Category: killer whale

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Something fun: which cetacean has the prettiest flukes, in your opinion?

I’m quite partial to killer whales, myself!

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AP18 is the biggest and oldest bull in his pod.

Though he will not sire any calves within his own pod, his sheer size and old age means he (barring any reproductive problems) has likely sired many calves in other pods. For reasons we still don’t totally understand, female killer whales prefer to mate with with old, large bulls. There is likely some aspect of mate choice but recent evidence of infanticide in other killer whale populations suggests that females may not have much say in some instances.

Due to the fact they spend nearly their entire lives underwater, we know virtually nothing about the reproductive behaviors and courtship of killer whales!

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Alaska is vast and fieldwork with marine mammals is often fraught with difficultly. It can be particularly challenging to study the resident killer whales here.

Despite their name, many pods do not stick to one area. Each pod has its own range and some are larger than others. When researching other resident killer whale populations, such as the southern residents, it’s possible to document every individual in the population on a yearly basis. This is not possible in Alaska! Pods go years without being seen and new pods are constantly being discovered.

Take AX27 pod for example. Their section of the southern Alaska resident photo-identification catalog has not been updated in eight years! The main killer whale biologists in Alaska conduct fieldwork in the Kenai Fjords and Prince William Sound. AX27 pod is mainly found around Kodiak, Cook Inlet, and Kachemak Bay and only makes a rare trip to the main study regions. As a result, they have not been officially censused in nearly a decade.

Luckily for me, though, I see them on a regular basis during the summer. In August we found part of AX27 pod and I found that AX84 (I believe) has a calf that has not been documented before! She has one other offspring, AX114, who has sprouted and is becoming a mature bull.

Working in Kachemak Bay, I can help document pods that are not often seen by the biologists at the North Gulf Oceanic Society. Every encounter yields new information about pod structure and behavior. I feel very lucky to be able to work with these animals and learn something new every time I see them!

New effort will analyze genes of endangered No…

New effort will analyze genes of endangered Northwest orcas:

NOAA, the Nature Conservancy, and Beijing Genomics Institute are collaborating to sequence the entire genomes of 100+ individual southern resident killer whales with the goal of understanding how genetics are influencing survival. They will compare the genomes to those of healthy Alaskan resident killer whales and transient killer whales. 

Prey availability is without a doubt the number one issue, but I think having supplementary information on their genetics (especially when it sounds like it will be extracted from existing samples––researchers don’t necessarily have to go out and collect more, potentially stressing the whales in the process) can help us create more targeted solutions. I think it’s also worth pointing out that studies like this can happen in conjunction with prey recovery (which is actively ongoing––NOAA is working on salmon habitat restoration) and that doing genomics research doesn’t necessarily take away resources for other recovery actions. 

That being said, I am very interested in what this study will reveal! Genes can have a major impact on how a population deals with environmental stress. We know that the southern residents are beginning to inbreed but we don’t know how this is impacting their health and this study could give us that information. Some females, like J31, are not producing calves though they are well into their breeding years while others still are. Do genes impact this? How does prey availability impact gene expression? Perhaps we can identify which whales have weaker immune systems and figure out ways to enhance their survival while salmon stocks recover––I don’t think many people realize that it takes a few years for this happen. 

Killer Whale Personalities

Personalities are not limited to humans. A wide variety of animals display different personalities, which are known as behavioral syndromes in the field of animal behavior. Behavioral syndromes (aka personalities) can be defined as: a collection of traits that characterize an individual’s response and is relatively stable over time. In other words, an individual animal will tend to react a certain way to a particular stimuli pretty much every single time. Behavioral syndromes have been documented in arthropods, mollusks, mammals, birds, reptiles, fish, and amphibians.

For example, animals can differ in their degrees of boldness; when presented with a certain stimuli, some animals are more apt to approach it directly and investigate. Others might be more timid and choose not to approach it. Fascinatingly, personalities can have a big impact on evolution and on an animal’s fitness.

There has not been much formal study into the personalities of killer whales, but if you have spent any time around them, you will notice different behavioral traits in individuals. I have noted this in some individuals in the southern Alaska resident killer whale population. This is AP3, an adult female killer whale from AP pod:

She appears to be a particularly bold individual. Most of the time, the other whales in her pod will ignore our vessel and continue on foraging, traveling, or socializing with one another. AP3, however, tends to approach our vessel nearly every single time we encounter her. Here are a couple of photos of her on the numerous occasions she has surfaced near our boat:

What is particularly interesting is that AP3 has a calf. There is evidence that personalities have a hereditary basis and can be passed on to offspring. Killer whale calves and young females (prior to their first calf) tend to be particularly inquisitive in general so we will have to wait and see if AP3′s calf displays its mother’s bold personality when it matures or after (if female) she has her own calf.

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Sometimes photo-ID is hard, even when you know what pod the whale belongs to.

AP pod’s ID photos were taken 6 years ago. The calves at the time were documented but the saddle patches of young killer whales are often faint and difficult to make out. Those same calves are now juveniles and are much more distinct, but unfortunately matching tbem to their calf ID photos is proving to be a challenge.

Photos from the North Gulf Oceanic Society.

I believe this is AP15 based on the dorsal fin curvature, but I am not 100% sure!

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It’s that time of year again!

There was significant interest for a calendar in my last Instagram poll, so I have created a 2019 Killer Whales of Alaska calendar featuring photos of resident killer whales in Kachemak Bay.

Each calendar is $20 and $5 for shipping! All proceeds will help me with the costs of applying to graduate school. I can ship to anywhere in the US or Canada at this time. Please message me if you would like to purchase one!

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Just half a second before AP3’s calf exploded out of the water next to her!

