JAKARTA — Conservationists in Indonesia are pushing for the establishment of a protected area along a stretch of Borneo’s Mahakam River to save the remaining population of the nearly extinct Irrawaddy dolphin.

The government of Kutai Kartanegara district in East Kalimantan province has requested the approval of the fisheries ministry to designate the part of the Mahakam River that runs through the district as a hydrological park. This would confer some protection on the ecosystem while still allowing for sustainable local fisheries.

The proposed conservation area would cover 43,117 hectares (106,545 acres) of the Mahakam watershed in the district. Nearly 16% of this area would be designated the core zone, including the known habitat of the Irrawaddy dolphin (Orcaella brevirostris), according to an official document reviewed by Mongabay. About 90% of the last 80 Irrawaddy dolphins in the Mahakam inhabit this particular stretch of the river, according to the nonprofit Conservation Foundation for Rare Aquatic Species of Indonesia (YK-RASI). At the same time, the area is also a key source of income for fishers from 27 villages.

“If the center [national government] says everything seems to be OK, it will be the first conservation area actually in freshwater areas that will be obtaining a ministerial decree,” Danielle Kreb, scientific program manager for YK-RASI, which is assisting the Kutai Kartanegara district government with the proposal, told Mongabay in a phone interview.

“I think for more complex areas that need different zones and stuff, this might be a good example, because we had to make zones inside of the area,” she said.

The Mahakam River runs 980 kilometers (610 miles) from its headwaters in the heart of Borneo’s remaining thick rainforest, past East Kalimantan’s mosaic of oil palm plantations, coal mines and logging concessions, before ending in a delta on the Makassar Strait on Borneo’s east coast. The freshwater dolphins of the Mahakam, known locally in Indonesia as pesut, represents one of just three riverine populations of Irrawaddy dolphins in the world, with the other two in the Mekong and the Irrawaddy rivers.

Kreb said the proposed conservation area would alleviate the threats to the endangered species’ existence. The dolphins have been driven from much of their range to this particular stretch of the Mahakam because of changes to the flow and quality of river water as a result of the clearing of peat forests for oil palm plantations, Kreb said. Between 2002 and 2019, East Kalimantan lost 9% of its primary rainforest, or 1.13 million hectares (2.8 million acres), according to Global Forest Watch.

“So we had to inform the government of Kutai Kartanegara to make sure that the same mistakes are not being made in this area because then they [the dolphins] cannot go anywhere anymore,” Kreb said.

The dolphins’ current range also happens to be the busiest stretch of the Mahakam, with constant large vessel traffic, particularly coal barges. The proposed conservation area would limit shipping traffic lanes to less than 1% of the total coverage, according to the document.

“Boats will still be going to the area in the main river, but for the tributaries, we really would like no coal barges in the tributaries,” Kreb said. “Because the rivers are only 100 meters wide [330 feet], but then you have 300-foot coal barges passing through that.

“It’s actually not acceptable that you do that, that excavates the slopes of the river,” she added.

The fisheries ministry’s approval of the plan will be crucial, in part because it will ensure the inclusion of the conservation area into the provincial zoning plan and allocate funding from the state budget for protection measures, Kreb said.

The proposed establishment of the conservation area in this part of the Mahakam River has received virtually zero opposition, Kreb added, and supporters of the plan hope the fisheries ministry will give its approval as soon as the end of the year.

“We hope other ministries will be concerned about this as well, you know, together we can find a solution to make sure that all the industrial activities can be settled in the more downstream area of the [river],” Kreb said. “We want to create something that will be there for generations in a good way.”

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