An Ancient Instinct Hits a Wall
The Chinese sturgeon, Acipenser sinensis, carries the genetic memory of 140 million years. This anadromous fish spends most of its adult life in the coastal waters of the East China Sea before instinct compels it on one of the most demanding reproductive migrations known. Historically, these fish swam up the Yangtze River and its tributaries, including the Minjiang River in Fujian, traveling as far as 3,300 kilometers inland to reach their spawning grounds. This migration is biologically necessary.
In 1981, this ancient cycle was abruptly broken. The construction of the Gezhouba Dam on the Yangtze, followed by the Three Gorges Dam in 2003, created impassable barriers. The dams physically blocked the sturgeons' path, cutting them off from their ancestral spawning sites. The population, which was estimated at over 10,000 spawning individuals in the 1970s, collapsed. By the early 2000s, fewer than 400 spawning adults were estimated to remain, a decline of over 97%. Tagging studies show a tragic reality: the sturgeon still attempt the migration, swimming hundreds of kilometers until they meet the concrete walls of the dams. The altered water temperatures and flows caused by the dams also inhibit gonadal development, rendering many of the surviving fish unable to reproduce successfully. For years, natural reproduction in the wild effectively ceased.
A Lifeline of Last Resort
With Acipenser sinensis extirpated from the Minjiang River and functionally extinct in much of its former range, the only hope for the species became human intervention. Chinese scientists embarked on a massive captive breeding and release program. The Chinese Sturgeon Research Institute, part of the China Three Gorges Corporation, is an important center for this effort. The initial work was challenging; early attempts required dissecting wild-caught females to harvest eggs, a method that was often lethal.
Over decades, researchers refined their techniques. By 2009, they achieved a major success: breeding a second generation of sturgeon entirely in captivity from captive-bred parents. This breakthrough meant that the few remaining wild individuals were no longer needed for the breeding program. Since the 1980s, millions of artificially bred Chinese sturgeon, from small fry to mature, 1.5-meter-long individuals, have been released into the Yangtze. Many of these larger fish are fitted with satellite and ultrasonic tags to track their movements, providing data on their attempts to adapt to the changed river system. While the species remains critically endangered, these releases are the only thing standing between this 140-million-year-old lineage and extinction.