Volunteering at the Bremer Trench
As a marine biologist who has worked and played in most of the oceans of the world, I struck gold when a population of orca or killer whales were sighted in Western Australian waters in 2016.
Such sightings have not been common so this discovery was just as much a surprise to the world as it was to me. As a local, it gave me the opportunity of a lifetime to explore the orca in our Southern oceans right on my doorstep.
Killer Whales or orca hold a special fascination for us whether we identify with their obvious family bonds and cooperative lifestyle or are awed by their rating as the top ocean predator.
I applied to work as a volunteer research assistant with the Bremer Canyon Killer Whale Expeditions joining a research team investigating the orcas. My work included taking photographs to identify them, undertaking underwater videography and making acoustic recordings as well as acting as a tour guide for the company.
Bremer Bay is a tiny Western Australia south coast town surrounded by a rugged coastline and is spectacularly beautiful. UNESCO has recognised its pristine state and biological diversity by creating a Biosphere Reserve.
The key to this diversity lies under the sea floor. A fuel deposit was laid down in the time of the dinosaurs with a leak releasing methane that formed ice-like reefs on contact with cold seawater. The reefs provided a food source for specialised bacteria that in turn became food for ever larger predators- a complex food web topped by the ultimate apex predator, the orca.
Sixty kilometres offshore lies a less well known ecological treasure. Beyond the continental shelf, the landscape of the deep ocean is driven by canyons. One of these canyons is different. The Bremer Canyon supports a diversity of life unusual in the deep ocean. In my time here I have seen sperm whales, pilot whales, false killer whales and even the largest animal that has ever lived- the blue whale. Dolphins often surrounded our vessel in pods of well over a thousand. The remains of a giant squid floated on the surface, a predator of the deep, reduced to scraps, squabbled over by a multitude of seabirds. Disc-shaped sunfish, some as large as a small car, come to the surface and become a regular inclusion on the orca menu. Every Southern Ocean shark species including the iconic great white has been sighted in this rich playground of the Bremer Canyon.
The Bremer Canyon orca are summer visitors, but where have they come from? Bec Wellard of Curtin University’s Centre for Marine Science aims to find out. Killer whales spend their life in a family pod, communicating via a complex language of sounds including clicks and whistles. Each family has a unique dialect, so recordings of the vocalizations of different families have a unique pattern of sounds.
The distinctive black-and-white bodies are all quite different as well. Every individual orca has variations in the shape of the dorsal fin, the white- eye patch, and the grey marking on the back so these can be used for reliable identification. The Bremer Canyon acoustic and photographic data is used to compare data from other parts of the world. A match will help solve the mystery appearance and disappearance of the Killer Whales each year.
A remote location and treacherous seas make research difficult and expensive, a problem solved by participating in the Bremer Canyon Killer Whale Expeditions. This project is a unique collaboration of a whale-watching operator, a documentary producer and the research team.
Citizen scientists join expeditions daily, their trip partly funding research, and their photographs assisting with orca identification.
In combining my career as a marine biologist and my love of travel and discovery, I have never been more awed by our amazing blue planet. Travel on the Southern Ocean is an experience in itself, our vessel often dwarfed by colossal swells both dramatic and exhilarating. Seeing so many of the oceans’ rock star species, unperturbed by our presence is unforgettable, confronting all of my senses and evoking the full spectrum of emotion. Orca often approach and surround our vessel, playful giants as curious about us as we are of them. The contrast is of those same orca as hunters transformed to deadly black and white missiles that rocket through the ocean, a boiling mass of bodies and blood as they make a kill. A sperm whale breaching, its 50 ton body landing in a storm of white water. An aquatic daycare of pilot whale calves, safe in the centre of a protective family. Rapt faces on board as the underwater symphony of socialising orca fills the air, all breathtaking moments captured forever in my mind’s eye.
Volunteering to work on a project that fits and fuels my passion has led to the most incredible adventure of my life, an experience with the priceless reward of new skills, friends and memories. The ultimate reward though, is the satisfaction of having contributed something positive to the world, to the understanding and ultimate protection of this unique ecosystem of the Bremer Canyon.
Written by: Kirsty Alexander
Photographs by: Keith Lightbody
This article first appeared in our Winter 2016 Issue