Dolphins sighted in Saptakoshi [In Pictures]

ITAHARI: Rare Gangetic dolphins were sighted in the Saptakoshi River on Monday. The endangered mammals were seen near the sections flowing through gates 44, 45, 46, and 47 of the Koshi Barrage.

These freshwater dolphins migrate from the Ganges River delta and roam the Koshi waters. According to local expert and conservationist Umesh Mandal, dolphins are typically swept downstream to the Ganges during the monsoon floods but can be spotted in the Saptakoshi from October to April when floodwaters recede. “The clean waters of Saptakoshi attract dolphins. These mammals also draw a significant number of foreign tourists,” Mandal told Himal Press. “Dolphins prefer areas with calm waters, currents and avoiding fast-flowing sections.”

Mandal explained that Gangetic dolphins give birth to a single calf after a gestation period of 10-11 months, which is shorter than the 10-17 month period of other dolphin species. The mother creates a shallow pit in still water to deliver the calf, which is about a foot long. Both male and female dolphins care for the young—when the male tends to the calf, the female hunts in deeper waters and vice versa. As the calf grows, it joins its parents in foraging, often moving upstream in search of fish.

“Dolphins follow the fish upstream, which is why we see them here,” Mandal said.

In Nepal, Gangetic dolphins inhabit the Saptakoshi, Karnali, Narayani and Mohana – a tributary of Karnali.

Birendra Gautam, head of the Koshi Conservation Center under the National Trust for Nature Conservation, said that the last dolphin count in Saptakoshi, conducted in 2023, recorded 19 individuals. “There are various challenges in the conservation of this aquatic species. Dams and hydropower projects fragment their habitat, while illegal fishing with poisons and explosives threatens their survival,” he added.

He added that upstream movement past the Koshi Barrage is not possible due to a lack of suitable passage. Gautam also called on authorities to conduct awareness and training to curb poaching and trafficking.

Gautam added that a dolphin census is planned for June this year after flooding disrupted the plan in 2024.