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.

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.

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

The family structure of Biggs orca is much more fluid than with residents. This population is also organized into matrilines, but these are typically only 3-7 individuals traveling together. As the matriline grows, the oldest daughters will break away from their mother and siblings to travel with their own offspring, in their own matriline. However, like with residents, the relationship between a mother and her sons lasts a lifetime.

The range of Biggs orca on the west coast of North America stretches from southern California to the Aleutian Islands of Alaska. Biggs 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 Biggs orca share a common set of vocal signals, with some small varieties existing, but because of the Biggs fluid social structure, they have not developed unique calls/dialects within different families 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 Biggs orca calls over the hydrophones we know which population we are recording but cannot determine the family group by a distinct acoustic dialect. 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. If they were vocal while hunting, it could alert their prey to their presence. However, after a successful hunt, Biggs can be quite vocal when socializing.

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 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.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.