Using hydroacoustics to assess habitat restoration in a freshwater lake

Artificial structures are used in man-made reservoirs to increase bottom complexity and aim to increase fishery production by providing improved refuge, forage, and reproduction habitat.  Electrofishing is typically employed to assess the effectiveness of these structures but is limited to shallow water sites and short periods of time.  Hydroacoustic technology is a non-invasive sampling method that is more flexible than electrofishing, as it is operational at any depth and provides a continuous data series at one location to obtain high temporal resolution information.  An Acoustic Water Column Profiler (AWCP) was deployed for one week intervals at each of two types of sites; 1) control sites with no introduced structure and 2) treatment sites with artificial habitat structure.  Difference in fish abundance, distribution and diurnal behavior between sites with and without artificial structure was assessed from the volume backscatter time series.  Variation in fish activity between sites was compared.  This work demonstrates the utility of hydroacoustics in assessing freshwater habitat alteration beyond the scope of conventional techniques.  A more comprehensive evaluation of habitat restoration is crucial in guiding the development of future conservation efforts.