The Environment Report
12:40 pm
Thu April 3, 2014

The extensive ice cover could delay fish migrations in the Great Lakes

 

The story about delayed fish migrations begins one minute in.

The prolonged winter and the ice cover on the Great Lakes could lead to some lasting effects on wildlife.

For one thing, scientists expect that a lot of the fish that people like to catch will be showing up late to the places they usually spawn.

Solomon David is a research scientist at Shedd Aquarium in Chicago.

David basically chases fish around for a living.

He says that the spawning season will happen a bit later than it usually does. It's expected that Northern pike, lake sturgeon, steelhead, rainbow trout, and even some yellow perch and walleye will be late to spawning grounds.

"A lot of the migrations are triggered by water temperature and, to a lesser extent, light availability and the (water) flow."

"A lot of the migrations are triggered by water temperature and, to a lesser extent, light availability and the (water) flow. So the longer the winter lasts, and the stronger the ice cover is, the colder the water will be and they may not get those triggers to move into their spawning grounds until later in the year."

The effects of the cold temperatures could also impact fish that haven't been born yet.

"If the migration is later, the eggs will be laid later, they will hatch later and those young fish will have less time to grow up." 

David says that if the fish are smaller going into next winter, they may not have enough energy to keep them going throughout the winter.

So researchers are watching whether fish populations will take a hit because of the long winter.

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