The Elusive False Killer Whale

In 2013, Jens Currie came to Pacific Whale Foundation as a data analyst from Canada’s Department of Fisheries and Oceans. With an ambition to explore more robust statistical methods of potential anthropogenic impacts on cetacean populations, Jens is now Senior Research Analyst. Here, he lends a helping hand for those of us that are new to understanding and appreciating the endangered false killer whale.

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What is a false killer whale, and can you dissect the name for me?
False killer whales are the fourth largest species of dolphin. They are characterized by their dark coloration, slender body, crescent-shaped dorsal fin, and small rounded head with no beak. Individuals of this species weigh between 1,000-3,000 lbs. Adult females reach lengths of 16 feet, while adult males are almost 20 feet long.

The name Pseudorca (pseudo-orca) comes from the similarly shaped skulls that false killer whales have to that of killer whales (Orcinus orca). The “crassidens” in their scientific name Pseudorca crassidens means “thick tooth.” They were first discovered and described by fossils.

What is their lifespan, what do they eat, how do they stand out?
These animals have a lifespan of 60 years or more.  False killer whales feed primarily on fish and cephalopods in open water habitats.  The prey items of this species include economically important fish, such as mahi-mahi and tuna, and occasionally other marine mammal species. It has been documented that false killer whales cooperatively hunt, and will share food between individuals in their group.

Where are they found in the world?
False killer whales are distributed throughout warm and temperate waters in the tropics and subtropics, with the highest abundance in warmer waters. They are typically found in the open ocean but can also occur closer to shore, particularly near tropical oceanic islands such as the Hawaiian Islands. Based on genetic and photographic data, there are three populations of false killer whales surrounding the Hawaiian Islands: the main Hawaiian Islands insular population, the northwestern Hawaiian Islands insular population, and an offshore/open-ocean population.

Do they migrate? Are they kama’aina?
They do not migrate and the main Hawaiian Islands insular population is kama’aina

Why are there so few remaining?
The endangered main Hawaiian Islands insular false killer whale population is estimated to be around 150 individuals. The historical population size is unknown; however, spotter planes from the 1980s report seeing large aggregations of 350-400 whales in a single area. Aerial data suggest that the population has declined at an average rate of 9% per year through the early 2000’s (NOAA Fisheries, 2018).

The reason why there are so few false killer whales is unknown; however, there are several factors that likely play a role. Given their endangered status, in 2010 a Biological Review Team (BRT) was established to conduct a status review of the species. In the Status Review report (Oleson et al. 2010) of the 29 identified threats identified, the most substantial threats to the population include: the effects of small population size (inbreeding depression and Allee effects), exposure to environmental contaminants, competition for food with commercial fisheries, and hooking, entanglement, and/or intentional harm by fishermen.

How can citizen scientists help us ID these elusive animals?
Citizen scientists can help us ID these animals by donating any photos they have of false killer whales in Hawaii. We can photo-identify individual Pseudorca through unique scars and markings, and by using their dorsal fin. Photo-identification is an important part of our research and how we can track changes in population size over time.

Another way to help is to notify PWF’s researchers when false killer whales are sighted in the Maui Nui region! We would greatly appreciate a phone call or text if any water users see false killer whales so we can initiate a rapid response (weather and time permitting).

Can you give me 3-5 reasons why they are awesome?

  • They share food with each other, and have been documented offering fish to humans that are diving or boating.
  • They are one of very few species known to enter menopause. Most animals continue to reproduce until they die; the only known exceptions to this are humans, killer whales, false killer whales, and short-finned pilot whales.
  • False killer whales were first discovered by their fossils and were thought to be an extinct species until a pod was observed in 1861.

All photos and videos were taken under NMFS Permit # 16479.

Pilot whale encounters 30 miles offshore

Our Research Team has begun surveying the deeper waters southwest of Maui as part of our new false killer whale study. The first day of research took us ~30 nautical miles off the coast of Maui in waters >2,500 feet. Although we didn’t see any false killer whales, we did have two encounters with short-finned pilot whales, a species we do not typically observe in the near-shore waters of the Maui 4-island region. This species has distinctive bulbous heads, wide dorsal fins, and sleek black bodies. Short-finned pilot whales are sexually dimorphic, which means that males and females look different. Males typically grow to 18 ft long compared to females who grow to an average length of 12 ft. The dorsal fins on males are also larger and wider than females, making it easy to tell the two apart.

During our encounter with short-finned pilot whales, two researchers were taking above water photographs of the whale’s dorsal fins, another researcher was collecting underwater footage using a pole-mounted camera, while a fourth research was collecting detailed observations on pod behavior and composition. We observed two mother-calf pairs, two subadults, and the rest were adults, spread out into smaller sub-groups of 2-3 individuals. During the encounters we observed the pod feeding and resting at the surface of the water.

The majority of our research takes place after our field work ends, because the data we collected in the field must be processed. This involved looking through 520 pictures of dorsal fins, assessing each image’s quality, and matching each image within the encounter to see how many different individuals we saw. After data processing was completed, we had photographically identified 19 different animals. These individuals were then compared to our existing catalog of 133 short-finned pilot whales to see if any have been previously sighted. One individual matched to our catalog and was sighted back in September 2002. The other 18 animals had never been seen before and were added as new individuals, increasing our catalog size to 152 individuals. Since we do not often see this species, it was expected that there would be many new individuals to add, as the estimated population size for the entire Hawaiian Islands EEZ is 12,422 whales (Bradford et al. 2013).

This was a very successful day offshore! Stay tuned for other research updates from this exciting new study.

What’s it like to do a research internship at PWF?

On the first field day for our two summer interns, you could sense the excitement as we set out on our research vessel, Ocean Protector, to survey for dolphins. Pacific Whale Foundation Research Department offers internships that give individuals the opportunity to get hands on experience in collecting and analyzing field data on marine mammals.

