Fishing Lines: The boys in blue are wrong to say it's mad and bad to fish for shad

If there's no angling column next week, it's because I'm in the chokey. I'm expecting to find the street blocked and sirens wailing, armed police in riot gear surrounding the house, and to hear the Welsh equivalent of: "You're nicked, my old chummy."

And all because I went shad fishing. Not once but twice, which probably makes it doubly heinous. Thank goodness I didn't stay for a third day.They'd be bringing back the electric chair.

Lest you think I'm joking, listen to the solemn words of Sgt Ian Guildford. He's a police wildlife and environmental crime officer, seconded to the Countryside Council for Wales just to nab miscreants like me. "Shad are protected under the Wildlife and Countryside Act, which means anyone who intentionally sets out to fish for them will be committing a crime," he intones.

This isn't a lone anti-angling copper giving fishermen a hard time. Sgt Guildford, who spends his normal days helping old ladies in Dyfed across the road, has the backing not only of the Countryside Council for Wales but the Environment Agency Wales in his campaign. These august bodies have just held a Shad Awareness Day to spread the message that the fish are off-limits.

For years, I've travelled to Builth Wells in central Wales to catch shad. I stay with Peter Smith, who owns the delightful Caer Beris Manor. Its big appeal is that the hotel, once the home of Lord Swansea, owns nearlya mile of the River Irfon, oneof the very few places where shad breed.

Only two species live in the British Isles. They spend their lives at sea but, like sturgeon or salmon, come into fresh water to spawn. If you're a sturgeon (which can grow bigger than a Volvo estate), this is not a problem. Two flicks of the tail and you're there. But if you're a shad, weighing little more than 1lb, swimming 80 miles to the Irfon is hard work.

Superficially, shad look like herring. Their bright silver flanks are tinged with green and blue, with a dash of purple. Twaite shad have several round, dark spots along each flank; the much rarer allis shad has just one. When hooked (not easy, because they have hard mouths) they fling themselves around as spectacularly as any trout. In style and spirit, they are more like tarpon.

The allis shad is so rare that it's fully protected under the Wildlife and Countryside Act. According to a press release from Dyfed-Powys Police, so is its smaller cousin. Except that I reckon the boys in blue are wrong.

My reading of the act (not easy, as it appears to have been written by a team of lawyers banned from using punctuation) is that you can fish for them, but that you face prosecution if you damage or destroy their place of shelter or protection.

I was so convinced that I was tempted to phone Dyfed police and tell them that I was wilfully breaking the law, in their eyes at least. "Angling Writers' chairman nicked for illegal fishing": it promised to be a great story. But I didn't. The battery on my mobile had run out and it was too far to walk to find a phone.

Still, writing about it is surely tantamount to admitting my "crime". And they have my wader prints.