Abstract
Natural area of the stone moroco Pseudorasboraparva (Temminck etSchlegel, 1846) ranges waters of the Amur watershed, Korea and Southeast Asia. This paper presents some results of investigation of its recentrange in water bodies of the Syrdarya basin in borders of the Republic ofKazakhstan. This species was observed in many investigated sites of themain river as well as in several tributaries. Stone morocco was revealedin runny and stagnant waters. Habitual methods of fish biology and morphology investigations were applied to analyze samples from the KarashykRiver. This population was chosen by ordinary living conditions for stonemoroco in the whole basin. A method of pathologies investigation at morphological level namely index of unfavorable state evaluation was appliedtoo. Maximal size of investigated samples was less than for the native andsome alien populations. Fishes from 0 to 3 years old were presented in theKarashyk river. Some not significant abnormalities in external morphologyof liver and kidneys of the samples of stone morocowere revealed, butcommon index of unfavorable state (IUS) fitted to relatively favorable conditions. The stone moroco often is a pest for indigenous fishes, but sometimes it can be used for control of water larvae of bloodsucking mosquitoin water bodies with unstable water regimen.Key words: stone moroco, alien, introduction, morphology, pathology, Syrdarya, age, population.