Heavy metals in abiotic and biotic components of aquaculture hydroecosystem “Ishkhan”

Abstract

Purpose. To determine the heavy metal content in abiotic components (water and bottom sediments of tanks), feeds, organs and tissues of rainbow trout in the conditions of industrial aquaculture. Methodology. The materials for the study were 1+ rainbow trout cultivated in 2011-2012, which were produced from brood rainbow trout reared in the tank aquaculture farm "Ishkhan". Experimental fish were collected from rearing tanks №№ 3-4. Mean fish weight was 466 g with mean fork length of 36 cm. Fish stocking density at the final stage of rearing was 50 kg/m 3 or 100 fish/m 2. Fish were kept according to standard salmon culture methods. Quantitative determination of heavy metal concentrations in water, bottom sediments and fish were performed by direct suction of solution in propane-butane-air flame with the aid of absorption spectrophotometer S-115-M1. Findings. The results of the performed studies include the determined ecological state of rearing tanks and quality of marketable rainbow trout of the fish farm "Ishkhan" by the above-mentioned characteristics. Main hydrochemical parameters, which characterized water quality, complied with aquaculture norms. However, a tendency for an increase in heavy metal content was noted in bottom sediments. In particular, an increased content of copper, nickel as well as toxic elements-lead and cadmium was observed. Originality. First study of the ecological state of rearing tanks of the fish farm "Ishkhan". Practical value. The obtained results of the ecological state of rearing tanks of the fish farm "Ishkhan" will allow crating optimum conditions for fish rearing.