Abstract
Aim. The purpose of this work was to assess the current state of crayfish populations in their habitats on the eastern shelf of the Caspian Sea (Alexander Bekovich‐Cherkassky Bay).Material and Methods. Fieldwork was based on underwater research methods using light diving equipment. Collection of research material was carried out according to an established crayfish survey protocol using fixed grid sites of 100 square metres. Collected crayfish were identified by species, measured and weighed, fecundity of females and the condition of crayfish shells were recorded. Crayfish were then released back into the sea. Calculation of numbers was carried out on the basis of determination of cluster density (ind/m2) with a further assessment of useful biotype areas. Calculation of commercial stocks based on crayfish length. The research synthesized information derived from comparative analysis of modern research results and archival data from the 1970s to 1990s.Results. Analysis showed that significant changes in the composition of populations had occurred. The dominant species recorded was Caspiastacus pachypus Rathke which has substantially displaced from the biotopes Pontastacus eichwald Воtt. which was previously the dominant species here.Conclusion. Comparative analysis of the modern state of the astacofauna on the eastern shelf and historical data indicates significant changes in the structure of populations of Caspian crayfish. The resilient C. pachypus has become the dominant species. Its small commercial size has significantly reduced the economic value of crayfish stocks. In general, however, commercial stocks of these crayfish make it possible to develop these marine biological resources.
Highlights
МАТЕРИАЛ И МЕТОДЫ ИССЛЕДОВАНИЙ В основу работ были положены методы подводных исследований с применением легководолазной техни‐ ки на глубинах 3‐12 м
The purpose of this work was to assess the current state of crayfish popula‐ tions in their habitats on the eastern shelf of the Caspian Sea (Alexander Bekovich‐ Cherkassky Bay)
Calculation of commercial stocks based on crayfish length
Summary
Формат цитирования Ушивцев В.Б., Востоков С.В., Ахмедова Г.А., Галактионова М.Л., Котеньков С.А. Современное состояние и хозяйствен‐ ная ценность астакофауны в отдельных районах восточного шельфа Каспийско‐ го моря// Юг России: экология, разви‐ тие. Резюме Целью данной работы стала оценка современного состояния популяций ра‐ ков (Astacidae) на восточном шельфе Каспийского моря в местах их массового обитания (залив Александра Бековича‐Черкасского). Сбор исследовательского материала осуществлялся в марте‐апреле 2018 г. Сбор исследователь‐ ского материала осуществлялся методом маршрутного учета на трансектах площадью 100 м2. Анализ современного состояния астакофауны на восточном шельфе и исторических данных свидетельствует о существенных изменениях структуры популяции каспийских раков. При этом запасы раков сохраняют промышленный потенциал для освоения этих биоресурсов Каспийского моря. Ключевые слова Каспийское море, восточное побережье, раки, распространение, видовой состав популяций, особенности биологии видов, промысловая и хозяйствен‐ ная ценность запасов, допустимые объемы вылова
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