Maximum body length of rotan in different water bodies of the native distribution range fluctuated from 14 to 25 cm (Soldatov and Lindberg, 1930; Kirpichnikov, 1945; Berg, 1949; Nikolsky, 1956). Its growth rate in native water bodies is relatively low and quite variable. In the native distribuiton range individuals older than 4+ occur extremely seldom (Kirpichnikov, 1945; Nikolsky, 1956).
According to the evidence obtained by Yakovlev (1925) for rotan from a small lake in the basin of Lake Khanka by the end of the first year fry had hardly reached weight of 1 g (on the average 0.8 g) and length of 3.5 cm. Two year individuals have body length of approximately 5.5 cm on the average and weight of approximately 4 g. Three year old individuals have body length 7.7 cm and body weight 11.6 g, seven year old rotan had body length 13.6 cm and weight 53.5 g. The author assigns this to high density of population of the particular water body up to 3-4 adult individuals per square meter.
In non-native range for Lake Glubokoye in Moscow region Reshetnikov (2001) indicates total length of 250 mm and mass of 250 g at the age of approximately 10 years.
According to the data of Kudersky (1982), in a pond in Sestroretsk in St. Petersburg Region in October 1981 individuals of three age classes were represented: 1+, 3+, and 4+.
Unlike natural water bodies in aquariums (Spanovskaya et al., 1964) rotan in the first year of life may attain a length of 5-6 cm in length. Thus its potential growth abilities are high.
In natural water bodies in Moscow region considerable of fluctuations of rotan body in the same water body are noted, which the authors attribute to uneven growth. Increase of irregularity of linear and weigh growth of the population of rotan is related to deterioration of life conditions in the studied pond. In the first years of existence in that pond rotan was scanty and feeding conditions (and therefore growth conditions) were favourable.
Its growth rate was much higher than in the Suifun River and in the lower Amur River. The range of variation of length and weight of different age groups was approximately the same. In the subsequent years as numbers of rotan in the pond increased fish weight declined and variation of growth rate rose. Growth rate of the major part of the population (data for 1961-1962) slowed down and approached growth rate in the basin of the Siufun River.
At the same time there appeared individuals growing very rapidly, much more rapidly than in 1955-1956. The increasing unevenness of growth was displayed not only in the division into rapidly and slowly growing fishes, but also in the increasingly varied character of linear weight growth and accumulation of depot nutritive substances in the liver, fat on the internal organs within each age group of rapidly and slowly growing fishes, particularly three and four year old fishes, i.e. in fishes forming the basis of the population.
In Mordovia (Volga River basin) rotan at the age of 4-5 years attains a length of 8-10 cm. Limiting length is 25 cm, body mass 350 g. In Lake Trostnoye (Sura River flood plain) a specimen with mass of 350 g at the age 8 years was caught (Vechkanov, 2000).
Linear and weight growth in non-native range can vary notably depending on food supply. Thus, indices of linear and weight growth of rotan in Lake Gusinoye, Moscow Region were high. Maximum weight of rotan attained 260-270 g (Bolonev and others, 2002), whereas in maternal water body (Amur River) and in Ivlevsky fish farm of Gorkovskaya Region maximum weight of fishes of older age at the age of 7 years did not exceed 60-70 g (Kudersky, 1980). This indicates that rotan found very good conditions with rich food supply in shallow water areas of Lake Gusinoye.
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