During our survey the interns were overjoyed when we came across a pod of Hawaiian spinner dolphins, as it was the first time ever seeing this species of dolphin for both young researchers. Spinner dolphins are named for their acrobatic spinning leaps that are unique to this species. These dolphins can spin up to seven times when they propel themselves out of the water. Scientists do not know for certain why they spin, but believe the dolphins may use the aerial spinning behavior as a form of communication or as a way to remove parasites.

As the interns took turns on the research camera, trying to capture photos of individual dorsal fins, they made several important observations about the group of around 80 spinner dolphins that we encountered.  They were first struck by the sheer size of the group. Spinner dolphins are usually sighted in large groups of 100-1000 individuals. The interns quickly learned that it can be very overwhelming to take photographs and get an accurate group count of the animals since multiple dolphins will surface at the same time. Due to these difficulties, we also use underwater footage captured on a GoPro to help us gather data on group size. As we continued following the pod and collect data, one of the interns asked why the animals were not spinning. We explained to the interns that spinner dolphins here in Hawaii typically rest during the day time, and feed in large groups offshore at night. Spinner dolphins’ resting behavior usually involves slow swimming, but spins and leaps can also be observed on occasion and can be a sign that the pod has been disturbed. After spending a memorable hour collecting the data and photos needed, we continued on with our field day.

Once back in the office, the interns got the chance to process the data that was collected in the field.  This involves looking through the photos that were taken, finding the best photo of each individual, and matching the individuals to our existing spinner dolphin catalog. The interns matched the photos to our spinner dolphin catalog that currently has 438 individuals, and found 27 matches. The current population of Hawaiian spinner dolphins in the Maui 4-island region is unknown; our catalog will to help us estimate the number of individuals and look at their distribution and movements. These valuable data will help us protect these dolphins, which are facing increasing disturbances and threats from human interactions.

Kaho’olawe Island Restoration

In February 2018 twelve Pacific Whale Foundation volunteers participated in a public access to one of Hawaii’s most sacred islands – Kaho’olawe. Kaho’olawe is believed to be the kino lau or manifestation of Kanaloa a sacred ground for the people of Hawaii to practice and embrace their culture. This island is known as the piko, or navel of the Hawaiian islands, the crossroads of past and future generations where Hawaiian culture was spread. But the history of Kaho’olawe has not been an easy one. The island is thought to have been settled by Native Hawaiians since 400 AD but, as the years went on, a dark evolution of the island began to take place.

In the 1800’s it was used as a penal colony for adult men, in the early 1900’s the uncontrolled grazing of cattle, sheep, and goats on the ranch lands started to decimate native vegetation. In 1953, in the wake of the attack on Pearl Harbor, the U.S. Navy took the island under Martial Law as a bombing site. Ordnance were dropped on Kaho’olawe until the early 1990’s, destroying sections of land, eliminating acres of native vegetation, and causing massive amounts of erosion to come from the island.

In 2004 the process of removing unexploded ordnance from the island started, in hopes of restoring it to its once accessible state. Around 75% of the surface area of Kaho’olawe is cleared today and, of this, 11% is cleared to a depth of 4 feet. The next step in the restoration project has been to re-plant native vegetation to stunt the erosion and combat the extensive network of invasive plants that have moved in.

Nowadays so many volunteers apply to assist with this restoration that there is a multi-year waiting list. After a three year wait, a small group of Pacific Whale Foundation employees were admitted access to Kaho’olawe with a conservation mission to help restore the island. Our staff spent three days pulling invasive plant species and replacing them with over 1,000 new native plants, while exploring and learning of the cultural significance this island has to the Hawaiian people. Our staff were honored and  privileged to be allowed to partake in this conservation experience of a lifetime. Hard work and dedication to restoring this island was given to Kaho’olawe by a small group of volunteers, upholding one of Pacific Whale Foundation’s main tiers, conservation and environmental stewardship.

 

Kaho’olawe has generations of restoration work ahead of it, but with passionate volunteers dedicated to conservation and cultural understanding, this island will hopefully one day be restored.

Seeing Some Familiar Fins

The PWF research team recently had a great encounter with a pod of bottlenose dolphins that were hunting fish. Back in the office, we used the bottlenose dolphin photo-identification catalog to reveal some interesting information about the group. As it turns out, this pod contained an adoption animal (#095, “Pa‘ani”), our oldest cataloged animal (#005), a dolphin newly confirmed as a male (#114), and a female who had a calf last summer (#006).

Dolphin #005 was sighted in the very first pod added to the PWF bottlenose dolphin catalog in 1996, and dolphin #006 was first seen in 1997, making them at least 21 and 20 years old, respectively. Our adoptable female, #095 (“Pa‘ani”), was first seen in 2010, meaning she is potentially a bit younger than #005 and #006. Since she had already reached her adult size when she was first seen, it is difficult to determine her actual age, but we know she is at least 7 years old.

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FACT OF THE WEEK: False Killer Whales Call Hawaii Home

MORE ON THIS: False killer whales, while a globally distributed species, have a special tie to Maui and the four-island region. Recent research has found that a very small group of this odontocete, or toothed whale species,  calls Hawaiian waters home, making them genetically different from offshore groups. This makes this population especially interesting because false killer whales are generally thought to prefer deep ocean environments far from any land.

Genetic tests were completed on samples collected from groups of false killer whales around the main Hawaiian islands and locations throughout the North Pacific. Researchers found samples collected from individual whales close to the Islands were most genetically unique when compared to samples from whales in the Pacific Ocean, Panama and Mexico. The uniqueness of the samples indicates there are two separate populations; an inshore population and an offshore population.

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