Terry Hearn on tainted lakebeds

Question:

Have any of the other contributors ever experienced fishing a venue on which the lakebed has become ‘tainted’ to such an extreme that the older ‘original’ fish no longer seem happy to feed. It seems to sometimes occur on waters that suffer from really serious algae blooms or those that are unfortunate enough to receive an influx of really dirty (filthy) floodwater.
I remember reading about Savay after the big floods that occurred in October 1987 that caused the Colne to flood (exacerbated by fallen trees) and massive volumes of contaminated floodwater entered the lake from the sluices and later rendered that area largely unproductive. The same thing happened on White Swan. A few waters had terrible algae issue last year and the originals seemed to have stopped coming out on one that I fish in the Colne Valley (at least that’s what I think is going on).

Really good topic this from my old mucka Lew. Yes, I’ve experienced that exact situation with ‘tainted lakebeds’ many times. You mentioned Dinton’s White Swan Lake, so I’ll start there as I was also fishing it during the summer of ‘07 when that nasty floodwater came in. It’s probably worth pointing out that Dinton has always been prone to flooding, it’s just that on this occasion it was particularly bad as it happened in the warmer months, and as such it’s likely that fertilisers and other undesirables went into the mix.

That particular year at Dinton things were going really well, and in big carp terms it was one of the best waters in the country. The stock was truly mind-blowing, not just big fish but really good lookers too. From memory there were three fifty pounders: Bruno, Sid, and The Twin, with another, The Dustbin knocking on the door. Add a long list of forties into the equation and remember that this is going back almost a decade, and you can see that it was a very special lake indeed.
I remember that just prior to the floods I was fishing the big gravelly swim on the bend, just before the river bank at the wider end of the lake, and over the previous couple of trips I’d been lucky enough to get on a bit of a roll, catching Sid at 51lbs, and the stunning mirror known as Apple Slice at 42lbs.

That trip it rained and rained and then rained some more, but the fish were in that corner and at one point I actually saw Bruno swim right into the margins just to the left of where I was fishing. She was tight and looked as fit and healthy as could be, as was everything else that was swimming around in there at that time, but once the floodwater came in things definitely went a bit pear shaped.

I was at home the day the river flowed in, but I drove straight back as soon as I heard, more than anything to help out with the rescue operation as a lot of fish had escaped onto surrounding land. In all we rescued over thirty carp that day, and what ones we missed went on to be recovered from a nearby pond further down the line. As far as I remember I don’t think anything was actually lost in the floods, certainly not any of the known big ‘uns anyway, but even so, those Dinton fish didn’t do so well for a while after that.

I carried on fishing it but it was clear that the bottom of the lake had changed in a big way, and getting takes became very difficult indeed. Baits would come in stinking of rotting eggs and it was as though the bottom was constantly releasing gas. Whole weedbeds lifted up off the bottom, forming huge rafts at either end of the lake, and for several weeks on the bounce this is where the carp were doing most of their feeding, not on the rancid bottom but amongst the surface weed which was absolutely stuffed full of snails. You’d see the carp tenting beneath the weed all the time, day and night, but fishing for them was virtually impossible. I even remember trying a bagging waggler type rig, basically a clear bodied sub float with a short hooklink and a handful of groundbait moulded around the hookbait, so that I could underarm it through the surface weed, but it was really hard work and I only remember catching a couple more carp from the lake despite continuing on for several weeks after the floods.

There wasn’t a great deal caught by anybody for a long while after that, only Bernie Loftus who was really working his spots hard, and I remember him getting amongst some of the better fish a bit later in the year, but it was noticeable that they were dropping in weight, possibly because they didn’t want to, or simply couldn’t feed on the bottom anymore. A lot of those older, big fish have gone now, but Simon who looks after the fishing there has helped the stock to recover and nowadays it’s well and truly on its way back to its former glory, certainly one to keep an eye on for the future.

Weed clearing at Dinton, the year of the summer flooding. Removing as much of the dying weed as possible minimised the possibility of low dissolved oxygen problems further into the year. Fishery management at its best

I wrote a fair bit about poor water quality and rancid bottoms in another Rotary Letter a few months back, mainly based around one particular pool containing a very low stock of carp, somewhere I’ve done a lot of time over the past few years. This particular pool really is hard work, and having spent so much time on the place, and seeing the effects that different weather conditions have, I’m 100% certain it’s down to poor water quality and the stagnant nature of the bottom. In this case it’s caused by a high level of run-off from surrounding land, which in turn helps fuel the Ivy Duckweed which has all but taken over the pond. Seriously, in terms of difficulty, nowhere I’ve ever fished can compare to this place. At times I’ve seen the whole of the bottom covered in a thick mat of duckweed, and at other times the whole of the surface too.

Without going over the same stuff as that past Rotary Letter, basically no light results in a rancid bottom, and I’ve actually seen the most stagnant areas turn a milky white colour over a period of days, which is a sure sign of oxygen depletion. In short, it’s a water quality nightmare, difficult for the wrong reasons, but you know what it’s like, once you’ve put a lot of time and effort into something it’s a hell of a job leaving without closure.

Last year I fished it hard through spring and summer, at times in really hot conditions when I knew that any chance of a take was incredibly slim, but I was stubborn and the place had really got under my skin. I remember thinking that we needed some nice cool, wet and windy weather to breathe some life into the place and as hoped for, that weather came around the middle of August.

Everything seemed perfect, I knew where the big ‘un was living and I knew its route out into open water each evening, but for three mornings on the bounce that fish showed all over my baits and I failed to get a pick up. It didn’t matter what I had out there, it just wasn’t going to tip its head down onto that rancid bottom. Proper firm, clean spots were very few and far between, and in all honesty, what ones were there were only so because I’d kept them that way through regular baiting, and even then it was birds doing the cleaning, not fish.

I did get one last chance right at the end of the month when I got it feeding on a firmer shallow spot which I’d been baiting for months, but unfortunately, the smaller of the carp slipped up first (for a third time) and that was the end of that. Obviously with such a low stock you’re always going to be up against it, but here it was much more than very few carp making things difficult, here it was all about poor water quality and a filthy bottom.