I pull the outboard out of gear and let the boat’s momentum wash away until we’re dead in the water. Then I switch everything off – engine, echo sounder, even the radio – and there’s silence. Not even the sound of water lapping against the hull. Because it’s breathless out here today. The surface of the gulf is silky. The sky is cloudless, a shade paler than the water. And behind us, onshore, the arid ridges and canyons of the Cape Range are mottled pink and blond in the morning light.

There’s only the two of us aboard, and although the air and water are still enough to be dreamlike we’re not at all relaxed. In fact, each of us is craning at opposite sides of the boat, heads cocked, tense with anticipation.

Exmouth split over pipeline factory proposed for gulf that supports Ningaloo Reef Read more

We wait. A full minute. Then another. Speaking only in murmurs. Until, just as our initial confidence begins to wane, there it is – blam! – just off the stern. And even though we’ve been expecting this eruption, the scale and proximity of it startle us into shrieks and oaths. With a single guttural blast that ends in a groan so deep-throated it sounds positively subterranean, the whale breaks the surface and lies shining and glossy beneath its pall of reeking vapour. Then another rises beside it, a calf. It tilts sideways, showing a flash of white belly. It lifts its pectoral fin a moment as if contemplating a body roll, but others surface close by, hemming it in, so it pulls its wings in and nuzzles up beside its mother.

We count seven of them, take a few photos. It’s the same group from earlier in the morning. They seem to have swum a long lap out toward the shoals and come back for another look. Only this time they’re emboldened. They park on the surface for a minute or two before spreading out for the drive by.

Humpbacks are curious. Especially about other mammals. When they’re comfortable enough they’ll come up for a look, single or in pairs, then pull back to regroup again, as if conferring. Often, they’ll repeat the procedure two or three times, easing in closer each run until they’re right under the boat or spy-hopping so close they’re all but leaning into the cockpit for a gander. And today, as they roll on their backs to check out the dimensions of the boat’s hull, we see the corrugations of their white bellies and the yellow beards of barnacles beneath their jaws. Their movements stir the water underfoot and we turn a half circle in the currents they’ve made.

A humpback whale in Exmouth Gulf

Then, when everything’s still again, and it seems as if they’re gone, the largest and boldest of them rises perpendicular to check us out. It’s the cow. The sun shines on her knobbly head. Her unprepossessing eye appears ancient and vulnerable, somehow too small for the mass of the body below it. She leans in a little to take us in, the tip of her head at my own eye level, and I can sense her trying to figure out how much of what she’s looking at is creature and how much is just a lifeless thing. There’s no doubt she can tell the difference between a mammal and a machine.

We been doing this for a few years, Denise and me. We know that after five or 10 minutes the pod’s interest will wane. Pretty soon these humpbacks will mooch off down the gulf and leave us in their wake. Unless, of course, we show ourselves properly.

Denise looking underwater at the mother and calf

Sure enough, the mother whale dives and the group peels away. But about a hundred metres out they round up and mill a while, socialising languidly. That’s when Denise shucks off her shirt and shorts, dons her mask and climbs down the ladder at the transom. She doesn’t swim toward the whales – that’s not only unwise, it’s illegal. She just hangs there, arm through one rung, to wait. She’s face down and hopeful. Her breaths sound a little ragged in the snorkel.

And soon enough she has company. The calf surfaces 20 metres distant. Shortly joined by its watchful mother. After a few moments they ease in side-by-side, reading Denise with their sonar, literally feeling her out with their bodies, until they roll on their sides and lean toward her, as if reaching out. They lie like that a while until the calf can’t wait another moment. It dives and circles, then sinks vertically with its tail near the surface and its pecs spread like wings to steady itself midwater. And it takes Denise in that way, from directly beneath her, as the adult hovers in the background. Five minutes, 10, 20. Closer. It comes in at every possible angle. And it’s like a dance. These two strangers. Juvenile and middle-aged. Turning and turning. Pirouetting, tilting, reaching, backing away. Breathing huge, breathing small.

