THE Advertiser’s angling correspondent MARTIN READ explains the cold, harsh facts of trying to catch fish in icy waters and why sitting indoors with a drink in hand isn’t the best time to ponder whether to go out and do it
I hate to say it but a number of things are gradually getting me down, nothing too specific, just things like Covid, lockdowns, snow, the cold, etc.
Do you know that last month was the coldest January on record for ten years? And they talk about global warming.
I decided a day or two ago that what I needed desperately was some time on the bank, but in this weather? It was time for a decision.
Sitting in a warm room, enjoying a drink was perhaps not the best time to make it, but it had to be done. The question needing an urgent answer: “To fish or not to fish the following morning”.
According to the weather forecast, temperatures were at last on the up with a comfortable 9C promised in the next 24 hours. It was hard to imagine the changes in the weather.
Just over one week ago it was 8C with bright, warm sunshine, although admittedly overnight temperatures had fallen below zero for the umpteenth time, then less than two days later it was below zero again and lots of snow.
On face value the warmer temperature looked promising. Rivers, of course, were out of the question; the melting snow would have pushed them way above a sensible level and they would be full of salt.
Not to worry, ponds or the canal would be my target. They had been covered in ice for days but with the warmer temperatures, the ice had just melted and with the increase in temperature the fish would be ravenous, wouldn't they?
It sounded just too good to be true. I poured myself another large gin and tonic, popped in another three ice cubes and began to focus on the nagging little doubt in my mind that said all would not be as good as I was beginning to believe. I carefully weighed up the pros and cons in my mind.
Not too long ago I'd watched an angler fishing through a hole in the ice and catching a few fish. He'd broken the hole himself using what by now is almost standard equipment for the practice, a 5lbs weight to which is welded a metre or so length of chain which in turn is attached to a length of rope.
On a cold day it's a great way of getting warm before fishing, smashing the ice with the weight and then sawing the chain backwards and forwards to clear a channel.
It's something I've done myself many times and I've even been known to go pimpling in Scandinavia — that's fishing with the little rod through a hole, cut with an auger often through more than a metre of ice.
The fact that you can catch fish after all this disturbance was never in doubt in my mind but now even that was being called into question.
I asked myself, having been taught from being a young lad to approach the water with caution, just why ice breaking doesn't scare every fish for miles?
After a little deliberation, some ideas came to mind.
Perhaps the ice itself, by covering the surface, offers the fish some sense of protection. By effectively closing the fishes' world from the outside, it eliminates any dangers arising there, things like herons, gulls, cormorants and kingfishers and even anglers, for that matter, are effectively no threat at all once the ice cover has formed.
But it's a double-edged sword. When the ice melts the safety cover disappears and it's back to normal trying to catch fish that aren't really hungry in extremely cold water.
Strangely, breaking the ice can create another set of unusual circumstances because as that huge lump of metal drops to the bottom, retrieving it, momentarily through silt, not only creates a disturbance but also a cloud of colour near the bottom, something which the fish come to investigate.
Sounds silly? Well perhaps not. Tench anglers have for years raked the bottom immediately prior to fishing, a technique that certainly works.
Of course, the main way that ice helps not only anglers but the aquatic world generally is by being ice.
My mind wandered back to days in the physics laboratory with thermometers and flasks full of water and ice. If I'd realised how important the answers were then I'd have paid more attention.
Fortunately, water is a unique substance. Like most liquids its density increases as it cools, down to 4C that is.
Then an unusual thing happens. Below 4C the density decreases — that is the water becomes lighter — and it gradually begins to float to the surface where it comes into contact with the cold air and freezes. The resultant ice, as we've already discussed, forms a “skin” over the denser water below, effectively keeping it warm, relatively speaking that is.
The bonus for anglers, fish and all aquatic life is that if it didn't then the water, like other liquids, would freeze from the bottom and over time ponds, lakes, canals and the like would freeze solid, especially in extremely cold areas of the world!
In practice, we anglers can be sitting on the bank in sub-zero temperatures while the fish continue to swim around in temperatures not much lower than 4C and again, importantly, with little variation or the ice would begin to melt.
The thought of melting ice brought me back to the decision in hand — there definitely wouldn't be any ice on the ponds tomorrow — it had just melted— so what was it to be?
I reached down for my gin and tonic as if seeking mental stimulus. The three ice cubes had melted and the drink was beautifully cold.
Memories of more physics lessons came flooding back, of terms like latent heat and other forgotten aspects. What had happened to my gin and tonic also happens on a larger scale on ponds, canals etc as the ice upon them melts.
If my memory is correct, it takes around 80 times as much energy to change ice into water, without raising its temperature, as it does to raise the water formed by 1C.
In short, the ice is absorbing energy from the atmosphere above it and the water below it in order to simply change from solid to liquid. And while the outside temperature can in the short term become increasingly warmer, the melting ice seriously delays the liquid below it from simultaneously warming. And, of course, where does all that ice cold melted water go? As a result, it can be more difficult catching fish as the ice melts than when it was present
Without further consideration the decision was taken, I would stay at home, at least for a day or two until the water temperature stabilised.
There is a moral of course and it's that it's easier to understand physics with a gin and tonic, but only if it has ice cubes.