Using Hydroacoustic Techniques to Quantify Fish Populations in Shallow Riverine Environments: Rupert River 2007-2012 Spawning Cisco Abundance Studies

Annual mobile hydroacoustic surveys to quantify spawning lake herring, or Cisco (Coregonus artedii) populations were conducted in the lower Rupert River in Quebec from 2007-2012.  The shallow water environment and the patchy, aggregated nature of the spawning Cisco schools in the Rupert River resulted in an underestimation of the population size in 2007.  Refinements to the hydroacoustic sampling methods and analysis techniques were implemented in 2008, improving the ability to enumerate Cisco present in the lower Rupert River study areas.  A combined target tracking and echo integration approach using simultaneously-sampled horizontal and vertical transducers was employed to estimate Cisco biomass, acoustic size and distribution.  The standardized sampling approach developed in 2008 was successfully employed during the subsequent 2009-2012 Rupert River spawning Cisco surveys to quantify the annual population size and distribution under varying hydraulic conditions.  

Data collection and analysis techniques will be presented, which may be suitable for other applications using scientific hydroacoustic sampling methods for studying fish populations in shallow water environments.