Invasion in the Arctic: The adaptation, and coexistence dynamics between invasive pink salmon and native Atlantic salmon

Hakemuksen tiivistelmä

The Arctic region is disproportionately affected by environmental change. Atlantic salmon (Salmo salar) hold high value for Arctic communities, but dramatic recent salmon declines are affecting food security, economies and Indigenous culture. Determining the relative importance of anthropogenic and environmental factors such as climate change is a key aspect for appropriate management to promote population resilience. Further, understanding whether population responses are heritable, and the genetic loci are involved, enables predicting the occurrence and rate of evolutionary change, critical for predicting potential future adaptations. The recent significant increase of invasive pink salmon (Oncorhynchus gorbuscha) - which outnumbers the native Atlantic salmon by orders of magnitude - adds to the list of stressors on the dramatically declining native populations in the north, but there is lack of knowledge regarding the nature and magnitude of potential interactions and impacts. Here, we use the Teno River as a model ecosystem to better understand the impact of the ongoing rapid pink salmon invasion in the Arctic ecological systems. We will first pinpoint genetic and demographic factors affecting the success and dynamics of the pink salmon invasion using evolutionary genetic approaches (WP1). Next, we will explore phenotypic and genetic changes in the performance of juvenile Atlantic salmon (WP2) associated with the influx of nutrients from the ocean, linked to pink salmon biomass. Finally, we will identify the changes in the migration and distribution patterns of Atlantic salmon in response to the coexistence of two species (WP3). Our study will not only provide the first detailed time-series data and information about the population dynamics, population genetics of the recent invader, pink salmon, and possible impacts on Atlantic salmon, it will enhance informed decision-making on mitigation with better safeguarding of the dwindling Atlantic salmon populations.