When it comes to killer whales, biologist Dena Matkin can rattle off the names, relationships, and histories of the animals that pass through Glacier Bay National Park. “Being near them makes me feel more alive,” she says. “It gives me purpose. Once I started studying them, I didn’t want to stop. I just knew this was what I was going to do.”
Matkin was 25 when she arrived in Alaska to work for the Alaska Department of Fish and Game. In 1979 she moved to Gustavus, built a cabin, bought a 20-foot boat, and set out to study killer whales. Hers is a life alongside one of Alaska’s most iconic marine mammals.
Killer whales (Orcinus orca) live in all the world’s oceans and have three distinct populations: residents, transients, and offshores. These groups have not interbred for thousands of years and are considered unique cultures with different habits, language, and food. Residents specialize in fish; offshore animals eat sharks; and transients hunt marine mammals. Matkin works with the West Coast (Bigg’s) Transients, which travel from southeast Alaska to Washington’s Salish Sea.
Most summer days see Matkin armed with a pair of binoculars and lots of warm clothes, motoring into the mouth of Glacier Bay to wait for her elusive quarry. A whopping 1,600 trips and 7,400 hours of patience pay off. When a black dorsal fin breaks the surface, she carefully positions her boat to snap photos. These images are used by British Columbia’s Pacific Biological Station to identify individuals. Each animal has a unique dorsal fin and saddle patch (the light swirl at the base of the dorsal fin). Over the past 38 years, Matkin and fellow biologists have compiled killer whale identification catalogs showing dorsal fin images and family genealogy.
Many of the animals Matkin observes are old friends. One male, T87, has a 34-year history in the region. Matkin’s observations of T87 help biologists understand the movements of adult males. About half stay with their mothers for her lifetime while half travel alone, occasionally joining other single males or related groups of females and young.
In 1988, Matkin met T85, a female transient easily recognized by her jagged dorsal fin. She named her Eve after her own daughter. T85 has visited Glacier Bay almost every year since, eventually bringing her own calves. “I could identify with her caring for her calves and keeping her family together,” Matkin says. In matriarchal killer whale societies, daughters and other female associates help with births, “babysit” the juveniles, and eventually care for their aging mother. “I think that’s why people love them so much,” Matkin reflects. “They represent not only a powerful animal but an animal that is intensely involved with teaching and caring for their family.”
Since beginning her work, Matkin has documented 158 kills and seen a shift in the West Coast Transients’ diet. Until 2003, they primarily targeted Glacier Bay’s harbor seals. Retreating glaciers and predation by killer whales and sleeper sharks, however, contributed to a steep decline in the seal population. With fewer seals to go around, killer whales turned to harbor porpoises and Steller sea lions. “Going after sea lions is a whole new level of coordination, strength, and time to make a successful kill,” Matkin states. “But the payoff in subduing such a large ferocious animal is that it can feed several orcas.”
Hunting skills are passed from generation to generation within a family. A group of killer whales pursue prey to exhaustion, then incapacitate it with head butting and slaps from their flukes and dorsal fin. One of the females keeps the juveniles at a safe distance until the prey is immobilized, then allows them to practice their hunting techniques. The youngsters excitedly mimic the adults’ behaviors.
Occasionally killer whales come up next to Matkin’s boat and show her what they are killing. “They’ll lift a carcass out of the water and sometimes carry little porpoises on their heads!” Matkin says. “This amazing behavior shows so much intent and intelligence.” If she cannot identify the kill, she gathers remains for genetic identification. She also lowers a hydrophone into the water to listen to echolocation clicks, calls, and whistles used during the hunt and a distinctive crunch indicating the killer whales are consuming their prey.
In recent years, Matkin has seen fewer large multi-matriline groups. Transients are spending more time in the Salish Sea, where increasing populations of seals and sea lions provide a plentiful buffet. Salish Sea resident animals are well known for their high levels of deadly toxins, but transients also experience this crippling reality. Throughout the food chain, animals ingest toxins including PCBs, DDT, and a variety of other industrial chemicals. These toxins become lodged in an animal’s fatty tissues and pass from prey to predator, eventually reaching killer whales at potentially lethal levels. Mothers pass toxins on to their young, threatening the health and viability of the species.
Matkin’s scientific career has contributed to a deeper understanding of killer whale behavior, predation, and social structure. Greg Streveler, local naturalist in the Glacier Bay region since 1967, says, “Dena’s life has been a testament to focus and determination. Often alone and with minimal support from outside, she has maintained a laser focus on killer whale comings and goings in our vicinity. She has bridged an information gap between larger studies of this ecologically critical apex predator in the Pacific Northwest and Prince William Sound. Perhaps most importantly, she radiates an infectious love for these marvelous creatures, which induces others to care deeply as well.”
During her 35-year tenure in Glacier Bay, Matkin has provided identification and names to over 500 killer whales. She hopes her work will inspire interest and protection for the species. Each year she shares her findings with park staff, fellow researchers, and the public, emphasizing the killer whale’s value as a complex social species and indicator of ocean health. But her work goes far deeper than a job. For Matkin, now a grandmother of two, it is personal. “Seeing mothers nursing their calves and letting me quietly drift nearby and witness it is just…” Matkin pauses, “a blessing.”