Human created noise impacts behaviour and physiology of underwater creatures. Stressed by noise pollution, fishes are not able to ward off diseases and this eventually leads to early death.
There is no escape to the man-made clamour, be it honking on roads, planes flying overhead, loud music within the neighbourhood, the clatter of factories, noise is just everywhere. Ocean going vessels’ propellors interfere with whale sonar communications, thus disorienting aquatic animals.
Previously we thought, underwater could be an escape but unfortunately, for the fishes and other creatures, it is not the case. Whir of ship propellers is a constant noise that the creatures have to bear with.
Last year, researchers at Queen’s University Belfast found that cacophony created by human industry and transportation is a major global pollutant that impacts nearly all species of amphibians, arthropods, birds, fish, mammals, molluscs and reptilians.
As per a new research by University of Cardiff in Britain underwater noise pollution not only leads to anxiety, hearing loss and behavioural changes but it also effects immunity. In a way, noise impacts resistance to disease.
Researchers made three groups
In order to study the effect of noise on fishes, researchers introduced random blasts of white noise into fish tanks. These fishes were then infected with parasitic infection.
White noise refers to the ‘sh’ noise that is of the same intensity. Some examples include whirring fan, radio noise, hissing radiator or humming air conditioner.
For the experiment, following three groups were made:
Group A: fish was exposed to “acute” noise played for 24 hours. Then the fish was anaesthetised and infected with parasite, after the noise exposure.
Group B: fish was exposed to “chronic” noise played for 7 days. Here, the fish was infected during the noise exposure.
Group C: this was the controlled group. After infecting the fish, it was left in a silent tank.
Researchers concluded that
1. Group A fish, that was exposed to “acute noise” had disease burden of over 17 days.
2. Group B fish, that was exposed to “chronic noise” had higher chance of dying earlier, somewhere around twelfth day, with relative to day 14 for other fish groups.
Researchers envision that sound pollution could be one of the main reasons that lead to increase in disease susceptibility and so it might also impact mortality levels.
Since, freshwater fishes are facing high mortality rate. The study may have implications that might help in conservation efforts and fish farms.