An acoustical analysis of the variability of the diel vertical migration of zooplankton in Saanich Inlet

H. Boddy \ Oceans First, Issue 1, 2014, pgs. 1-11.

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The diel vertical migration of zooplankton exhibits variation due to a number of environmental factors. In this research, active sonar technology was used to remotely observe and map zooplankton behaviour in Saanich Inlet, off of Vancouver Island. A zooplankton acoustic profiler (ZAP) was placed 100m below the surface on the Venus Instrument Platform (VIP) where it continuously emitted ~300 microsecond pulses of 200 kHz frequency sound. The acoustic images from the ZAP were then used to attempt to understand zooplankton’s migratory trends. It was noted that daylight influenced migration length, temperature and oxygen affected zooplankton abundance, and the mixing of oceanic pycnoclines caused a uniform distribution of zooplankton with depth. Overall, the results from this study suggested that zooplankton migrations vary as a result of multiple environmental factors, but further study is needed to understand the implications of these results.