Orcas swim 5,000 miles for warm-water ‘spa treatment’

Transient killer whales near Unimak Island, eastern Aleutian Islands, Alaska. PHOTO COURTESY NOAA.

NOAA researchers document unusual long-distance killer whale migration

By Summit Voice

SUMMIT COUNTY — Killer whales from Antarctic waters may be making long-distance treks to warmer water as a type of marine mammal spa treatment, shedding skin that’s covered with diatoms and algae.

National Oceanic and Atmospheric Administration researchers tagged a dozen killer whales in Antarctic waters and tracked five that showed consistent movement to subtropical waters.

Some of the orcas made the 5,000-mile round trip to southern Brazil in just 42 days, returning to Antarctica immediately. The researchers, who published their findings in the science journal Biology Letters, This was the first long distance migration ever reported for killer whales.

“They went to the edge of the tropics at high speed, turned around and came straight back to Antarctica, at the onset of winter”, said Robert Pitman, co-author of the study. “The standard feeding or breeding migration does not seem to apply here.”

“The whales are traveling so quickly, and in such a consistent track, that it is unlikely they are foraging for food or giving birth,” said John Durban, lead author from NOAA’s Southwest Fisheries Science Center in La Jolla, California. “We believe these movements are likely undertaken to help the whales regenerate skin tissue in a warmer environment with less heat loss.”

As evidence, the researchers point to the yellowish coating on Antarctic killer whales caused by a thick accumulation of diatoms or algae on the outer skin of the animals. The coloring is noticeably absent when they return from warmer waters indicating the upper epidermis of the skin has been shed.

The whales tended to slow in the warmest waters although there was no obvious interruption in swim speed or direction to indicate calving or prolonged feeding.

“They went to the edge of the tropics at high speed, turned around and came straight back to Antarctica, at the onset of winter”, said Robert Pitman, co-author of the study. “The standard feeding or breeding migration does not seem to apply here.”

A killer whale surfaces in the waters of the Antarctic Sound. PHOTO BY BOB BERWYN.

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One Response

  1. Very interesting. Hope they follow up with more research? Other question, the post on the Greenland Icecap Melting, was missing the follow up page as well as being able to comment. Was there a reason the page was missing?

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