Fishy Smell (Don’t Ask, Don’t Smell)

Group of Fish

When our noses are plugged, we sound stuffy and have trouble breathing. When fish noses are plugged, they get lost, and lose the ability to have sex. Bummer.

They also can't detect other animals that want to eat them. So, their stuffy noses have life and death consequences.

Scientists have known this for decades, but only recently discovered that dissolved herbicides, pesticides and copper produce similar effects. In fact, a series of studies conducted over the past six years found that exposure to these substances, which are commonly found in streams, interferes with a fish's finely-tuned olfactory communications. Not only does this happen with fish, but to every water organism they tested including fleas and leaches.

Run-off of pollutants from rural and urban developments has increased dramatically in recent years. And because fish like salmon rely on smell to find their way home to spawn, it might help explain why they're disappearing from our streams.

One thing we do know for certain, is that while fish may smell funny to us, losing their sense of smell is no laughing matter for them.

Script by Dan Maxwell
Copyright 2007, Catalina Island Conservancy

Discovery Links

To learn more about today’s topic, please explore the links below:

• Northwest Fisheries Science Center
• Sublethal Effects of the Carbamate InsecticideCarbarylon Coastal Cutthroat Trout (pdf)
• Descent of Smell
• Nonpoint Source Pollution and Stormwater (NOAA Coastal Storms Program)