Even before our boat left the shelter of Bremer Bay boat harbour, in south-west Western Australia, shortly after dawn on the first day of the region’s 2015 killer whale season, it felt like we were already at the edge of the world.

I was there to see a tiny place, far out to sea, that marine scientists and environmentalists regard as one of the most special ocean ecosystems anywhere in Australia’s commonwealth waters.

We would motor more than 65km offshore to a location not much bigger than a few football fields, where the ocean is 4.5km deep and weather conditions are almost always treacherous. Where we were going there was a not a single distinguishing feature or landmark – just a GPS point.

That spot is the scene of a phenomenon whose astonishing value has only recently been discovered, that few know about but whose fate hangs in the balance – right now.

More than anything, though, no one yet knows for sure why each year, during February and March, life from around the Southern Ocean converges on that relatively minute speck in the ocean wilderness.

What is known is that there is a sudden, annual explosion of life that leads to feasting by an array of animals, attracting every level of the marine food chain – from bacteria and jellyfish through to killer whales, large pelagic sharks and wandering albatross.

As I stood waiting to board, it was easy to see why this area has a negligible national profile. Bremer Bay is a lonely, isolated spot, 500km south of Perth. It was so remote that I only just made the drive from Perth airport without running out of petrol, because I could not find a service station open after dark.

The coastal village is dominated by a 45m-tall wind generator on a hill above it, testament to the fact that this is also one of the windiest of coastlines. Beyond the rocky breakwater and the tiny cove where we gathered for our departure, the ocean looked choppy and vast. The crew told us, ominously, to brace ourselves because today was rougher than usual.

As we clambered on board all 11 of us looked with grimaces at the wild sea just beyond the tiny anchorage. The organiser of the trip, the tour operator Naturaliste Charters, had warned there were two things that those making the voyage would need to consider: seasickness and sea spray.

Out in the open ocean, pounding into the 3.5m seas, it didn’t take long for about half of those on board to be so sick that the boat’s deckhand was soon retrieving an alarming number of seasickness bags. For the next two hours his main job was tending to several people who were so ill that they lay on the floor inside the cabin groaning with misery.

We think that hydrocarbons, under pressure, are … slowly leaking to the surface, providing a rich source of nutrients David Riggs, film-maker

One woman sat at the stern, sick to the point that she didn’t care that the spray from the crashing waves was leaving her drenched. No one could convince her to leave her exposed spot.

With us that day was a film-maker, David Riggs, whose 2013 film, The Search for the Ocean’s Super Predator, featured a story about the mystery of what ate a tagged three-metre white shark. As part of the research for that documentary Riggs discovered the annual killer whale aggregation off Bremer Bay. He now spends every February and March filming and studying the event.

He explained as we steamed offshore that the first indication something special was happening off Bremer Bay came from research produced by Cathay Petroleum, whose marine mammal surveys a decade ago showed there was a cetacean “hotspot” off Bremer Bay. Riggs set about nailing down the nature of that hotspot and today it is fast becoming the centrepiece of a tourism operation, increasingly important to Bremer Bay’s economy.



Just east of the location of the killer whale aggregation is the Bremer commonwealth marine reserve, the whole of which is being reviewed by the Abbott government. But environmentalists and researchers say the process is flawed on multiple levels. First, the region’s most significant environmental feature, the aggregation point, is outside the reserve’s boundaries, and second, the closest part of the reserve is zoned as open to industry.

“The hotspot is slightly to the west of the Bremer commonwealth marine reserve, next to a multiple-use zone,” Riggs said. Multiple-use zones are available to petroleum exploration and drilling, and to commercial fishing.

And the risk from industry is real; not only is the area a hotspot for super-predators eating through the food chain, it is also an untapped potential source of petroleum.

And yet it is the very existence of the hydrocarbons stored under the seabed that may be the fuel for the Bremer Canyon killer whale phenomenon.

Riggs and the crew from Naturaliste Charters regularly find oil floating to the surface in the area. He says the 4.5km-deep Bremer Canyon is about 60km long and 20km wide.

“It has several undersea tributaries that run into the main canyon,” says Riggs. “At the mouth of one of these tributaries is what looks like a dome that rises to within 800m of the sea’s surface.

“We think that hydrocarbons, under pressure, are inside this dome and are slowly leaking to the surface, providing a rich source of nutrients to the base of the food chain.”

