Hydroacoustic surveys may be underestimating or overestimating biomass due to species avoidance of vessel light. Therefore we propose a controlled environment experiment to quantify the effect of light on fish behaviour. A small change in the orientation of fish can cause large changes in biomass estimates from acoustic surveys. What are the changes in the orientation of fish due to light from vessels? Are research vessel based hydroacoustic surveys underestimating fish biomass?
AZKABAN (Arrested Zooplankton Kept Alive for Broadband Acoustic Net) experiment is a 12000 L microcosm that will be mounted off the side of a research vessel for acoustic measurements of a known population of zooplankton and fish. The behaviour of the species in the microcosm due to different light regimes will be studied with an optical camera. The effect on the change in behaviour will be evaluated to quantify the impact of artificial light on hydroacoustic biomass estimates. In addition, I will compare the results to a method, inverse informed method. that can account for behaviour change from orientation changes (evasion or attraction) within the biomass calculation.