John Bailey: the first scent of some hard times to come

The days coincided with that recent period of north-westerly winds and squally showers. Daytime temperatures had fallen from an average of 18 degrees to around 13 degrees, with the wind making everything feel appreciably colder. Water temperatures, especially in areas of the lakes exposed to these winds, also plummeted.

I had two dear friends with me hoping for an autumn 'tinca' extravaganza and we were all massively disappointed. We hardly had a smidgeon of a bite for all the three days and didn't see a single sight of a moving tench. Until the wind dropped.

There was, unexpectedly, one of those golden, glowing periods that all experienced anglers recognise. Not only did the wind drop but the autumnal sun suddenly found some of its warmth. A tench rolled. There was some bubbling a little further out from our floats. Then, isolated bubbles appeared here and there in the baited swim. We just knew it was going to happen and happen it did. At last, at long last, the float dipped and a very lean, long, female tench scrapped hard all the way to the net. The boys had to leave almost immediately, it was just so close to a complete tenching disaster.

But then you realise how knife-edge everything is when it comes to wild fishing, the dangerous end of the sport if you like. Nothing is simple, everything has consequences. For example, there has been a lot of talk about why and where our River Wensum weed has gone of late. Does it occur to anyone that there are far more swans on the river than there used to be years back? I suppose in some ways, as a birder, this is to be applauded, but on one stretch of river, a shallow one at that, I recently counted 40 swans busily at work over a one-mile beat. It's hardly any wonder that four or five days after they had arrived, every skerrick of weed had disappeared.

That's hardly a good thing in itself, but worse was to follow. Over the next few days, I marked upwards of eight cormorants visiting this very stretch every morning at first light. Once again, within a few days, all the small fish appeared to have followed the way of the weed. Eaten.

My maths is pretty appalling. It's a fact that I've long kept hidden but when I was 14 and when I should have been working for maths 'O' level, I began to write my very first angling articles hidden away in the back of the classroom. The maths was mumbo-jumbo to me but the angling, even then, was what life was truly about. As a result, I made a bit of extra pocket money as a young teenager but was still taking maths 'O' level when I finally got to college! That's a long prelude to saying the following tot-up of figures could well be wrong.

My knowledge of the Wensum in intimate detail extends to about 15 miles. Let's say the river is approximately 10 yards wide on average along this length. If we then work out that there are nearly 5,000 square yards in an acre, this roughly computes to my stretch of the River Wensum covering in all just 60 acres. We tend to think of rivers as larger waters but a 60-acre pit wouldn't be considered massive in this day and age.

What I'm trying to say is that a 60-acre lake can go up and down in terms of fish stocks very rapidly indeed. It's nothing for a lake that size to be top of its form one decade and plunge into disaster the next. So with an average lowland river. They might seem long and meandering but, in fact, when we consider the water that they contain, there's not much at all. Especially when you take into account that the average depth of the Wensum is perhaps four feet and the average depth of a 60-acre lake could well be in excess of 10. In terms of water volume we're comparing my stretch of the Wensum to a 25-acre lake, and that's scary stuff.

I guess the over-riding lesson that I've learned is that nature works on very small margins indeed. The tiniest gust of wind can alter the entire aquatic scene, never mind something far more permanent and far more damaging like a squadron of cormorants.