The settling behavior and benthic transport of fish feed pellets under steady flows

Settling and erosion experiments were carried out on a size range of fish feed pellets using an annular flume. A strong positive correlation was observed between settling rate and pellet dimension (pellet length, pellet dimeter, and equivalent sedimentation diameter). Erosion thresholds also showed a strong positive correlation with pellet dimensions. Experiments were also carried out to examine the effect of the number of pellets on erosion threshold of two sizes. The results show an asymptotic increase in erosion threshold with increasing number of pellets present, possibly due to sheltering effects. The chemical composition of the pellets was analyzed in terms of water and organic, carbon, and nitrogen contents as well as stable carbon and nitrogen isotopes. The results arising from this study will provide, information regarding potential tracers of waste feed material and help validate model predictions associated with dispersal of waste material.