And this dance goes on and on until eventually Denise gets cold and retreats up the ladder for a towel and a bit of sun. As she sits on the coaming, buzzed and blissed, the two whales move away. But when I scuttle down the ladder they’re back in no time, right up in my face: dark and massive, freckled and frilled, sleek and gnarly. We’re head-to-head, me and the youngster. Mutually curious, I think. Certainly enthralled. And from my end, just a tad apprehensive. Because even this little fellow is bigger than the boat I’m clinging to. With one deft swipe or a single clumsy mistake he could kill me. In a heartbeat. But we just turn our heads, he and I, making eye contact, feeling each other’s presence the best we can, as long and as close as we dare.

A whale shark at Ningaloo Reef

So how does it feel to be face to face with a creature whose heart is several times bigger than your own body, whose eye is curious and watchful and whose intelligence is palpable? Despite how many times I’ve done this before, the experience feels … well, it feels holy. Yes, it feels sacred. It’s a privilege, a joy. It’s like being 10 years old again and realising the world around you is a living miracle. A meeting like this renews my spirit; it makes me glad to be alive.

When, eventually, I climb up and towel off on deck, the mother and calf linger a while. But once it’s clear neither of us boat-bound creatures is coming back in, they mosey off to join the pod still huffing and groaning in the distance. I lean against the rail a while to let the sun and the heat of the encounter soak in, and that’s long enough to consider where I am and what’s at stake.

Exmouth Gulf from Charles Knife Road in Cape Range national park

This is Exmouth Gulf, in northern Western Australia, one of the last intact arid-zone estuaries in the world. Right in the shadow of the world heritage area at Ningaloo. I’m grateful for this place, and grateful to it. Because over many years I’ve had the pleasure of swimming with its whales and dolphins and I’ve spent many hours observing its dugongs and manta rays. I’ve paddle-boarded beside a marlin out here, picked my way through the waterway’s rich sheltering mangroves to gather crabs, and fish for jacks, and on summer afternoons I’m happiest just lying in the shallows out the front of an oyster-crusted rock-bar as hundreds of tiny coral trout pour past to feed on the outgoing tide.

Dolphins and turtles inhabit the area

The gulf is a special place, a site of respite and regeneration. Not just for me, but for the coral reef I’ve spent 20 years defending. This is where so much of Ningaloo Reef’s biodiversity is generated, where fish and prawns and crabs are spawned. It’s Ningaloo’s nursery.

But as I sit here, warming in the sun, my inner glow gutters a little. Because this remarkable waterway is no longer safe. Exmouth Gulf has been slated for industrial development. Already Ningaloo Reef is encircled by oil-and-gas tenements. Every year the industry grows closer: the flares of offshore rigs are visible at night. This year their service vessels have been thundering up and down the gulf as never before. But until now fossil fuel interests have never been granted a foothold onshore. Next year the Subsea 7 corporation wants to build a 500-hectare pipe-launching facility to service the offshore gas boom. Right here, on the empty beach behind me. And the local shire and the chamber of commerce are all for it. Just as they’re barracking for a new salt mine and a deepwater port.

Places like Exmouth Gulf are vanishingly precious. They help keep our natural estate and our world heritage assets alive. They challenge and feed our scientific knowledge. And they help keep ordinary citizens sane. So, this development is an awful prospect, a disaster in the making.

Yes, it’s a very lucky person who swims face to face with a whale. And not all of us can snorkel on a coral reef or paddle through a mangrove forest. But many people take heart from knowing such ecosystems and experiences still exist; their persistence in a degraded world gives us hope, wherever we live.

Ordinary citizens want to believe there are some places too precious to surrender to corporate interests, unspoilt places that shouldn’t be industrialised. We need to know there’s a line we’ll draw and will not cross. Because a world given over entirely to the engine of industry becomes a world no longer fit for creatures, human or otherwise; it becomes a world without hope.

Like whales, we humans recognise the difference between a being and a contraption, a creature and a machine, a community and an industry. We want the chance to look the enormity of life in the face and be reminded that it’s precious and holy. Humans need hope, reasons to feel glad to be alive.

Wheatstone, Onslow

This is one of those places, and one of those reasons. One of those lines in the sand we can’t afford to cross.

I pull on a shirt. In the distance a cloud of breath hangs in the air. A tail catches the sun. And they’re gone.