THE GENERAL appearance of the perch is so familiar to anglers that a detailed description would be out of place here. In British waters only the ruffe and small pike-perch or zander could be confused with perch, and even then the likelihood of a mistake is not great. The zander at all sizes is longer and thinner than the perch and has quite transparent pectoral and pelvic fins: the pectoral fins of the perch are coloured, usually greenish or brownish, while the pelvic fins are red. The anal and tail fins of the perch usually also have plenty of red colouration, whereas those of the zander, are, at their brightest, greenish or brownish. The zander has more, but paler, stripes (eight to 12) than the perch, a set of wicked-looking grasping teeth in the upper and lower jaws at the front of the mouth, and scales which are spiny, giving the body of the fish a rougher feel. There are many other detailed distinctions, such as the number of scales along the lateral line.
The ruffe (Acerina cernus) is a small (up to 3 to 4 oz.) perch-like fish, but usually mottled brown or greenish in colour, without stripes, having the dorsal fins joined, and with a spiny area on the gill covers as well as the usual perch family (Percidae) back- ward pointing sharp edge to the opercular bone.
Thus in spite of the fact that the perch belongs to a family with the order of nearly 100 species (grouped into 15 genera) it is a particularly recognisable fish so far as we are concerned. It shows the usual characteristics of the family, namely paired pelvic fins situated directly below paired pectoral fins, two closely linked dorsal fins, and the number of hard rays in the dorsal fins. It rejoices also under the scientific name Perca fluviatilis Linnaeus, 1758; which simply means that Linnaeus, the Swedish naturalist, formally described the perch under that name in a scientific publication in 1758. The surname is Perca and the ‘Christian’ name fluviatilis: rather like filling in a form ‘Rickards, Barrie’. There is a whole group belonging to Perca, but only one species fluviatilis, a name which at least implies that the perch occurs in rivers.
Perhaps it is as well that I do not intend giving a full biological description here, because as soon as you delve into existing biological descriptions considerable discrepancies emerge. consider the perch to have ‘About five vertical black bands down the sides of the fish’. They mean stripes. But Holcfk, Mihalik and Maly (1968, p. 121) give about eight stripes (including one bifurcating dorsally) while Wells (Warne & Co.) gives at least nine. That most accurate observer of nature, Bernard Venables (e.g. 1962) more or less agrees with Jones and Tombleson and has usually six stripes on his big perch, the third one with a dorsal bifurcation., and points out that younger perch may have more stripes.
More serious discrepancies are seen between the figures given by Jones and Tombleson for the number of scales along the lateral line (55-60) and the figures of Holefk et al. (62-74): they might almost be different species! One suspects that the perch, like many other coarse fish, is in dire need of rigid, modern, biological analysis; although, if I were to recommend to the modern angler works of reference, those by Jones and Tombleson and Wheeler (1969) would be at the top of the list. Wheeler incidently, working on collections in the
British Museum, gives a lateral line count of 58 to 68.
At this point I shall revert to the powers of observation of Bernard Venables who considers the back of the perch to be darkish green, becoming lighter green suffused with gold on the flanks, and finally with a white belly. The colouration, however, can vary greatly from water to water. The dark green can be almost black, particularly with out-of-condition fish, while other fish can be very pale and the stripes barely visible. I have noticed that in clear streams the colours are usual hardest and brightest, and in cloudy lakes or rivers the fish are often pale and anaemic-looking although in every other sense perfectly fit. Wells notes that there is a cultivated golden variety in Germany.
Similarly there is great variation in shape. It is usual to regard sizeable perch as humpbacked, and most artists depict them so. I used to catch quite small perch, up to I lb, from the Yorkshire Derwent, and these were true to form, with the back immediately behind the head often rising almost vertically and capped by the spiny first dorsal fin. Almost equally commonly there is no hump at all, and the fish is more streamlined and closer to the zander’s fusiform shape. This seems to me to be true of most fenland waters, although there are certainly spanking great hump-backed perch in the Great Ouse itself.
The Taylor brothers noted that in the upper Great Ouse there seemed to be two varieties of perch found fairly commonly , the one being normally bold-headed and large-mouthed, and the other with a relatively short and steeply plunging upper jaw. Angling experience with the two types suggested that the blunt nosed type was a true bottom feeder. Possibly the shorter upper jaw, dropping away rapidly in front of the eyes, gives greater visibility for bottom grubbing.
I have only observed this phenomenon on one other water, a small clay pit near Gilber-dyke in the East Riding of Yorkshire. In this water the upper jaw of some fish was as Taylor describes, but the lower jaw on a half pound fish, was up to half an inch longer than the upper jaw. I have seen a similar thing in Great Ouse pike, though more rarely, but in all of the cases I have met with I have had insufficient experience to say whether they were mainly bottom feeders or not.
Another point about the make up of perch from the angler’s point of view is that they have several sharp spines. The backward edge of the operculum has a savage point, while the spines at the leading edges of the pelvic and anal fins are only slightly less dangerous. The spiny first dorsal fin is well known to most anglers, with its conspicuous black patch to the rear. If it’s picked up a perch will often raise the dorsal fin sharply and at the same time flare the gill covers and pelvic fins: the unwary angler can get quite severe lacerations, just as does the preying pike.
Perch are supposed to move out of deeper water in March, April and May to lay sticky ribbons of eggs on the weeds. Holcfik et al. report between 20,000 and 200,000 eggs per fish depending upon the size: maturity is reached in 3 years according to Wells. Most of the perch eggs I have seen have been in May (in Eire, and the east of England) and seem to me to have been somewhat randomly deposited. On the Great Ouse for example I have seen them lying on sand, rocks, in soft weeds, in common reed beds and in tree roots. Usually they are in the form of a tube-like ribbon perhaps up to 2 in. in diameter (when ‘flat’) and up to 2 feet long, the eggs themselves being extremely tiny but quite visible to the naked eye. The tube as a whole seems rather sticky and adheres to the surface upon which it falls. The myriad of tiny, striped fry which emerge from these eggs can be impressive, but predation on them is tremendous and only a tiny proportion, probably less than 1 per cent, reach maturity. When you are tench fishing and being bothered by small perch all day, you are sometimes inclined to think that all last year’s fry survived, but this certainly isn’t the case.
Perch are predators and are particularly fond of small fish, but also eat snails, caddis, worms, flies, grubs, larvae, and less commonly silkweed. At Sutton-on-Derwent in Yorkshire, perch up to H lbs. could be caught right against the lip of the weir and would take a bunch of silkweed fished in that area, but I am inclined to think they were feeding really upon the myriad of freshwater shrimps (Gammarus) that abounded in the silkweed and the perch were prepared to put up with the silkweed itself.
Earthworms, of course, find their way into stillwaters as well as into streams subjected to periodic floods. Many anglers do not appreciate this, but the anglers’ footfalls on the bankside often brings the earthworm out of its hole and eventually into the water. I once watched a lobworm fall into the water and crawl several feet across the shallows before falling over a lip into deeper water: that lip provided lots of nice perch up to 12oz.
What is lacking in our knowledge of the behaviour of perch is simply the way they spend their day. Do they patrol a set beat, or stay in a shoal in one place ? Feed regularly, or live at a certain depth in deep water ? There are many behavioural questions of this kind to which the angler must find answers for the waters he is fishing