For the first time, scientists have recorded songs of blue whales in Indian waters near the Lakshadweep Islands, off the coast of Kerala.
Published in Marine Mammal Science, the analyzed acoustic recordings over a span of 13 months, from late 2018 to early 2020, to reveal that blue whales were present in Lakshadweep waters — with peak activity during April and May of 2019.
“Our study provides the first evidence for northern Indian Ocean blue whale songs in Indian waters… The song is made up of three notes and ranges between 30 and 100Hz,” Divya Panicker, a marine mammal scientist from the University of Washington in the U.S., who led the study, said in a statement. She added that the study’s findings “extend the known range of this song type a further 1,000 kilometers northwest of Sri Lanka.”
Researchers believe the presence of blue whales in this region indicates that the waters are rich in biodiversity. “[Blue whales] feed on some of the smallest animals in the ocean — zooplankton and shrimp — which are prey to a whole host of pelagic fishes and mammals… Therefore, studying blue whale distributions gives a glimpse into the most productive and rich habitats in the Arabian Sea,” Panicker explained.
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Experts also note the songs may suggest that waters around the Lakshadweep Islands are suitable for the seasonal breeding of blue whales. According to Dipani Sutaria, a marine mammal expert, who wasn’t involved in the study, blue whale songs are often used by males to finding mates. “[I]f you have singing whales in an area at a certain time of the year, it means this area is likely a seasonal breeding ground, told Mongabay.
In the recent past, scientists have discovered two new populations of blue whales in Indian waters — first, in December last year, then in June. These discoveries, too, were made based on songs; each population of blue whales is known to have a unique, signature song. “It’s like hearing different songs within a genre — Stevie Ray Vaughan versus B.B. King. It’s all blues, but you know the different styles…” Salvatore Cerchio, a marine mammal biologist at the African Aquatic Conservation Fund, who led the December discovery, told the press.
However, scientists noted that in this region, whales are threatened by climate change. On the one hand, research suggests that the Indian Ocean has warmed faster than the global average — indicating that extreme climate events could follow. “We also know from recent studies that there are changes in the monsoon patterns and an intensification of the frequency and duration of cyclones — this is likely to have major impacts on blue whale prey and in turn will affect whales as well,” Panicker cautioned.
On the other hand, the proposed changes to local development laws in the Lakshadweep Islands — directed at creating a more tourist-friendly location — could further endanger the ecosystem in the region.
