The Gray whales do the longest known migration of any mammal. They travel 10,000-12,000 miles round trip every year between their winter calving lagoons in the warm waters of Mexico and their summer feeding grounds in the cold Arctic seas. For the migration period of March-April 2018 I used my dorone to photography them. As people walk on the beaches of south California they get to see maybe just the back bone or tail of a whale, but from right about them I got to observe their behaviour.
From NOAA - How Climate change is affecting Gray whales; While the physical changes in the Arctic environment associated with climate change, such as reduced ice cover and loss of multi-year ice, are well documented, the biological impacts of these changes are not as well understood. There are indications that formerly sub Arctic species of mid trophic organisms (primarily zooplankton and fish) are extending their ranges northward and the introduction of these may disrupt the direct linkage between primary production and the rich benthic communities that have historically been the primary prey base for gray whales.
Since the early 1990s, there has been a general northward shift in the primary feeding grounds for gray whales from the previously rich benthic communities of the Chirikov Basin into the Chukchi Sea. Now large aggregations of gray whales have become a nuisance to native hunters out of Barrow, Alaska who are in pursuit of bowhead whales. How much of this shift in feeding behavior is the result of the slow warming of the Arctic environment and how much is caused by over grazing of benthic communities by a large gray whale population is still a matter of debate.
What is clear is that gray whales have increased the amount of time they spend feeding far north of the Bering Straits. In addition the timing of their southbound migration is occurring later and there is a strong link between the timing of the melt of seasonal ice in the Bering Sea and the number of calves counted in the following spring. There have also been more observations of “skinny whales” in the lagoons and along the Pacific Coast, but it is difficult to determine how much of this is the result of more sensitivity of scientists and the public to gray whale condition following the unusual mortality event of 1999 and 2000.