The presence of iteroparous salmonid spawning grounds affects the stable isotope signatures of food web components in Swedish boreal streams.

Marine-derived nutrients (MDN) translocated by anadromous fish can strongly be linked to the dynamics and structure of resident freshwater communities. Yet there is limited knowledge on the transport of marine nutrients by Atlantic salmon () and sea trout () from the Baltic Sea and their incorporation into the trophic system of the boreal streams. Here, stable carbon (δC) and nitrogen (δN) isotopes were measured in food web components (periphyton, benthic macroinvertebrates, and a predatory fish (freshwater-resident brown trout) of four sites with and without salmonid spawning grounds.