The effect of infestation with Diplostomum sp. on growth rate of Siberian sturgeon fry Acipenser baeri Brandt

The objective of the experiment was to compare the growth rate in two groups of Siberian sturgeon fry, one of which was infested with metacercariae of Diplostomum, the infestation degree was from 1 to 160/fish. The fish fed on natural as well as artificial food; the latter was given at the rate sufficient to cover 50% of the fish requirements. The average initial body weight in the control group was 16.8 ± 1.9g, and in the group with Diplostomum - 28.4 ± 3.6 g. During the period of favorable temperatures, viz. for about 90 days, the fry was showed satisfactory growth, but the growth rate becaine inhibited as the temperatures decreased to below 12°C, so that throughout the wintering period the fish weight decreased by some 10%. Fish from the control group showed a higher growth rate than the infested ones, and by the end of the experiment the controls weighted 7.5% more than the infested group in spite of their lower initial weight.