An innovative ocean soundscape study in India is expected to make valuable contributions in complementing ongoing scientific studies to better understand global marine life’s many mysteries.
A press release of the study was sent to Statecraft via email. It was led by a team of the International Quiet Ocean Experiment (IQOE) near the Goan coast, and has helped advance a new “low-cost way to monitor changes in the world’s murky marine environments.”
The results of the study carried out along the reefs attached to the Grande Island archipelago have been published in the latest edition of the Journal of the Acoustical Society of America (JASA), and the same is slated for international media release on 26 April 2023.
Novel Findings
The study found that while some species within the underwater community work the early shift and ruckus from 3 a.m. to 1:45 p.m. and others work the late shift and ruckus from 2 p.m. to 2:45 a.m. the plankton predators were “strongly influenced by the moon.”
It also registered the degree of difference in the abundance of marine life before and after a monsoon.
The shift refers to the active feeding time of an underwater species, while ruckus is the noise and sound caused by them. A ruckus can occur as different species compete for food or during communication. It is part of underwater species’ social behaviour, especially their feeding behaviour.
Moreover, certain species’ behaviour and feeding pattern can be influenced by the moon and weather patterns.
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The team was able to discern, record, and identify the calls of a medium-sized grunter fish (Terapon theraps), fish of the Sciaenidae family, and choruses of plankton-eating fish species and snapping shrimp, including commercially-valuable tiger prawns. Also captured was a “buzz” call of a species of unknown origin, one of the oceans’ countless marine life mysteries.
The study was carried out during the pre-monsoon period by scientists using hydrophones, artificial intelligence and other pioneering techniques to eavesdrop on the duration and timing of mating and feeding sounds — songs, croaks, trumpets, and drums — of 21 of the world’s noise-making ocean species.
Significance for Protection of Marine Life
According to the paper, hydrophones are a “powerful tool” that could help monitor fish stocks in the ecosystem in real time. It would help in efforts to delineate essential fish habitats and estimate the biomass of several underwater species.
The study’s findings provide insights into fish movement, location, and quantity throughout a season. This would help understand changes in sea life when maritime ecosystems are under grave threat.
According to the UN, the world’s oceans are facing multiple threats, including overfishing and massive ecosystem degradation. The Food and Agriculture Organization (FAO) estimates that over a third of fish stocks globally are being overfished, with only 2.8% of the ocean’s surface protected from fishing.
Furthermore, rapid levels of global warming and pollution pose enormous challenges to conserving marine life. The International Union for the Conservation of Nature (IUCN) has warned that nearly 6% of assessed fish species are already threatened with extinction.
The Project
The study team comprised scientists Vasudev P. Mahale, Kranthikumar Chanda, Bishwajit Chakraborty, and Tejas Salkar — all of them from the National Institute of Oceanography, India — and G. B. Sreekanth from the Indian Council of Agricultural Research.
The research will be discussed at an IQOE meeting in Woods Hole, USA, on 26-27 April. The IQOE is a global scientific initiative that aims to study and understand the impact of human-generated noise on marine life in the world’s oceans. The project was launched in 2015 by the International Oceanographic Commission (IOC) of UNESCO and involves a network of researchers and scientists from around the world.