© Tavish Campbell
Orcas/Killer whales – Orcinus Orca
Musgamagw Dzawada’enuxw territory (Broughton Archipelago) is an ideal environment for orca (killer whales).
Its inlets, islands and estuaries provide protective marine habitat, food and a haven of silence for these whales that use sound to navigate.
Outside the quiet inlets, whales must contend with the chatter of pebble beach, the roar of tidal action, the scream of speedboats and the underwater noise of big ships that obliterates all other sound. But within the archipelago, its waters are so silent that the calls of once abundant orca could be heard echoing back and forth off the cliffs, like the ringing of church bells.
Studying whales in the wild
Raincoast Research has been studying orca in the Archipelago since 1984 – focusing on their natural history and use of sound. As the whales swim through inlets, they communicate to one another in a rich language of calls and echolocation.
Using underwater hydrophones, Raincoast monitors underwater for these whale calls. The whales are identified by audio recordings of their calls, as well as, photo-identification of their dorsal fins and markings.
Every pod of resident orca uses a different dialect. The Biggs whales – mammal-eating transient orca – use calls that are completely different from the resident orca calls.
Home to the “A” pod
The archipelago belongs to the “A” pods – resident fish-eating killer whales of the Northern Resident population. All other resident pods of whales traveling through the region were generally escorted by an “A” pod member.
Biggs orca are also found hunting seals and harbour porpoises in the area. On one occasion, a group of offshore orca – normally located off the continental shelf – was encountered.
In the early 1990s, the resident orca here were displaced by acoustic harassment devices used to scare seals from salmon farms. Raincoast has largely recorded their absence over the past 12 years.
While the Biggs orca continue to frequent the area, they rerouted themselves to avoid passing close to salmon farms using acoustic harassment. The acoustic devices were turned off within a few years but the orca have yet to re-establish use of the archipelago.
Seasonal orca use of the Archipelago
April and May
- Historically, “A” pod members would enter the inlets as the herring and oolichan began to spawn. Orca don’t appear to eat oolichan or herring, but they pursue the Chinook salmon that do.
- Oolichans are an oil-rich member of the smelt family. ‘Grease’ extracted from the fish provided an essential food and trade item for First Nations in the region.
July to September
- Large groups of orca gather in Johnstone Strait during the annual summer salmon migration. Individual A-clan families used the adjacent waters of the archipelago to sleep, feed and relax for a day, following predictable routes through the islands.
- The whales entered Fife Sound, often swimming against the ebbing tide. Like wolves hunting downwind to smell their prey, orca hunt against the tide. When they reached Tribune Channel, they napped as they swam slowly down the deep channel until they reached Knight Inlet.
October to November
- Large runs of chum salmon used to enter the archipelago in the fall, attracting resident orca (including G-clan whales). These huge salmon runs are greatly diminished in Musgamagw Dzawada’enuxw territory.
- Young chum salmon are highly susceptible to sea lice from salmon farms. The young fry leave the rivers and enter the ocean immediately after emerging from the gravel. They are tiny – weighing less than .5 gram – and with no scales, making them extremely vulnerable to sea lice. Raincoast Research has been publishing on sea lice impacts on salmon since 2001.
Winter
- In winter, the large migratory schools of salmon were replaced by overwintering Chinook salmon and small Coho, often called ‘bluebacks’. Orca hunted the Chinook and bottom fish in the archipelago. Its sheltered inlets provided easy hunting and respite from the windy, coastal winter weather.
- During the winter months, whale families broke down into their smallest divisible units of mothers and offspring. In many orca groups, all members stay with mom for their entire lives. If families are small, a mother and her sisters sometimes remain together with their children and grandchildren.
Salmon farms and ocean noise
In 1993, the salmon farming industry introduced technology to deter seals from preying on penned salmon. Underwater noise was used to hurt the ears of seals to ward them off.
The acoustic harassment devices (ahds) had drastic impacts on sound sensitive orca. The whales abandoned the area, ending thousands of years of passage through this archipelago.
In 1999, salmon farms turned off their noise, but the whales do not appear to trust the restored silence yet. They have not re-established their use of the area and many matriarchs that appeared to guide the families through the archipelago have died.
If wild salmon are given the opportunity to repopulate the area, these whales should have the capacity to relearn the timing of each run and how to fish them.