Volcanoes serve as natural laboratories expanding our understanding of the recent and past ecological and evolutionary processes. Here, we present data elucidating the developmental and phenotypic transformations providing rapid adaptation for the salmonid fish, Salvelinus malma, to volcanic impact. After being isolated by the mudflow in 1996, the locked descendants of sea-run charr managed to survive in the highly turbid and toxic environment. Initially, the population underwent a phase of high developmental instability accompanied by a surge in morphological deviations. Further, selection targeted the fish prone to migrate into the most toxic mainstream favoring a sedentary lifestyle at the less toxic spawning tributaries. In five–seven generations, the sedentary population recovered developmental homeostasis but diverged into a small-sized short-cycled form with low phenotypic variability. In response to toxicosis, the fish displayed an accelerated metabolic rate and precocious maturations. The spawners possessed fry morphology with no spawning dress. Sedentary fish also exhibited a decreased fecundity and did not build spawning nests. Thus, under the volcanic impact, S. malma demonstrated a rapid paedomorphic miniaturization, an evolutionary mechanism enabling to complete the reproductive cycle under the conditions of high risks of reaching the adaptive capacity limits.

中文翻译：

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Salvelinus 鱼的快速小型化以适应火山冲击

火山作为天然实验室，扩大了我们对最近和过去生态和进化过程的理解。在这里，我们提供了阐明发育和表型转变的数据，这些转变为鲑鱼 Salvelinus malma 提供了对火山影响的快速适应。1996年被泥石流隔离后，被锁住的海棠子孙在高度混浊、有毒的环境中生存下来。最初，该种群经历了一个高度发育不稳定的阶段，伴随着形态偏差的激增。此外，选择的目标是容易迁移到毒性最强的主流的鱼类，它们倾向于在毒性较小的产卵支流上过着久坐不动的生活方式。五七代，久坐人群恢复了发育稳态，但分化为具有低表型变异性的小型短周期形式。为了应对中毒，鱼表现出加速的代谢率和早熟。产卵者具有鱼苗形态，没有产卵衣。久坐不动的鱼也表现出繁殖力下降，并且没有建立产卵巢。因此，在火山冲击下，S. malma 表现出快速的幼形小型化，一种能够在达到适应能力极限的高风险条件下完成生殖周期的进化机制。久坐不动的鱼也表现出繁殖力下降，并且没有建立产卵巢。因此，在火山冲击下，S. malma 表现出快速的幼形小型化，一种能够在达到适应能力极限的高风险条件下完成生殖周期的进化机制。久坐不动的鱼也表现出繁殖力下降，并且没有建立产卵巢。因此，在火山冲击下，S. malma 表现出快速的幼形小型化，一种能够在达到适应能力极限的高风险条件下完成生殖周期的进化机制。