بياض (سمك)

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Perches Temporal range: Pliocene–recent PreЄ Є O S D C P T J K Pg N ↓
بياض أصفر (Perca flavescens)
التصنيف العلمي
أصنوفة غير معروفة (أصلحها):	Perca
Type species
Perca fluviatilis لينايوس، 1758
الأنواع
P. flavescens (بياض أصفر) P. fluviatilis (بياض أوروپي) P. schrenkii (بياض بلخاش)

البياض Perch هو الاسم الشائع للسمك من جنس Perca, freshwater gamefish belonging to the family Percidae. The perch, of which three species occur in different geographical areas, lend their name to a large order of vertebrates: the Perciformes, from the باليونانية: πέρκη (perke), simply meaning perch, and the Latin forma meaning shape. Many species of freshwater gamefish more or less resemble perch, but belong to different genera. In fact, the exclusively saltwater-dwelling red drum is often referred to as a red perch, though by definition perch are freshwater fish. Though many fish are referred to as perch as a common name, to be considered a true perch, the fish must be of the family Percidae.

The type species for this genus is the European perch, P. fluviatilis.

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 الأنواع

Most authorities recognize three species within the perch genus:

• The European perch (P. fluviatilis) is found in Europe and Asia. This species is typically greenish in color with dark vertical bars on its sides with a red or orange coloring in the tips of its fins. The European perch has been successfully introduced in New Zealand and Australia, where it is known as the redfin perch or English perch. In Australia, larger specimens have been bred, but the species rarely grows heavier than 2.7 kg (6 lb).
• The Balkhash perch (P. schrenkii) is found in Kazakhstan, (in Lake Balkhash and Lake Alakol), Uzbekistan, and China. It is very similar to the European perch, and grows to a comparable size.
• The yellow perch (P. flavescens), smaller and paler than the European perch, is found in North America. In northern areas, it is sometimes referred to as the lake perch. This species is prized for its food quality and has often been raised in hatcheries and introduced into areas in which it is not native. Yellow perch are almost identical in appearance to European perch, but have a more yellow coloring. These fish typically only reach a size of about 38 cm (15 in) and 1 kg (2.2 lb).

 التشريح

The general body type of a perch is somewhat long and rounded. True perch have "rough" or ctenoid scales. On the anterior side of the head are the maxilla and lower mandible for the mouth, a pair of nostrils, and two lidless eyes. On the posterior sides are the opercular series, which protect the gills, and the lateral line system, which is sensitive to vibrations in the water. The kidney of the perch runs along the backbone and forms a head, caudal to the gills. Perch have paired pectoral and pelvic fins, and two dorsal fins, the first one spiny and the second soft. These two fins can be separate or joined.

 الموائل

Perch are carnivorous fish most commonly found in small ponds, lakes, streams, or rivers. These fish feed on smaller fish, shellfish, or insect larvae, but can be caught with nearly any bait. They commonly spawn during the spring, when the females lay strings of eggs in covered areas such as near branches or underwater plants. Perch have a wide distribution throughout the world, and are very plentiful in the Great Lakes, especially Lake Erie.

 الصيد

Perch are popular sport fish species. They are known to put up a fight, and to be good eating. They can be caught with a variety of methods, including float fishing, lure fishing, and legering. Fly fishing for perch using patterns that imitate small fry or invertebrates can be successful. The record weight for this fish in Britain is 2.81 kg (6 lb 3 oz), and in America 2.83 kg (6 lb 4 oz).

Perch grow to around 50 cm and 2.3 kg (5 lb) or more, but the most common size caught are around 30 cm (1 ft) and 0.45 kg (1 lb) or less and anything over 40 cm and 0.9 kg (2 lb) is considered a prize catch.