Are salmon-derived nutrients being incorporated in food webs of invaded streams? Evidence from southern Chile

Abstract

Using stable isotope analyses of N and C we present preliminary evidence of marine-derived nutrients from introduced Chinook salmon (Oncorhynchus tshawytscha Walbaum) in stream food webs of Laguna Los Patos, NW Patagonia. Similar to values reported within Chinook salmon's native distributional range periphyton and aquatic insects are the trophic levels that show the greatest enrichment of δ15N (5–6‰). Since there is a rapid expansion of Chinook salmon in South America future effort is needed to elucidate the mechanisms and consequences of nutrients subsidies from salmon carcasses in those invaded ecosystems.

Keywords

• invasive species
• Patagonia
• salmonids
• periphyton
• freshwater snail