Noisy boats lead to fish heartache

Recreational boating is one of many forms of noise pollution from urban development. Its expansion may have adverse effects on fish communities.

Anthropogenic noise messes with the natural ambient soundscape in marine environments. Our recent laboratory study [1] provides the first evidence of the adverse effects of noise pollution on the developmental trajectories of marine fish embryos. Interestingly, we also found that noise affects various species differently.

Anthropogenic noise pollution comes from diverse sources, including recreational boating. This kind of noise is known[2] to have a negative effect on the behaviour, physiology and survival of marine fishes.

Our lab study investigated whether motorboat noise affected the embryo development of two coral reef damselfishes: the cinnamon clownfish, Amphiprion melanopus;and the spiny chromis,Acanthochromis polyacanthus.

We found that noise treatments did not alter the survival rates of embryos under laboratory conditions. However, our findings suggest that anthropogenic noise causes physiological responses in fishes during development.

For both species, the embryos reared under the playback of boat noise had faster heart rates compared to the ambient reef controls.The spiny chromis also had distorted morphological development and used their yolk reserves faster in the presence of noise. This resulted in smaller yolk sacs at the end of development. Larvae use their yolk as a food source until they are able to feed and larger yolks are associated with higher survival rates. Additionally, the fundamental interrelationships between early life history characteristics changed dramatically under boat noise.

These changes have direct impacts on the development of the fishes, which may have adverse carry-over effects to later life stages.Larval size and growth rates are important in determining success rates of fishes, so the stressors that alter them can have an influence on individual survival and potentially cohort success.

The study uses playback of boat noise in tanks, and so must be interpreted cautiously due to the limitations of reproducing soundscapes within enclosed spaces. However, these results align with the findings of a recent field study on another tropical damselfish (Amblyglyphidodon curacao) where real boat noise on a reef resulted in a quickening of embryo heart rates[3].

[1] Fakan, E. P., & McCormick, M. I. (2019). Boat noise affects the early life history of two damselfishes. Marine Pollution Bulletin, 141, 493-500.

[2] Simpson, S. D., Radford, A. N., Nedelec, S. L., Ferrari, M. C., Chivers, D. P., McCormick, M. I., & Meekan, M. G. (2016). Anthropogenic noise increases fish mortality by predation. Nature communications, 7, 10544.

[3] Jain-Schlaepfer, S., Fakan, E., Rummer, J. L., Simpson, S. D., & McCormick, M. I. (2018). Impact of motorboats on fish embryos depends on engine type. Conservation physiology, 6(1), coy014.