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.

New research study on false killer whales

The Research Team is excited to announce that we have started a new study on false killer whales! We started field work for this study in May 2018 and will survey the leeward waters surrounding the Maui 4-island region; up to 50 miles offshore. This brings us into deep waters (> 2,500 ft) where the possibility of seeing other species is also very likely. In case this does happen, we also have authorization to collect data and photo-ID of 15 other toothed-whale species. The main objectives of this study are to assess the distribution, population structure, habitat use, body condition, and behavior of false killer whales.

The majority of false killer whales encountered within the waters of the Maui 4-island region are part of the Main Hawaiian Islands (MHI) insular stock which is currently listed as “endangered” under the Endangered Species Act. The minimum population estimate for the MHI insular stock is 151, based on the number of unique individuals photographed (Baird et al. 2013). This stock faces a number of threats such as the effects from small population size, high levels of contaminants, interactions with fisheries, and a decrease in their prey species biomass.

Given the “endangered” status of the MHI insular false killer whales, there is a need to gain a better understanding of the species in order to develop effective management plans to aid in their recovery. Our research will provide a continuous, long-term data set using new techniques and technologies to  address gaps in our knowledge of this population. In addition to photo-identification, location, and behavioral observations, we will be using unmanned aerial vehicles (commonly called ‘drones’), photogrammetry, and underwater footage to gain information on body condition, growth rates, and possibly detect pregnant females.

We are excited to begin this new study and to learn more about this endangered population. Stay tuned for updates from the field!

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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Double Take: False Killer Whales and Pilot Whales in the Same Day

When the research team carries out odontocete transects, we are looking for all species of toothed whales, but most commonly we see bottlenose, spotted and spinner dolphins. On rare occasions we see false killer whales, of which the insular Hawaiian population is on the endangered species list, and short-finned pilot whales, which is a deeper water species not commonly found in the shallower waters of our survey area. We might see these two species a handful of days per year. Well, believe it or not, we were recently lucky enough to see them both on the same day!

We were surveying the area behind the island of Lana‘i and we had a feeling it was going to be a special day when we set off from Ma‘alaea Harbor. We had just arrived at the start of our first transect line when we saw a large black dorsal fin. We soon realized that this was a false killer whale. At first we only saw one solitary individual, but it soon swam and joined the rest of its pod, which we estimated at 15 individuals. We photographed them to obtain ID’s for our false killer whale catalog and collected behavioral data. When we were satisfied that we had photographed all the individuals present we returned to our transect line, excited that we had such an exciting experience so early in the day.

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