IRONDEQUOIT, N.Y. (WROC) — If you’ve been to Lake Ontario recently, you might have noticed thousands of little dead fish all along the shoreline, leaving many to ask if this a big environmental concern, or caused by pollution? 

“It’s a mass killing, so the question is ‘what killed them?’ Is it like an algae bloom?” said Nick Hessong, who expressed concern about fish and the quality of the water.

Others have said it’s no big deal, like Greg McHugh, who is visiting from Jamaica.

“We’re used to seeing the skeletons of the fish on the beach and sand,” McHugh said.

So what gives? Christopher Legard with the Department of Environmental Conservation says these fish are probably alewives or round goby, non-native fish at their northernmost point. 

Dead fish scattered along Durand Eastman Beach

“So, in the springtime, these kinds of fish die off, so we see these [types of fish] every year,” Legard said.

DEC officials say this thing is actually kind of normal, seeing these thousands of dead fish all up and down the shoreline. And they say don’t worry, it’s not due to anything like pollution. This time of year, when cold winds shift the water temperatures around, it’s a shock to a fish’s system. 

“And that’s what causes the spring-time die-offs,” says Legard.

There should not be any reason for concern he says.

“As things get warmed up, the die-offs usually taper off,” Legard said. “So when we get into the swimming season, they’re typically not so many of these happening. These springtime die-offs are generally not connected to any type of pollution or fish disease.”

Legard says the fish and fishing are great in Lake Ontario and encourages all to get out there on the water.