Today's the day all anglers who love our rivers dread as we turn away from running water for the next three months.

It might have started with a bang, but 2011/12 went out with a whimper on many of the rivers and drains. Fishing has its ups and downs, the good years and the lean ones, but the season now departing leaves a worrying legacy. I don't know what worries me the most – the drought and its likely consequences if we have another drier than normal year in the Fens, or the obvious decline in pike and zander.

Drought means an increasing risk of catastrophic fish kills on some of our shallower waters. Hosepipe bans, turning the tap off when you clean your teeth and other water-saving measures will only do so much to lessen the chances of disaster.

It clearly won't just be the predators which suffer if the worst happens. What worries me is that while populations of other species seem to be in rude health, if the numbers of fish you actually see on some waters are anything to go by, whole year classes of pike appear to be absent from them. On one water, I had eight fish last winter. Three of them were twenties, three were doubles and two were jacks. There were some big fish knocking about, which clearly weren't short of food.

But what's going to happen when they end up in the big weigh sling in the sky. What's going to grow through to replace them. Where have all the smaller fish gone, bearing in mind that part of the system hasn't had a real flush through for several winters.

Word on the bank mostly points the finger in one direction. But I wonder if the blame now lies with people fishing for the pot armed with lure rods and carrier bags. The decline is so pronounced that I think it lies with more effective means of removing fish wholesale, like long lines and gill nets.

For the next three months, those intent on doing so will largely have the banks to themselves and they know it. This will certainly be one of the talking points at next week's King's Lynn PAC meeting. The two guest speakers – Andy Blazey and Richard Wesley – are accomplished pike anglers from the Cambridgeshire end of the Fens who are also involved in efforts to set up a river watch scheme.

That means getting people out patrolling the banks, looking for signs of suspicious activity which can be passed on to the Environment Agency.

If we're serious about doing something to protect our waters, we have to get out there and start helping to keep an eye on them whether it's checking a stretch of river you pass on your way to and from work, or giving up some of your time.

If it's left to the same old stalwarts, we've only got ourselves to blame when we sit there in a few years' time wondering why we're blanking.

Predator fishing in some parts of the Fens is probably more vulnerable now than in the dark days of culls or when pike were routinely whacked on the head.

The meeting's at the Wm Burt Club, next Wednesday night (7.30pm).