Kodiak Killers make their spring appearance
May 4, 2015
907-486-1517
4/29/2015
Enjoying the rare opportunity to watch killer whales from the shores of Kodiak harbor is an early spring tradition for island residents.
For decades, a group of killer whales has periodically come into the Port of Kodiak and spent days to weeks cruising the length of the harbor — to the delight of human onlookers but to the consternation of local sea lions.
These are the Kodiak Killers, a group of mammal-eating Gulf of Alaska transient killer whales (now called Biggs’ killer whales). Members of this pod are known to chase and eat Steller sea lions. Although they visit in other seasons, the Kodiak Killers are most frequently seen in the harbor from February to May, when the number of sea lions resting, foraging, and scavenging fish from docked fishing vessels is greatest.
From the 1990s through the 2000s, the orca pod seen in Kodiak Harbor usually included two adult females, two to three of their calves, and a huge bull with a bent (and later, flopped over) dorsal fin. One of the adult females also had a distinctive dorsal fin, and she and the bull (a.k.a. Bentley) were hard to miss. In the Alaska killer whale photo catalog, these two are named AT126 and AT127.
But this spring — and for the past few years — AT126 and AT127 have not been among the orcas seen cruising through the harbor.
So who are the killer whales currently in Kodiak Harbor? Are they a new pod?
Fortunately, individual orcas can be identified by the characteristics of their dorsal fins and the pigment behind them. Because a young orca calf will stay close to its mother’s side, photo histories can help determine who is related to whom. Long-term photo history of killer whale pods allows researchers to monitor births, deaths and social dynamics within these groups. Photo histories have shown that orca pods are matriarchal — mother-driven — and offspring travel extensively or exclusively with their mothers for years. Members in a pod may represent one or more matrilines — mothers traveling with their offspring.
This month’s near-daily sightings of four orcas in the harbor allowed me to get the photographs needed to identify current members of the pod — one large female, two juveniles and a tiny calf. The large female has two small but distinctive nicks in the trailing edge of her dorsal fin. The nicks are hard to see from a distance, but photos confirm this is none other than AT128, the third adult that has traveled with AT126 and AT127 since the mid-1980s and has accompanied them into Kodiak harbor to hunt sea lions for decades.
This year she is the lone adult. Her photo history shows the orcas traveling with her are her own offspring — a new calf born this winter, a 10-year old and a 7-year-old. This is the AT128 matriline, and mom is training her kids to hunt Steller sea lions in Kodiak Harbor.
But what happened to AT126 and AT127?
Nearly 30 years ago, AT126 and AT128 were photographed together near Prince William Sound. At that time, female AT128 was definitely smaller than female AT126 but was too old to be confirmed as her daughter. Even though Bentley (AT127) was not photographed with them at that time, researchers assume he is the son of AT126, with whom he continues to travel because sons stay with their moms in matrilines. Photos taken in the past several years have documented that AT126 and AT127 are alive and well and traveling together in northern Gulf of Alaska and Prince William Sound waters, while AT128 has been seen many times in the Kodiak area without them.
Killer whale expert Craig Matkin says this is not unusual. He explained that unlike fish-eating killer whale pods, the mammal-eating (Biggs’) killer whale pods are dynamic. Multiple matrilines may travel together for years, then break off to join other matrilines, and may rejoin again years later. This spring, the AT128 matriline apparently is cruising Kodiak Harbor alone.
Orcas are long-lived mammals — we know AT128 is at least 30 years old and AT126 is even older. By gathering photos of Kodiak Killers over the coming years, researchers will be able to follow them as they age, document how pod membership changes and see if matrilines rejoin to prey on Steller sea lions together in Kodiak Harbor.
Kate Wynne is a professor and marine mammal specialist with the University of Alaska Fairbanks School of Fisheries and Ocean Sciences. She works at the school's Kodiak Seafood and Marine Science Center.