Scientists have recorded the sounds of 21 marine species with the aim of understanding more about the marine environment.
Researchers used hydrophones – microphones designed to be used underwater – to listen to aquatic creatures living in reefs off the coast of Goa, India.
The scientists discovered that some species are early risers, making noise from 3am onwards, while others were more active later in the day, creating a ruckus from 2pm.
The team said their work, published in The Journal of the Acoustical Society of America, could help to better understand the lives of underwater creatures and their breeding seasons, as well as the impact of human-led activities on the lives of marine
Study author Dr Bishwajit Chakraborty, retired former chief scientist at India’s National Institute of Oceanography, said: “Acoustic monitoring of underwater environments will enable us to learn more about climate and its long-term changes belongs to her in physical education. and the biological condition of the underwater environment.
“For example, because coral reefs are the heart of underwater biodiversity, it is essential to carry out acoustic studies here to find out about the state and health of the reef and its inhabitants.
“Acoustic monitoring of underwater environments will enable us to learn more about the climate and its long-term changes.
“Marine life is directly affected by changing temperature and climatic conditions because they are mostly endothermic in nature (except mammals) which loosely adapt to … regulate their body temperature based on the surrounding temperature.
“So, in such cases, they will be affected by climate changes, which will affect their behavior patterns.
“It is therefore absolutely necessary to study these behaviors – and behavior change – to have a deep understanding of the climate and its impact on underwater organisms.”
About 250,000 marine species are known, and thousands are estimated to emit sounds.
These include fully aquatic marine mammals, such as whales, along with 100 invertebrates, such as polecats, and a thousand species of fish.
For these underwater creatures, sound is a means of communication.
Many species also use sounds to gather and understand information about their environment – such as finding prey, identifying others, finding offspring, avoiding predators and finding habitat.
Experts involved in the International Pacific Ocean Experiment (IQOE) – a program aimed at understanding more about the effects of sound on marine organisms – listened to the mating and feeding sounds of 21 marine species, including songs, croaks, trumpets and drums.
They used artificial intelligence and other techniques to identify the species making the sounds, including spinning shrimp as well as a chorus of fish species that eat plankton – microscopic organisms that live in the ocean.
The researchers also found that Terapon therapies – a medium-sized grunter species – were taller during dusk.
The team found that some species work the early shift, making noise from 3am to 1.45pm, while others take the late shift, creating a ruckus from 2pm to 2.45am.
Meanwhile, plankton predators were found to be nocturnal and “strongly influenced by the moon”.
But some marine sounds remain unidentified and the researchers hope that their work on Glubs (Global Library of Underwater Biological Sounds) – the world’s first library of underwater biological sounds – could eventually help identify species unknown to the science they are currently exposed to.
Miles Parsons, of the Australian Institute of Marine Science and head of Glubs, said: “Unidentified sounds can provide valuable information on the richness of the soundscape, the acoustic communities that contribute to it and the behavioral interactions among acoustic groups.
“However, unknown, cryptic and uncommon sounds are rarely the target beacons for research and monitoring projects and are therefore largely under-reported.”