Performance of a glider-mounted multifrequency echosounder for detecting dense mesozooplankton layers in situ
University of New Brunswick
The goal of this thesis is to test the performance of a glider-mounted multifrequency echosounder for measuring the biomass distribution of zooplanktonic prey, Calanus finmarchicus, of large whales in the Bay of Fundy. Biomass data from biological samples obtained using plankton net tows was compared to acoustic data from the echosounder collected concurrently over a nine-day period in the Bay of Fundy. The correlation between expected and observed backscatter was found to depend primarily on the frequency band and not other factors such as community composition or site. C. finmarchicus biomass was best predicted by observed backscatter in the 200 to 455 kHz frequency band, though there was considerable uncertainty in the relationship. The linear model developed in this thesis may be built upon to estimate C. finmarchicus biomass from acoustic backscatter in other areas of the North Atlantic without the need for validation with biological samples.