Fish die-offs final remnant of long, hard winter

Just about everyone will agree that the winter of 2013-14 was one of the harshest in several years.

Now, however, the long lingering snow is gone, the massive ice floes on Lake Superior have blown off shore (for now) and temperatures are rising, and winter is only a fading memory – almost.

For those who enjoy spending time along the streams and inland lakes across the region, one more sign of the tough winter remains. This remnant is dead fish, just recently floating to the surface after dying over the winter due to lack of oxygen.

According to the Michigan Department of natural Resources, winter-kill is the most common type of fish kill, particularly during severe and long winters, and most commonly occurs in shallow lakes, streams and ponds.

The reason behind the die-offs of large numbers of fish is the oxygen is diminished by thick ice and snow cover, which triggers a chain-reaction process involving decomposition of dead aquatic animals that further reduces the dissolved oxygen level.

The fish are coming to the surface now because the water is warming up and the fish are bloating, after being preserved in the frigid water.

Anyone discovering numerous dead fish floating on bodies of water or washed up on shore shouldn’t be alarmed, though, as the DNR reports the fish populations can overcome the large die-offs and rebound quite quickly.

Anglers might notice a few less fish taking their offerings, but DNR Fisheries Division research section manager Gary Whelan said most of the die-offs are localized and usually there is little damage to the fish populations and the quality of fishing.

That said, if anyone discovers a situation that appears as though large numbers of fish were killed by other than natural causes – such as contaminants in the water, for example – they should call the nearest DNR office or Michigan’s Pollution Emergency Alert System at 800-292-4706.

It won’t be long before this last reminder of the long, harsh winter of 2013-14 is gone, and we can all settle in to a hopefully pleasant summer.