Abstract:
TThe study aims to determine the chemical composition of water in six ponds from the Republic of Moldova (Falesti and Glodeni
districts) and two ponds from eastern part of Romania (Iasi and Botosani counties) and to evaluate their water quality as one of the
vital resources for an efficiency-oriented fish production and from an environmental perspective. Instantaneous samples were
collected in April and July 2021 in Moldovan ponds and in May 2021 - in Romanian ones. It was revealed that the thermal regime
of water, regime of oxygen, content of nutrients, main ions and mineralization were favourable for the growth of European carp and
Asian cyprinids. In 38% of analysed samples water pH was equal or higher (≥9) than the maximum allowable value for summer
fish ponds. CO3
2- + HCO3
-
dominated among the anions and Na++K+ - among the cations in the water of Romanian ponds and two
ponds from the Republic of Moldova. In other four ponds the dominance of SO4
2- among anions and of Na++K+- among cations
was recorded. Increased mineralization of water in the studied Moldovan ponds (from 2.14 to 6.11 g/L, depending on the pond and
sampling time) offers the opportunity to cultivate fish species that live in saline waters, for example, the pelengas mullet (Mugil
soiuy). Even the investigated ponds are located in areas with similar altitude and climate conditions, their water quality revealed
high differences, the main factors being the type of water supply, presence or absence of water exchange and the applied
management practices.