This is scientific American 60 second science.

I'm Christopher Intagiyata.

As the world's oceans heat up, salmon are migrating earlier.

Plankton are shifting their range, but warmer water temperatures also mean warmer fish

and faster running metabolisms.

Fish that are in water of higher temperature have a higher metabolic rate, meaning they have to consume more oxygen.

Daniel Polly, a fishery scientist at the University of British Columbia.

Because essentially the whole metabolism, all the chemical reaction in your body are accelerated.

So how about growing bigger gills to allow for more oxygen intake?

Polly did the physiological math on that and concluded that bigger gills just won't do the job

because he says gills being relatively two-dimensional simply can't keep up with the

three-dimensional growth of the rest of a fish's body.

Instead, Polly's calculations suggest that to feed their increasing need for oxygen,

fish of all kinds may actually shrink as a result of climate change.

With decreased supply, they'll need to lower demand.

The studies in the journal Global Change Biology.

One more detail bears mentioning, that is that warmer water also holds less dissolved oxygen.

So the two effects, the increased demand and a lowered supply

are working toward making the fish smaller.

Which means future fishermen might find a lot of lower value small fry in their nets.

Thanks for listening.

For Scientific American 60 Second Science, I'm Christopher and D'Eljata.

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