The aim of this study was to examine the genetic structuring, based on c . 4300 single nucleotide polymorphic markers, of juvenile Atlantic salmon Salmo salar sampled from 11 rivers in north‐east Scotland, which form part of a radial drainage system. Within this area, sites in the upper mountainous and lower coastal sections of the different rivers were more closely related than sites from the upper and lower sections of the s...

The relationship between aquaculture and infestations of sea lice on sea trout, Salmo trutta L., is controversial. Here, the association between sea lice infestations on wild sea trout and characteristics of local Atlantic salmon, Salmo salar L., farms were investigated using data collected on the Scottish west coast. The proportion of sea trout with louse burdens above a critical level was positively related to the fork lengt...

In 2005, a high percentage (50%) of Atlantic salmon Salmo salar fitted with acoustic transmitters, which entered rivers in the Cromarty Firth area of north–east Scotland dropped back to the estuary and ascended adjacent rivers after 33–80 days of freshwater residence. Fish residing in non‐natal rivers generate mixed stock fisheries, and movements of fish between rivers could increase the risk of disease transmission between ca...

Post‐smolt anadromous brown trout Salmo trutta , sea trout, from two Scottish west coast rivers, the Balgy and Shieldaig, flowing into adjacent sea lochs were tracked simultaneously using arrays of moored acoustic receivers to determine dispersal patterns and loss rates. Fish tended to stay close to their natal rivers for the first 14 day after entering the sea, during which time about half the fish were lost to the study. Alt...

Bioenergetics were used to model the potential impacts on adult Atlantic salmon, Salmo salar L., stocks and rod fisheries of removing harbour seals, Phoca vitulina L., from three rivers of different scales in the Moray Firth, Scotland, viz: the Spey (large), Conon (medium) and Moriston (small). Overall, seals had the greatest impact on the Moriston, where removal of a single animal could increase cumulative catch by 17% during...

Analyses of regressions of atlas bone width against fish length (mixed regressions) of Atlantic salmon Salmo salar can be used to infer the parr:smolt ratio of the source populations. Analyses of mixed regressions have been used to infer that, contrary to previous reports, sawbill ducks Mergus spp. eat only a few smolts. Here a Monte Carlo simulation model is presented which quantifies the effect of variation in the smolt:parr...