Early warning: detection of exotic Coho salmon (Oncorhynchus kisutch) by environmental DNA and evidence of establishment at the extreme south Patagonia

FERNÁNDEZ, DANIEL ALFREDO; NARDI, CRISTINA FERNANDA; CHALDE, TOMÁS

CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES

NATL RESEARCH COUNCIL CANADA-N R C RESEARCH PRESS

Año: 2019

0706-652X

The global expansion of aquaculture is a constant propagule pressure that enables the establishment of exotic species in freshwater and marine environments. Here, we provide the first report on the presence of exotic Coho salmon (Oncorhynchus kisutch) at the extreme south of Patagonia, in the island of Tierra del Fuego (TDF). During the last six years, 43 juvenile Coho salmon were captured along the Beagle Channel, while one adult was captured in freshwater. Scale analysis showed that migration from freshwater as smolt would occur during their first winter of life. Mitochondrial DNA analyses revealed two haplotypes previously reported in North America and a new haplotype not reported before. At last, we developed an environmental DNA assay for detecting Coho salmon DNA from freshwater, obtaining positive results in three rivers. Additionally, one of these rivers was monitored monthly for a year and we detected Coho salmon DNA over 7 months, revealing the probable occurrence of Coho salmon juveniles in freshwater. These results suggest the potential establishment of self-sustaining populations of Coho salmon in TDF.