Scientists Tag Humpback Whales In Southeast Pacific

2017-04-17T10:27:10+00:00 April 17, 2017|
A humpback whale and its calf in NOAA's Hawaiian Islands Humpback Whale National Marine Sanctuary. (Credit: NOAA)

(Click to enlarge) A humpback whale and its calf in NOAA’s Hawaiian Islands Humpback Whale National Marine Sanctuary. (Credit: NOAA)

Whales from both poles migrate long distances to breed in tropical waters. Smithsonian scientist Hector M. Guzman and Fernando Félix at the Salinas Whale Museum in Ecuador, tagged 47 humpbacks with satellite transmitters to understand how the humpbacks’ Southeastern Pacific population moves within breeding areas.

(From Science Daily) — “Our work fills an informational void: we’ve known these whales move between feeding areas and breeding areas, but we hadn’t characterized their movements, and we couldn’t exactly pinpoint the range of the breeding area,” said Guzman, marine ecologist at the Smithsonian Tropical Research Institute (STRI) in Panama. “Now we know that individuals move between countries within the breeding season and that their entire breeding area extends approximately 2,600 kilometers of non-straight coastline from Costa Rica to Peru.”

For years, scientists have identified individual humpback whales (Megaptera novaeangliae) based on their unique fluke and dorsal fin patterns. In this study funded by STRI, Panama’s National Office of Science and Technology, the Candeo Fund at the International Community Foundation and the Whale Museum, 25 whales were satellite tagged in Panama and 22 in Ecuador between 2009 and 2015 according to methods approved by the Smithsonian’s Animal Care and Use Committee (IACUC). On average, tags transmitted for about two weeks, although one tag lasted for 69 days during which a mother whale swam nearly 6,000 kilometers. Information from the 37 tags that transmitted for at least 1 day revealed the movements of 23 mothers accompanied by newborn calves and 14 unsexed animals.

“Thanks to new spatial models that were used to evaluate the movement of the whales, we could differentiate behaviors and gauge the speed of the whales during their reproductive and migratory periods,” Félix said.

Part of the Southeast Pacific humpback whale population breeds in Panama’s Las Perlas Archipelago and in the Gulf of Guayaquil in Ecuador. The roughly 60,000 square kilometers of home range of the group in Panama was about twice the size of the home range of the group breeding in Ecuador — about 26,000 square kilometers, which means whales are not randomly distributed but show site fidelity. Whales tended to spend time in short-range movement, alternating with long-range, faster, directed movement. Mothers spent more time closer to shore than other tagged, unsexed individuals. Both types of whales swam into deeper waters mainly during migration. Mothers in Panamanian waters spent much more time in long-range movements than did mothers in Ecuadorian waters, perhaps because they were shifting from a nursing phase to a migratory phase.

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