Stocking efficiency and the effects of diet preconditioning on the post-release adaptation of hatchery-reared juveniles of Atlantic salmon (Salmo salar L.) in an Atlantic temperate stream

Change in food ingestion induces rapid shifts in the diversity of microbiota associated with cutaneous mucus of Atlantic salmon Salmo salar

“…This ration corresponds to known consumption rates of macroinvertebrates by restocked S . salar in the area (Costas et al ., ). Following the three‐day acclimation period, the experiment ran for seven days (11–17 February 2011) during which skin mucous samples were obtained from S .…”

“…2 individuals m −2 , which is the density at which the hatchery stocks S . salar (Costas et al ., ). On days 3 and 7, one individual from each tank ( n = 3 per treatment) was collected and a water sample also collected to analyse for microorganisms that could potentially colonize mucus.…”

“…Fish were manually fed 25 pellets or 25 macroinvertebrates per individual daily, except the food deprivation group. This ration corresponds to known consumption rates of macroinvertebrates by restocked S. salar in the area (Costas et al, 2013). Following the three-day acclimation period, the experiment ran for seven days (11-17 February 2011) during which skin mucous samples were obtained from S. salar on days 0 (initial sampling, before starting the experiment), 3 and 7.…”

“…Three additional tanks were then selected, one fish was removed from each tank and skin samples were harvested for histological analysis (n = 27). One fish was also removed from each of the remaining tanks (n = 6) to standardize density at c. 2 individuals m −2 , which is the density at which the hatchery stocks S. salar (Costas et al, 2013). On days 3 and 7, one individual from each tank (n = 3 per treatment) was collected and a water sample also collected to analyse for microorganisms that could potentially colonize mucus.…”

Food deprivation causes rapid changes in the abundance and glucidic composition of the cutaneous mucous cells of Atlantic salmon Salmo salar L.

“…Groups of 7 hatchery‐reared juveniles of A. salmon (mean initial fork length ± SE = 14.0 ± 0.28 cm; mean initial weight ± SE = 30.42 ± 1.11 g and mean initial condition factor ± SE = 1.10 ± 0.02) were randomly allocated into six circular plastic tanks (2.25 m 3 ): three for the fed fish and three for the unfed group. Water was withdrawn from a weir situated in the nearby Almofrei stream, passed through a sand filter system and continuously discharged from the filter to the tanks by gravity (see further details in Costas, Álvarez & Pardo ; Landeira‐Dabarca, Sieiro & Álvarez ).…”