Effects of global warming on Atlantic salmon sea-run timing at the southern edge of the European distribution

No abstracts are to be cited without prior reference to the author.

Atlantic salmon Salmo salar populations at the edge of the species distribution are the most vulnerable to environmental changes. Those inhabiting southern European rivers are expected to be particularly affected by global warming. However, they are exploited as a very valuable resource for the region, attracting tourism and generating high incomes. In the central part of northern Spain (Asturias) there is a long tradition of sport fisheries (angling). The first salmon caught in a river each year is called “campanu' and is highly prized in a public auction. Analysis of a 50-year time series demonstrates that the main Asturian populations of Atlantic salmon have declined significantly. Their run timing has changed over the last 20 years as inferred from significant delays in the date of capture of the campanu. This change is statistically associated with an increase in temperature indices and is independent of the annual start date of the fishery. Such a disturbance in the life history timing of a species due to global change can be considered a warning signal of future asynchrony in the freshwater ecosystems where this anadromous species is present.