Annual Gray Whale Report for Laguna San Ignacio and Bahía Magdalena, B.C.S., México

Annual Gray Whale Report for Laguna San Ignacio and Bahía Magdalena, B.C.S., México

Winter 2023

Two gray whales at the surface of a calm sea

2023 Program Summary

Beginning in 2018 observations of declining gray whale body condition, low calf counts, and higher mortality rates in both Laguna San Ignacio and Bahía Magdalena were indications of the pending Unusual Mortality Event (UME) which has continued from 2019 through 2023. However, information gathered in in 2023 in these southernmost gray whale wintering areas suggests that the UME may be slowing in 2023 and include: fewer individual whales in “poor” body condition, the first increase in the numbers of calves observed during the previous 5 winters of low female-calf counts, and fewer stranded dead whales in these wintering lagoon areas.

In this report we present our initial findings during the 2023 winter concerning the status of gray whales, their condition and reproduction, and our outreach activities from hosting university students on field trips, to introducing the public to a new gray whale research and whale-watching monitoring program in Bahía Magdalena.

Outstanding events and activities in 2023 include:  2023 Research Staff and collaborators(Page 4), Abundance of single gray whales in both Laguna San Ignacio and Bahía Magdalena wintering areas were greater than that observed in recent years, along with some modest increase in the numbers of female-calf pairs indicating improved overall condition (Page 5), Boat-based traditional photo-Identification surveys documented the number and residence times of 1,540 individual whales that visited Laguna San Ignacio and Bahía Magdalena (Page 11), Photographic identification from Unmanned Aerial Vehicles (UAVs) updates historical photo-id data (Page 14), Declining number of dead stranded gray whales in the wintering lagoons suggests the 2019-2023 UME may be slowing (Page 15), Boat-based gray whale body condition assessment suggests some improvement in the overall condition of whales (Page 16), Unmanned Aerial Vehicles (UAV) assessment of body condition complements the boat-based method for evaluating body condition (Page 21), Gray whale strandings and mortality in Mexico lowest in five winters (Page 24), Sightings of additional cetacean species in 2023 (Page 28), Community outreach and educational activities (Page 29), and Reference Documents and Reports (Page 34).