How Do Healthy Reef Sounds Increase Coral Larvae Settlement?

Researchers are investigating innovative techniques to support the restoration of coral reefs, with a new study revealing the potential of ‘acoustic enhancement’. This method, which uses sounds from thriving coral reefs, shows promise for attracting coral larvae to settle in degraded reef areas. Healthy coral reefs, filled with the sounds of feeding fish, territorial grunts, and the crunching sounds of shrimp, emit a unique chorus that coral larvae recognize as a suitable habitat.

A study conducted by the Woods Hole Oceanographic Institution (WHOI) found that playing recorded sounds from live reefs can cause certain coral species, specifically golf ball coral larvae, to settle and grow in degraded reef environments.

Encouraging Coral Settlement with Soundscapes:

In the study, researchers collected larvae of Favia fragum, known as golf ball coral, from the U.S. Virgin Islands. The larvae divided and became St. It was placed in two quiet bays off the coast of St. John. At one site in Great Lameshur Bay, researchers set up solar-powered speakers near larvae and played sounds from a nearby healthy Tektite reef. Meanwhile, another site, Grootpan Bay, used either silence or local bay sounds for comparison.

The results showed that after 24 hours, approximately 30% of larvae exposed to healthy reef sounds had settled, while in the control group without reef sounds, no larvae had settled. Although initial acoustic reinforcement was most effective in the first 36 hours, this pattern continued, with settling rates increasing within 48 hours in both groups. However, after this period, larvae settled at similar rates regardless of sound.

These findings are consistent with previous research on the response of coral larvae to auditory cues; Here, larval corals drifting through the water column rely on environmental cues such as chemicals, light, and sound to find suitable places to attach and grow. By enriching soundscapes on degraded reefs, scientists hope to provide coral larvae with the clues they need to recognize a hospitable environment and support the restoration of coral reefs on a larger scale.

WHOI researchers, led by doctoral candidate Nadège Aoki, pointed out that golf ball coral larvae, like many coral species, have a limited time frame in the larval stage to find a suitable habitat before resources are exhausted. Larvae are most sensitive to sound cues during the first 8 to 36 hours. After this critical period, they settle quickly and place less priority on location as they deplete their energy reserves.

This research highlights the potential for soundscapes to support coral regeneration, especially in controlled environments such as aquariums where natural coral reproduction can be difficult to replicate. Using recorded reef sounds can improve establishment rates in nurseries and increase coral populations for restoration projects. WHOI marine biologist Aran Mooney said this study offers a broader understanding of coral biology and reproductive strategies because the response to sound cues can vary significantly between coral species.

The scalability potential of this technique is promising. While WHOI researchers emphasize that simply broadcasting sound alone is not a solution, integrating acoustic enhancement with other conservation methods can provide significant gains for reef restoration efforts. As coral reefs face serious threats from climate change, pollution and other human impacts, such integrative strategies are becoming increasingly valuable for the survival of these important ecosystems.

Covering less than 1% of the ocean floor, coral reefs support more than a quarter of all marine species and protect coastlines, providing food, shelter and economic opportunities to millions of people around the world. However, approximately 25% of coral reefs have been lost in the last three decades.

This research, supported by the Vere and Oceankind Foundations, the National Science Foundation, and WHOI’s Reef Solutions Initiative, points to an exciting frontier in coral restoration and suggests that, with the right approach, acoustic enrichment can be a valuable tool in ongoing conservation efforts. and restoring coral ecosystems globally.

(Source: Woods Hole Oceanographic Institution)

First published date: 30 October 2024, 04:33 IST