Cages’ farming foundation as a limiting factor in cultivation of sturgeon fish hybrids

Abstract

The work experimentally confirmed the negative influence of fouling of cage structures on the growth and survival rates of reared young sturgeon hybrid — bester (Huso (Linnaeus, 1758) × Acipenser ruthenus (Linnaeus, 1758)). A significant decrease in growth and an increase in fish mortality in modules with a maximum biofouling area was noted. The possibility of using alternative cleaning methods in comparison with traditional mechanical and chemical ones has been investigated. The positive results of the experimental approbation of the author’s development — the practical application of a specially designed structure made of tarpaulin for the cage are given. The use of an easy-to-manufacture and operate device prevented active contamination of the cells, increased the efficiency of keeping fish, which is economically beneficial for commercial sturgeon growing in cages. In general, in fish farms located in a natural reservoir in the spring-summer period, the overgrowth of fodder bottoms and cage walls with filamentous algae has a strong negative effect on the cultivation of sturgeon fish. To optimize the fish-breeding process and reduce the number of algae during the period of their active growth on cages (the timing must be determined according to the conditions of a particular reservoir), special canvas covers should be used. This device will reduce the amount of sunlight entering the cage bottoms and slow down the growth of filamentous algae. To install this device on the cage, two workers are required, the approximate installation time (and, if necessary, dismantling) will be 20 minutes. To reduce the negative effect of algae fouling of the cage bed, measures should be taken to mechanically clean the stern bottoms and walls of the cage with high-pressure cleaning (washer) devices, after transplanting the cultivated objects into another fish hatchery