“Resident” vs “Transient”

When to Use These Terms and What They Mean

I have a big pet peeve. Anybody who is interested in killer whales knows about the different ecotypes/subspecies and the most well known of these are the resident and transient (sometimes called Bigg’s) killer whales. However, I see these names used in ways which are not correct and I see people apply the names to populations of killer whales where it is not appropriate! I want to clear up some misunderstandings surrounding the names of these groups.

Resident Killer Whales  

Resident killer whales reside exclusively in the North Pacific Ocean. There are 4 populations in North America: Western Alaska residents, southern Alaska residents, northern residents, and southern residents. There are also populations of residents in Russia and Japan but they are not well studied. These whales are piscivores and only eat fish. They do not consume marine mammals whatsoever. Additionally, the name ‘resident’ itself is a bit of a misnomer! They were originally given this name by Dr. Michael Bigg, who discovered there are different types of killer whales. He named them ‘residents’ because he noted they were frequently found in a relatively small geographic area. However, populations of residents can range widely and they do not necessarily stay in one region all of the time. Their travels largely revolve around finding food and finding other whales to socialize with. 

The most common mistake I see people make is applying the term “resident” to any type of killer whale that eats fish. This is not accurate. “Resident” only applies to the aforementioned groups of whales. They are considered a unique subspecies (still unnamed) and are genetically distinct compared to other killer whale ecotypes. This is why we don’t call other fish-eating populations of killer whales “residents.” They do not belong to that subspecies. 

I also see people use “resident” when talking about groups of killer whales that are local and have a restricted range, such as the West Coast Community of killer whales found in the United Kingdom. People, even news organizations, frequently refer to them as a “resident” pod of whales because they do not tend to stray very far from local waters. I would dissuade people from using this term and instead refer to them as a local pod rather than resident as I think this may add more confusion to the term. 

Transient Killer Whales 

Like resident killer whales, transient killer whales are also restricted to the North Pacific. Well-studied populations include the West Coast transients, Gulf of Alaska transients, and AT1 transients. Other transient populations live in Western Alaska and there are likely some in Russia and Japan. Unlike resident killer whales, transients do not eat fish and feed primarily on marine mammals, such as seals, sea lions, dolphins, porpoises, and baleen whales. They will also eat seabirds and cephalopods on occasion. Dr. Michael Bigg was also the one to christen these whales as “transients” because during his study, they were elusive and seemed to roam larger ranges than residents do. “Transient” can also be a misnomer. Transient killer whales do have larger ranges than most resident killer whale populations but they can sometimes become “resident” when they find a particularly good source of food. For example, transient killer whales used to be a fairly uncommon sight in the Salish Sea and residents were seen on a daily basis. Due to shifts in prey availability for both populations, their “residency” patterns swapped. Transients took advantage of the plentiful seals and porpoises and can now be seen nearly every day in the Salish Sea, while southern resident sightings are far scarcer due to fact the whales are having to travel elsewhere to find food. The name “transient” is not necessarily indicative of where they go and how long they stay in a region. 

Again, like with residents, it’s very common for people to apply the term “transient” to any population of mammal-eating killer whales, such as those in Patagonia or other regions of South America. Transient killer whales are also classified as an unnamed subspecies and thus their name is not applicable to any other population. 

Other Thoughts

There are many killer whale populations in the world that are still poorly known and studied very little. Though we have classified 10 distinct ecotypes (and are now splitting some into subspecies), the taxonomy of killer whales as a whole is still unresolved and up for debate. There is even debate on whether or not type 1 and type 2 North Atlantic killer whales are “true” ecotypes. We have a very good understanding of the diet, evolutionary history, population dynamics of resident killer whales and transient killer whales but we are still learning about other populations around the world. It is very hard to place these whales into categorical boxes and we can’t simply call them “transients” or “residents” based on whether or not they eat fish or mammals (some eat both! Some eat reptiles! Some eat birds! Some eat anything they can find!) or whether or not they hang out in particular areas for long or short periods of time. 

Predicting global killer whale population coll…

Predicting global killer whale population collapse from PCB pollution:

Using models, a newly published paper has demonstrated that PCBs represent a potentially catastrophic threat to killer whale populations all around the world. 

The model they used incorporates data on population fecundity, average population PCB concentration in tissues, immune suppression, and PCB changes due lactation/placental transfer to calves and ingestion from prey. 

They found that particular populations are predicted to collapse in the next 100 years due to PCB contamination. 

Populations that are at low risk of collapse due to little impact of PCBs on growth:

  • Alaska offshore
  • Alaska resident
  • Antarctic type C
  • Northern resident
  • Crozet Archipelago
  • Eastern Tropical Pacific
  • Faroe Islands
  • Iceland
  • Norway 

Populations that are moderate risk of collapse with stagnant growth caused by PCBs:

  • Southern resident
  • Alaska transient 

Populations that are at high risk of collapse due to declines caused by PCBs:

  • Brazil
  • West Coast Transients
  • Canary Islands
  • Hawaii
  • Japan
  • Strait of Gibraltar
  • Greenland
  • United Kingdom

While this information is startling, do keep in mind that it is a mathematical model that does not incorporate all threats to particular killer whale populations. For me, it highlights the need to provide killer whales with adequate prey.

The southern residents, while asssesed as at moderate risk in this model, are declining in comparison to West Coast transient killer whales, which were listed as high risk. The southern residents are declining due to lack of prey and this is likely exacerbating impacts of PCBs on reproduction. If killer whales have adequate prey access, then they likely will not be as exposed to the detrimental impacts of PCBs as a food-stressed population would be.

I have access to this article so if you would like to read it, let me know and I can send it to you.