Synchrony and multimodality in the timing of Atlantic salmon smolt migration in two Norwegian fjords.

The timing of the smolt migration of Atlantic salmon (Salmo salar) is a phenological trait increasingly important to the fitness of this species. Understanding when and how smolts migrate to the sea is crucial to understanding how salmon populations will be affected by both climate change and the elevated salmon lice concentrations produced by salmon farms. Here, acoustic telemetry was used to monitor the fjord migration of wild post-smolts from four rivers across two fjord systems in western Norway.

Transcriptional effects of metal-rich acid drainage water from the abandoned Løkken Mine on Atlantic salmon (Salmo salar) smolt.

Runoff of metals represents one of the major environmental challenges related to historic and ongoing mining activity. In this study, transcriptomics (direct RNA sequencing [RNA-seq] and reverse-transcription quantitative polymerase chain reaction [RT-qPCR]) was used to predict toxicity of metal-rich acid mine drainage (AMD) water collected in the abandoned copper (Cu) mine called Løkken Mine on Atlantic salmon liver and kidney, the main target organs of Cu-induced toxicity in fish. Smolts were exposed to control and diluted AMD water, which contains a mixture of metals but is especially enriched with Cu, at 4 concentrations in freshwater (FW) for 96 h, and then were transferred to and kept in seawater (SW) for another 24 h.

Effects of mining chemicals on fish: exposure to tailings containing Lilaflot D817M induces CYP1A transcription in Atlantic salmon smolt.

Background: Mine tailings, containing metals and production chemicals such as flotation chemicals and flocculants, may pose an environmental threat to aquatic organisms living in downstream ecosystems. The aim of this work was to study to which degree Lilaflot D817M, a flotation chemical extensively used by the mining industry, represents a hazard for migrating salmon in rivers affected by mining activity. Smoltifying Atlantic salmon were exposed to four concentrations of iron-ore mine tailings containing residual Lilaflot D817M [water versus tailing volumes of 0.