- Noise pollution can impact how marine organisms process and respond to visual and chemical stimuli.
- This has primarily been studied through tank experiments with species that are not reliant on acoustic communication, such as damselfish and cuttlefish.
- These species may be less adept at avoiding predators and capturing prey in noisy environments near cities.
Noise pollution doesn’t only affect organisms that vocalize. It also impairs the ability of some marine life to process visual and chemical stimuli. This in turn may make them more vulnerable to predation and less effective at acquiring food and communicating with one another.
For instance, Ambon damselfish (Pomacentrus amboinensis) are small fish that live in the Western Pacific and make a tasty treat for predators like the dusky dottyback (Pseudochromis fuscus). Dusky dottybacks are stinky, and damselfish learn to run and hide when they smell a dottyback coming. However, in a recent study by Maud Ferrari and colleagues, young damselfish that learned to fear dusky dottybacks in the presence of boat noise later forgot to be afraid when exposed to dottyback odor, while those who learned in the absence of boat noise ran for cover.
Cuttlefish use visual signaling to communicate with one another, deter predators, and confuse prey. Elastic pigment sacs called chromatophores allow them to change the color of their skin, and they undergo impressive transformations in the blink of an eye:
This skill is important for capturing prey and deterring predators. Yet, cuttlefish appear to use it almost spastically when subjected to noise pollution. In a 2014 study by Hansjoerg Kunc and colleagues, the common cuttlefish (Sepia officinalis) was found to change its color more frequently while subjected to boat noise. As Kunc et al. note, this suggest “that anthropogenic noise has a marked effect on the behavior of species that are not reliant on acoustic communication.”
Further work is needed to confirm these findings in wild populations and assess impacts on survival. However, they suggest that noisy environments near cities may have consequences even for non-vocalizing species, by challenging their ability to avoid predators and inciting energy expenditure that would otherwise go towards foraging and other activities that ensure survival.