Relating fish distributions to physical characteristics of a tidal energy candidate site in the Banks Strait, Australia

Abstract

With the tidal energy industry moving towards commercial-scale developments, it is important to consider potential interactions between tidal energy converters (TECs) and the marine environment prior to the instalment of large-scale TEC arrays. The Banks Strait, a tidal channel located in the northeast of Tasmania, Australia, was identified as a promising candidate site for tidal energy by the Australian Tidal Energy (AUSTEn) project. To gain an understanding about potential overlap between TEC arrays and fish usage of the Banks Strait tidal channel, fish density distributions were estimated from hydroacoustic surveys during the tidal resource characterization campaign. Differences in fish density were examined according to bottom-depth, bottom - type, current speed, temperature and vertical distribution. Fish densities were significantly higher at night and displayed preferences for depths between 20 - 40 m and current speeds between 1.75 - 2 m/s. Fish density was generally highest in the bottom 10 m from the sea floor at all depths sampled. Variation by temperature and bottom-type sampled was not significant. Future studies involving long-term, stationary surveys of fish densities along with repeated surveys across different seasons would provide a more wholistic picture of fish distributions in the Banks Strait to inform developers about potential device encounter probabilities.