Ms Brittany Williams1, Dr Dominic McAfee1, Professor Sean Connell1
1Southern Seas Ecology Laboratories, School of Biological Sciences, University Of Adelaide, Adelaide, Australia
Marine soundscapes that convey navigable information to larvae are silencing. As a result, larvae may be unable to recruit to adult habitat. Native flat oyster (Ostrea angasi) restoration is underway in Australia, but relies upon successful recruitment of larvae. To ensure restoration success, “acoustic enrichment” of the soundscape using speakers that replenish these lost audio cues, might work to entice reef-building oysters to target sites. We tested whether acoustic enrichment might act as a directional cue for O. angasi larvae. In the laboratory, we tested whether larval settlement increases along a gradient of increasing sound intensity (8m tank) versus a silent control, and whether settlement increases with soundscapes that approximate healthy reefs. In the field, we observed the settlement rates of wild oysters when exposed to acoustic enrichment relative to controls. In the laboratory, we showed that 83% of larvae swim horizontally towards reef sound to settle in greater densities closer to it, a near doubling of the larvae (44%) that dispersed in the silent controls. Settlement also increased by 300% in the presence of reef sound relative to controls in the laboratory. In the field, acoustic enrichment increased settlement by 105-233%, but not where high anthropogenic noise was in the ambient soundscape. To our knowledge, this is the first evidence that oyster larvae can swim horizontally and choose to move towards a sound source relative to controls. We propose that where recruitment and anthropogenic noise is limited, restoration practitioners use acoustic enrichment to guide oyster larvae to boost recovery.
Presentation Slides – Brittany Williams
Biography:
I’m a marine biology PhD candidate playing music to baby oysters to help restore our lost oyster reefs. Our future oceans could be ones full of rhythms and melodies that are engineered to attract and restore organisms to degraded habitats. I’m also fascinated by the deep sea and the ever-advancing technology that is taking us there. I’d love to use my knowledge on underwater acoustics to help discover it!
