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BiologyIn Europe the upper courses of rivers, in Siberia also in lakes and lowland rivers (Ref. 12323). Freshwater, in rivers, brooks, and lakes. Ammocoetes live in oozy substrate. Metamorphosing ammocoetes are mostly found in areas with abundant aquatic vegetation at the mouth of small streams (Ref. 89241). Ammocoetes feed on detritus, green algae, diatoms, and zooplankton (Ref. 12323. 89241). Larval life lasts 6+ yrs. Onset of metamorphosis is at the end of July beginning of August and is complete at the end of October to the middle of November. The population in the upper Irtysh River Basin is apparently unique among lampreys in that it continues to feed during metamorphosis gradually switching from a detritus and unicellular algae diet to an exclusively unicellular algae diet. This would explain the fact that the maximum total length of the metamorphosing ammocoete exceeds the maximum total length of the ammocoete; mean of 233 mm in the former versus 218 in the latter. Unicellular algae consumed include Cyanophyceae (Oscillatoria), Chlorophyceae (Spirogyra, Chlorella), and Diatomeae (Fragilaria, Pinnularia). This phenomenon is particularly interesting as it implies that the metamorphosing ammocoetes must switch from a filter-feeding mode to a grazing mode of feeding, since, during the process of metamorphosis, the oral cirrhi are lost. The grazing may be achieved possibly with the help of the lingual laminae and the action of the piston cartilage (Ref. 89241). Adults are nonparasitic (Ref. 89241, 12323). Spawning period in Japan in early May. Fecundity, 1,387-2,125 eggs/female in Japan, with long diameter of eggs varying from 1.12 to 1.22 mm and the short diameter from 0.91 to 1.11 mm. Kucheryavyi et al. (2007) reported a fecundity of 468-3,441 eggs/female in non-feeding adult stage resident L. camtschaticum (= L. kessleri?) on Kamchatka (Ref. 89241). Ammocoetes used as lures for bait casting (Ref. 12323).