Age structure and growth features of the fire-bellied toad (Bombina bombina, Amphibia, Anura, Bombinatoridae) in Kaliningrad Oblast (East Baltic Region, Russia)

This article presents the results of a study on the age and growth of the fire-bellied toad ( Bombina bombina ) using skeletochronology. Thirty adult toads were captured from a spawning pond during the first decade of May 2024 near Bolshakovskoe settlement in the Bagrationovsky District of Kaliningrad Oblast, Russia. The age of the sampled toads ranged from 2 to 6 years, with a mean age of 3.90 years. The modal age was 3.5 years (66%). Post-maturity life expectancy (ESP) was 3.5 years, with an annual survival rate (S) of 0.663. The authors noted that studies conducted since the 1990s indicate a decrease in the maximum age observed in fire-bellied toad populations. This apparent change is likely attributable to methodological differences rather than a decline in population health. The mean body length and the asymptotic size of the fire-bellied toads from Kaliningrad Oblast were greater than those reported for populations in France, Denmark, Poland, Subcarpathia and Transcarpathia, Romania, Bulgaria, Turkey, the Republic of Mordovia, the Republic of Tatarstan, the Samara Oblast, Western Ciscaucasia, and Central Ciscaucasia. It is hypothesized that accelerated growth rates may represent an adaptive response to suboptimal habitat conditions.