It’s a fact that acidic oceans become corrosive and prevent sea creatures from growing skeletons and shells.
Now, for the first time, scientists have shown that acidic waters snuff out wild salmon’s sense of smell.
Salmon use smells to hunt for food, avoid predators and navigate back to their home streams to spawn.
The same has been proven in other fishes, but University of Washington and NOAA researchers are the first to put wild salmon to the test.
Their experiments on young cohos showed that high levels of acidity literally ‘messes with the salmon’s brains’ and turns off their ability to smell.
The fish didn’t sense alarm smells from predators or unsafe settings that would normally make them freeze up or swim away.
Copper also snuffs out wild salmon’s sense of smell.
In studies of road runoff into waterways, Oregon State University scientists found copper levels as low as two parts per billion affects juvenile salmon and avoidance behavior was almost nonexistent at higher levels. Jason Sandahl is study co-author –
“In the environment, that has some serious implications. If there are predators around and the fish are not able to respond to these danger signals in the water, I guess they would be the next snack for these larger predators in the water.”
Research indicates copper from highway runoff into waterways may play a key role in the declining salmon stocks of the Pacific Northwest.
Today’s off kilter ocean cocktail has scientists looking closely at potential impacts on sea creatures.
“Are they going to grow slower? Yes, it’s going to affect their metabolism, their growth, maybe their reproductive output.”
Bob Foy is director of the NOAA research lab at Kodiak. More critically, he says, are impacts on food webs. Already, tiny snail-like pteropods are showing signs of struggle with growing their shells. Pteropods account for nearly 50 percent of the diet of wild pink salmon.
“Understanding the impacts on fish, mammals and sea birds – it’s not only going to directly impact some animals – it is going to impact the ecosystem and the food webs. And that may be more important to us than we realize.”