БІОЛОГІЧНА ХАРАКТЕРИСТИКА НЕРЕСТОВОГО СТАДА ОСЕЛЕДЦЯ ЧОРНОМОРСЬКОГО ALOSA IMMACULATA (BENNET, 1835) НА УКРАЇНСЬКІЙ ДІЛЯНЦІ НИЖНЬОГО ДУНАЮ

• Дата: 2025
• Автори: Бушуєв, С.Г., Гулак, Б.С.
• Формат: Стаття
• Мова: Українська
• Опубліковано: Marine Ecological Journal 2025
• Теми: оселедець чорноморський; Дунай; структура популяції; параметри росту; природна смертність; коефіцієнт експлуатації
• Онлайн доступ: https://mej.od.ua/index.php/mej/article/view/721
• Назва журналу: Marine Ecological Journal

The aim of the study was to clarify the biological parameters of the spawning stock of the of pontic shad Alosa immaculata (Bennet, 1835) in the Ukrainian part of the lower Danube. Materials were collected in 2017–2024 in the area of the Kiliya estuary below 24 km and Solomon’s Arm (3–1 km). We examined 112 catches from shad driftnets with a mesh size of 30–32 mm. The key population parameters were determined: sex, age, size and weight structure, fatness coefficients, growth rates, natural and fishing mortality. The ratio of males to females in the samples was 1 : 2.36 (p < 0.05), with a predominance of females (68.5%). The age composition is stable, with the dominance of 3–4-year-old individuals (85.3%), while older age groups (6–7 years) are represented exclusively by females. The average total length of shad ranged from 29.3 to 32.13 cm (mean 30.6 ± 2.6 cm), females were larger than males (p < 0.05). Fulton’s fatness index ranged from 1.15–1.36 (mean 1.23 ± 0.16), indicating stable feeding conditions in the Black Sea. The Bertalanffy growth equation was estimated as L∞ = 41.74 cm, k = 0.322, t0 = –0.51, with faster growth of females compared to males (B = 2.83, p < 0.05), which corresponds to a negative allometric growth model. Mortality coefficients: total (Z) – 1.72, natural (M) – 0.83 (0.51 for 3–4+ years), fishing (F) – 0.89. The exploitation rate (E = 0.517) is close to the optimal one (E = 0.5), indicating a relatively stable level of population exploitation. Changes in the sex and age structure are partly due to the selectivity of the fishery, in particular, an increase in the mesh size of the nets to 32 mm, which reduced the proportion of smaller males. The data obtained can be used to predict population dynamics and develop science-based approaches to fisheries management, contributing to the rational use and conservation of the species.