WASHINGTON (CN) - Scientists have drone photographs showing healthy killer whales off the coast of Washington state, a federal agency said Wednesday.
Scientists photographed endangered killer whales with an unmanned aerial vehicle, or drone, called a "hexacopter," to study their health ahead of the oncoming El Nino.
Primarily they wanted to know if the Southern Resident population is getting enough to eat, since a main prey source, Chinook salmon, is also endangered, according to the National Oceanic and Atmospheric Administration (NOAA). El Nino and warm ocean conditions have in the past led to declines in salmon.
Currently, scientists do a summer census to learn out how many whales have died since the year before, according to NOAA's website. "But mortality is a pretty coarse measure of how well the population is doing because the problem, if there is one, has already occurred," said John Durban, a biologist with NOAA's Southwest Fisheries Science Center in La Jolla, California. The hexacopter, Durban said, "can give us a more sensitive measure that we might be able to respond to before whales die."
Initial examination of this year's data suggests improved condition for some Southern Resident whales, offering hope for the population, NOAA said in a statement. The photos are studied using photogrammetry, or the science of making measurements from photographs.
Photogrammetry efforts in 2008 and 2013 documented a decline in the overall body condition of the Southern Resident killer whales, as well as the apparent loss of calves by some pregnant females.
Researchers plan to measure the whales again next year and in different seasons to determine whether they face shortages of salmon prey at certain times of the year. The data will help NOAA Fisheries prioritize salmon recovery actions to improve salmon numbers at the times of year when the whales may be food-limited, Lynn Barre, branch chief for protected resources in NOAA Fisheries' Seattle office said.
"There are only 81 of them left in the wild. That's the bad news. But the good news is that 81 is five more than there were last year. There was a baby boom among the Southern Residents recently, and for a population of this size, five new individuals is a very big deal," Durbin said.
The United States' NOAA teamed up with Canada's Vancouver Aquarium to study the Southern Resident killer whale population, with NOAA providing the hexacopter and the aquarium providing the boat from which it operated, according to Michael Milstein, Public Affairs Officer for NOAA Fisheries.
The whales are called "resident" because they spend much of the year in the inland waterways north of Seattle, Wash. The Northern Resident killer whales are off the coast of western Canada and are also being studied.
The photos are full of data that help scientists monitor the health and reproductive success of this population. One of the photos shows a new mother eating a salmon caught and given to her by other members of the family group, showing that relatives help her as she cares for her calf, the caption states.
Historically, threats to the southern residents included commercial hunting and live capture for aquarium display.
Currently, threats include: contaminants (e.g., PCBs), depletion of prey due to overfishing and habitat degradation, ship collisions, oil spills, noise disturbance from industrial and military activities and interactions with fishing gear.
This research was conducted by scientists from the NOAA Southwest Fisheries Science Center's Marine Mammal and Turtle Division in partnership with scientists from the Vancouver Aquarium. They were operating under research permits from NOAA Fisheries and flight authorization from the Federal Aviation Administration when in U.S. waters, and from Fisheries and Oceans Canada with flight authorization from Transport Canada when in Canadian waters.
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