Man-made underwater noise has a multitude of effects on marine fauna. There are two main types of acoustic underwater pollution. First there is the byproduct of ship’s engines through water, which includes the grinding of the props. Boats/ships today produce vast amounts of sound energy that is at low frequencies and propagates very efficiently in water
Second are the more detrimental sounds that are seismic from oil and gas exploration and naval sonar.
These sounds can have negative physiological, behavioral and physical effects on marine organisms, but our acknowledgment and understanding of the sounds is still limited. To this point our understanding is largely limited to intraspecific impacts.
Recently, collaborative research undertaken in Moorea, French Polynesia, has examined how motorboats affect an interspecific cleaning mutualism critical for coral reef health, abundance and diversity. Nedelec et al. conducted in situ observations of cleaning interactions between bluestreak cleaner wrasses (Labroides dimidiatus) and their fish clients before, during and after repeated, standardized approaches with motorboats. What could be the long-term effects on coral reef health if this mutualism continues to be impacted upon?
Interestingly, they observed that the cleaners inspected client fish for a longer duration and were signicantly less cooperative during exposure to boat noise. Also, while boat disturbance appeared to have little effect on the fish client behavior, as evidenced by consistency of visit rates, clientele composition, and use of cleaning incitation signals, clients did not retaliate as expected (i.e., by chasing) in response to increased cheating by cleaners. Their results were consistent with the idea of some sort of cognitive impairments, possibly due to both parties becoming distracted. Alternatively, the authors suggest that just maybe the cleaner wrasse may be taking advantage of distracted clients to reduce their service quality. However, this latter idea could be a bit of an energetic waste of time.
To read this interesting paper please follow the link:
https://www.nature.com/articles/s41598-017-06515-2.pdf
Nedelec, S.L., Mills, S.C., Radford, A.N., Beldade, R., Simpson, S.D., Nedelec, B. and I.M., Côté (2017) Motorboat noise disrupts co-operative interspecific interactions. Scientific Reports 7, Article number: 6987
