Whales divided: how adults and calves use Hervey Bay differently

If you go whalewatching in Hervey Bay after mid-September, you may notice that there is a calf in nearly every pod you see. Mothers with calves are typically the last to arrive in the bay, and they may be the group that benefits most from the shallow, protected waters near Fraser Island.

Our research on the East Australia population of humpback whales allows us to ask questions about long-term trends in behavior and habitat use within the area. Using sighting data collected by our research team from 2004 – 2016, we looked at whether pods with a calf preferred different areas of the bay compared to pods without a calf. As it turns out, mothers with calves do show a preference for an place just inside the U-shaped coastline of Fraser Island, known colloquially by whalewatch operators as “the pocket”. Pods without a calf show an opposite preference for waters a bit farther offshore.

Although depth and distance to shore do not vary much throughout the bay due to the overall shallow waters and the U-shape of the coastline, mothers may prefer that area because it might be the most protected from rougher weather conditions. They may also use it as a place to avoid pursuing males and competition pods. Pods that do not have a calf may prefer the area slightly farther out of the pocket if they are seeking mating or socializing opportunities from other adults or subadults.

The study provides a baseline to compare future observations of whale distribution within the Hervey Bay area, particularly as this population continues to coexist with human activities in the bay including recreational boating, commercial whalewatching, and swim-with-whales tourism.

How can you tell a male and female humpback whale apart?

In many animals, different sexes have different appearances, with males often being larger, showier, or both: think of brightly colored male songbirds or male lions with their luscious manes. For humpback whales, however, this is not the case. Apart from females being slightly larger than males on average, humpback whale males and females look very similar to each other, making it very difficult to visually determine sex. Adding to this, all reproductive organs in both females and males are neatly tucked away behind a genital slit to help them be more hydrodynamic and sleek in the water.

Luckily for us researchers, though, we have a few tricks up our sleeves to tell the difference between the sexes, allowing us to collect additional data for our photo-identification catalog.

The easiest way to determine a female humpback whale is a close association with a calf. Mothers and calves maintain a strong bond throughout the first year of the calf’s life, so when we see an adult whale closely accompanied by a calf, we can safely assume that she is the mother of that calf.

In the absence of a calf, though, things become trickier. If the whales roll over onto their backs, often we can see the genital slit on their abdomen. The relative location of the genital slit offers some clues: For males, the genital slit is located closer to the whale’s belly, while the females’ genital slit is closer to their tail flukes. Immediately towards the tail from the genital slit, females have a grapefruit-sized lump known as a hemispherical lobe. No one knows what exactly this structure does, but we do know that it is only present on females. Females also have two mammary slits, one on either side of the genital slit, which they will use when nursing their calves.

Click through the photos in this gallery and our researchers will explain how we were able to identify the sex of these humpback whales

When we are able to determine the sex of a whale, this information is included along with the animal’s fluke photo when it is added to the catalog. Knowing the sex of different individuals enables us to more accurately determine calving rate and sex ratios of different habitat areas.

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.

scroll below to watch video

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.

Are Swim-With-Whale Operations Ethical? PWF Strives to Learn More

Swim-with-whales tours are becoming more and more popular around the world as travelers become increasingly interested in ecotourism and engagement with nature and wildlife. But, with more and more visitors jumping into the backyard of these vulnerable marine mammals, how can we keep track of the effects on their well being? We can’t manage an operation properly if we don’t understand its effects.

So, are swim-with-whales operations ethical? It’s not an easy question. The challenge is that, as interest and demand for these activities grows exponentially, scientific research simply cannot keep up; it takes time, patience, and careful precision to collect reliable data.

Yes, ecotourism is an alternative to the overuse of natural resources. It can also bring money into poor countries that are rich in biodiversity but have little else to offer in terms of world trade. These swim-with-humpback-whale operations are up and running in places such as Tonga, the Dominican Republic, Tahiti, Norway, Western Australia, and the Fraser Coast in Queensland, Australia. But as hard as the governments of these countries might work to ensure that the operations are ecologically viable, many projects are unaudited and not subject to stringent regulations. Pacific Whale Foundation is interested in finding out more about this tourist offering, specifically in Hervey Bay. In 2014, the Queensland government authorized commercial operators to begin immersive “swim-with-whales” tours with the vulnerable humpback whale, and we want to learn more.

Photo taken August 3, 2018 from Pacific Whale Foundation’s Swim-With-Whales Impact Study. This humpback whale approached the passengers and swam around them a few times.

Our research team has developed an impact study with three objectives:  (1) to better understand if humpback whales change their behaviour due to in-water interactions with humans, (2) to identify factors which may influence behaviour change, and (3) to provide recommendations to governing authorities, resource managers, and tour operators to ensure that Hervey Bay’s humpback whales are not negatively impacted by swim-with-whales tourism.

We believe that wherever possible, baseline research into natural behaviour patterns should be carried out before tourism activities are undertaken. This is also a very unique opportunity for the public to get involved with our research, as we allow a limited number of passengers to enter the water as part of our research. Are you interested in being in the water alongside a humpback whale, or learning more about the study? Please visit us here.

We’re excited as we embark on this new adventure, which will have significant implications for humpback whales in Hervey Bay and around the world. Come and join us!

New research study on “Swim-with-Whales” tourism

Beginning in July 2018, our “Swim-with-Whales” Impact Study invites a small number of vessel passengers to enter the water with humpback whales.

In Hervey Bay, Queensland the government has recently authorized commercial tour operators to allow passengers in the water alongside humpback whales and Pacific Whale Foundation wants to conduct scientific research to see how the presence of swimmers affects humpback whales in an important resting area. Our research will help ensure that this tourism activity is developed in a responsible and sustainable manner.

Our data collection supports the Australian National Guidelines for Whale and Dolphin Watching which state that commercial swim programs should be accompanied by ongoing research to monitor whale and dolphin response to swimmers. This will be an exciting way for the public to get directly involved in citizen science while enjoying the rare opportunity to be in the water alongside a humpback whale, and it will allow our research team to identify any potential detrimental effects of these tours and hopefully mitigate them through adaptive management protocols.

If you’re in Hervey Bay between July and September and you’d like to help our researchers with this study, please visit us at the Great Sandy Straits Marina or book a trip online.

We also encourage you to check out our website for more information on this study and our research in Australia.

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.