I believe that it was that wonderful writer, Bernard Venables of Mr. Crabtree fame, who wrote that to catch big fish consistently you have to understand how they live and feed. I'm fully in agreement with this observation and hope that this second piece in the series will help shed some light on the habits of perch. Only then should we really consider tactics and tackle, which are so often put ahead of the fish themselves. Understand the quarry, whatever species you're after, and everything else then just falls into place.
Whilst much of what follows is relevant to many other species, I'm going to concentrate on how perch differ from other fish, particularly other predators. I'll then finish this piece by describing the four main methods that I believe perch use to hunt their food, which is a subject I've rarely yet written about but which I feel is of fundamental importance.
The first point of difference is that perch have a different swim bladder arrangement to most other fish. The swim bladder works like the ballast tank on a submarine and enables a fish to adjust its buoyancy so that it can change depth, usually by absorbing or releasing air into the intestine. However, the perch's swim bladder isn't connected to its intestine, and so air exchange is via special glands that work very much slower. The result is that perch are unable to sustain rapid depth changes. Whilst they can for instance chase their prey from deep water up to the surface, they then have to return to their original depth very quickly otherwise they'll "gas up". This is why if you catch perch from deep water it's vital that you return them very quickly otherwise they could well die.
In fact, biologists tell us that perch can make sustained depth changes of only about 20% of their starting depth. In other words a perch at 10 feet can comfortably increase or decrease its depth by no more than 2 feet or so. If it wants to swim up or down by more than this amount for any length of time it has to adjust its buoyancy, and apparently it can tolerate long term changes at a rate of only approximately 1 foot per hour.
I'm totally convinced that light intensity affects perch feeding far more than any other factor. In fact, apart from its relative the zander, the perch has better eyesight than any other U.K. coarse fish. Not surprisingly, perch use this superior eyesight when feeding. However, once again the old authorities have misinterpreted a scientific fact. Although perch are primarily sight feeders, they don't feed best in bright conditions as their prey can easily see them coming then and avoid capture. Rather perch feed best when their superior sight gives them most advantage over their prey - which is in dim light. Perch also have a special chemical in their eyes, called porphropsin, which enables them to see red better than any other freshwater species. This is especially advantageous at dawn and dusk when the light is reddened, especially with a spectacular sunset.
In fact dusk and dawn have been far and away the best times to catch big perch on all the shallow waters I've ever fished. On the other hand if the perch are in deep water the light will be lower and then the fish will feed more in daylight. Indeed, Dick Walker found perch at a depth of 40 feet in winter at Arlesey, when the best time was in the middle of a bright sunny day. This is where the confusion began as subsequent writers stated that bright conditions were therefore always the best for perch. However this is absolutely wrong as the depth must be taken into account as well. In fact, I suspect that 40 feet down on a sunny winter's day the light intensity would be about the same as at dusk in shallow water.
It's interesting that on trout reservoirs we can catch perch at a depth of say 25 feet in the middle of a bright November day. Once the light fades these fish stop biting but simultaneously those in shallower water then come on the feed. This happens not just occasionally but time and time again. Bearing in mind what I wrote earlier about perch not being able to change depth quickly, I'm sure that there are perch shoals at varying depths and the light intensity decides which ones are feeding at a given time.
Nevertheless, perch do gradually move shallower as the light fades and deeper again early in the morning. At night, when they can't see at all they almost totally stop feeding. On several occasions I've found big perch by torchlight right under the bank and they've taken several prods with a landing net pole to wake them up!
To sum up, there's no doubt in my mind that on shallow waters dawn and, better still in winter, dusk is by far the best time to catch specimen stripies. It's interesting to note that small perch seem to instinctively know this as they seem to stop feeding just as their cannibalistic grandparents go on the prowl!
Water temperature, whilst not so important as light intensity, does have a bearing on the feeding habits of perch. For instance, I've observed that big still water perch rarely feed when the water temperature falls below 4ºC (39ºF). This may have something to do with water being at its heaviest then and therefore sinking to the bottom. In fact in deep lakes water temperatures near the bottom may never fall below 4ºC, and thus even in very cold conditions the perch will continue to feed there even if they've long since switched off on shallower stillwaters. On rivers, where the temperature is usually similar at all depths, perch will feed at lower temperatures down to perhaps 2ºC (36ºF) once they've acclimatised, perhaps because they have to replace the energy used in fighting the current, especially during and after a flood.
I've no practical experience of the perch's upper limit for feeding as I don't fish for them in hot weather, preferring to go after other species then. However, they supposedly begin to go off the feed at 23ºC (73ºF). One thing is apparent though. Perch are more active in summer than in winter and, as they digest their food quicker then, eat more often. Perversely, perch are often harder to catch in summer as they are less tightly shoaled then and the angler's bait is in competition with a huge larder of natural food.
It's often said that perch capture their food by ambushing, and many writers have pointed to the perch's stripes as evidence of this, as perch are perfectly camouflaged hiding amongst the weed stems. This is only partly right as many years of specialising in the species has convinced me that big perch use four main methods of hunting depending on the venue, the conditions, and also the number of perch in the wate
Certainly ambushing is one of the methods used and is most useful to perch in clear water. Such venues are usually weedy, but anything that gives cover, especially if the perch are in shade where they're hard to spot, can be utilised.
The second feeding tactic adopted by perch is "herding". Here the perch hunt in a pack rather like wolves and encircle a shoal of small fish or pin them against the bank. A few of the perch then chase into the shoal whilst the majority of stripies hold position and pick up those prey fish trying to break out of the circle. This type of hunting occurs mainly in clear water and there obviously has to be a fair number of perch to make it effective. If there's not and the perch use up more energy than they gain from eating the food caught, they soon switch to other methods of attack. Failure to do so would simply result in them starving to death.
Another method used, especially by shoals of perch, is "beating". This can be likened to pheasant shooting where the perch flush out insects and small fish from weedbeds etc. Those that panic and try to make a run for it are invariably picked off, especially if the perch are working the area as a group.
The final feeding ploy used is stalking. This is used by solitary perch in particular and, as these fish are often the sole survivors of a shoal and therefore the biggest, this is of special interest to specimen hunters. A few of you may remember a TV programme featuring Tom Williams (A River for All Seasons), which showed a perch creeping up like a cat on a pre-occupied minnow and catching it before the poor minnow knew what was happening! Stalking is particularly used in murky waters, such as overstocked commercial fisheries. Here the perch lose their bold colouration and their stripes fade, as in such conditions pronounced stripes would show up too clearly rather than act as camouflage.
Of course perch don't always succeed with an attack, whatever the tactics used. However, whilst they don't have anywhere near the acceleration of a pike, perch do have more stamina and thanks to their fin arrangement, far more manoeuverability. One of the best adjectives to describe perch is dogged, as like a wild dog they'll continue to chase and harry their prey, biting at its tail until it's crippled and slowed down enough to be sucked into the perch's huge mouth. If you see a single small fish frantically skipping along the surface, it's odds on that it's not a pike doing the chasing but a perch.
Having read through the foregoing, you may be thinking "So what?" Well, future articles will put all this theory into practice, both from the point of view of location and also presentation. I guarantee that if you remember just some of what you've learned today and use it intelligently you will catch more perch!
© Steve Burke