Gray Whales in the Eastern Pacific
A sign of oceans in peril?
Each winter gray whales migrate from their feeding grounds in Alaska to peaceful embayment’s along Mexico’s Pacific coast. They make one of the longest migrations of any mammal, up-to 12,000 miles. In recent years a mysterious die-off has occurred cutting down the grey whale population by a quarter and in Baja, whales have been arriving much later and look malnourished too. A large number of whales had been washing up on shore and many of them with a jagged outline of vertebrae on their typically fatty backs.
The grey whale reaches a length of 14.9 meters and can weigh up to 40 tons. It has an average life span of 55–70 years although some can also live up to 80. The species were once called “Devil Fish” due to their aggressive fighting behavior and retaliation when hunted in the early 1800’s and 1900’s. Their blubber was used to produce oil in lamps and these whales were easily accessible to hunters due to the fact that they stay close to the coast. For this reason, they became overhunted in Mexico and Southern California. After nearly being extinct, Pacific Gray Whales became protected by international organizations. In 1946, the International Whaling Commission was established and since 1947, gray whales have been protected under that as well as the Endangered Species Act and Marine Mammal Protection Act in the US. The population in the Eastern Pacific has now rebounded to an estimated 19,000 which is considered a healthy population. Furthermore, in 1994 Gray Whales were de-listed from the Endangered Species List.
Since 2019, a group of international scientists and field biologists have been working on this Unusual Mortality Event. However, the issue is that there is no clear-cut explanation for this, yet. In-between the years of 2016–2020, grey whale population dropped from nearly 27,000 of them to 20,500. Drone footage also shows that the whales have been arriving much leaner than in previous years and appear to not be migrating with enough food. In 2020 when 174 whales washed up on their migration route, the Marine Mammal Center was only able to complete one necropsy which showed that they were not leaving the Arctic with enough food.
Some scientists say that this is a result of overcapacity whilst others turn towards the hazards whales face such as plastic pollution, ship strikes and everchanging eco-systems. Most blame climate change and the melting ice sheets in the arctic which alter water temperatures and oceanic currents as well as changing the food supply for sea creatures. However, researchers do come to agree that whales have been a conservation success story having bounced back from near extinction and commercial whaling, hence their ups and downs are key gauges for the health of the ocean. This Unusual Mortality Event has also had an effect in Mexico, where villages on the Baja Peninsula have to rely financially on the yearly arrival of the whales. The operators and guides for these small whale watching companies were also the first to notice that grey whales started arriving late in 2019, with very few mother-calf pairs. This pattern was last seen in Baja nearly 20 years back when there was a significant die off in grey whales, which could be a concerning indication that something is going wrong.
In March 2021 a gray whale was spotted in the San Francisco Bay, swimming around Angel Island. It remained in the bay for forty days before it washed ashore, dead. The necropsy indicated that this specific whale was malnourished. In a recent CNN article, published in March of this year, Kathi George, director of field operations at the Marine Mammal Center is quoted saying, “We’re seeing more whales come into the bay. We are seeing them stay for longer periods and they are feeding.” Whales that make their way into the bay are malnourished and looking for food, which means they are often more susceptible to ship strikes. All whales are extremely sensitive to unnatural ocean noises, which means that a revving engine could easily startle them into a shipping line, where they could get hit.
On Alaska’s Kodiak Island many gray whales have been rolling around in shallow waters using their eight feet long jaws to search for shrimp like creatures. An LA Times article published in early 2021 reports that dozens of whales had been appearing in the San Francisco Bay, which amused and excited the general public, but puzzled experts such as Bill Keener, a whale expert at the Marine Mammal Center based in Sausalito, who was quoted saying “It’s amazing to see them here, so close, but really concerning too.” The article later states that after the National Oceanic and Atmospheric Administration had analyzed many dead whales over three years, it was still extremely difficult to give an outright reason as to why so many were dying. 246 of the whales that they had analyzed were in a state of advanced decomposition making it impossible to understand what happened.
In the same CNN article, Jackie Grebmeier, a professor at the University of Maryland Center for Environmental Science conducts her research about the food cycle focusing on ecology through prey life. She concludes her research saying that, “I think the quality of food that are getting is less than what they did in the past.” She found that there was just less of any single source. The main reasons for the reduction in variety for the gray whales are changing currents and warmer waters. Fattier sea bugs which whales feed on cannot survive warm waters for long periods. A change in the temperature of water also changes the speed of currents. Slower water means more fine sediment reaches the sea bed where the sea creatures live which all results in less choice of food for the whale.
The die-off in gray whales could very well be an interaction of many factors. The most alarming thing amongst scientists is that many gray whales have been veering off into strange places such as Washington’s Puget Sound, which is way off their migratory path. Many suggest that they are hungry and looking for food, since they appear to be malnourished. Consequently, by swimming into places such as the San Francisco Bay, an area with high vessel population, the are at a higher risk of being hit or being frightened by unnatural ocean sounds. The warming water temperatures are also affecting their food. Before migrating to warm waters, gray whales feed in Alaska. They are able to feed in big amounts over just a few weeks and now, appearing malnourished can only tell us that there might as well be a lack of food in the ocean. Sea bugs which gray whales feed on, cannot survive warm waters for long, hence the warming waters may be causing peril for the gray whales.
It is important to remember that most scientists believe that the gray whales are very important indicators of our oceans health since they survived commercial whaling and rebounded in population with the help of protection laws. As humans we can always reduce our carbon footprint to help keep the ocean cleaner for these mammals. Less use of plastic and little changes in the way we live can go a long way in reducing energy use and carbon dioxide. We can also encourage sensible vessel practice and understanding the distribution of marine mammals so that there is reduced number of vessels strikes. There is a possibility that the resilient gray whale population will rebound naturally, just as they did decades ago. However, the bigger picture is that there are signs of massive change our ecosystem is undertaking, which is all a result of climate change. We must take environmentally-friendly decisions in the next few years and work together on what is in our control, so that we can protect species which have forever been on this earth.