AEI 12:117-129 (2020)  -  DOI: https://doi.org/10.3354/aei00350

ABSTRACT: The influence of substrate type and particle age on the remobilization of settled Atlantic salmon Salmo salar faecal material was studied through a set of controlled experiments in horizontal flow flumes, simulating different bottom conditions present in fish-farming locations along the coast of Norway. There was no significant effect of pellet age on remobilization for up to 1 week old faecal material, but critical shear stresses (τ_c) and velocities required for resuspending faecal pellets were strongly dependent on substrate type. Smooth substrates such as mud and rock slate required lower stresses for the onset of faeces resuspension (τ_c ≈ 0.06 Pa) than rougher surfaces such as sand (τ_c ≈ 0.12 Pa) or fragmented rock (τ_c ≈ 0.32 Pa), where bedforms and large fractures shield the particles from the direct influence of the drag forces. These newly determined substrate-dependent τ_c resuspension thresholds will contribute to the construction of more accurate numerical models that include bottom type as a parameter regulating the extent of particle spreading, in contrast to the constant-value approach that has been used to date.

KEY WORDS: Benthic boundary layer · Resuspension · Parametrization

Full text in pdf format

Cite this article as: Carvajalino-Fernández MA, Keeley NB, Fer I, Law BA, Bannister RJ (2020) Effect of substrate type and pellet age on the resuspension of Atlantic salmon faecal material. Aquacult Environ Interact 12:117-129. https://doi.org/10.3354/aei00350 Export citation Share:    Facebook - - linkedIn