Authorities Say Minnesota Fish Kill Was Not a Pure Occasion

Authorities in southeast Minnesota are nonetheless investigating a fish kill that concerned a minimum of 2,500 fish in Rush Creek. The Minnesota Air pollution Management Company, the Division of Agriculture, and the Division of of Pure Sources launched an investigation into the die-off occasion final week. The trigger remains to be unclear, however authorities (and a few anglers) consider it was probably the results of fertilizer runoff from close by farms.

“Area crews from the three companies have collected fish and water samples and are analyzing outcomes to assist decide the reason for the fish kill,” MPCA spokesperson Mike Rafferty informed Minnesota Public Radio final week.

Related die-off occasions up to now have been linked to fertilizer and pesticide runoff after rain occasions. And as MPR identified, storms dropped heavy rain in southern Minnesota on July 23, which is across the identical time the fish kill occurred.

The DNR explains on its website that it sees as many as 500 of those die-off occasions yearly, most of that are attributed to pure causes equivalent to heat water temperatures and low dissolved oxygen ranges. Human-caused fish kills, then again, are often the results of poisonous chemical substances, fertilizers, pesticides, or another pollutant spilling right into a stream.

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The company notes that when a die-off occasion appears to have an effect on just one species or measurement vary, it’s often the results of some illness or different pure trigger. However when the die-off contains a number of species and measurement ranges, “human exercise is extra more likely to be trigger.”

The fish kill that happened within the higher finish of Rush Creek on or round July 23 concerned 75 p.c brown trout. The remaining had been warm-water species equivalent to suckers, in keeping with the Rochester Post-Bulletin.

Whereas Authorities Search the Trigger, Advocates Ask for Change

Rush Creek, situated in Winona County, is among the extra well-known trout streams within the space. The DNR estimates a inhabitants measurement of between 65 and 230 trout per mile, and the state maintains these numbers by stocking as much as 20,000 brown trout fingerlings yearly.

However whereas subsequent yr’s stockings ought to assist mitigate the losses, this hasn’t saved some advocates from talking out. John Lenczewski, the manager director of the Minnesota chapter of Trout Limitless, and Mark Reisetter, the vice chairman of the TU chapter, informed reporters that many anglers are pissed off by these die-off occasions. During the last 5 years, they’ve witnessed a minimum of one trout kill per yr in that nook of the state, together with main die-off occasions on the South Department of the Whitewater River in 2015 and in Garvin Brook in 2019.

Reisetter, who lives close to Rush Creek, informed the Publish-Bulletin he may scent manure being unfold within the days main as much as the July 23 rainstorm. He additionally famous that a few of the useless fish had been discovered up within the grass, signifying that they died when the river was larger.

MPCA spokesperson Lauren Lewandowski additionally confirmed on Tuesday that the fish kill was not a pure occasion.

“We might not be capable to pinpoint [the cause] as a result of nature of the river and flowing water,” she informed the native information outlet. However she additionally introduced up the heavy rain that occurred on July 23, saying “such rainfall occasions are identified to lead to contaminated runoff to streams and rivers.”

Whereas the MPCA and different authorities look again to find out the reason for the fish kill, Lenczewski says he’s extra involved in regards to the future. He desires regulators to make the mandatory adjustments in an effort to defend Minnesota’s trout streams from air pollution.

“What we wish is to see one thing occur,” Lenczewski mentioned. “If it’s a query of when manure software ought to happen, and the foundations aren’t clear sufficient or have to create some cushion for timing, then let’s change these guidelines. If it’s pesticide or fungicide software guidelines, nicely, let’s change these guidelines so this doesn’t proceed to occur.”