Abstract

Juvenile paddlefish (Polyodon spathula) hatched in 1988 have been cultivated in ponds up to sexual maturity (age 11+) in Moldavia, located in central European Plain with an altitude ranging from 429.5 m to 147 m. The average annual air temperature is 9.5-10 °C and the growing season for pond fish is 180 to 210 days The first summer the fish were reared under either mono- or polyculture conditions starting at an initial stocking density of 10000 and 5000 fish ha 1 . By the autumn the individual weights were 72 and 139 g and the survival rate 48 and 63%. respectively. In subsequent years the paddlefish were associated in ponds with various sturgeon species. A polyculture experiment associating the sturgeon, Acipenser baeri (density 4300 ind. ha ) and paddlefish (density of 8300 ind. ha 1 ) yielded respectively 59% survival and 432 kg ha 1 productivity for Polyodon and 77% survival and 174 kg ha productivity for A. baeri. By the third year (2 + ) the paddlefish reached average weight of 1.5-2..5 kg and their final survival and productivity values were 50-70% and 150-463 kg ha - 1 . respectively. Males (6-7 kg) matured at the age of 5 + -6 + . Females rached sub-final stage IV at the age of 11+ + (30%) or 12 + (70%) and a weight of 10-16 kg with spawning and production of viable fry. Caviar was made from the roe of these females. In I + - 3 + aged firsh, the proportion of flesh and skin was stable at 54-57% while the proportion of head decreased from 44% at 0 + to 26% at 3 + .

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