Tridentiger bifasciatus (Gobiiformes, Gobiidae): nuevo registro de una especie exótica en el río Negro, Argentina

Abstract

Biological invasions represent one of the main causes of biodiversity loss, second only to habitat destruction. These exotic species alter natural ecosystems and generate environmental impacts. The goby Tridentiger bifasciatus, native to the northwestern Pacific of Asia, has expanded its distribution in recent decades. After being recorded in California, North America, and more recently in Belgium and Argentina (Pehuen-Co). The aim of this study is to report the first record of the exotic goby Tridentiger bifasciatus in the Negro River, Argentina. The finding took place in the Negro River (-40.803579 S; -62.985768 W), in March 2025. Two specimens of 53 and 84 mm total length were collected from the riverbank, later analyzed morphologically, and preserved in the LaByCAA-UNRN collection. The specimens showed distinctive diagnostic traits, such as dark longitudinal bands, tricuspid teeth, and fused pelvic fins. The presence of T. bifasciatus in the Negro River may be linked to its expansion from Pehuen-Co (Buenos Aires). Its generalist nature, broad diet, and tolerance to low salinity favor its establishment and spread. Considering that almost half of the fish species in the Negro River are introduced, this record highlights a concerning increase in the invasion of exotic fishes, with potentially negative consequences for regional biodiversity.