When her coughing and wailing subsided, Rosie looked up to see her twin brother Robert grinning back at her from the stem. He had managed to get back to the boat under his own strength and their father had helped him back on board. with a kinder hand, before slapping his back and shouting his praises. As she pushed her shaking fists into her eyes, squeezing out the tears with the brackish water, Rosie heard her father’s disparaging whisper, ‘Girls.’

There was only ever one swimming lesson. That was the limit of her father’s patience. But Rosie’s failure didn’t even nibble at the joy of fishing with Robert the next morning, off the end of the little jetty that struck out into the curve of still water below the holiday shack. Every day of that summer break was another long blue sky burning the skin off their noses and drying their hair to straw as they perched, legs dangling, toes tipping the cool water, fingers flicking at cork-wound lines.

The inlet fish had long been wise to jetty children. Only the puffer-fish fell for the wormy bait and the twins exacted a misplaced revenge by flipping, each catch onto the splintery boards and whacking them with a fierce-wielded thong. But not until the fish had filled itself with as much air as it could hold, not until its prickled throat had swelled to twice the size of its body, not until they could almost see its innards through the balloon-thin skin. Robert held his thong high until Rosie judged the moment when the puffer could puff no more. Then she yelled 'Now!' And they greeted the almighty pop with a great circus of leaping and shrieking.

'The best yet!' Robert declared every single time and Rosie grinned her agreement.

In the afternoons, their mother laid towels on the thin strip of beach, and their father speared the sand with a rainbow-coloured umbrella for shade. At first, the twins played together but, after the swimming lesson, Rosie found herself paddling alone at the foamy fringes while her brother stretched his newfound skills further out. Their father pushed him on by swimming a distance, then standing and waiting for Robert to meet the challenge. Deeper and deeper each time. Until one day they strode out of the water together and the boy announced, 'Dad's taking me fishing. Out in the boat. Out in the channel. Tomorrow.'

The disappointed quiver of Rosie's lip went unnoticed amongst the torrent of objections from their mother. 'No, Bill, the boy's only eight- I don't mind you taking them out on the calm waters. But not the channel. He's too young.'

'C'mon, Emmy, you've seen him. He's a champion. And I'll be there to watch over him. It's time he learned to catch some real fish.'

Any further motherly concerns were smothered by a whirlwind of whooping as Robert tore back into the water and plunged, fingers outstretched, toes disappearing, as neat as a dolphin.

'See,' their father assured. 'Swims like a fish.'

Rosie ducked her head and wandered along the edge of the water. One chance, that was it, and she'd wasted it. She should have tried harder to stay above that sucking water. Tomorrow morning, there'd be no fishing from the jetty and she'd be the only one missing it. She kicked at the wet sand, refusing to look up at Robert with his splashing and yelling.

'Rosie, look at me! I'm a fish!'

'You're an idiot,' she whispered, not meaning a word of it.

Rosie heard them leave before dawn the next morning, bushing and shuffling around in the kitchen, clicking the door softly closed, crunching along the gravel path down to the jetty. Then the slow-fading slap of oars.

She mooched her way around the longest morning- A few pieces placed in the holiday jigsaw, a halfhearted game of snap with her mother, a postcard written to Grand. She sniffed at her mother's suggestion to go down to the beach before lunch, but followed all the same.

While her mother spread towels on the sand, Rosie peered across the inlet. A long smudge of mangroves marked the far side and she could make out a dip in the horizon, a gap in the rim. The channel. She wondered how many fish they'd caught already. Real fish, no puffers. Her father would go again tomorrow. And he'd take Robert again, most likely.

It suddenly occurred to Rosie that she had time right now to practice her swimming, away from the critical eyes of her father and the jeering teases of her brother. She waded out just over knee-deep and crouched in the warm, clear water.

Then she reached down and pressed her palms onto the spongy sand, before locking her elbows and slowly stretching out her legs. Her chin just dipped the surface, as she kicked up her feet, and, immediately, she felt her body rising to the surface. Floating at last.

She started to hand-walk back and forth, and, when she was sure she had this much mastered, she stood and looked back at the beach. Her mother was nodding and miming a round of encouraging applause. Getting there, she was certain of it.

'Watch, Mum!' she yelled out, before throwing herself into a lunge, fingers outstretched, no hands touching the bottom, this time. For a brief moment, she was gliding over the surface. But the next instant, she was sinking, water surging in her open mouth and rushing up her nose. She flailed with arms and legs until her knees found the sand, and her head pushed through the surface. Then, spluttering, shaking, warm tears welling, she stumbled back to the safety of the beach.

