Whale Vocalizations

Whales use sounds for communication and navigation in their underwater habitat. Different species make different sounds for various reasons, such as courtship or long-distance communication. For example, toothed whales use echolocation to locate prey and navigate.

Human activity on the water creates noise that can disrupt this whale communication and navigation, therefore the studying and understanding of whale vocalizations becomes crucial to whale conservation.

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Orcas use sound for communication and navigation. Orcas make three primary types of vocalizations: clicks, whistles, and discrete calls. Orcas rely on sound production and reception to
navigate, communicate, and hunt in dark or murky waters, where sight is of little use.

The Northern resident orca community has over 300 whales with strong family bonds and unique acoustic dialects that distinguish one pod from another. Resident orcas have stable social structures based on matrilines, with males and females remaining with their mothers and closely related family members for life. Daughters may establish their own line of descendants, creating sub-pods. Pods consist of 1-3 matrilines and travel together, sharing a common dialect learned from their mothers and family. The community is divided into 3 clans, each consisting of pods that share common calls resulting from a shared ancestral pod that developed distinct dialects over generations. Closely related clan members share more calls. Listen to examples of each clan.

Southern Resident Orca share many characteristics and cultural traditions as the members of the Northern Resident community. Strong family bonds govern this endangered population and the bonds between members of related families remain stable over the course of their lifespans and are held together through generations by a matriarchal structure. Despite their similarities and a partial range overlap, Southern Residents and Northern Residents are not known to associate and maintain genetic and acoustic separation.

The population size of the Southern Resident community has been closely monitored and tracked through dedicated photo-identification surveys beginning in 1976. While the exact historic population size for Southern Residents is not known, intensive capture efforts for marine parks in the 1960s and early 1970s caused a severe reduction in the population size through the removal of at least 47 individuals. As of December 31st 2021 the population of Southern Residents was determined to be 73 individuals — this small population size combined with high food stress, ocean noise, and marine contaminants all contribute to the “Endangered” population status assigned by both Canadian and American governments.

All Southern Residents belong to the same acoustic clan (J-Clan) and share a variety of call types. Within this clan are three distinct pods — J, K, and L — with unique dialects. The data collected from our remote hydrophone sites located within the Salish Sea will be extremely valuable to detect the presence of Southern Residents in addition to tracking the noise levels this community must endure while trying to find enough salmon to survive.

Formerly known as ‘transients’, Bigg’s orca are often referred to as the wolves of the seas. They are the whale that lead to the term “killer whale” since they hunt marine mammals, including other whales. What sets Bigg’s orca apart from the fish-eating resident orca is that Bigg’s prey on marine mammals. Most commonly, they predate on harbour seals, but they are known to also hunt harbour porpoise, Dall’s porpoise, Pacific white sided dolphins, gray whales, minke whales and Steller sea lions. Seabirds are also attacked, but not usually eaten. Many times juvenile orca are seen “playing” with seabirds, which might be an important means of developing hunting techniques.

They are more difficult to study because they live in smaller groups, usually consisting of 2-6 individuals. The family structure of Bigg’s orca is much more fluid, with families breaking apart and joining other families for periods of time. However, like residents the relationship between a mother and her oldest son lasts a lifetime.

The range of Bigg’s orca on the west coast of North America stretches from southern California to the Aleutian Islands of Alaska. Bigg’s orca cover a large area in search of prey, continuously on the move to maintain their stealth tactic of hunting. If they stayed in the same area for a prolonged amount of time, prey would be alerted to their presence, thus reducing successful hunting. With this on-the-move lifestyle, they can easily travel over 100km a day.

All Bigg’s orca share a common set of vocal signals, with some small varieties existing, but because of the Bigg’s fluid social order, they have not developed the unique calls/dialects, like resident orcas. Additionally, because this population travels mostly in silence to prevent other species from detecting them, the opportunity for a specific dialect to be passed on to family members is minimized. When we detect Bigg’s orca call types over the hydrophone we know which population we are recording but cannot determine the family group by distinct acoustic call types. They tend to use passive sonar, listening for the sounds of their prey, such as a splash from a swimming seal or a whistle from a dolphin. This is part of their stealth hunting style/tactic. If they were vocal while hunting, it could alert their prey to their presence. However, after a successful hunt, Bigg’s can be quite vocal when socializing.

