Geoff Thomas: And the gold shell goes to...

There was a muted buzz as thousands of spectators waited, burning with anticipation.

Then the bubbles crashed out all around the arena as the contestants strutted on to the sand and the crowd roared.

Fins slapped together, sending the waving kelp fronds into crazy vibrations.

This was the glamour event. The finalists had travelled from all over the world's oceans to be here in the murky waters of the English Channel to settle the question once and for all: Who is the fastest fish on the planet?

At the last gathering four years ago, the speedster from the Caribbean, wahoo, bolted home in just under five seconds. But there was a four-knot current running through the channel and American tuna was pushing hard, beating wahoo by a nose in a preliminary meet 12 months ago.

Could the record-holder do it again?

On the far side of the sandy arena the heavyweights were hurling the clam shells, sending the white discs spinning over the rocks with a practised flip of a fin. Giant groper, bass and manta ray were all in the running for the gold shell but only one would prevail.

Flying fish was way out in front in the triple jump, soaring over the choppy surface, and it looked as if the gold would be heading for the South Pacific.

The endurance swimmers, the many different sharks, were getting close to the arena after 40km of slogging out into the Atlantic and back. Great white was swimming strongly but mako might push him at the end.

In one corner the billfish were dancing back and forth, jabbing lightly with their swords as they tried to slip a fast tip past the defence. Blue marlin was heavier and bigger but sailfish was much faster and it looked as if speed and agility would prevail again.

The finalists lined up for the final of the 100m dash, preening themselves and waving coloured fins at the cameras. In a few minutes the world would know who was fastest. Wahoo lined up beside tuna, with mackerel and barracouda following rainbow runner and kingfish towards the start line. Then snapper led a bunch of stragglers around the rock pillars and, gulping water in a frenzy, surged over the line to take the gold shell in the marinathon, with seven disciplines the most gruelling event at the games. It was a heart-stopping moment for the small contingent from the other side of the world and all around the coast of Aotearoa the cheering bounced off the reefs.

Elsewhere, brightly coloured mahi-mahi leaped from the sea, reaching up and flipping over as her tail registered the highest leap of the week, ensuring a rare gold for the Cook Islands.

Delicate seahorses undulated in the current, dancing up and down as they tried to impress the judges with their synchronised grace and timing.

A hush descended on the packed throng seated on tiered rocks around the sandy arena as the eight fastest swimmers lined up though.

This was the moment they had been waiting for. The eight leaned forward, tails coiled ready to unleash powerful muscles. The starter dropped the coral branch and they were off. Mackerel surged ahead and kingfish was right on his fin, with rainbow runner pushing hard on the other side. Then wahoo drew on his last reserves, with blood pumping through his muscles, side fins slotted into recesses in his torpedo-shaped body to reduce drag, he went into overdrive, screaming through the water to hit 100km/h and cross the line half a body length ahead of the pack.

It was all over in 4.78 seconds, 0.14 seconds under his record.

The packed throng was gurgling and bubbling, fins clapping madly. Through the bubbles one could faintly make out the beat: "Yahoo wahoo! Yahoo wahoo! Yahoo wahoo!"