Pink Salmon Invasion of the North Atlantic: Evaluation of Stable isotopes as a method to detect potential impacts

Biological invasions threaten global biodiversity and cause billions of Euros of damage to the European economy annually.

The recent invasion of northern Europe by Pacific pink salmon, Oncorhynchus gorbuscha (Walbaum), has attracted much attention.

Introduced into rivers of the White Sea by the USSR in the 1950s/1970s, a sudden dramatic increase in occurrence was observed around the North Atlantic in 2017.

Negative impacts on native Atlantic salmon stocks are expected, including competition for food at sea, with economic implications for member states.

The aim of this project is to determine the impact of pink salmon on native salmonids both at sea and in recently invaded rivers by determination of the distribution of pink salmon feeding grounds in the North Atlantic, assessment of competition with Atlantic salmon at sea, determination of field metabolic rates (hence thermal sensitivity) of both salmon species, prediction of future marine distributions, and evaluation of the ecological role of pink salmon fry in recently-invaded rivers.

To achieve these aims, stable isotopes of material from pink salmon (otoliths, scale and muscle tissues) will be analysed, along with gut contents of juveniles and predators.

Whilst stable isotopes have been used to study the distribution of salmon in the oceans, this is the first time that the approach will be used to assess the impact of an invasive fish species on native species at sea, as well as application of a novel otolith derived isotope proxy to establish their sensitivity to global warming.

There is little research on the ecology of pink salmon fry in invaded rivers.

The proposed fellowship is a holistic study of this invading species: the results will expand our knowledge of the environmental biology of this invasive species in Europe and provide a scientific basis for decision-makers responsible for protecting the wild Atlantic salmon stocks.