Speciation of invasive fishes

Intentionally introduced plants and animals are in effect founder populations, sensu Mayr. Since the Middle Ages, fishes have been introduced both purposefully and unintentionally and subsequently have established viable populations. Certainly, invasive species have caused the extinction/extirpation of native species and ecosystem structuring. Many studies have shown that invasive species can evolve rapidly, adapting to new environments through a combination of phenotypic plasticity and genetic changes, potentially leading to the formation of new species. Given the global scale of the introduction of fishes, understanding the processes of adaptation and speciation within these founder populations is critical. In this study, I explore two non-native, sympatric species of Salmo found in Spruce Creek, Pennsylvania, documenting the discovery of Salmo epimolos, a new species coexisting with Salmo trutta, and present evidence of their morphological divergence. Detailed morphological and meristic analyses revealed clear distinctions between the two populations, supporting reproductive isolation and divergence. This case provides insights into the processes of speciation in invasive species, highlighting the evolutionary potential of founder populations in novel environments and their impact on biodiversity and conservation. http://www.zoobank.org/urn:lsid:zoobank.org:pub:8EE192E4-ED8D-44AC-AD4E-81F719E4575F.