On the Arctic Feeding Grounds
The whales haven't eaten much for months, mostly fasting until their arctic feeding grounds are once again ice-free. When the gray whales finally reach their summer feeding grounds in the Bering and Chukchi Seas, it's time to feast!
By June and July, the whales are said to be as thick as a huge grazing herd. For months they've been living off fat reserves in the calving and mating lagoons, and along the migration trail. Even though they appear to do a small amount of feeding in fall and winter whenever they can find a food source, whales have a LOT of weight to gain back. Each whale must grow strong and fat before migrating in autumn to the breeding and calving grounds over 5,000 miles south. During its five- or six-month feast on the arctic feeding grounds, an adult gray whale will swallow about 70 metric tons of food.
feeding is better at higher latitudes. Why? Daylight is almost 24 hours,
and such long
days produce lots of phytoplankton. These tiny
marine plants are eaten by zooplankton (tiny marine animals). Together,
these are the basic food for all ocean life. A lot of plankton stimulates
growth of the marine food web, including bottom-dwelling amphipods. Amphipods
are the primary prey of gray whales. It takes a lot of those tiny critters—an
estimated 300 kg (660 lb.)—to
fill a gray whale's stomach!
days shorten. The air chills, and water starts turning into ice. The
know it is time to swim south again in a yearly cycle continues
for as long as they live.