Status of the Azov Sea populations of roach and zander at the present time

Roach and zander are valuable semi-anadromous fish species, targeted by fishing operations in the Azov Sea, which necessitates evaluation of their current status. This article analyzes the data collected during the trawl surveys in the Azov Sea, the assessment of the juveniles of exploitable fish species in the Lower Don, the investigation of the reproduction in the water bodies of the Azov limans and spawning and rearing farms (hatcheries), and the monitoring of fishing catches in 2018–2020. In these three years, the feeding area of roach and zander decreased from 2,618 to 1,400 and from 1,230 to 822 km2, respectively. Roach catch decreased from 730.243 to 282.110 t. For the time, the exploitation of zander was suspended after the temporary fishing ban introduced in 2017. Age composition of the roach fishing stock consisted of four age groups; among them, three-yearlings (30.5 % by abundance, 23.6 % by weight) and four-yearlings (54.2 % by abundance, 51.4 % by weight) prevailed. Average age decreased from 3.1 to 2.8 years. Age composition of the zander fishing stock in the Don River was characterized by three age groups. In terms of abundance, three-yearlings prevailed (69.5 %), four-yearlings comprised 25.7 % of the total abundance, and five-yearlings comprised 1.5 % of it. In the Kuban River population of zander consisted of seven age groups. The most abundant were yearlings (54.4 %). Two-yearlings comprised 8.9 % of the total abundance, the share of three-yearlings was 25.0 %, and the eldest age groups of 4–7 years comprised 10.7 %. Quantities of the juveniles released in 2018–2020 from the water bodies used for natural and artificial reproduction came to be insufficient for proper recruitment to roach and zander stocks. Water bodies belonging with the hatcheries are the main sources for roach recruitment, and the Azov limans of the Krasnodar Territory serve the same purpose for zander.