26th May 2018
After last year’s invasion of pink (or humpback) salmon (Oncorhynchus gorbuscha) across much of northern Europe (see article here and here), experts were expecting far fewer to appear in 2018. However, the first pink salmon has been reported (May 21st) by an angler fishing a southern Norwegian river. Pink salmon have a very a strict two-year life cycle; the offspring produced in any particular autumn will return to spawn two years later. One consequence of this is that there are two distinct types of pink salmon: odd-year and even-year spawners.
Pink salmon are a non-native Pacific salmon species, introduced for food production to Russia from the late 1950-90s. They have since spread from the rivers where they were originally stocked and are establishing breeding populations. As you may have read in previous issues of the magazine, last year pink salmon were widely reported across Scandinavia, Denmark, Iceland, France, the UK, Ireland and even as far away as Newfoundland. Although pink salmon all die after spawning (like all 5 Pacific salmon species), there is much uncertainty surrounding the species and the exact impacts they will have on Atlantic salmon populations and the rivers in which they live.