Summer in the Arctic

Just what is a self-respecting whale doing in the cold Arctic waters?

Polar regions are rich in whale food. The long days and abundant sunlight of the summer favor the growth of tiny plants called phytoplankton. During this time, cold water from the bottom moves up toward the surface. The cold water is full of the nutrients phytoplankton need to grow. Lots of nutrients, lots of light cause a rapid increase in phytoplankton numbers; the phytoplankton “blooms”.

There are lots of these tiny plants available to be eaten. As a result, the populations of tiny animals called zooplankton also explode. Other animal populations, including the bottom dwellers, also increase. These populations of bottom dwellers provide food for California gray whales.

So, grey whales spend their summers in cold Arctic waters because so much food is available.

But some dangers are on the horizon. The warming climate is melting the ice cover. This melting is changing how much food is available for gray whales. Less ice cover means less phytoplankton which means fewer bottom dwellers. Fewer bottom dwellers means less food for gray whales. So, there may be more days to feed but less food to eat.

Shorter days and falling temperatures signal that it is time for the whales to stop feeding. They turn south and begin their great swim.

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