Scientists are puzzled over why three mammal-eating killer whales appeared in Seattle waters in March, after apparently migrating 1,500 to 2,000 miles (2,400 to 3,200 kilometers) south from Alaska.
Monica Wieland Shields, director of the Orca Behavior Institute, a Seattle-based nonprofit research organization, told Live Science in an email: “It’s extremely rare for a previously unrecorded killer whale to appear in local waters, so we’re very excited to see them, but we have more questions than answers at this point.”
you may like
Killer whales (Orcinus orca) tend to move within defined ranges and return to the same areas or hunting grounds over years and even generations. If these killer whales are indeed well outside their normal range, their presence could indicate that something has changed in prey availability, ocean conditions, or the whales’ own behavior.
“We have no idea what causes individual whales to move outside of their normal territory,” Wieland-Shields said. “Thanks to decades of research and the ability to identify individual whales by photo ID, we know all the individuals and families who regularly visit this area, including their approximate ages and familial relationships.…Without this research, we would not have even known that these new visitors were rare!”
Changes in whale population
The Salish Sea between Washington and Canada is home to two types of orcas: the endangered fish-eating southern orca and the mammal-eating big orca.
The ranges of these groups have changed dramatically in recent years as a result of changes in food availability, Wieland Shields said.
“Southern residents are shifting their travel patterns elsewhere because they no longer have an abundance of reliable wild salmon to feed on here,” Wieland-Shields said. “The number of big killer whales in the area continues to grow due to the high population of harbor seals and porpoises, which are their main prey.[s] And sea lions are all doing well. ”
Experts believe this may be why the new pod, identified as Big Killer Whale, is so far south.
“I tend to agree with reports that they may be following some food choices,” Heather Hill, a psychologist who specializes in marine mammal behavior at Saint Mary’s University in San Antonio, told Live Science via email. “They could be indicators of [the] Community health—thinking about the entire food chain. Studying different pods can also help understand their social dynamics, such as how they share the same space with other transients and residents. ”
For Seattle-based Wieland Shields, the pod’s arrival raises even more questions. “Until we have further acoustic and/or genetic evidence, we don’t know exactly what population they came from, nor do we know how long they will stay.”
Think you know your killer whale? Test your knowledge with our killer whale quiz!
Source link
