Delta and Dawn
pair of humpback whales who swam up the Sacramento River
Delta and Dawn, also known as the Delta whales, are two humpback whales, a mother and her calf, who entered San Francisco Bay in early May 2007. They swam up the Sacramento River approximately 90 nautical miles (170 km) upstream from the Golden Gate, about 20 miles (32 km) farther inland than Humphrey the Whale had gone two decades earlier. Under the Endangered Species Act, California state officials were required to rescue the animals. Their journey was thought to be the longest freshwater incursion by humpback whales ever documented.
Efforts to save the whales
Staff from the Marine Mammal Center, researchers, Coast Guard personnel, and volunteers tried several methods to coax Delta and Dawn back downriver. The Marine Mammal Center was appointed by the California Office of Emergency Services as the lead rescue agency. Officials played recordings of the sounds of other humpback whales feeding and socializing to lure them, and banged on submerged metal pipes and sprayed high-powered blasts of water to repel them, but it is not clear whether any of these methods were particularly effective. There was heightened concern for the whales' well-being this time, because both of them had sizable gash wounds, most likely sustained from boat keel or propeller strikes. Veterinarians from the Marine Mammal Center and the Woods Hole Oceanographic Institution administered antibiotics to the whales to help heal these deep open wounds, and they took samples of skin lesions incurred during the whales' extended time away from seawater to analyze them for possible freshwater bacterial infection. This was the first time antibiotics had been administered to free-swimming whales in the wild.
The public source identifies “Delta and Dawn” as pair of humpback whales who swam up the Sacramento River. This brief keeps that definition visible, then builds a research path around Delta, Dawn and pair.
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This entry incorporates text from “Delta and Dawn” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.