Segmentation is clearly visible on the body. It has split dorsal fins. The coloration is characterized by a yellowish-gray tone of the body, the abdomen is yellowish, the back is gray. Fins are transparent. The color of the larvae (sandworms) is light, usually yellow. If there are lower labial teeth, then they are poorly developed, not keratinized. The mandibular plate often has 6-7 sharp teeth. The middle lateral teeth are bifid.
SPREAD
It lives in the rivers of the Pacific Ocean, in Russia it is found from Anadyr and Kamchatka to Sakhalin. Found in Japan and the Korean Peninsula. Inhabits the Amur basin in small tributaries throughout the entire basin.
MAIN FEATURES OF BIOLOGY AND ECOLOGY
The lifestyle of this lamprey is the least studied. Lives in foothill rivers and their mountain tributaries. Typical habitats are quiet areas with sandy-silty soils. In summer, it often concentrates in the mouths and at the confluence of rivers. The maximum length of adult lampreys is 26 cm, individuals 15-20 cm in size are more common. Development with metamorphosis (transformation). Larvae can eat phytoplankton and zooplankton. Lampreys do not feed as adults.
Monocyclic species, after spawning all adults die. Spawning occurs in spring and summer (from the second half of May to the first half of June) in a fast current on sandy-pebble ground, where the lamprey builds nests. Caviar is large, light yellow. The larvae live in pools with silty ground and channels with a slow current, burrowing into the ground. The larval period lasts more than three years.
POPULATION AND LIMITING FACTORS
Due to the fact that the species is not commercial, its abundance in habitats is mainly regulated by natural causes (hydrological regime, level of development of the food supply, the number of predators).
The number is relatively low. The main limiting factor is the pollution and transformation of habitats, especially in the areas of development of placer gold deposits.
STATUS AND COMMERCIAL VALUE
Due to its small size, it has no commercial value. It is used as bait by amateur anglers.
