In a report released on March 15, NOAA announced that new advances in genetic testing have allowed scientists to determine the origin of the Chinook salmon that are consumed by a group of endangered killer whales in the inland waters of Washington and British Columbia.
This group of killer whales, known to scientists as the Southern Resident population, is protected under the U.S. Endangered Species Act and Canada’s Species at Risk Act. The Southern Resident killer whales spend there time in the inland waters of Washington and British Columbia from late spring to early fall before swimming to the Pacific Ocean for the winter months.
“Our findings identified specific Chinook stocks from Canada’s Fraser River that fish managers need to pay particular attention to because these killer whales are so dependent on them,” said Dr. Brad Hanson, lead author of the study and a marine mammal scientist with NOAA’s Northwest Fisheries Science Center in Seattle. Both governments identified lack of food as a risk factor that could interfere with the recovery of these killer whales. The results of this study will play a significant role in assisting the recovery of these whales.
Salmon return to the same stream or river each year so they become a genetically distinct population and they can be easily distinguished from Chinook who spawn in other parts of the river. Scientists estimated that as much as 90 percent of the Chinook the whales ate came from the Fraser River.
“This study not only confirmed previous research that suggested these whales eat mostly Chinook salmon, it also allowed us to identify the specific genetic groups, and therefore the specific areas from within the river system, from which these salmon came,” said Hanson. This gives managers more information with which to make decisions about conservation measures to ensure survival of these salmon stocks, which in turn are vital to the survival of the killer whales.
Copyright © 2010 by Marine Science Today, a publication of OceanLines LLC