Is Traffic Calming the Key to Robust Coral Reefs?

A team of researchers led by the Universities of Exeter and Bristol showed that reducing noise from motorboats through traffic calming could help fish breed more successfully in coral reefs.

The scientists monitored three reefs for an entire breeding season to track the reproduction of the spiny chromis.

The research was conducted on reefs near Lizard Island Research Station on the Great Barrier Reef in Australia.

They implemented traffic calming by increasing the number of boats allowed within 100 meters of the reefs.

The boats that are within this distance have to reduce their speed.

Findings

Their study reveals that 65% of nests on calmer reefs still had offspring at the end of the season. In contrast, only 40% of nests on reefs with busy motorboat traffic contained offspring.

The scientists also found that offspring were larger and more numerous at the end of the season on calmer reefs.

The group also conducted aquarium tests with the same species.

They observed that noise disrupted important parental behaviors. For example, spiny chromis parents fanned the eggs with their fins to ensure oxygenation.

Dr. Sophie Nedelec, the lead author of the study from the University of Exeter, said the results of the experiment offer a way to help endangered coral reefs as they face multiple threats worldwide.

Recommendations

Nedelec added that reducing boat noise on the reefs will give the fish much-needed relief to enable successful production.

The study author talked about three simple changes that any boater can make.

First, boat channels should be farther away from reefs; second, drive slowly when approaching reefs; and third, avoid anchoring next to reefs.

Nedelec pointed out that the above solutions put power in the hands of local people to protect fragile ecosystems.

Monitoring Six Coral Reefs

The doctor further explained that they have monitored a total of six reefs. Three reefs without traffic calming, also known as control reefs, and three reefs where traffic calming was implemented.

Their data collection lasted an entire summer breeding season. The team swam along each reef every other day to monitor the survival of 86 Spiny Chromis broods in their natural habitat.

On reefs that were traffic-calmed, they observed 46 nests. Thirty still contained offspring at the end of the breeding season. On control reefs, only 16 of 40 nests still had offspring.

Dr. Laura Velasquez Jimenez, co-author of the study from James Cook University explained that it is difficult to find the nests before the offspring hatch because the spiny chromis hide their eggs in caves in the reef.

Therefore, the team conducted a parallel study in aquaria to examine embryonic development.

The team recorded an audio playback of natural reef sounds.

This was used in the aquarium study, where some spiny chromis parents and eggs were kept. Others were exposed to intermittent and beautiful playbacks.

Professor Andy Radford, a co-author of the study from the University of Bristol, explained that the complementary laboratory study showed that the improvements in breathing were actually due to the boats limiting most of the pollution.

The combined results showed that reducing boat noise benefits the population of coral reef fish. Marine life becomes more resilient to changes currently caused by human activities.