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Reactions of temperate reef fish larvae to boat sound

Authors


C. A. Jung, University of Melbourne – Zoology, Gate 12 Royal Parade, Parkville, Victoria 3010, Australia. Email: jung@unimelb.edu.au

ABSTRACT

  1. Anthropogenic sound as a stressor in aquatic systems is of increasing concern. The present study evaluated whether boat sound either deters larval fish or interferes with their ability to use biological sounds for navigating.
  2. Pre-metamorphic larval fishes were caught in a pair of light traps deployed off a shallow rocky reef in Port Phillip Bay, Australia, with one trap randomly assigned one of two boat sound treatments, at sound pressure levels experienced in situ, and the other without any sound treatment.
  3. The boat sound treatment included either (1) boat engine sound without any other sound, or (2) boat engine sound with biological and physical sound from a pier, a positive but weak cue indicative of much of the available benthic habitat in the vicinity.
  4. Total larval abundance and species composition of the assemblage were compared between the sound-exposed trap and the control trap. When only boat sound was broadcast, no significant differences between sound-exposed and control traps was observed. When boat sound was broadcast together with pier sound, significantly more fishes were caught in the sound-exposed trap (~300% of ‘control’ traps).
  5. The results of this study suggest that a) common boat sound is not readily avoided by larval fishes, and that b) larval fishes are attracted to biological sound in spite of the presence of boat sound. Together the results suggest that boat sound at levels experienced in situ might not have deleterious effects on recruitment of larval fishes, i.e. the capacity to alter recruitment patterns. Copyright © 2011 John Wiley & Sons, Ltd.

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