Fin Whales

Fin whales are the second largest baleen whale and are found worldwide in all major oceans, including the continental shelf of Pacific Canada. World-wide commercial whaling that occurred in the 20th century reduced fin whale populations by more than 50%. The Canadian Pacific population is now showing evidence of recovery.

The management of recovering fin whale populations has been informed in part by passive acoustic monitoring with hydrophone technology, which has proven to be an effective, non-invasive tool for studying fin whale populations off the coast of BC.

The most common vocalization produced by fin whales is a down-swept 20 Hz call that is 1s in duration and is universally used by populations in all ocean basins. Patterned 20 Hz call sequences or “song” can last up to several hours and are composed of predictable frequency components and arranged in stable time increments. There is evidence that subpopulations use their own distinct variations of song, which has been suggested as an indication for population association as well as inter-population connectivity. A second call type produced in the 40 Hz range is thought to be associated with feeding patterns, but further research is required. Due to the low frequency of fin whale call types, these calls can travel hundreds of kilometres underwater.

Humpback Whales

Humpback whale communication is diverse, continually evolving, and has captivated and inspired people world-wide for generations. Some believe the melancholy notes and heartfelt quality of humpback whale song turned the page for many whale species from decades of hunting to valued measures of protection.

For decades, researchers have been following this complex underwater whale song that is constantly shifting and reshaping as each season passes. Only male humpback whales sing, the song is learned socially and is culturally transmitted within a population. During the breeding season this song display can last many hours. Along the coast of BC, it has been proposed that humpback whales practice and prepare a song for the coming year. During the song, humpback whales produce an intricate series of sounds ranging from high frequency squeals to deep low frequency rumbles.

The structure of humpback whale song can be predictable, and researchers have deconstructed its components into hierarchal elements. The base units (called notes) are singular units of sound, which are linked together to form what is referred to as a sub-phrase. Sub-phrases contain 4-6 notes, and a combination of subphrases forms a phrase. Humpbacks tend to repeat phrases over and over, and the repetition of select phrases leads to a theme. The male humpback song is then composed of a collection of various themes that are repeated in a specific order. This whale song changes from year to year. The structure and components that form humpback whale song are amazingly similar to human music composition and, as far as we know, humpback whales may be the only animals other than humans that create such complex and hierarchal patterns of sound.

Bubble Net Feeding

Bubble net feeding is a unique and specialized feeding strategy used by humpback whales only in specific parts of the world, and only by certain individuals within those populations. What is of great interest is this feeding technique is a learned behavior that is socially passed on to other individuals within a population. This includes a unique feeding call only used with this feeding strategy.

During these bubble net feeding events, humpback whales trap schools of fish (herring in the Northeast Pacific) through a combination of bubble blowing and specialized vocalizations.

In a typical bubble net feeding scenario, groups of 2 to 15 whales will descend together to a depth of approximately 20 – 60 metres and organize themselves into two known roles: callers and bubble blowers. It is currently believed that the callers will remain below a school of fish to vocalize a “bubble net feeding call” while the remaining members of the feeding group will swim upwards in a tightening spiral while blowing bubbles out of their blowholes to create the bubble net.

Experimental studies investigating how herring respond to being enclosed by a bubble net revealed that they are extremely unlikely to attempt to swim through the curtains of bubbles that surround them, even in the presence of a simulated predator. Other studies exploring the differences in the acoustic propagation of bubble net feeding calls found that the calls become the loudest within the physical bubble net spiral. This essentially creates a “wall of sound” and is believed to promote schooling behaviour and further prevent prey from escaping the quieter waters within the center of the bubble net. As the bubble net rises and begins to reach the surface with the fish enclosed within the center, every whale in the feeding group will lunge through the net with their mouths agape to eat the trapped fish.

The BC Hydrophone Network is a partnership between the North Coast Cetacean Society (NCCS/BC Whales), the Gitga’at First Nation, the Pacific Orca Society (Orcalab), the Kitasoo/Xai’xais First Nation, Saturna Island Marine Research and Education Society (SIMRES), the Heiltsuk First Nation and WWF-Canada.

Photographs, videos, and audio sound tracks are the sole property of the contributing partners.