Abstract

Based on long-term data (1959−2017), a comparative analysis of the size–age structure of eight navaga Eleginus nawaga populations in the White, Barents, and Kara seas was carried out. The relationship between the growth rate of the navaga and the duration of the period with the optimum water temperature for feeding (0−12°C) was revealed. Individuals of the same age groups have the largest sizes in the central part of the range (Mezen Bay and the White Sea Voronka, Cheshskaya Bay of the Barents Sea), and the smallest ones in Pechora Bay of the Barents Sea. The higher growth rate of navaga in the northern part of the range (Kara Bay of the Kara Sea) compared with the southern (Onega Bay of the White Sea) is explained by the absence of heating of coastal waters above the limit favorable for feeding. The increase in the average size of the navaga of the populations under consideration in 1991–2017 relative to those in 1960−1990 is due to the lengthening of the period with a temperature >0°C for almost 1 month. In Mezen Bay and the White Sea Voronka and in the Barents Sea bays, the average length and weight increased only in the younger age groups, and they hardly changed or even decreased in the older ones. This was the result of an increase in the number of fish of older age groups in these areas as a result of a reduction in catch.

中文翻译：

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白海，巴伦支海和卡拉海的纳瓦加纳瓦加（Navaga Eleginus nawaga）的年龄结构

摘要

基于长期数据（1959-2017年），对八只纳瓦加羚羊的年龄-年龄结构进行了比较分析在怀特，巴伦支和卡拉海进行了人口调查。揭示了纳瓦加族的生长速度和该时期的持续时间与最佳摄食温度（0-12℃）之间的关系。同一年龄段的个体在该范围的中部最大（梅岑湾和白海沃龙卡，巴伦支海的切什卡亚湾），而巴伦支海的佩乔拉湾的个体最小。山脉北部（卡拉海的卡拉湾）与南部（白海的奥涅加湾）相比，纳瓦加河的增长率更高，这是由于没有将沿海水域加热到超过觅食限制而造成的。相对于1960-1990年，1991-2017年所考虑的种群的平均导航量增加是由于温度> 0°C的时间延长了将近1个月。在梅曾湾和白海沃龙卡以及巴伦支海湾，平均身长和体重仅在较年轻的年龄组中有所增加，而在较年长的年龄组中几乎没有变化，甚至没有下降。这是由于渔获量减少而导致这些地区中年龄较大的鱼类数量增加的结果。