The role of temporal reproductive isolation, trophic polymorphism and growth rate fluctuations in the diversification of Arctic charr Salvelinus alpinus (L.) in Lake Kalarskii Davatchan, Transbaikalia, Russia.

Autor: Alekseyev, Sergey S., Samusenok, Vitalii P., Gordeeva, Natalia V., Yur'ev, Anatolii L., Korostelev, Nikolai B., Matveev, Arkadii N.
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Zdroj: Hydrobiologia; May2024, Vol. 851 Issue 9, p2099-2123, 25p
Abstrakt: Trophic polymorphism and temporal reproductive isolation are the drivers of sympatric differentiation in many fish taxa. We present a new case of ecologically based diversification of Arctic charr in a Transbaikalian mountain lake inhabited by reproductively isolated dwarf and normal forms. These forms differ in size, diets and morphology and breed, respectively, in April–May and in September–October representing a rare example of sympatric spring- and autumn-spawning charr pair. Microsatellite analysis reveals clear-cut genetic differences and low-level hybridization between them. Dwarf form charr are planktivorous and manifest uniform slow growth. Normal form charr, though genetically homogeneous, are highly heterogeneous in size-at-age. They are subdivided into omnivorous small-size and piscivorous large-size groups, which can be considered as incipient forms at an early divergence stage. As evidenced by back-calculated growth data, their size-at-age heterogeneity results from highly variable individual growth patterns, which include different combinations of slow and fast growth periods presumably associated with spawning and non-spawning years. Growth acceleration in late ontogeny may result in the transformation of some normal charr from the smaller into the larger group during their lifetime. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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