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BiologyIn fresh waters, occurs in rivers and lakes (Ref. 89241). Adults inhabit coastal and estuarine waters (Ref. 59043). Ammocoetes occur along river banks in silty-muddy substrate where current is slight (Ref. 89241). Prefer sites with stony or sandy bottom, shaded by riparian vegetation (Ref. 41072). Spawning adults found in gravel riffles and runs of clear streams; feeding adults usually in oceans or lakes; ammocoetes in muddy margins and backwaters of river and lakes (Ref. 5723). Spawning occurs on pebble-sand substrate (Ref. 89241). Anadromous (Ref. 58426, 89241). The Great Slave Lake Basin population is believed to be a permanent freshwater resident population (Ref. 89241). There are non-migratory freshwater populations. Probably parasitizes any species of fish of suitable size (Ref. 27547), including commercial species (Ref. 58426). Subadults are non-parasitic (Ref. 12218). Feed on small aquatic invertebrates, algae and organic matter contained in detritus (Ref. 41072). Larval period lasts 4 years. Age classes range in total length approximately as follows: 0+ up to 35 mm; 1+ 30-65 mm; 2+ 60-155 mm; 3+ 150-220 mm. They tend to disperse downstream as they age. Mean densities in the Hay River, Northwest Territories, have been estimated at 137 ammocoetes/m2. Larvae feed mainly on organic detritus and algae. Ammocoetes are preyed upon by fishes. Metamorphosis begins in late summer (mid-August) and continues through the winter in Great Slave Lake Basin, Northwest Territories, Canada and recently metamorphosed adults enter the lake in May to July. Downstream movement of recently metamorphosed adults towards the sea begins in late May and ends in July in Kamchatka. Adults parasitic on various fishes in both fresh and marine waters. The site of attachment is usually below the lateral line and anterior to the pelvic fins. Adults are preyed upon by fishes and birds (gulls). Spawning adults ascend rivers in Japan between October and January, while this occurs between the end of May and June in Utkholok River Basin, Kamchatka, and between the end of November and the end of April in the Yukon River, Alaska. The spawning migration distance up the Yukon River exceeds 1,600 km. Both sexes participate in the building of the oval-shaped redd. Spawning occurs in June in Utkholok River Basin, Kamchatka, from April to July in Japan and mid June - early July in Great Slave Lake Basin, Canada. Fecundity, 9,790-29,780 eggs/female in Great Slave Lake Basin (believed to be a permanent freshwater resident population), 12,272-34,586 eggs/female in an anadromous population from Kamchatka, and 62,936-119,180 eggs/female in anadromous populations from rivers in Japan. In the latter case, the long diameter of the eggs varies from 0.85 to 1.23 mm and the short diameter from 0.75 to 1.14 mm. The eggs are dark blue and adhesive. When they emerge from the egg after about a one-month incubation period, larvae measure about 7 mm total length. Adult life is about two years (Ref. 89241). Arctic lamprey has high quality flesh rich in fat (Ref. 41072). Around 1879 it was of great importance for native peoples along the Yukon River at Russian Mission and Anvik, Alaska, where they would catch upstream spawning migrants by the dozens through the ice using long multi-forked poles or dipnets (Turner, 1886, Nelson, 1887). The oil in the lamprey would be rendered through boiling in water and used for human food or in lamps as a substitute for seal oil. Recently, there has been an interest in starting a commercial fishery for upstream migrants targeting the Asian market in the USA and abroad in addition to the traditional subsistence harvest. The 2003 quota was set at 20,000 kg. The taste has been compared to that of sardine because of the high lipid content that can reach 38% of the body weight. In Japan, in the Shinano River estuary, upstream spawning migrants are caught between October and January using large handnets; in 1959, daily catches varied from a few dozen to over 1,000 lampreys (Honma 1960). In winter, lampreys are caught at the same place but using a gang of about ten bell-shaped leather fishing traps that is laid in a string along the river floor (Honma, 1960). The lampreys are served in a number of different ways in restaurants, and in salt-dried form are highly valued as a medicine against night blindness (Honma, 1960) (Ref. 89241).