The relative influence of prior residency and dominance on the early feeding behaviour of juvenile Atlantic salmon
In many species where social hierarchy mediates conflict over resources, dominant individuals monopolize food, shelter and reproductive opportunities. The benefits of social dominance, however, can often be offset by a prior residence advantage, whereby individuals arriving first in a new habitat obtain, and subsequently defend, the most profitable sites. We investigated the relative influence of […]
Social network analysis of the behavioural interactions that influence the development of fin damage in Atlantic salmon parr (Salmo salar) held at different stocking densities
Social network analysis of behavioural interactions was used to quantify the effect of high (HD, 30 kg m-3) and low (LD, 8 kg m-3) stocking densities on the frequency and severity of fin damage in Atlantic salmon. Dorsal fin damage (erosion, splits, fin index) was significantly higher in HD compared to LD groups with higher amounts of dorsal fin […]
Assessment of different stunning methods and recovery of farmed Atlantic salmon (Salmo salar): isoeugenol, nitrogen and three levels of carbon dioxide
Isoeugenol (17 mg L–1), nitrogen, and three levels of carbon dioxide (low: 70–80, medium: 180–250 and high: > 400 mg CO2 L–1) were tested as stunning agents for Atlantic salmon (Salmo salar) fasted for six days. All methods were tested under optimised conditions (starting with rested fish, and stunning and recovery under good water quality […]
Investigating the influence of predictable and unpredictable feed delivery schedules upon the behaviour and welfare of Atlantic salmon parr (Salmo salar) using social network analysis and fin damage
Social network analysis was utilised to quantify the effect of short-term predictable (PD) and unpredictable (UD) feed delivery schedules of 10 days on behavioural interactions and the frequency and severity of fin damage in Atlantic salmon. Fin damage was only observed on the dorsal fin and its frequency and severity was significantly higher in UD […]
Salmon Fishing by Bears and the Dawn of Cooperative Predation
Although bears are an epitome of solitary predation, black (Ursus americanus) and brown bears (U. arctos) occasionally act in pairs to capture salmon (Onchorynchousspp.). I sought to identify conditions that promote pairing and how this relates to optimal foraging. This study on Alaskan black bears assessed whether each mode of fishing (solo vs. paired) occurs […]
Effect of predictability on the stress response to chasing in Atlantic salmon (Salmo salar L.) parr
The possibility to prepare for and respond to challenges in a proper manner is essential to cope with a changing environment, and learning allows fish to up or downregulate the stress response based on experience. The regulation of the response to predicted needs should be easier in more predictable environments. We exposed salmon parr to […]