Status of the Azov Sea populations of common bream and vimba bream at the present time
After introduction of the fishing ban on sturgeons and zander, common bream and vimba bream became the most valuable fishing target for the fisheries organizations. For this reason, characterization of the current status of the populations of these two native species becomes rather crucial. In this article, the data collected by research catches with a bottom trawl in the Azov Sea, recurrent trips for assessment of the juveniles with fry dragnet in the Lower Don mainstream, and the monitoring of fishing catches for years 2018–2020 are presented. In these 3 years (high-water 2018 and low-water 2019–2020), the status of the Azov Sea populations of these two valuable fish species changed considerably. The average weight and average age of common bream decreased; however, these values in vimba bream grew higher. The generation of common bream born in the high-water 2018 played a dominant role in its fishing stock in 2020: the share of common bream 3-yearling was 40.8 % out of entire population abundance. As for vimba bream, in 2020, the generation born in 2016 prevailed; its share was 56.3 % in terms of abundance. Fishing exploitation of these species also underwent notable changes: in these years, the annual catch of common bream and vimba bream increased by 4 and 2 times, respectively. Recruitment with juveniles in both species depended on hydrological conditions in the spring season. With the exception of high-water 2018, the conditions for natural spawning of anadromous and semi-anadromous fish species in 2019–2020 were unfavorable; the reduction of feeding area resulting from salinization of the Azov Sea was observed for both species. Thus, by 2020, vimba bream abundance stayed at a low but stable level, which indicates a certain degree of equilibrium between recruitment and mortality. The status of common bream population should be considered as depressed.
| Main Authors: | , |
|---|---|
| Format: | Journal Contribution biblioteca |
| Language: | Russian |
| Published: |
2021
|
| Subjects: | Dragnets, Biological properties, Bottom trawling, Population abundance, Annual catches, Abramis brama, Vimba vimba, Fish catch statistics, Донное траление, Мальковые волокуши, Годовой улов, Численность популяции, ASFA_2015::S::Stock assessment, ASFA_2015::P::Population abundance (in number), |
| Online Access: | http://hdl.handle.net/1834/41818 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|