Fishing Lines: Out in the midday sun, I was mad enough to help save the mahseer

It must have been the fierce Indian sun that scrambled my brain. By noon, the temperature on the River Cauvery was over 40C and still climbing. Even the mad camp dogs had slunk into the shade. Normally, at this time we would be heading back to camp for a beer, a light lunch and a siesta.

But that day, we watched an epic scrap as Chris the Stuffer hooked a big mahseer that ran half a mile downstream and wedged itself under a rock. Despite almost insane bravery by the guides, flinging themselves into the raging torrent in an effort to dislodge the fish, it came off after an hour.

By then, it was hot enough to fry an egg, and your brains. Camp was a stiff climb and a mile walk away. Most of our water (you take two litres every session, or risk dehydration) was gone. That's when we came up with this great idea. Or it seemed like it at the time.

Mahseer are one of the world's largest freshwater fish. They found fame when British officers from the days of the Raj went out to rule the Indian subcontinent. In those days, every officer was a sportsman, and as well as guns, they took along their salmon rods. They were in for an almighty shock.

Salmon are powerful fish – but not compared to mahseer. The colonels found their rods shattered, their reels jammed and their lines snapped by a mysterious Indian fish that looked like a giant silver carp.

Furious, the anglers wrote angry letters to Hardy's of Alnwick, then the world'spre-eminent tackle company. Hardy's apologised for inferior equipment and sent over some replacements. The same thing happened. It wasn't the tackle that was sub-standard; mahseer were just too strong.

Hardy's had to build extra-powerful rods and reels. Many big ones still escaped. Even these days, with hi-tech tackle, standard mahseer gear is stuff that could subdue a shark. Indians pronounce the word in English "masher". And maybe they're right. It mashes your tackle and your hopes.

But very little is known about the fish itself. Most of the stuff I found has been regurgitated from books written 70 or more years ago. How many different types are there? When and how do they spawn? What's being done to protect them? How old is a 100-pounder? Supposedly, they also exist in Malaysia, Pakistan, Myanmar, even Iraq and Afghanistan (I must try fishing those two).

A couple of cold litres ofKingfisher beer does strange things when you're hot and dehydrated. Before I knew it, we had set up an organisation to become the mahseer's saviour. Our host, Saad bin Jung, whose grandfather was the Nawab of Pataudi (the only man to play cricket for both India and England), offered some riverside land to set up a research station. Why not? So we established the Mahseer Trust too.

Still euphoric about the scheme, I bought a couple of websites. But back in England, now comes the hard work. I've got to become a webmaster, whatever one of those is, build two websites, gather information from far and wide, research the history, design a logo. And does anyone know two keen young fishery scientists who fancy spending a few months in India?