Wednesday, April 1, 2009
Lenok or Siberian trout
In Russian this fish has two names: most common one is lenok, and the old one with limited use – uskuch. Fish biologists agree that lenok (Brachymystax) is the most primitive and ancient genus of all Salmonid fishes. By the way, lenok is a link between true salmonid fishes (Salmonidae) and graylings (Thymallidae). The most primitive species, Mongolian grayling Thymallus brevirostris, is rather similar to lenok.
There are 2 distinct forms of lenok, which are considered to be separate species.
The sharp-nose lenok with subterminal mouth has scientific name Brachymistax lenok. This species is more numerous closer to the upper reaches of the streams, and has better adaptations to the swift current. Sharp-nose lenok has pointed upper jaw which is longer than the lower one. This fish can be up to 4 kg.
On its sides there are several crimson spots with diffuse outlines or red vertical strips which can look like parr-marks.
The blunt-nose form with terminal mouth has scientific name Brachymistax savinovi. Itis olive-brown or red-brown fish with jaws of similar length. Generally, the species looks like brown trout. Its maximum size is bigger than of its sharp-nose cousin - up to 10 kg!
Body, dorsal and adipose fins of blunt-nose lenok are covered by regular black dots of the size of its eye pupil.
Middle reaches of the Munikan River (tributary to Tugur River). Same as in many other streams, here dwell both species of lenok. Grayling, lenok, and Siberian taimen form typical fish community of the inland mountainous streams of the North-East Asia.