Endangered blue whales recorded off southwest coast of India

Divya Panicker set out the underwater microphone, or hydrophone, off India’s Kavaratti Island. Credit score: Sayed Abdullakoya

Analysis from the College of Washington exhibits that endangered blue whales are current and singing off the southwest coast of India. The outcomes recommend that conservation measures ought to embrace this area, which is contemplating increasing tourism.

Evaluation of recordings from late 2018 to early 2020 in Lakshadweep, an archipelago of 36 low-lying islands west of the Indian state of Kerala, detected whales with a peak exercise in April and Might.

The research was printed in Might within the journal Marine Mammal Science.

“The presence of blue whales in Indian waters is well-known from a number of strandings and a few stay sightings of blue whales,” mentioned lead creator Divya Panicker, a UW doctoral pupil in oceanography. “However fundamental questions equivalent to the place blue whales are discovered, what songs do they sing, what do they eat, how lengthy do they spend in Indian waters and in what seasons are nonetheless largely a thriller.”

Solutions to these questions will probably be vital for the area, which can also be experiencing results of local weather change.

“This research offers conclusive proof for the persistent incidence of blue whales in Lakshadweep,” Panicker mentioned. “It’s important to reply these questions to attract up science-based administration and conservation plans right here.”

Whereas huge blue whales feed within the waters round Antarctica, smaller pygmy blue whale populations are identified to inhabit the Indian Ocean, the third-largest ocean on the earth.

This recording was from 28 April 2019 off Kavaratti Island in India. The recording has been sped up by 10 instances to deliver it throughout the vary of human listening to. Credit score: Panicker and Stafford/Marine Mammal Science

In earlier preliminary analysis, Panicker—who grew up in Cochin, India—talked to native fishers who reported seeing whale blows through the spring months.

However since whales floor solely sometimes and soundwaves journey effectively in water, one of the simplest ways to review whales is similar approach they convey.

The everyday blue whale tune is a collection of 1 to 6 low moans, every as much as 20 seconds lengthy, under the brink of human listening to. The sample and variety of moans varies for various populations. Songs present insights into this poorly studied inhabitants; a potential new tune was lately reported within the central Indian Ocean and off the coasts of Madagascar and Oman.

For the brand new research, scuba divers positioned underwater microphones at two ends of Kavaratti Island. Different research in close by waters steered that the presence of blue whales could be seasonal, and recordings confirmed their presence between the winter and summer season monsoons.

“Our research extends the identified vary of this tune sort an additional 1,000 kilometers (620 miles) northwest of Sri Lanka,” Panicker mentioned. “Our research offers the primary proof for northern Indian Ocean blue whale songs in Indian waters.”

Endangered blue whales recorded off southwest coast of India
The crimson star exhibits the place divers positioned two underwater microphones, from late 2018 to fall 2019 and from fall 2019 to early 2020, at depths of 11 meters (36 toes) and 29 meters (95 toes), off the southwest Indian coast. The field on the proper is a magnified view of the research area. Black dots present the place unlawful Soviet whaling ships hunted blue whales prior to now. Credit score: Panicker and Stafford/Marine Mammal Science

The researchers imagine that the whales are seemingly resident to the northern Indian Ocean, and are available to the Lakshadweep atoll seasonally.

“The Indian Ocean is clearly vital habitat for blue whales—an endangered species that’s solely very slowly recovering from Twentieth-century business and unlawful whaling, particularly within the Indian Ocean,” mentioned senior creator Kate Stafford, an oceanographer on the UW Utilized Physics Laboratory.

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Extra info:
Divya Panicker et al, Northern Indian Ocean blue whale songs recorded off the coast of India, Marine Mammal Science (2021). DOI: 10.1111/mms.12827

Offered by
College of Washington

Endangered blue whales recorded off southwest coast of India (2021, June 10)
retrieved 10 June 2021
from https://phys.org/information/2021-06-endangered-blue-whales-southwest-coast.html

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