Killer whales congregate at Bremer Canyon. Photograph: James Woodford for the Guardian

But if that is the case, why doesn’t the aggregation take place all year?

Riggs thinks that during February and March currents in the area change, allowing upwelling of the nutrient rich water to the surface. Giving weight to the theory that there is some kind of nutrient “emanantion” at the sea floor is the fact that, while always in the same general area, the exact hotspot moves position depending on the currents.

“In the big scheme of things, in this huge ocean, this phenomenon is a tiny pinprick.”

I am sceptical that there is any chance in this churned-up sea we will see anything other than the seabirds tailing our boat, let alone a gathering of killer whales.

After about an hour and a half of crashing through the swell, the last of the continent had disappeared over the horizon. One of the final things that I could see of the Australian mainland was the enormous wind turbine.

The skipper was now closing in on the GPS location. I asked Riggs how we would find the killer whales when we were at the GPS point. Once in the vicinity, he said, the telltale sign of where they were actually hunting would be the flocks of seabirds feasting on the orcas’ leftovers.

“They’re cunning buggers,” Riggs says to me. “They will hear us coming and when we arrive they will dive to hide and we will have to wait until they surface again before we will see them.”

After two and a half hours the boat’s engines slowed and, instead of driving through the swell, we were bobbing between the waves. Riggs called out: “Eleven o’clock, killer whales. They’re here.”

Those who were still standing stared in the direction Riggs was pointing and, sure enough, the distinctive dorsal fin of a killer whale broke the surface. And then another. Several of those on board were too sick to care.

This was what I had expected would be the ideal outcome of such a rough journey – a distant glimpse of a dorsal fin, a burst from a blowhole and the splash of a tail hundreds of metres away. And sure enough it was the birds that showed the way to the whales. They wheeled above the predators, occasionally diving to collect chunks of flesh left behind.

And then something surprising happened. Out of nowhere, appeared half a dozen black and white apparitions surging under and around the boat. There were mothers, calves and bull killer whales diving and cavorting everywhere. At one point four surfed the face of a large wave behind the boat – their power was immense. Then, as quickly as they had arrived, they were gone.

Over the next couple of hours, which seemed like barely more than a few minutes, we drifted and slowly motored towards wherever the birds were. Each time the killer whales would speed past, under and in front of the boat. For the entire time pods of killer whales were all around us.

‘For the entire time, pods of killer whales were all around us.’ Photograph: James Woodford/Guardian

The whole event took place, exactly as Riggs had said, in a patch of just a couple of square nautical miles of sea.

Killer whales are incredibly difficult to plan to see in Australia, yet this was a spot, an exact spot, where every year at the same time more than 100 gather for more than two months. For a tourist operator like Naturaliste Charters, such predictability for such a rarely seen animal is gold.

Riggs announced that we would soon be leaving for the trip back to the harbour. “But first there’s a bull killer whale ahead!”

The boat drifted towards the enormous animal but as quickly as it had appeared it was gone. The skipper powered up the boat’s engines, turned north towards Australia and we headed for home, this time with the sea following behind us.

I felt genuine dismay that we had to leave. But it was not a place where people could stay for more than fleeting visits. We had gained a glimpse into a whole other wild world that seemed both fragile and vast; beyond us but also at our mercy. Decisions being made by politicians and petroleum industry geologists will, in the coming months, decide the long-term future of Bremer Bay’s killer whale aggregation.

After I returned home I spoke to Adrian Meder, a marine campaigner at the Australian Marine Conservation Society.

“At every stage of this commonwealth marine reserve process we have said that the Bremer Canyon deserves protection as a marine sanctuary because of the ecological values that have so captured the imagination of the public,” he said. “But at every stage industry has been able to have that consideration scrapped. They have always succeeded in having the canyon excised from sanctuary zoning.”

Recently, however, the company that held the exploration lease over the canyon relinquished it. The fact that industry has backed away from developing the area for petroleum drilling means there is finally an opportunity for the canyon to receive proper protection.

Riggs says the opportunity must be seized. “Yes, we need fuel, but we also need biological systems as fragile as this one to remain as intact as possible,” he said.

• James Woodford is Guardian Australia’s ocean correspondent. The position is a non-profit journalism project funded by the Pew Charitable Trusts. For more information on Woodford’s work for Guardian Australia, click here. He is on Twitter at @jameswoodford1.