NEWS: Don't be shad. Fish die-off is common, natural

In recent weeks, hikers along Metroparks streams or winter-stroll beachgoers may have seen a surge of dead fish washed up on the shore.

Is the die-off of these silvery blue-green fish a sign of environmental turmoil, or a natural occurrence? It’s the latter, and it happens regularly.

Shad can’t stand the change: Known as the eastern gizzard shad, this fish species (Dorosoma cepedianum) is not native to Lake Erie or its tributaries, and is very sensitive to rapid temperature changes. Lake Erie’s and streams' water temperature—because of shallow depth and northerly locations—can change very quickly in early and late winter months, causing die-offs of significant numbers of gizzard shad.

“It can be unsightly, but it’s important to note that in most cases the die-offs are natural,” said John Rhoades, Northeast Ohio Regional Sewer District Supervisor of Environmental Assessment.

Colder temperatures slow the shad’s body’s ability to draw nutrients from surrounding water, which commonly leads to starvation during colder months as well, causing further die-offs in December, January and February.

VIDEO: Dead fish near our treatment plant? It's nature and temperature, not pollution.

Are we poisoning fish by releasing polluted water into the Cuyahoga River? Contrary to the YouTube video's inaccurate captions above, we are not.

We were alerted to this video today, a clip that was posted to YouTube January 31 with the title, "NEORSD sewage kills fish in Cuyahoga River." The title and captions were incorrect, but the occurrence is worth a closer look to understand the issues and results.

The simple answer: This kind of fish die-off is a natural event at this time of year, not a result of sewage pollution in our effluent. It comes down to water temperature and temperature-sensitive fish.