Overview of retrospective and modern data on arrival fodder organisms in lake Balkhash

Abstract

The article analyzes the acclimatization work carried out, the current state of the food supply and the feasibility of introducing new food items. Lake Balkhash, in the first years of commercial development, was characterized by extreme poverty of the food base, especially the bottom fauna. During the period of planned acclimatization work, 1958–1965, 10 species of valuable food items were introduced into the reservoir. Many species, as expected, settled in the western part of the lake, where they not only expanded the species composition of bentonts, but also increased the feeding capacity of the reservoir — from 1.3 to 20 times. However, with an increase in salinity from west to east, the composition of benthos became poorer and its biomass decreased due to the gradual loss of mysids, corophiids, polychaetes and monodacnae from its composition. At the present stage, the biomass of zoobenthos in the eastern part of Lake Balkhash is 20–40 times lower than the indicators of the western part. To increase feed in Eastern Balkhash in 2012–2014. Experimental work was carried out on the survival in the Balkhash water of euryhaline invertebrates from the Aral Sea — polychaetes and bivalve molluscs. Based on the positive result, a biological justification was developed for the acclimatization of these invertebrates in the lake. Balkhash, but due to lack of funding, the work itself was not carried out. Within the framework of the above program, it is necessary to continue work on the introduction of brackish-water benthic organisms from the Aral Sea, as well as to ensure the feeding needs of juvenile fish throughout the growing season, there is a proposal for the introduction of Calanipeda aquae-dulcis Kritsch into the reservoir. Research on the issues raised in the article is funded by the Ministry of Ecology, Geology and Natural Resources of the Republic of Kazakhstan (Grant No. BR10264205,).