The Cambodian population of the critically endangered Irrawaddy dolphins in the Mekong River has increased for the first time in two decades, officials announced on Monday, though the figure still falls below the riverine mammal’s population in 2007 when it stood at 95.

The World Wildlife Fund (WWF) Cambodia and the government released the 2017 dolphin census during a press conference at the Fisheries Administration on Monday, saying the population had increased to 92 in 2017, up from 80 in 2015. When counting began in 1997, the dolphins numbered 200, a figure that had fallen by more than half – to 95 – by the time conservation efforts took off in 2007.

While Seng Teak, country director for WWF-Cambodia, was quoted in a press release saying officials “finally have a reason to believe that these iconic dolphins can be protected against extinction”, he later acknowledged during an interview that the population is still far too low.

“The dolphins [are] still critically endangered. It’s a small population, to be honest,” he said. “The population of 92 is still critical.”

Though he maintained the gains are a positive sign, Teak wasn’t able to specify what population level would be considered healthy.

The census also revealed an increase in new calves and a decrease in deaths, with only two dolphins dying in 2017, compared to nine in 2015. Four calves have been born so far in 2018, though two didn’t survive. Last December, the International Union for Conservation of Nature upgraded the species’ status to critically endangered on its Red List.

Teak credited the recent population increase to effective law enforcement and patrolling in the core conservation zone, removing gillnets and poisons, halting dynamite fishing and curbing other unsustainable fishing practices.

Some $350,000, including around $140,000 from the government, is spent annually on conservation efforts, Teak said.

But illegal fishing remains a challenge, and officials plan to redouble their efforts in coming years, said Phay Somany, deputy director of the Department of Fisheries Conservation and Government Liaison at WWF, who carried out most of the research.

“It’s hard to control fishing at night,” he said.

Randall Reeves, chairman of the IUCN Species Survival Commission’s Cetacean Specialist Group, who was not involved in the census, said the news of the population increase was “encouraging”, but progress hinged on few important factors.

“The animals appear to be in good health and are capable of regular reproduction, and therefore as long as they are protected from entanglement or entrapment in fishing gear, and as long as their habitat remains intact and productive (and is unobstructed by more dams), they should be able to recover to at least several hundred animals, at which point our concern about their long-term survival might begin to ease,” he said in an email.

However, multiple dam projects currently pose a threat to the area, including the 260-megawatt Don Sahong Dam on the Mekong mainstream. The dam, still under construction, is less than 2 kilometres from the Cambodian border, WWF’s Somany said, and once operational, it will “fully block” fish migration from Cambodia to Laos during the dry season, putting more pressure on the ecosystem and the fishermen who rely on it.

“It will cause a big problem,” he said.

The 2,600-megawatt Sambor Dam in Kratie province is also being discussed by the government. While Somany declined to speak on the impacts of Sambor, WWF’s Teak said the proposed dam would pose another major challenge to the dolphins’ continued existence.

A very cautious assessment will be needed to analyse the risks, benefits and losses, he said, “and I wish [it’s] based on the importance of the benefits of the fishery or aquatic resources out there”.