I am an Elongate Loach, and for generations my family has lived in the clear waters of the lower reaches of the Dadu River in southwest China's Sichuan province.
As far back as I can remember, my mother would always remind me, "When spring comes, swim upstream. That is where our ancestors' spawning grounds are." But she had never been there herself. When she was young, she once tried to migrate upstream, only to have her journey cut short by a towering gray concrete wall. It was a dam built to develop southwest China and harness hydropower, and it became an insurmountable barrier for fish like us. Every early summer, my companions and I — Elongate Loaches, Prenant's Schizothoracin and White-jacket Fish among them — would gather again and again at the foot of the dam. The familiar sound of the upstream waters was so close, yet the way home seemed impossibly far away.
Yet humans never forgot about us.
In 2022, a new sound finally broke the long silence on the Dadu River. Humans launched the construction of China's first fish passage project at an operational high-head hydropower station, planning to build a dedicated route home for us along the right bank of the dam. The project was exceptionally challenging. The aging power station could not be shut down, so construction had to proceed slowly while the station remained in operation. The construction site was all hard granite, making conventional blasting impossible. The workers could only rely on drilling rigs, chipping away at the rock bit by bit, day after day.
I cannot imagine how difficult those more than 700 days and nights must have been. But I remember that whenever I swam near the site late at night, the lights along the bank were always still shining. Once, when I surfaced near the water, I heard a man speaking into his radio: "Eat the birthday cake for me, and tell my child that dad is building a pathway for the fish." His work clothes were covered in stone dust, but he was smiling as he spoke.
In March 2025, water finally flowed through the fishway. The tunnel was not as bright and open as a natural river channel, but humans had carefully installed soft lighting and a sound-wave fish attraction system inside. The dedicated light patterns and specific sound frequencies seemed like signals designed especially to guide us home. I cautiously ventured inside, swimming with the light guiding me along the way. Before I knew it, I had made it through the entire tunnel. It was only after emerging from the other end that I realized this was merely the new beginning of our journey home.
Full connection of fishways across eight hydropower stations on the Dadu River
Today, fishways across all eight cascade hydropower stations along the Dadu River are connected, creating a quiet 200-kilometer ecological corridor along the river. It links eight hydropower stations, including Angu, Shawan, Tongjiezi and Gongzui. Six of the fishways at hydropower stations operated by CHN Energy Dadu River Hydropower Development Co., Ltd. are vertical-slot fishways. They dissipate energy through the shearing action of water flow and precisely control water velocities within a range suitable for fish migrating upstream.
Last summer, I did not complete the entire journey. As I passed through the new fishway at Gongzui Hydropower Station, the water and mist around me suddenly felt completely different — fresh, cool and clear. This was the upstream world my mother had talked about all her life but had never seen with her own eyes. After returning downstream, I told every fish around me about the incredible journey. At first, no one believed me. Then several young White-jacket Fish followed me through the passage once. When they came back, their tails were flicking excitedly against the water, as if to say that the route was truly open.
The news spread like ripples, and so this spring, we agreed to make the journey together.
Aerial view of the open-channel section of a vertical-slot fishway
On the day we set out, the group was far larger than I had imagined. Elongate Loaches, Prenant's Schizothoracin and White-jacket Fish traveled together in great numbers. Old fish and young fish moved in a long, winding stream through the spring waters. Fish that had spent their entire lives below the dam and young fish making their first long journey came from all directions. We gently brushed fins, checked our bearings and then swam together against the warm current, heading upstream.
This passage built especially for us was remarkably gentle. At each hydropower station, the fishway breaks the rushing current into successive stretches of calmer water, dividing the enormous difference in water levels into a series of gentle steps. The water flows at just the right pace and force, perfectly suited to every movement of our tails. We swam steadily through the fishways of several hydropower stations, stopping briefly to rest in the resting pool of the fishway at Zhenzaoba II Hydropower Station. Most astonishing of all was the fishway at Zhenzaoba I Hydropower Station, where a super-high head difference of 34 meters — roughly the height of a ten-story building — had once seemed like an impossible natural barrier.
Yet after following the fish attraction signals into the vertical-slot fishway, the fierce turbulence we had expected was nowhere to be found. The successive water steps dissipated the force of the current and transformed it into a steady lifting force that gently carried us upward. Gradually, I began to understand the conversations coming from the bank. This was China's first ecological fishway project for a high-head hydropower station, setting a precedent for similar projects nationwide. Meanwhile, the newly built fishway at Gongzui Hydropower Station was selected as one of the Ten Landmark Achievements in Ecological and Environmental Protection in China's Hydropower Industry during the 14th Five-Year Plan period. The old and new projects complement each other, linking eight fishways into a continuous route and protecting a 200-kilometer migration corridor for us.
I am just an ordinary fish. I cannot understand complicated engineering designs, but I can truly feel the care humans have put into this. The entire fishway was built to closely match our habits and behavior. Underwater cameras, flow meters, sonar and other smart devices are installed throughout the route to precisely monitor the aquatic environment and our passage. Humans have even implanted tiny PIT tags in some fish, quietly tracking our migration routes and carefully checking that every section of the passage remains unobstructed, doing everything they can to protect our journey home.
And even greater changes are on the way. I hear that work on fishways at Shuangjiangkou and Jinchuan upstream is being accelerated, while reconnaissance and design are already underway for the hydropower stations at Houziyan, Dagangshan, Pubugou and Shenxigou in the middle reaches. By 2029, the entire main stream of the Dadu River is expected to form a complete ecological corridor, and humans are also planning to build a River Basin Fish Passage Museum.
Real-time monitoring of fish migration
I cannot understand the grand blueprint humans have drawn, but I can feel the hope it brings. The waters of the Dadu River still rush eastward, but now they carry something more — a gentler sense of inclusion. Our silent longing has finally been heard, and our instinctive urge to migrate has finally been respected.
Some people call this an engineering project. Others call it a mission. To me, it is simply that every spring, when the waters warm, I can finally follow the sounds I remember and return to the place where I belong.
I have seen the moonlight over the spawning grounds for my mother.
