It was sad and disturbing to find out that seven Puget Sound killer whales have died so far this year.

We haven’t had that number of deaths since 1998 — the year after 19 orcas visited Dyes Inlet between Bremerton and Silverdale. To those who study these whales, the orcas aren’t just seven animals in a herd; they are individuals with unique characteristics; they are members of an extended family that stays together for life.

Ken Balcomb of the Center for Whale Research believes the deaths are related to a shortage of chinook salmon seen this year from California to Washington to British Columbia. I went into some detail about this in a story in today’s Kitsap Sun. I also included a brief “obit” on the animals that died.

I would like to take a moment to remind myself and others that it is unlikely that the deaths were caused by a single factor. I have long been intrigued by the prospect of synergism in these animals, and I would hope that researchers will one day be able to accumulate enough data to support or deny this hypothesis.

What I’m talking about is this: Researchers have promoted three principal causes of the decline in Puget Sound whales, officially known as Southern Residents. They are toxic chemicals (such as PCBs) that have accumulated in their bodies, lack of prey (chinook primarily), and stresses caused by noise, whale-watching boats and other things. For more info, check out the recovery plan for the Southern Residents.

Follow this train of thought:

• PCBs and other chemicals are believed to damage the orcas’ immune systems and reduce their ability to fight off disease.
• If the animals are not getting enough food, they draw upon fat reserves in their blubber. Metabolizing these fats tend to release the toxic chemicals into their bloodstream, exposing their immune systems to more chemicals and further increasing their risk of disease.
• Although the whales seem accustomed to whale-watching boats, anything that causes them to use up excess energy to replenish their energy supplies by hunting for food cannot be a good thing, especially in times of a food shortage. Uninformed boaters sometimes interfere with the whales’ travel during foraging, and noise caused by boats is believed to decrease their efficiency in finding fish through echolocation (their natural sonar system).

In my mind, all of these factors tend to work together. What is often hard to sort out is whether an animal dies of starvation or disease. When food is in short supply, disease may set in before an animal literally starves to death. Also, especially for a hunting species, a disease can reduce their ability to get food, so the outcome is the same. For many species, a higher-level predator may kill an individual that is starving or diseased. But with an animal at the top of the food web, such as killer whales and humans, the dynamics may be different.

I guess I’m just trying to point out that it could be an oversimplification to say the whales starved to death, even if food were a certain factor.

With regard to news sources, I have to confess that this story of the seven missing whales has been in the wind since Oct. 8, but I missed it. Howard Garrett and Susan Berta of Orca Network put something on their Web site, but I overlooked it. Richard Walker, editor of the Journal of the San Juans had talked to Ken Balcomb about that time, but I missed his story until someone pointed it out to me.

Finally, several people have mentioned the coincidental stranding of a killer whale on the island of Kauai in Hawaii. Diana Leone of the Honolulu Advertiser reported that the 18-foot female was emaciated and had “cookie-cutter shark bites” and whale lice, all signs that it had been sick for some time.

CNN posted a user-generated video about the whale.

I understand that researchers are trying to see if the female orca, who was euthanized, can be connected with previous sightings.

I looked up a 2004 Marine Mammal Stock Assessment Report (PDF 56 kb) for a little background. It says Hawaiian killer whales are rarely seen, but the best population estimate is 430. Minimal genetic data indicate that the animals may be related to Gulf of Alaska transient killer whales.

The Center for Whale Research has reported a new baby orca in L pod, and researchers captured photos within a few hours of its birth.

Newborn calf born to L-47, “Marina.” Photo courtesy of Center for Whale Research

The calf, spotted Tuesday afternoon off the west side of San Juan Island, has been designated L-111, the next number in the sequence for members of L pod. The young animal is the sixth calf born to L-47, a 34-year-old female nicknamed “Marina.” She was one of the 19 whales that visited Dyes Inlet for a month in 1997.

The new calf joins sisters L-83, “Moonlight,” and L-91, “Muncher,” which were other Dyes Inlet whales. Moonlight had a calf, L-110, which was born last year, making Marina a grandmother. Marina’s previous calf, L-107, was born in 2005 but survived no more than a few months, according to researchers at the center.

Because the new mother was observed without a calf Monday evening, the baby could not have been more than a day old when the photos were taken. The orange coloration and “fetal folds” in the skin are evidence of a newborn orca.

The calf is a welcome addition to L pod, which may be missing two animals this year, researchers say. As of December, the population of L pod was listed at 43.

For more information and additional photos, check the Center’s “Encounters” page.