51. Insights into Blue Whale (Balaenoptera musculus L.) Population Movements in the Galapagos Archipelago and Southeast Pacific.
- Author
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Guzman, Hector M., Estévez, Rocío M., and Kaiser, Stefanie
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BLUE whale , *WATER temperature , *ARTIFICIAL satellite tracking , *FORAGING behavior ,EL Nino - Abstract
Simple Summary: The Galapagos Marine Reserve supports cetaceans such as blue whales by providing essential foraging areas and resting areas. From 2021 to 2023, a study utilized satellite tags on 16 blue whales to monitor their movements and gain insights into their interactions with the marine environment. This involved the identification of their feeding grounds, indicated by chlorophyll levels, surface water temperature (SST), and ocean productivity. The study revealed that blue whales prefer areas with presumed increased prey abundance, cooler water temperatures, and specific underwater features such as ridges that likely enhance favored food sources. Most of the tagged whales remained in the Galapagos, particularly near Isabela Island, where there is an elevated risk of collisions with boats due to increased marine traffic. Some whales ventured into Ecuador's waters, and one even traveled to Peru. In 2023, an intense El Niño event led to changes in water temperatures and food availability, significantly impacting whale habitats. This research contributes to efforts to protect whales from ship collisions and understand and adapt to changes in their migration patterns due to climate variations. The Galapagos Marine Reserve is vital for cetaceans, serving as both a stopover and residency site. However, blue whales, occasionally sighted here, exhibit poorly understood migratory behavior within the Galapagos and the broader Eastern Tropical Pacific. This study, the first to satellite tag blue whales in the Galapagos (16 tagged between 2021 and 2023), explored their behavior in relation to environmental variables like chlorophyll-a concentration, sea surface temperature (SST), and productivity. Key findings show a strong correlation between foraging behavior, high chlorophyll-a levels, productivity, and lower SSTs, indicating a preference for food-rich areas. Additionally, there is a notable association with geomorphic features like ridges, which potentially enhance food abundance. Most tagged whales stayed near the Galapagos archipelago, with higher concentrations observed around Isabela Island, which is increasingly frequented by tourist vessels, posing heightened ship strike risks. Some whales ventured into Ecuador's exclusive economic zone, while one migrated southward to Peru. The strong 2023 El Niño–Southern Oscillation event led to SST and primary production changes, likely impacting whale resource availability. Our study provides crucial insights into blue whale habitat utilization, informing adaptive management strategies to mitigate ship strike risks and address altered migration routes due to climate-driven environmental shifts. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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