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California Killer Whale Project (CKWP) has a long-term data record of killer whales (Orcinus orca) along the California coast. CKWP was officially established in December 2019, but research started long before then.

We have seen 3 recognized ecotypes of killer whales in Monterey Bay, including the transients (Bigg's), the residents, and the offshores. However, we have seen other whales off the California coast that do not appear to belong to these three ecotypes. We have had multiple groups of killer whales that have come up from the Eastern Tropical Pacific, often referred to as ETPs, as well as unidentified killer whales encountered offshore that may specialize in preying on sperm whales.

How can you tell the difference? Find out by reading below.

Bigg's (Transients)

Our most frequently seen ecotype of killer whale in Monterey Bay is the transient population, also known as Bigg’s killer whales, named after Dr. Michael Bigg. There are different subgroups of the transients, including the West Coast transients and, further north, the Gulf of Alaska transients, and the Alaska Peninsula and Aleutian transients. They range from Southern California to Southeast Alaska and are relatively unpredictable. We generally encounter them along the edge of the submarine canyon, but we have also seen them playing in the kelp along the coastline. We have many different matriarchal groups that we can see of the coast of California, 7 of which are most commonly seen, including one we’ve followed through a probable four generations (Emma’s mother, Emma, her kids, and grandkids). From our 33 years of research, we’ve found that our transient population trend is on the rise!


Bigg's Features:

DIET: Our West Coast Bigg’s population of killer whales almost exclusively eats mammals, but are known to occasionally predate on seabirds and possibly squid too.


POD SIZE: Our West Coast population of Bigg’s (transient) killer whale tend to travel in small groups, usually of 2-7, made up of the matriarch and her most recent offspring, as well as her sons, who do not leave.


SIGHTINGS: We have sightings of them year-round, but most frequently in the spring when the gray whale mothers are migrating north with their calves. They are also frequently seen in the bay in the fall when they come to feed on pinnipeds, particularly the elephant seals that are headed back into the water from a hiatus on shore. In the summer they tend to travel north to Washington and British Columbia, often co-mingling with other BC whales, perhaps in efforts to mate with less closely related animals. Another theory as to why they are sighted so much up in the BC area is that they are following the gray whales on their migration north. The furthest match we have of our Bigg’s population is in Southeast Alaska.




The resident killer whales are the most well-known of the different ecotypes. The northern resident killer whales are listed as threatened, numbering around 300 whales, and the southern resident killer whales are endangered, with only 74 in their population. The northern residents are found between Vancouver Island and Alaska, whereas the southern residents, comprised of J, K, and L pod, are most often seen around northern Washington and Vancouver Island. Due to the shortage of salmon, however, the southern residents have started to travel further south to Monterey Bay, first sighted by Nancy Black in 2000.


DIET: Both the Northern and Southern resident killer whales are fish eaters, primarily prey upon salmon.


POD SIZE: Northern resident and Southern resident killer whales live in matrilineal pods of 10-40.


SIGHTINGS: They have been seen in the bay several times since, mostly in the winter and spring and over the past few years less frequently. Our most recent encounter was in March of 2019 with 35 southern resident killer whales from L Pod! Our documentation of the sightings in Monterey Bay has increased the official protected range of the southern resident killer whales, which now spans to just south of San Francisco (see map below, all proposed areas have now officially been added), and we hope this will encourage the recovery of the salmon population and of the southern residents in turn.

Map courtesy of WDC

NEWS: Check out this recent article describing how the endangered southern resident orca's critical habitat has been expanded just past Monterey Bay. We were the first group to ever observe southern resident killer whales in Monterey Bay in the year 2000. This will help protect important feeding areas for these whales.


The offshore killer whale population count is difficult to estimate as they are infrequently encountered and they do not always travel together, thus it is hard to account for births and deaths. Though the offshores are often elusive and frequently travel offshore, our use of drones allowed us to collect remarkable footage of them – including the first known documentation of them predating on a six-gill shark (therefore a newly confirmed prey species).

Offshore Killer Whales eating Sevengil Shark 12.13.16

DIET: Both the Northern and Southern resident killer whales are fish eaters, primarily prey upon salmon.


POD SIZE: The offshore population in total is between 300-360 whales. They usually travel in groups of 60-100 or more.


SIGHTINGS: They have the greatest known range of these various ecotypes, traveling from Southern California to Alaska in large groups of over 100.


How can you tell the difference?


How to Help:

We are a nonprofit organization with one of our ongoing projects being to create an updated photo-ID catalogue. We plan to continue studying predation events, movement patterns, humpback whale and killer whale interactions, population size, pollutant levels, critical habitat for the southern resident orcas, behaviors of the whales we see off California, and collaborate on projects with scientists in the Pacific northwest.


These projects can only be made possible by your kind donations. Giving online has never been more convenient or hassle-free with our one-click donation. We also accept cash and check donations at our location.

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