Fishing lines: Rock legends even bigger than Elton

Indian guides call the fish "masher". I thought this was a charming inability to pronounce mahseer. Now, having had my tackle comprehensively smashed, bashed and shattered by the "Indian salmon", I realise it's a very clever play on words.

Nothing prepares you for the masher's might. The first I saw hooked was near the fearsomely named Crocodile Rock on the River Cauvery at Bush Betta in southern Karnataka. This particular masher hotspot is not named after the Elton John song.

The remarkable Indian prince who owns the camp, Saad bin Jung, told us in our pre-fishing briefing: "You'll probably have to jump in here and swim with your rod if you hook a big one". Why is it called Crocodile Rock, someone asked. "Well, most of the crocodiles are fish-eaters," he said, "but at Crocodile they are man-eaters..." Er, excuse me...

Fortunately for John Gillman, the estate agent who was running across house-sized boulders in an attempt to follow his first masher, the fish charged down rapids and stopped under a rock. It was only a baby by masher standards, perhaps 15lb. But it gave us early warning of what we could be in for.

How big do they grow? On the Tigris nearly a century ago, there are records of fish over 200lb. Goodness knows if such fish still exist. In India, they do not grow as large, and most recognise J de Wet Van Ingen's 1946 fish of 120lb as the official record. Suban, best of the guides, had caught one of 130lb on a handline, and the biggest he had heard of was 150lb. If a 15-pounder could pull like the fish John landed, what hope did we have of a 100-pounder?

Saad, who himself has caught one of 110lb, talked of pools holding fish of 70lb, 80lb, 100lb, then added casually: "...and this spot is where a big one could be caught". Even with 50lb line and rods strong enough to tackle sharks, we felt ill-prepared. These were old, old fish, wise in their ways. Saad reckoned that they grew at perhaps 1lb a year. That meant that some of the very big fish must have been around when Queen Victoria was on the throne.

On the third day, I found out what it was all about. Saad took me to The Chair at Ajibora, famed place for a whopper. Langur monkeys watched as Saad cast the bait, a cricket-ball-sized lump of ragi paste, into a foaming mass of water, passed me the rod, and chuckled.

Huge rocks of granite towered above me, a watermark 20ft above the river showing how high it gets when the rains come (though two years without the life-giving monsoons have left the land parched).

You hold the rod. If you don't, a masher will pull it in before you can react. One minute the line was in front of me, the next it was 50 yards downstream, my thumb in agony (you don't try to stop a charging mahseer unless you like the sight of your own blood). Ten seconds later, the fish had twisted around several sharp rocks, and the line broke.

"Big fish," said Saad.