The Chinook salmon is a species that inhabits both freshwater and marine environments. It uses rivers for reproduction and early-stage rearing, then migrates to the sea where it spends most of its life until reaching large sizes and sexual maturity. Upon reaching this stage, the Chinook salmon undertakes a remarkable journey, migrating upstream in rivers from the saltwater it inhabited to freshwater to reproduce and die, completing its life cycle. This migration marks a pivotal moment as the salmon returns to its birthplace, embarking on a cyclical journey essential for the continuation of its species.
In its native habitat spanning the northern Pacific and associated basins, the Chinook salmon plays a pivotal role in the intricate web of life. During its arduous upstream migration and within its spawning grounds, it faces numerous natural predators. These predators, ranging from bears to birds of prey, contribute to the delicate balance of ecosystems, underscoring the Chinook salmon’s significance as a vital component of the food chain.
However, in Patagonia where it was introduced, the absence of natural predators raises several questions: which species could be taking advantage of this new resource? Do scavengers choose to feed on its remains? How is this new nutrient source incorporated into the trophic web and who are the beneficiaries in rivers and riparian environments? To what extent could these events modify species behavior?
Alongside GT collaborator the biologist Javier Ciancio from CENPAT-CONICET, and the biologist and founder of the NGO Fundación Anfibia in El Chalten, Rodrigo Clarke, Rune conducted a field trip in March. Their aim was to observe the interaction of scavenging vertebrates with Chinook salmon carcasses in spawning sites across various tributaries of the Santa Cruz River. Employing camera traps and conducting in situ observations, the team delved into understanding the dynamics of this ecosystem. These new records allow them to identify the consumers of the carcasses and providing information for the various studies conducted in recent years on the effect of the Chinook invasion and its socio-environmental impacts in Argentinian Patagonia.