Summary:
It was unusual to watch Dolphins that have made an appearance along Mumbai’s coastline earlier than usual this year.
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It was unusual to watch Dolphins that have made an appearance along Mumbai’s coastline earlier than usual this year.
Conservation biologist and Malabar Hill resident Darshan Khatau, who has been documenting the movement of the Indian Ocean humpback dolphin annually for the last four years, said sporadic sightings of dolphins were usually seen from the second or third week of December annually up to last week of May (just before the monsoon season).
“This year, they arrived unusually early during the third week of November,” said Khatau.
He spotted three individuals off Malabar Hill from November 15 and 16 onwards and has been regularly photographing them since.
“In the previous years, the maximum number of individuals has been 12 in one pod.
The early arrival could be due to shifts in ocean currents leading to more prey availability along the Mumbai coast.”
Last Wednesday, a video was circulated on social media by environmentalist Zoru Bhathena of an Indian Ocean humpback dolphin spotted off Juhu beach.
Marine biologists concurred with Khatau’s finding but said it cannot be verified as no official survey or study to monitor the population or behaviour of this species was carried out along Mumbai so far.
“The Mumbai coast is used by Indian Ocean humpback dolphins (Sousa plumbea) for biologically important activities.
Darshan has been observing foraging, socialising and mating in the area he observes.
It is possible that their early arrival is related to oceanographic characteristics - currents, productivity, and prey availability,” said Dr Dipani Sutaria, senior research fellow, who has undertaken extensive research in cetaceans (whales, dolphins and porpoises) along the west coast of India.
Dr Baban Ingole, visiting scientist, National Centre for Polar and Ocean Research under the Ministry of Earth Sciences and former chief scientist, National Institute of Oceanography, said, “Since these are observations over four years, I certainly support it, and this may be happening across other areas along the west coast too, but we must understand the specific reason why this might be happening.”
Ingole explained that from April onwards till early November, fishing activities had been at its lowest due to the Covid-19 pandemic and associated lockdown followed by the southwest monsoon (when the annual fishing ban is in place).