Order:	Perciformes
Family:	Percidae
Genus and species:	Stizostedion lucioperca

Alwyne Wheeler (1969) in "The Fishes of the British Isles and North West Europe":

Zander [Pikeperch]

Stizostedion lucioperca (Linnaeus, 1758) [Lucioperca lucioperca and L. sandra]

NAMES Fr. Sandre; Du. Snoekbaars; Ge. Zander; Da. Sandart; Sw. Gös.

IDENTIFICATION The elongate head and body with the very prominent and pointed snout and the large jaws are distinguishing features of the pikeperch. The upper jaw extends to well past the pupil, often to the extremity of the orbit; the teeth in both jaws are large and pointed and at their tips are long canine teeth; there is a row of large curved teeth on each side of the palate. The scales are small, firmly attached and are present on the gill cover; there are eighty to ninety-five scales in the lateral line, which continues on to the tail. The dorsal fin is divided, thirteen to seventeen spines in the first, one or two spines and nineteen to twenty-four rays in the second. The anal fin has two or three slender spines and eleven to twelve rays. It grows to 16-20 in (41-50 cm).
The back and sides are greeny brown, or greyish, the sides lighter, and the belly a matt white. Young fish have eight to ten indistinct and irregular dark bars on the back and sides, but these are frequently lost in adults. The dorsal fins have distinct lines of dark spots on the membranes, and there are scattered dark spots on the tail.

BIOLOGY The pikeperch in its natural range appears to favour large lakes and the bigger rivers, particularly where the bottom is hard and the water relatively shallow. It has been widely cultivated and artificially spread and is now found in many atypical localities. In the British Isles it has been introduced to lakes at Woburn, Beds. (1878 and 1910), Leighton Buzzard (1947), Claydon Lakes (1950) and has bred in these and other waters. It has also been released in the Great Ouse and certain Fenland waterways and there is thus the possibility that it will spread through England as it has done in France from occasional introductions.
The pikeperch is an excellent food fish and is widely exploited for food in continental Europe. There are natural populations in Swedish lakes and numerous rivers in the U.S.S.R., and it is widely reared in ponds, often in its first year with carp. It is also a valued angling fish and is highly considered for its fighting qualities as well as its willingness to take a bait, and for its size.
Spawning takes place in spring, from April to early June at a water temperature of around 15 °C (59 °F). The eggs are shed in shallow water on plants like Typha and Phragmites and on hard gravel or clay bottoms at annually used spawning grounds near the edges of lakes or rivers. The breeding fish migrate from deep water to the shallows early in spring (in northern waters, when the winter's ice breaks). Populations living in brackish water (i.e. in the Baltic) migrate into fresh water to spawn. Migrations within lakes are essentially local, but may involve journeys of 16 miles (26 km) or more.
Pikeperch are entirely carnivorous. For the first five months of their life they eat invertebrates, chiefly crustaceans (Daphnia and cyclopid copepods), and chironomid and other insect larvae. From five months onwards they eat fishes of all kinds, preying especially on those which are seasonally or locally abundant.
Growth in this species is rapid; from a length of 3.5 mm at hatching the one year old fish measures an average of 7½-11½ in (18-29 cm), at two years 9-16 in (23-41 cm), and at three years 15-27 in (38-69 cm). Growth rates are, however, very variable from water to water. Maturity occurs at three to four years, and a length of 13½-16½ in (34-42 cm). The pikeperch may live for ten to thirteen years, and weigh up to 22 lb (10 kg) in large waters, but usually averages around 6 lb (2.7 kg) and a length of 18-26 in (46-66 cm).

Note: It has recently been suggested that American pikeperch were introduced to a Cambridgeshire river in the 1930s. The continued existence of these fish, believed to be walleyes, Stizostedion vitreum (Mitchill, 1818), in England, remains to be proven. It can be distinguished from the European species by its coloration of brassy oblique lines on the head and body, giving a much freckled appearance, and by the distinct black spot on the membrane at the end of the first dorsal fin. The dorsal, pectoral and even the pelvic fins are dark flecked (while in the zander the pectoral and pelvic fins are unmarked). The maxillary bone in the walleye extends to the hind edge of the eye, and the cheeks are heavily scaled; in the zander the maxillary reaches beyond the eye (far beyond in large fish), and the cheeks are almost entirely scaleless.

DISTRIBUTION

Eastward to the Caspian basin. (Another pikeperch, Stizostedion volgensis (Gmelin, 1788) in the northern rivers of the Black and Caspian Seas, is distinguished by its scaled cheeks and gill covers, and by lacking large canine teeth as an adult.)