Conservationists heralded the Chinese government's pledge to close its domestic ivory industry as a "game-changer," and welcomed evidence it was being implemented.
"These closures prove that China means business in closing down the ivory trade and helping the African elephant," said Peter Knights, CEO of WildAid, a San-Francisco-based group that has played a leading role in raising public awareness in China about the link between ivory and poaching.
Knights said the latest price decline shows ivory "is now a very bad investment," and said he expected a further decline in prices by the end of the year.
Lucy Vigne, one of the authors of the Save The Elephants report, said the legal ivory trade in China was "severely diminished," with licensed outlets gradually reducing the quantity of items on display and cutting prices.
The legal trade in ivory in China, using a stockpile amassed before a global ban, was the cover for a much larger illegal trade that fuelled poaching, conservationists say.
"Law enforcement is key to success," Vigne said in a press release. "This is already improving in China - we have seen a decline in the number of illegal ivory items on display for sale since 2013."
China's State Forestry Administration announced the closure of the ivory carving workshops and retail outlets on its website on March 24, as part of an "orderly process" to end the trade. WildAid said 12 out of 34 ivory carving factories in China were being closed, and 45 out of 130 retail shops.
Although poaching may have peaked a few years ago, some 20,000 African elephants continue to be killed for their tusks every year, experts say, largely to meet demand from Asia, and particularly China, for ivory.
Africa's elephant population has dwindled from about 1.2 million 35 years ago to between 400,000 and 500,000 now. Central African forest elephants could be extinct within the next decade if current trends continue, while Tanzania's elephant population fell by 60 percent between 2009 and 2014, census data showed.
Knights said the ban was already helping, with seizures of ivory coming into China down by 80 percent in 2016 and poaching falling in Kenya. But Hong Kong and Britain have yet to pass proposed bans on the ivory trade, while Japan's market "remains wide open," according to WildAid.