Abstract
The Kamchatka River basin is the reproduction area for the secondary large Asian stock of sockeye salmon, one of the most valuable species of pacific salmons. Several major local stocks and groups of minor stocks occupy the basin, the main of them are: i) A — the aboriginal stock in Lake Azabachye (in the lower Kamchatka basin) which juveniles stay two winters in the lake and migrate to sea in the age 2+; ii) E — the transit group of local stocks spawning in the middle and lower tributaries of the Kamchatka which juveniles enter to Lake Azabachye for feeding and wintering and migrate to the sea after the wintering in the age 1+. The latter underyearlings get an additional mark on the scale (less than typical annuli) entering the Lake because of the feeding conditions change. That’s why almost all (90–95 %) juveniles have two zones of dense sclerites (ZDS) when leave Lake Azabachye, no matter of their 2+ or 1+ age. By the measurements in 1979–1987 of the smolts with two ZDS (A + E) in the year of their migration from Lake Azabachye to the sea, each sclerite on scale had formed in 6.61 days, on average, while the smolts staying in the lake for freshwater feeding (with one ZDS) formed each sclerite in 12.00 days, on average. Correspondingly, the migrants had wider distance between the sclerites (4–5 mm), as compared with those of non-migrants (2.0–2.5 mm) (with 150 times magnification). The aboriginal migrants demonstrate the effect of real compensatory growth in the year of emigration that is reflected in the scale structure as wider intersclerite distances. Negative dependence between the size of smolts and rate of their sclerites forming is observed on the data of 1987–2016 for the aboriginal stock A: the bigger the smolts at age 2+, the lower the rate, the longer the time of new sclerite forming, and the narrower the distance between sclerites, and vice versa. This dependence is interpreted as additional environment-dependent adjustment of the growth rate for the smolts with compensatory growth for their better adaptation and survival.
Highlights
Более 90–95 % всех смолтов нерки, скатывающихся из оз
Local stocks and groups of minor stocks occupy the basin, the main of them are: i) A — the aboriginal stock in Lake Azabachye which juveniles stay two winters in the lake and migrate to sea in the age 2+; ii) E — the transit group of local stocks spawning in the middle and lower tributaries of the Kamchatka which juveniles enter to Lake Azabachye for feeding and wintering and migrate to the sea after the wintering in the age 1+
By the measurements in 1979–1987 of the smolts with two ZDS (A + E) in the year of their migration from Lake Azabachye to the sea, each sclerite on scale had formed in 6.61 days, on average, while the smolts staying in the lake for freshwater feeding formed each sclerite in 12.00 days, on average
Summary
Азабачьего в море, на чешуе имеют две зоны сближенных склеритов, несмотря на то что часть из них имеет возраст 2+ (аборигенное стадо «А»), а другая — 1+ У смолтов нерки (стадо «А» + группировка «Е») с двумя зонами сближенных склеритов на чешуе в бассейне оз. Установили (Бугаев, 1995), что один склерит у мигрирующих в море смолтов (объединенные данные по стаду «А» и группировке «Е») из истока протоки Азабачьей с двумя ЗСС на чешуе в среднем формируется за 6,61 ± 0,40 сут (n = 11, где n — число сравниваемых пар выборок). Настоящее исследование в истоке протоки Азабачьей смолтов нерки стада «А» возраста 2+ (по группировке «Е» возраста 1+ материалы оказались недостаточными) демонстрирует, что скорость роста склеритов в год ската закономерно изменяется в зависимости от размеров смолтов, т.е. Поэтому цель работы — определение параметров истинного компенсационного роста в зависимости от размеров смолтов стада «А» возраста 2+ (с двумя ЗСС)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
