Orca Whales and Kayaks
ALL ABOUT ORCAS
Orcas are one of the biggest, most beautiful and most intelligent mammals to swim the oceans. Orcas are also unique in that they can be found swimming in almost all of the world’s oceans, from the frigid arctic to the balmy tropics. Although there are orcas swimming in waters all over the world, the best place to view an orca is right here in the Johnstone Strait where they have been coming to fish the plentiful salmon run and rub on the rocks at Robson Bight for decades, maybe even centuries.
The word orca comes from a Latin word that means whale. This is the word ‘orc’ that can mean sea monster or large fish as well as whale. It is also commonly called the killer whale and its scientific name is Orcinus Orca. Orcas are the largest member of the oceanic dolphin family, Delphinidae. The distinctive markings of an orca make it hard to miss in the wild. They have black backs, white chests and sides and a patch of white behind their eyes. Their torpedo-shaped bodies are stocky and they have a large black dorsal fin; their hulking size does not slow them down and they reach speeds of up to 30 miles per hour. Males can grow to be up to 8 meters long while females can get to be about 7 meters long. These are heavy animals with males commonly weighing in excess of 6 tons and females weighing in at 4 to 5 tons.
Despite their smaller size, females are at the top of the orca’s social structure. Most orca groups are matrilineal and consist of a mother swimming with her offspring. These groups are called “pods” and there are pods that consist of a grandmother, her offspring and their offspring. Males commonly stay with their mother for over a decade and will learn their hunting style from their mother. Oftentimes, offspring will remain with their mother until her death. This can mean several decades as females can live to be 70-years-old and there is record of a female orca living past 80 years.
The social structure of the orcas is essential to their hunting style and a pod of orcas is among the world’s top ocean predators. Orcas are often called “wolves of the sea” because they hunt in packs, just like wolves. Orcas maintain their size by treating themselves to about 227 kg. or 500 lb. of food on a daily basis. In the Johnstone Strait, salmon probably account for 95% of the orca’s diet. This is why the multinational fish farms in Broughton Archipelago serve as a threat to the orcas as well as the First Nations people.
Orcas often hunt for big, fatty Chinook salmon in small group by simply attacking and eating. The pack becomes more creative when they decide to hunt for different fish, such as herring. To hunt herring, orcas use a method nicknamed carousel feeding. To do this they force a group of herring into a tightly enclosed group by either blowing bubbles or flashing their white undersides. Once the group is compressed into a neat ball, the orca slaps the ball with its tail, potential killing the entire group with one successful slap.
Orcas in the Johnstone Strait almost exclusively focus on fish for their food supply but other transient orcas often prey on other mammals. There is evidence that orcas has attacked fellow whales such at Minke, Gray Whales. The whales they attack would generally be younger, weaker whales but larger pods have been known to attack healthy adult whales also. Seals and sea lions are other popular mammal meals for transient orcas.
Types of Orcas
What an orca eats is often directly related to what group of orcas it belongs to. In the Northeastern Pacific, where we paddle, there are three recognized types of orcas: resident, transient and offshore orcas.
Resident orcas are what you can expect to see in the Johnstone Strait. This is the most commonly spotted type of orca as they customarily live in a large stable group, numbering up into the hundreds, that does not move around much. Resident orcas are known to feast on fish rather than mammals; the Robson Bight orcas and their obvious appetite for salmon exhibit this.
Resident orca pods are known to be extremely intelligent. Within pods, orcas form lifelong bonds and they also communicate for navigation purposes and to express their moods. Orcas whistle, screech or make a buzzing sound in order to communicate with the fellow members of its pod. Using a hydrophone, researchers have studied communication between orcas and found that different pods even speak in distinguishable dialects. Resident orcas are also known to use body language to express their moods. Blowing bubbles, breaching, tail slapping and head nods are all ways orcas have been observed expressing their emotions. A last method that all orcas are known to use is echolocation. This method is used in low visibility water. Here an orca produces a series of clicks inside their head, the sounds leave the body and echo off objects in the nearby water. The orca’s brain is able to process the clicks and maintain a three-dimensional sense of place.
Transient orcas travel in smaller pods than resident orcas and roam wildly from place to place. Their travel routes are extremely unpredictable, making research into their lifestyles difficult. Transient orcas distinguish themselves from resident orcas in several ways. First, their pods are not always matrilineal and they are not often noted for the strong familial bonds that resident orcas maintain. Secondly, they feed almost exclusively on marine mammals, with seals and sea lions commonly falling prey to their accelerated hunting skills. Third, they are much less vocal than resident orcas, probably communicating less so as not to scare off potential prey. Transients travel in groups of about 2 to 6 whales and it is less likely that they will stay together as a family unit. The name “transient” came from the belief that these orcas may have been cast out of their larger resident pods.
Much of the information on offshore orcas is speculation as this type of orca has only been studied for about twenty years. Offshore orcas travel in large groups of up to 60 whales in the open water. They feed on sharks, fish and sea turtles and opt for the open seas rather than a designated location like the resident orcas do. There have only been about 40 encounters with offshore orcas since they were discovered in 1988 and so not much can be said about their social structure and ability to communicate.
Are orcas dangerous?
As one of the ocean’s top predators, orcas are a dangerous to most of the ocean’s creatures but the instance of orca attacks on humans is extremely rare and mainly limited to orcas that have been held by humans in captivity. The resident orcas of the Johnstone Strait are focused on eating fish and there are no cases of an orca attacking a kayaker’s boat. Orcas are known to be playful animals and this is what kayakers coming to view orcas are most likely to observe. While the orca threat to humans is non-existent, the reverse is not the case and human behavior serves as the primary threat to orcas.
Threats to Orcas
Environmental degradation and depletion of their food supply are the main threats to today’s orca population. Orcas have been poisoned by human waste such as Polychlorinated biphenyls (PCB’s) that find their way from trash dumps to the water and into their bodies. Oil spills have been known to adversely affect the population of some pods. Spills not only hurt the whales themselves but also their food supply. Anything that depletes the salmon population in the Johnstone Strait will in turn threaten the orca population there. That is why the multinational salmon fisheries in the Broughton Archipelago have come under heat from not only First Nations People but from environmental groups concerned about the orca population as well.