'Never mind, honey,' her mother cooed, wrapping her in a sun-warmed towel. 'Give it time. You'll get there.'

But not today. She'd had enough of the water and she nodded gratefully at her mother's suggestion that they go back and make some sandwiches ready for when the hungry fishermen returned. The piled-high plate had just made it to the table when gravel-footsteps drew Rosie to the window. There was Robert holding high a silver-glistening fish, big enough for dinner, and she couldn't help conceding him a grudging smile of approval.

Over lunch, Rosie suggested the jetty but Robert shook his head. 'Nab. Just a bunch of puffer-fish. Who wants to catch rubbish?'

Rosie put down her half-eaten sandwich, and sat in silence for the remainder of the meal. She sneaked sideways glances at her brother, envying his salt-crusted hair, his wind-red eyes and his easy chatter with their father. Robert had been out in the channel and she didn't count anymore. He was Dad's mate, now.

Next morning, her brother and father were already gone when she woke and, by the time she'd finished breakfast, she'd decided to go to the jetty. Why should she miss out just because Robert wasn't here? And anyway, she could whack puffers with her own thong. Nothing hard about that.

'Not in the water, Rosie,' her mother insisted. 'Not by yourself. Stick to fishing off the jetty.'

But once she was sitting on the edge of the rough boards, she didn't feel like putting in a line. She peered over the edge and stared at the jetty ladder for a while, and wondered how deep the water might be down there. She might be able to touch bottom.

A second later, she was stripping down to her swimmers and climbing foot-over-foot down into the water, until she was perched on the lowest rung. Cool ripples lapped at her waist as she peered at the shafts of sunlight flickering over the sandy bottom. But it wasn't so easy to tell how deep that might be. Moving her hands down to the last dry rung, she stretched one leg down into the depths. Even with her toes pointed to their limit, she couldn't touch. She shivered at the thought of all that water beneath her and quickly drew herself back up, pressing her cheek against the safety of the ladder.

Her mother's warning suddenly dropped into her head, and she screwed up her nose. It was because she was a girl. She'd heard her father say it. She was the same age as her brother, but Robert could swim, Robert was allowed to go fishing in the channel. She was left behind, alone on the jetty, because she was a girl.

Without another thought, she took one long breath and lowered into a crouch, fingers tightening on the ladder, toes curled around the bottom rung. Then she let both feet slip their hold and kick out. The harder she kicked the more her body rose to the surface, until she was floating there, arms outstretched, fingers clinging to the rung. When her legs began to tire, she stopped kicking and was surprised to find she didn't sink. Then she let go one hand. Gripping tighter with the other, she swept her free arm back and forth until she was facing the beach, parallel with the jetty. She could see the shack from here, and hoped her mother wouldn't look out and see what she was up to.

But it wasn't her mother at the window that suddenly made Rosie kick her legs and thrash her arm, desperately straining for the safety of the ladder. It wasn't the two men shouting and running up the gravel path that made her gulp great mouthfuls of salty water. It wasn't her mother flying through the door, barging past the men and tearing down to the beach that made her feet windmill against the deep, searching for the lifeline of the bottom rung.

It was her mother's screaming, over and over, that made Rosie haul herself up hand-over-hand, until she stood on the jetty, legs trembling in a puddle of her own dripping. She threw up her arms, waving and yelling between splutters, 'Mum, I'm here!'

But it didn't stop the screaming, and it was only when Rosie started to run along the jetty towards the beach that she realised her mother wasn't even looking in her direction. She was waiting across the inlet crying out to the channel gap. And it wasn't Rosie's name she was calling, but the names of her brother and her father.

Rosie never learned to swim. Not like her twin brother, clawing at the chilly deep of the channel, kicking against the drag of swirling eddies, filling his lungs with water until he was weighted with the swell, and drifted like a weed along the sandy bottom. Not like her father, diving again and again for his boy, until his arms gave out and he floated facedown on the outrunning tow.

High tide tumbled their bodies onto a surf-scoured beach, days later. Rosie was not allowed to see, but she heard whispered snippets, and she could imagine. They swell up, bodies that have been sucked down, held without breath for too long by the sea's selfish grip.

Learning to swim can be dangerous and, after so many long blue summers, it's something Rosie still believes. It's something she repeats over and over, as she stares across the inlet and thinks of her brother, burn-peeled nose, sun-strawed hair, stranded on the sand like a puffer fish.