Coregonus lavaretus is a fish of the genus Stenodus, family Coregonidae. They live in the basins of the Arctic Ocean, Baltic and North Seas, in Lakes Ladoga and Peipsi. They form many forms (semi-navigable, river, lake, lake-river), differing morphologically and ecologically from each other. In the water bodies of Russia described 33 subspecies and more than 100 forms. Particularly distinguished 6 subspecies: passable little whitefish (C. lavaretus lavaretus lavaretus). lavaretus lavaretus ), inhabiting the Baltic Sea basin; passage, lake, lake-river multi-thick whitefish of the Baltic Sea basin (Coregonus lavaretus pallasi); whitefish occupying an intermediate position between multi- and low-thickness whitefish of the Baltic Sea basin (Coregonus lavaretus palassi); Chuda whitefish (Coregonus maraenoides), inhabiting water bodies of Western Europe; puffer whitefish (Coregonus pidschian), inhabiting the Arctic Ocean basin, lake and lake-river Bauntov whitefish (Coregonus baunti), inhabiting the lake system of the Vitim River basin. Vitim River basin. Many whitefish are valuable commercial fish.
It is characterized by particularly strong variability, breaking up into many forms, similar only by the lower position of the mouth and a larger head with a less humped snout than Coregonus nasus. The number of gill stamens may vary from 15 to 60, they may be smooth or serrated; the body is high or low, elongated. Can be passerine, river and lake, large and small, can feed on bottom planktonic organisms and be predators. Wherever inhabited, splits into two forms, often living together. These are the small stamen form (gill stamens up to 30), which feeds on benthos and small fish, and the multi-stamen form (gill stamens more than 30), which consumes mainly plankton. River whitefish differs from the sandpiper grayish-green back with a noticeable steel tint, blue tint silver sides with light longitudinal stripes; head (maybe only in spring) is covered with dark spots, as well as the base of the gray dorsal fin; caudal and anal fins dark gray; pectoral and pelvic fins on the upper side of the greenish-gray, with the lower whitish, to the top blackish. Silver iris of the eye from above somewhat grayish. This whitefish weighs from 2-4 pounds, and very rarely reaches 7 pounds.
The passage form of the common whitefish feeds in the lower reaches of rivers and ascends into rivers to spawn, usually without making long journeys. River whitefish spawn and feed in the river, rising upstream to spawn. Numerous lake forms, which trace their origins to passage whitefish, spawn in lakes in some areas and ascend from lakes to rivers in others. In large lakes, both forms successfully coexist. For example, whitefish spawn in Lake Ladoga in the coastal zone on pebble ground in the fall. The deep-water Ladoga-Nezhsky whitefish Valaamka spawns in Ladoga from late November to mid-December. But Volkhov whitefish for reproduction rose from Lake Ladoga to the Volkhov River, then to Lake Ilmen and then to the Mstu River. On their way whitefish even overcame the eternally raging Peter and Paul rapids of the Volkhov. Along the Msta river whitefish reached almost to the lake Mstino and from October 18 to 26, sometimes in the beginning of November, hatched their small yellowish eggs on sand and pebbles in deep places. After spawning most of the fish descended into Lake Ladoga, but some remained in Lake Ilmen and in the rivers until the spring ice drift. Eggs scattered by the female on the bottom developed for a long time in cold water. Only in April the larvae emerged from the shell, and already in the first summer of life the young fish descended into Ladoga and fattened in the areas adjacent to the Volkhov for three to five years, until the first spawning.
Tags: coregonus lavaretus