Balkhash perch

The Balkhash perch, scientifically named in honor of the Livonian naturalist Alexander von Schrenk, Perca schrenkii, has developed on the southeast border of the distribution area of the Eurasian perch Perca fluviatilis in Kazakhstan, due to the relative isolation of the waters since the Tertiary, as a separate species. The species was named after the Lake Balkhash.

Features

The Balkhash perch forms from several different morphs that live sympatrically in the same waters, but in different biotopes. There are a pelagic and known a coastal form and dwarf forms. The used in the fishing industry pelagic form is about 50 inches long and up to 1.5 kilograms.

The Balkhash perch is slightly lower, slimmer than the perch, yellowish, with about five dark saddle bags over the back, usually strongly contrasting with the background. As with all bass vomer and Palatine are still dentate, the Praeoperculare is spined ventrally and the gill cover ( operculum ) back forms a sharp tip.

Along the sidelines are 41 to 54 scales. The first dorsal fin has 12-13 spines, the second 2-3 spines and 12-13 soft rays, the anal fin 2 spines and 7-9 soft rays.

Occurrence and risk

This Turkestan species is mainly known from the Balkhash Lake and the Alaköl having quite different and fluctuating salinity. In the associated catchment areas he komt prior to China. The Balkhash perch was introduced in the 1960s and 1970s to Uzbekistan and Kyrgyzstan. Greater economic importance not been given the kind, especially as (, catfish perch) has been used in their home waters often larger predators. Together with other native species makes the Balkhash perch only 10-17 % of the catches from. Formerly of considerable commercial value he gets today in inventory risk.