As It Happens

How these fish got stuck in a wall of ice

Kelly Preheim snapped this shot of a four-foot tall sheet of ice dotted with frozen fish while out birding in South Dakota. She explains to As It Happens guest host Helen Mann how they got there.
Photographer Kelly Preheim captured this image while out birding in the Lake Andes National Wildlife Refuge in South Dakota. (Kelly Preheim)

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We know this much: They're fish. They're dead. And they're frozen into a vertical sheet of ice. How did they get there? Kelly Preheim, the South Dakota birder who snapped the picture, explains the fishcicle mystery to As It Happens guest host Helen Mann.

Kelly Preheim teaches kindergarten in Armour, South Dakota. (Facebook)

Helen Mann: Ms Preheim, maybe you could create an image for our listeners of this photo that you took on Lake Andes?

Kelly Preheim: I was out birding, actually. And I looked up and I saw this — well, it looked like a wall of ice with fish trapped in it. And the fish, of course, were frozen and dead, but the way their stance is, it looks like they're leaping out of the water. 

HM: And how many fish are we talking about?

KP: Well in this picture it looks like there's about a dozen to 15. But the surface of the lake in some parts had thousands of dead fish. 
A bald eagle sits on Lake Andes in South Dakota surrounded by fish frozen in the ice. (Kelly Preheim)

HM: And this wall of ice and fish, how high is it?

KP: It was about 4 feet tall. And that was the nicest sheet of it, but all the way down there were pieces of it jutting out of the water. I wish I would have taken more pictures, but I didn't.
Another image of fish frozen in the ice at Lake Andes National Wildlife Refuge, taken a few days after the original, as the ice began to break up. (Kelly Preheim)

HM: How did you find out what happened to these fish?

KP: Well, I talked to the biologist at the Lake Andes Wildlife Refuge, and I also talked to the biologist at the university and asked them a lot of questions. This is what they think happened: There was thick ice on the lake and the heavy snowfall covered the surface, and that prevented the sunlight from getting down below. It prevented the algae and aquatic plants from conducting photosynthesis, and so the oxygen levels therefore dropped in the lake. So then the fish suffocated and died, and later the fish floated to the surface, and they were kind of stuck in the ice all along.

And then, I'm not really sure why, but the ice expanded, and when it hit the shoreline for some reason it was forced upward. It sort of buckled up. So whatever was stuck on the surface of the ice, those fish were pushed straight up, and that's how we got this strange image.

HM: Did all those fish smell?

KP: Oh, it smelled so bad out there. Not right away. When that fish picture was taken there wasn't a scent then but as it started to thaw, it was a really smelly spring. 

This transcript has been edited for length and clarity. For more on this story, listen to our full interview with Kelly Preheim.