On our blog we write frequently about the damages of noise on humans. And now we are increasingly writing about the effects of noise on animals. Here we discuss the latest findings regarding the damage to fish eggs.

Humans make a lot of noise, both on land and at sea. Ships, sonar and oil rigs are foreign noises in the ocean that can disorient fish. But for the first time a recent study has found that the noise can interfere with sea creatures even before they have hatched.

Under the sea A team of researchers looked at two types of common damselfish on Australian coral reefs – the spiny chromis and the red and black anemonefish. Both are fairly easy to rear in a lab while differing in the ways their embryos develop. During the experiment, the researchers observed the offspring mature while either ambient reef sounds, or reef sounds with motorboats passing over head was played every five minutes. They monitored the embryos’ yolk sizes, heart rates and physical characteristics. The team reported in Marine Pollution Bulletin that undersea noise can warp baby reef fish development. They found that the embryo hearts of both fish beat 10% faster when the boat noise was played. They also found that the spiny chromises that were exposed to the noise hatched about 5% larger than those under the ambient reef noise; their eyes were also 9% larger. The scientists believe the stress produced by the boat noise could boost embryo metabolism, draining yolk energy reserves and forcing embryos to grow faster. Indeed, the chromises that were reared with boat noises had yolks 13% smaller than their counterparts in the ambient setting at hatch time. Smaller yolks may mean less energy available to newly hatched, growing larvae. The scientists stated however that its still not clear whether any of these changes are detrimental to the fish. They say, if they are, noise pollution may be having an even more insidious impact than previously thought.

What can be done? Here at Echo Barrier we are interested in reducing noise pollution wherever it occurs. We have also worked on a number of projects relating to undersea work. These include the installation of undersea telecommunications cable, connecting New Zealand with Australia which took three months. The project used Echo Barriers around their site to create a wall that would mitigate noise hitting the residential houses on both sides of the road. We are yet to design something which would minimise impact on marine life too but are aware that there are mitigation measures in development. These include ‘curtains of bubbles’ or fixed screens to act as sound barriers. A report found that bubble curtains were unlikely to work well in areas with significant tidal currents but that fixed screens could be effective. A possible alternative would be the use of acoustic scaring devices to try to keep marine mammals sufficiently far away from noise sources to avoid injury. However, this would add to overall noise levels and further research is needed to establish whether such an approach would work. We make noise reduction our business – so we are 100% behind any new developments in this area and will be watching with interest.