VANCOUVER - The death of a whale considered the oldest in the West Coast's southern resident population could particularly affect one animal who may have lost yet another adoptive mother, a wildlife biologist says.
Brad Hanson of the Seattle-based Northwest Fisheries Science Center said an orca dubbed J2 and also known as Granny has not been spotted since mid-October and is believed to have died.
He said that while some estimates put Granny's age at over 100, researchers determined through a biopsy sample nearly two years ago that she was between her mid-60s and early 80s.
She was considered a matriarch of the J-pod, which is one of three family groups of southern resident killer whales.
J-pod now has about 24 members, including L87, who joined the clan about two years ago, Hanson said.
"L87 is actually an L-pod member but he lost his mom a number of years ago and he gravitated over to K-pod and hung out with an older female there until she passed," Hanson said Tuesday from Seattle. "Ironically, he went to J-pod so it'll be interesting to see what L87 does now because these adult males are used to staying with their mother their entire life."
Hanson said male whales sometimes die soon after their mother's death and that females tend to outlive them by up to three decades.
The movement of the entire J-pod will be of interest to scientists because Granny was seen as leading the group since the 1970s, he said.
"These animals are so long lived relative to a lot of other wildlife populations that it's an unprecedented situation. And I expect that we may learn some new things about how killer whale societies adjust to these changes."
At least two other females in the J-pod, including J16 and J19, were also born in the 1970s and could take on the matriarch role, Hanson said, adding J14 died last summer and that the number of older female whales is dwindling.
"We believe these older females are the keepers of corporate knowledge, if you will, so where (the pod) goes and when they go there, somebody has to make that initial decision."
Hanson said the J-pod spends most of its time in the northern Strait of Georgia or the western part of the Strait of Juan de Fuca and don't trek very far south to the Washington coast, unlike the K and L pods, which also venture as far as California.
The Center for Whale Research in Washington state said in a statement on its website that it does not know what killed Granny and that she was the eldest within the three family pods of endangered southern resident whales.
The centre said the total number of southern resident whales has fallen to 78.
The loss of Granny comes less than a month after J34, an 18-year-old male member of J-pod, was found washed up on a Sechelt beach after apparently being hit by something, and the October death of J28, a female with a one-year-old calf.
Southern resident killer whales, which almost exclusively eat salmon, were listed as endangered in 2005.