.wher.org).

 

In the interest of protecting waterfowl and other wildlife, scientists working in state, provincial, federal, academic and non-profit agencies are looking for your help to identify events that could be important in research on avian botulism and algal bloom outbreaks. Botulism has been responsible for the deaths of thousands of birds in the Great Lakes and events have been increasing in recent years. For a healthy Great Lakes ecosystem, do your part and share what you see!

 

GLRI-WHER was developed by the Wildlife Data Integration Network (WDIN), a program of the Nelson Institute for Environmental Studies at the University of Wisconsin-Madison, in partnership with the USGS National Wildlife Health Center. Project support was provided through a grant from the Great Lakes Restoration Initiative at the Environmental Protection Agency (http://greatlakesrestoration.us).

 

Geographically specific alerts and contacts for local agency reporting are provided with each report, when available. All reports from Canada are shared with our partners at the Canadian Cooperative Wildlife Health Centre (http://www.ccwhc.ca), and from the US at the USGS National Wildlife Health Center (http://www.nwhc.usgs.gov).

 

Citizen scientists involved in existing reporting efforts should continue to follow their program's protocols - get in touch if you would like to find out how to get your program's data included in the GLRI-WHER.

 

Find out more about the GLRI-WHER application online at http://glri.wher.org. Email questions to botnet@wdin.org

glri.wher.org

Photo Credit: USFWS

Flow Continues

May 4: Larry Schweiger, president and chief executive Officer of the National Wildlife Federation, talks with Rachel Maddow about the extent of damage to Gulf coast wildlife expected from the oil spill disaster and the anticipated long-term impact on the ecosystem.

Visit msnbc.com for Breaking News, World News, and News about the Economy

Lake Puckaway fish kill affects netted, penned game fish and rough fish

Contractor hired to remove rough fish from lake is faulted Public meeting scheduled for December 16

MONTELLO - “Final estimates of the number of dead fish as the result of a preventable fish kill in Lake Puckaway in Green Lake County are expected to be completed in several days,” says Ron Bruch, DNR Fisheries Team Leader in Oshkosh.

The fish kill was reported by a Puckaway lakeshore resident who had concerns about the way the rough fish removal contract was being carried out by a carp removal contractor who is permitted to harvest rough fish, primarily carp, from the lake. There has been a contracted removal of rough fish on this lake for several decades without any similar incident. This is the first year with this particular contractor and the contract with him has been terminated.

The north and south shores of the lake where most of the fish were killed are adjacent to the areas where the contractor had set up his net pens. The contractor’s failure to remove the game fish as required from these nets was the primary cause of the fish kill. Thirty per-cent of the fish killed were game fish. Various species of rough fish made up the remaining 70%.

Fresh dead walleye and drum have been collected and sent to the lab in Madison for necropsy and disease testing. “The final tallies of the numbers of walleye that we picked up or were seen dead on shore may be less than we originally thought,” said Bruch, “however the size of the walleyes was impressive -- with many fish over 5 pounds.”

DNR fisheries biologists are collecting the facts about the kill, doing dead fish counts, collecting biological information on the walleyes, and developing estimates of the size of the kill. DNR law enforcement officers are conducting a thorough investigation, have terminated the rough fish contract, and will hold discussions with the Green Lake District Attorney to determine what legal action may be taken.

Fisheries staff are working closely with the district to sort through the information and put together a plan of action to move forward with the management of the fishery. “Several individuals asked whether the DNR was going to stock the lake to re-build the walleye population,” said Bruch who explained that stocking the lake will not replace the large walleyes that were killed. He reports that the walleyes ranged from 18 to 28 inches and were probably 6 to 18 years in age.

Biologists will alter their lake assessment schedule to conduct a fisheries survey on Lake Puckaway after ice is out in the spring of 2010. Until the fish biologists do their assessment of the lake they won’t have an accurate picture of what kind of impact the kill actually had on the fish community. DNR and the lake associations will move forward from that point.

Prior to this fish kill, the DNR had planned to work with the lake district to prepare their walleye wagon to spawn and raise walleye fry for stocking in spring 2010. Biologists reaffirmed their commitment to work with them to make sure they get the eggs from the lake, that the walleye wagon is functioning properly, and that the fry stocked are marked for future assessment.

DNR has scheduled a public meeting to review and discuss the information about the kill and plans for the future. Members of surrounding communities, area businesses, and lakeshore residents are pleased that DNR is moving ahead to actively involve the public. The public meeting will be held at 6:30 p.m. on December 16 at the UW Extension facility, 480 Underwood Avenue in Montello.

The department will advertise this meeting in local newspapers in the Lake Puckaway area and the Lake Puckaway District and Association will get the meeting announcement posted on the Lake District/Association web site.

DNR biologists are confident they will have good data on this fish kill and that they have a solid strategy outlined to move forward.