I just completed 16 days of field research focusing on North Pacific humpback whales in their feeding grounds in Frederick Sound, Stephens Passage and Chatham Strait. These are some of the very same waters that TDI’s Lou Herman and his students and colleagues began their studies of summering humpbacks back in 1980. That research effort, which extended through 1987, documented the migratory destinations of Hawaii’s humpbacks, provided information on reproductive rates and calf survival, and described a distinct feeding call used in cooperative bubblenet feeding on herring.
In 2007, twenty years after these inaugural studies, I was presenting our Hawaii-based research at the Whale Quest Conference in Maui when Captain Dennis Rogers invited me to re-start our Alaska research aboard his vessel the Alaskan Adventurer. I seized that opportunity, and every year since, following our winter research in Hawaii, have migrated to Alaska with many of the same whales from those early years as well as new whales as the population has grown. The goals of this effort include continuing to trace the life histories of individually-identified humpbacks, examining the behavior and persistence of their associations inside and outside of cooperative feeding groups both in Alaska and also between Alaska and Hawaii, and comparing vocalizations employed on the feeding grounds with those in the breeding grounds.
This summer, under NOAA Permit 19655 and aboard Dennis Roger’s 85’ vessel Northern Song, we photographed over 100 individual humpbacks including “V-notch” whose fluke was first recorded 42 years earlier as an adult in 1977. We also documented humpbacks working together to hunt herring in a variety of different sized cooperative bubblenet feeding groups and recorded the different feeding calls and other social sounds present in these groups. Among these cooperative whales was “Dog-face” (see below), who amazingly I had photographed five months earlier in a competitive group of humpbacks in waters off Maui. The dramatic contrast of an individual whale cooperating in one area and competing in another is intriguing and a great example of our quest to better whether humpbacks that cooperate in the feeding grounds disperse to different areas in the breeding grounds to avoid competing with each other.
In addition to the many sightings of humpbacks, we were gratified to see at least four different mother-calf pairs. Last summer we sighted fewer humpbacks overall and only one mother-calf pair that along with lower sightings of both whales and calves in Hawaii since 2016 has been the cause of major concern among many researchers. Possibly, the improved numbers indicates an improvement in some food resources in these areas of SE Alaska. Indeed, in contrast to last summer when those few humpbacks we sighted seemed to be nearly always feeding on herring, during this summer’s surveys we noted some areas with considerable herring and others with krill, both of which the whales readily exploited.
Finally, in addition to the humpback work, we were fortunate enough to experience two gray whales feeding close to shore, several groups of transient killer whales which we identified, sea lions at several haul outs as well as feeding alongside the herring-hunting humpbacks, Dall’s porpoise bow-riding our vessel, harbor seals on ice flows, a variety of birds, and brown and black bears.
If you would like to join Adam Pack and Captain Dennis Rogers as a participant aboard the Northern Song on a future Focus on Whales Trip and assist in the data collection effort, click here.
Leave a Reply