Erodibility of aquaculture waste from different bottom substrates

A laboratory study was carried out to examine the effect of bed sediment texture on the erodibility of salmon aquaculture waste fecal material and salmon feed pellets. Erodibility measurements of this material were made using a Gust microcosm erosion chamber and artificially composed substrates of mud, sand, sand and gravel, sand and cobble, and cobble. Results show that cumulative mass eroded (CME) and erodibility constant (M) can vary by up to an order of magnitude depending on substrate composition, with a mud substrate having higher CME and M values than those of substrates composed of sand, gravel and cobble. Findings from this study suggest that bottom sediment texture plays a major role in aquaculture waste resuspension and subsequent transport and that predictive models of the transport of aquaculture waste should include the erosion dynamics of bottom texture.