Характеристика нерестового стада, нерест и плодовитость окуня (Perca fluvialilis L.) дельтовых водоемов Дуная

Abstract

The article deals with the results of studying Perea fluviatilis of the Kily arm estuary basins of the Danube. It is established that the Danube Perea fluviatilis is puberal at the age of three years old with the body length of 11—12 cm. In ІІ967 the spawning lasts from March 30—31 up to April 20 with water temperature 9.4—10.7°. Spawning of Perea fluviatilis is momentary, it lays spawn by long jelly-like lines on hard vegetation — reed, cane. In 1967 fish of three-six years old with the length of 11—26 cm and weight of 30—340 g took part in spawning. Males (81 %) prevail in the herd. The average fecundity of the individuals under study with the size of 120—230 mm and weight 45—310 g is 20616 hard roes (vibration in the limits of 5400—51 570 hard roes). The dependence is distinctly pronounced of fecundity from length, weight and age of Perea fluviatilis.