Update on Gray Whale Unusual Mortality Event: November 2020

November 2020: Update on Gray Whale Unusual Mortality Event

In May of 2019 the U.S. National Oceanic and Atmospheric Administration’s Fisheries Service (NOAA Fisheries) announced that the elevated rate of gray whale strandings during their spring northward migration along the West Coast of the United States constituted and Unusual Mortality Event (UME). In response, NOAA Fisheries activated a working group of experts that monitor gray whales throughout their North American range to investigate these gray whale mortalities. This UME continued into 2020 with additional strandings along the Pacific coasts of Mexico, the United States, and Canada. As of October 2020 NOAA reported that a total of 384 gray whale strandings had been reported and investigated. (See NOAA Fisheries announcement:  https://www.fisheries.noaa.gov/national/marine-life-distress/2019-gray-whale-unusual-mortality-event-along-west-coast)

As we reported earlier this year, LSIESP researchers monitoring the gray whales in Laguna San Ignacio and Bahía Magdalena, Baja California Sur, Mexico detected indications an impending UME as early as winter 2018 and again in 2019. Specifically, they documented declining calf counts in the breeding lagoons, increasing percentages of “skinny” and “emaciated” whales, and the late arrival of the whales (See previous research Blogs at:  https://www.sanignaciograywhales.org/research/research-blog/ ).

LSIESP researchers provided the NOAA UME working group two presentations of their observations of stranded gray whales in Mexico. The first report summarized the known gray whale strandings that occurred from winter 2019 to winter 2020 in Baja California and other locations in Mexico.

See full report at:  LSI web link here….

The second report summarized observations of the body condition of gray whales observed by LSIESP researchers in Laguna San Ignacio, Laguna Ojo de Liebre, and Bahia Magdalena in Baja California Sur, Mexico.

See full report at:  LSI web link here….

Of continuing concern is our lack of full understanding of the underlying cause of such mortalities. Oceanographers are describing conditions of warmer-than-normal sea temperatures in recent years in the North Pacific/Gulf of Alaska and along the west coast of North America. These oceanic conditions have persisted from 2015-present, and may have reduced the “carrying capacity” of the gray whales’ feeding areas.  Even more alarming is that changes in the northern seas are affecting the seasonal phytoplankton and primary production cycles, which form the base of the marine food chains for many Arctic species. Increased mortalities and reduced reproduction are also occurring in species of marine fish, birds, seals and whales. Skinny gray whales and low calf production, and increased mortalities during migration do suggest that insufficient food over the summer may be contributing to the overall increase in gray whale and other species mortalities.

LSIESP researchers are preparing to continue to monitor the whales’ abundance, calf births, and mortalities during the 2021 winter months in the Baja breeding lagoons. However, the COVID-19 pandemic outbreak in 2020 may severely limit travel, field operations, and group activities necessary to conduct this research. While the collection of new data on gray whale strandings and condition is highly desirable, our FIRST PRIORITY is to safeguard the health of LSIESP’s researchers and their families, and to reduce the potential for exposing the local lagoon residents and our researchers to coronavirus. LSIESP researchers may modify their proposed research program to ensure that everyone remains safe, and are not exposed to the risk of COVID-19 infections. We will post updates on our winter 2021 gray whale research plans in Baja California in the coming weeks as we approach the beginning of the research season in January 2021. We are hopeful that we will be able to gather additional information on the health and status of gray whales following the UME of 2019 and 2020, but our priority is to keep all our researchers safe and healthy by avoiding any unnecessary exposure to the COVID-19 virus.

Watch our website for updates on the winter 2021 gray whale research plan.