Melanized focal changes (MFCs) are a persistent challenge in Atlantic salmon ( Salmo salar ) aquaculture, affecting product quality and fish welfare. These lesions are generally considered to arise from red focal changes (RFCs), which are often attributed to handling‐related trauma, but underlying mechanisms remain poorly understood. In this case report, we investigated the occurrence and histopathological features of RFCs and...

Salmonid alphavirus (SAV) is the causative agent of pancreas disease (PD), a disease that can cause severe implications for marine farming of Atlantic salmon. This study examines physiological changes in Atlantic salmon during SAV infection through a controlled trial and two field trials. In the controlled trial, plasma creatine kinase (CK), alanine aminotransferase (ALAT) and aspartate aminotransferase (ASAT) levels increased...

The study investigated cause‐specific, fish‐level mortality of farmed Atlantic salmon following mechanical delousing. We visited three populations at two marine sites belonging to one company at four different time points, from 1 day before to 13 days after the mechanical delousing. A total of 453 dead fish were collected and necropsied during the four visits. The underlying mortality cause was determined by macroscopic pathol...

As Atlantic salmon depend on dissolved oxygen (DO) to survive and grow, managing DO is essential for welfare and growth. However, the dynamics of DO in the open sea cages are complex, caused by a range of factors that interact and create compounding effects. To understand DO dynamics, two pillars of knowledge are essential: the supply of DO to the cages and the consumption of DO in the cages. The components of these two pillar...

Flowering and fruiting phenology have been infrequently studied in the ever‐wet hyperdiverse lowland forests of northwestern equatorial Amazonía. These Neotropical forests are typically called aseasonal with reference to climate because they are ever‐wet, and it is often assumed they are also aseasonal with respect to phenology. The physiological limits to plant reproduction imposed by water and light availability are difficul...

Aim Macroecological studies that require habitat suitability data for many species often derive this information from expert opinion. However, expert‐based information is inherently subjective and thus prone to errors. The increasing availability of GPS tracking data offers opportunities to evaluate and supplement expert‐based information with detailed empirical evidence. Here, we compared expert‐based habitat suitability info...

Bacterial kidney disease (BKD) can be a devastating bacterial infection in salmonids, and it is present in aquaculture throughout the world. BKD is caused by the Gram‐positive facultative intracellular bacterium Renibacterium salmoninarum ( R . salmoninarum ) that is spread both horizontally and vertically. Disease signs include external ulcerations and blisters and internal signs such as organ swelling, granulomas, petechiae...

This study describes the patterns of mortality and investigates the sources of variation in mortality during the marine phase of commercial salmon farming. The study included daily mortality records from stocking to harvest of 21 million salmon from ten hatcheries in 136 fish‐groups (fish in the same cage from the same hatchery). The fish was stocked in 2017–2018 at 21 marine farms within two Norwegian companies. The sources o...

Arctic and subarctic ecosystems are experiencing substantial changes in hydrology, vegetation, permafrost conditions, and carbon cycling, in response to climatic change and other anthropogenic drivers, and these changes are likely to continue over this century. The total magnitude of these changes results from multiple interactions among these drivers. Field measurements can address the overall responses to different changing...

Fish gills are heavily exposed to the external milieu and may react against irritants with different cellular responses. We describe variations in mucous cell counts in gills from healthy Atlantic salmon ( Salmo salar ) presmolts in five recirculating aquaculture system (RAS) farms and one flow‐through farm. Based on certain criteria, mucous cells were histologically quantified in a defined lamellar region of the gills and the...

We present quantitative reconstructions of regional vegetation cover in north‐western Europe, western Europe north of the Alps, and eastern Europe for five time windows in the Holocene [around 6k, 3k, 0.5k, 0.2k, and 0.05k calendar years before present ( bp )] at a 1° × 1° spatial scale with the objective of producing vegetation descriptions suitable for climate modelling. The REVEALS model was applied on 636 pollen records fr...

Decades of conflicting results have fueled a debate about how O 2 affects organic matter (OM) degradation and carbon cycling. In a laboratory study, using both OM taken directly from a humic lake and chemically isolated fulvic acid, we monitored the mineralization of dissolved OM in freshwater under purely oxic and anoxic conditions, under oxic then anoxic conditions, and under anoxic then oxic conditions, for 426 d. Between 5...