Journey just 30 nautical miles from Fremantle in Western Australia and you will find yourself in the largest submarine canyon in Australia… the Perth Canyon. Stretching over 2,900 square kilometres and reaching down to depths as far as 4.5 kilometres, the Perth Canyon is truely enormous and can be easily sighted from satellite images of the Western Australian coastline. The history of the Perth Canyon dates back to the original Swan River mouth before water levels rose and the continental shelf was engulfed by the ocean. Larger than the Grand Canyon in size but displaying similar features such as deep gorges and sheer cliff faces, the Perth Canyons topography has only recently been discovered and better understood. Hosting visitors of every kind the Perth Canyon is one of only three known locations in Australia and one of very few places in the world Blue Whales are known to congregate and feed every year without fail.
Photo Credit – Geoscience Australia
The Perth Canyon is located within the pathway of two important currents located off the Western Australian coastline. The Leeuwin current is a warm, southward flowing current that travels at approximately 1 knot all the way to Cape Leeuwin (Australia’s most south westerly point) before making a sharp turn and continuing its reach all the way towards Tasmania. Mixing with this current is the cooler, northward bound Leeuwin Undercurrent and when the two combine within the walls of the Perth Canyon an incredible event eventuates. Eddies and upwelling begin to occur in the steep canyon walls and dissolved oxygen and micro nutrients from the Leeuwin Undercurrent provide a food source for the tiniest of creatures such as phytoplankton which begins the food chain. Euphausia Recurva is the main species of krill found in the Perth Canyon and is the finest of krill for the largest creature to have ever graced our planet, the Blue Whale.
The feeding season peaks in March to May as hundreds of Blue Whales gather to feast on up to 40 million krill per day. Sperm Whales, Oceanic Dolphins, Sunfish, Beaked Whales and pelagic species of fish and seabirds all join in on the plentiful food supply, a vitally important feeding ground for many. The Perth Canyon is an Australian Marine Park and importantly so to ensure that future generations of Blue Whales and many others species of cetaceans and sea life who visit always have a fridge full of food waiting for them in the cellars of the Perth Canyon.