Complex studies of seasonal differences of the ecological state of Masrik River (Armenia) were realized in 2017. Water quality was assessed by BMWP, ASPT and FBI indices based on studies of qualitative and quantitative structures of benthic macro-invertebrates. Potential reference sites in the basin were revealed using the %EPT taxa index in addition to water quality assessment by bioindication methods as well as hydro-chemical, -physical and -morphological measurements. The applicability of the used biotic indices for the different parts of Masrik River was discussed.

Sevan trout is an endemic fish species, registered in the Red Data Book of Armenian Animals as a ‘Critically Endangered’ species (IUCN category: CR A2cd) and is one of the most valuable fish of the Armenian ichthyofauna. For the purpose of preservation of this endangered fish species, rivers in the South-West part of Lake Sevan have been studied and their potential for spawning has been assessed through a relatively ‘cheap’ and ‘time-saving’ approach developed on the basis of hydrophysical, hydrochemical and hydrobiological studies. The results have shown that the highest potential to support natural reproduction of Sevan trout is in the middlestream part of Lichq river, as well as in the downstream part of Bakhtak river and the part of Bakhtak-Tsakqar system near the connection of the Bakhtak and Tsakqar rivers; however, all these areas need some remediation to achieve ‘high potential’.