Perch - striped hunters Perca fluviatilis

The perch is a handsome fish, with striking looks well suited to its predatory life. Its flanks are an olive-green with six or seven black stripes, camouflaging it among weeds and reeds. The tail is rather small, so it is not a high-speed swimmer, but it can cruise at quite a high speed for long periods.

Perch are hunters, preying on other species. Fry feed on water fleas and other tiny crustaceans but they soon graduate to insect larvae such as bloodworms. If small enough fish are available, perch switch to a mainly fish diet when they weigh about 113g(4oz).

Perch that have made this transition grow very rapidly. Where there is no prey of this type, perch remain stunted, weighing only 113g (4oz) at about seven years old.

Young perch hunt in schools, lying in wait among water plants until small fish such as bleak or roach stray too close. The school then sets off in pursuit, harrying the quarry until it is too tired to swim further. Perch catch their prey by biting the tail repeatedly from behind and below to restrict swimming. Characteristically the perch always captures and swallows its prey tail first.

Perch usually eat small fish with a 0.5-0.9kg (1-2lb) specimen typically taking prey of about 28-57g (1-2oz). Odd though it might seem, perch seem particularly fond of catching and eating the fry or smaller members of their own species.

Perch prefer slow-moving or still waters with a good head of small prey species. Good visibility is essential for their style of hunting and so they do best in clear water. They can also survive in relatively fast-flowing rivers if there is not too much suspended silt making the water cloudy. Perch are not found in either high, rocky streams or in acid lakes.

When young, perch form schools consisting of one age group but as they grow older they become more solitary. This is not because the older fish lose the instinct to form schools but is due to the shrinking of each school of perch as fish die and are eaten.

Male perch can be sexually mature at only 6-12 months old even though they are usually no more than 5-8cm (2-3in) long whereas females are seldom ready to mate until they are three years old. The females usually grow to a larger overall size than the males.

Spawning occurs between March and June when the female lays up to 300,000 eggs in lacy strands over weeds, twigs, stones or any other solid object in the shallows. The eggs begin to hatch out about a week after they are fertilized.

In the 60s and 70s an ulcer disease decimated the perch population in Britain. On waters where tests were carried out it was estimated that up to 99 per cent of the perch had died, with only a very few immature fish left.

Perch have more or less re-established themselves in British waters now but in some waters, which previously held large specimens, there are now numbers of stunted perch. With the sudden death of all the big perch which had kept the numbers of juveniles down, far more young survived. This leads to greater competition for the available food, so they all remain small.

Because of the perch disease there are few notable perch waters. But the following offer a good chance of big specimens.

A trout water at which coarse fishing is allowed during the autumn and winter, it regularly produces 1.4kg (3lb) fish.

Another trout water that provides excellent perch fishing during the close season for game fish.

The waters are warmed by a power station and this, coupled with a big stock of rudd, makes for good perch fishing.

River Trent, Sawley Marina, Derbyshire This is particularly good when the river is in flood, with perch to 1.4kg (3lb).

Weight: up to 3.2kg (7lb); average 170-228g (6-8oz)

Length: 50cm (20in)

Life-span: 13 years

Favourite waters: reservoirs and slow-flowing rivers

• The first dorsal fin is separate from the second and has 14-15 spines. It can be raised to frighten predators and rivals. There is a distinctive black spot to the rear of the first dorsal fin.

• The second dorsal fin has 1 or 2 spines and 13-14 soft rays.

• There is a strong spine on the gill cover.

• The lower fins and often the lower part of the tail are red.

The British rod-caught record is 2.523kg (5lb 9oz) landed in 1985 by J. Shayler at a private lake in Kent.

A specimen perch weighs about 0.9kg (2lb), a 1.4kg (3lb) perch is worth a small celebration and a 4lb (1.8kg) perch is the fish of a lifetime

Fish finder: In slow-flowing rivers, perch tend to wait to ambush their prey in and around reed beds.

In reservoirs in summer perch can be found roaming the shallows for food. As the weather gets cold, they move toward deeper water.

In winter they can be found in the deepest hole available.