The grey whale (Eschrichtius robustus) is set to begin its annual winter migration from Alaskan waters to the coast of Mexico. Scientists along the Big Sur coast are primed to watch these whales as they pass through the shallow, narrow shelf at Granite canyon.

The migration begins in December as the whales head south to breed, and they can be seen to complete this round trip by April. Often during the northern migration, mothers can be seen along the Pacific-side of calves, in order to protect the young from attack. According to Big Sur California, these calves may weigh up to 1,500 pounds at birth, at a length of 12 to 15 feet.

Scientists with NOAA’s Southwest Fisheries Science Center will be waiting to survey and catalog the entire population using binoculars and thermal cameras.

With over 50 years of survey data, scientists are able to recognize trends in the grey whale population. These whales were in danger of extinction around the beginning of the 20^th century. They have been protected from hunting by international law. In recent times their population has stabilized to around 22,000 and as a result they were taken off the United States endangered species list in 1994.

As the grey whale spends most of the summer in the northern Pacific, it is unclear how climate change will affect the species.

“For polar bears and walruses, the changing Arctic has definitely been bad for them…for gray whales, the jury is still out,” said Dave Weller, survey leader at the Granite Canyon research station.

As these whales migrate close to the shore, watching their migration has become a popular activity for enthusiasts. According to National Geographic, the whale feeds along the seafloor, dislodging food with its snout and filtering these morsels with its baleen—a comb-like strainer of whale bone in the upper jaw.