Implications for the environment of using adaptive feeding systems in the cage culture of Atlantic salmon

• Main Author: Corner, Richard Anthony
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: University of Stirling 2004
• Subjects: Portavadie Fish Farm (Argyll; Scotland); Rubha Stillaig Fish Farm (Argyll; Scotland)|; Atlantic salmon Scotland; Cage aquaculture; Fishes Feeds; Atlantic salmon; Salmo salar
• Online Access: http://hdl.handle.net/1893/26835; http://dspace.stir.ac.uk/bitstream/1893/26835/1/Corner-thesis.pdf; http://dspace.stir.ac.uk/bitstream/1893/26835/2/FullAquaSeqRC8.mpg

The use of adaptive feeding systems to deliver feed remotely to Atlantic salmon (Salmo salar) cages has the potential to improve the localised environment through a reduction in particulate waste. This can be achieved through improved growth and lower Feed Conversion Ratio (FCR). The aim of this project was to assess whether adaptive feeding systems confer any environmental benefit at salmon farms through by comparing two fish farm sites, one that uses a Computer Aided System (CAS) adaptive feeding system (AKVAsmart UK limited, Inverness, Scotland) (Portavaide fish farm) and one using hand feeding (Rubha Stillaig). This investigation comprised of 3 elements: 1) a comparative assessment of the quantity and nutrient composition of particulate waste material emanating from the cages; 2) collection of benthic samples plus a video survey along transects at each site including a reference station, with an analysis of differences in benthic fauna, sediment grain size and sediment nutrient composition; and 3) comparison of the distribution of waste under each feeding regime using a GIS-based modelling approach. Particulate waste was collected via sediment traps. Uneaten feed was caught in only 3 out of 184 separate collections and thus no estimate of feed loss for each feeding system could be made. Samples were analyzed for total solids (TS), faecal solids (FS), faecal carbon (FC), faecal nitrogen (FN) content and faecal sedimentation rate (FSR). The highest deposition occurred under the cages and decreased with increased distance from the cage centre. Maximal deposition of TS at Portavadie was higher than at Rubha Stillaig when feed was included, although average TS, FS, Fe and FN per tonne of production did not significantly vary between sites. Carbon sedimentation rate was analyzed using regression analysis and a General Linear Model Factorial ANOVA on faecal waste only and showed no significant differences between sites and, therefore, no difference between feeding methods . There were no differences observed in the ...