TITLE:
Vertically-Suspended Environmental Enrichment Alters the Velocity Profiles of Circular Fish Rearing Tanks
AUTHORS:
Alissa M. Muggli, Joseph M. Barnes, Michael E. Barnes
KEYWORDS:
Environmental Enrichment, Vertically-Suspended Structure, Circular Tank, Water Velocity
JOURNAL NAME:
World Journal of Engineering and Technology,
Vol.7 No.1,
February
14,
2019
ABSTRACT: The inclusion of vertically-suspended environmental enrichment in circular tanks has produced substantial benefits during fish rearing. This study examined the tank water velocity profiles of four different vertically-suspended structures(rod array, extended rod array, single angle array, double angle array) and a control (no environmental enrichment) at two incoming water velocities (18.3 cm/s and 54.9 cm/s) in 1.8-m diameter circular tanks. At both of the incoming water velocities, overall water velocities throughout the tank were significantly reduced with the addition of any environmental enrichment in comparison to the control. In addition, the overall water velocities in the double angle array were significantly lower than the other three enrichment treatments. The pattern of significant reductions in velocity with the use of any environmental enrichment, with further significant velocity reductions in the double angle treatment, was repeated when the data werecombined for each sampling depth, radius from the center, and degree (circular arc). Although considerable variation in water velocity was observed at each specific sampling location with both incoming velocities, significantly lower velocitieswere observed at nearly every sampling location with the addition of any environmental enrichment to the circular tank. In addition, the double angle array consistently produced the lowest velocities among the environmental enrichment treatments. The changes in velocity profiles from vertically-suspendedenvironmental enrichment may be at least partially-responsible for the frequently-observed improvements in fish growth.