Fish kills common following a long, brutal winter


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As much as people have complained about the extreme conditions of the winter of 2014, there has been an actual toll on aquatic life.

Long and brutal winters cause small ponds and lakes to freeze over and limit the resources that aquatic life need to survive.

As temperatures increase, the ice and snow melt, and dead organisms that used to live underwater wash up on shore.

Officials said the fish suffocate from a lack of dissolved oxygen as its resources diminish.

Christian LeSage, a fisheries biologist with the Department of Natural Resources, said the ice that freezes over these waters acts like a “tupperware container” over the lake or pond.

“Things that decay utilize oxygen, as well, so you used to have plants that were producing oxygen due to the sunlight,” he said. “The fish were allowed to utilize that, but as a longer duration of no oxygen getting into the system, the [remaining] oxygen begins to get used up.”

In addition, LeSage said the death of aquatic life also decreases dissolved oxygen levels in the water.

“When there is no sunlight, [the fish] are not producing oxygen,” he said. “They are expiring, as well, so they’re taking oxygen out of the system. Plus, when the die and start to decay, that activity strips oxygen from the system.”

LeSage said fish and other aquatic life may appear “fuzzy” on the surface because of secondary infection by fungus. Fungus is not the cause of death to the aquatic life.

He also said smaller bodies of water are more prone to fish kills because there is less oxygen circulation.

Along with fish, common aquatic life affected by winterkill are turtles, frogs, toads and crayfish.