Natural spawning experiment of split belly fish in Heishui River

In January 2024, the Yangtze River Biodiversity Research Center of the Three Gorges Group Ecological Engineering Center (hereinafter referred to as the Biodiversity Center) conducted a natural spawning experiment of split belly fish in the natural river channel of the Heishui River tributary, successfully achieving natural reproduction of split belly fish in the wild. The successful implementation of this experiment provides an example for research on the restoration of fish habitats in the upper reaches of the Yangtze River.

The picture shows the Heishui River Ecological Experimental Site

The Heishui River is an important alternative habitat and priority protected tributary for fish in the Baihetan Reservoir area of the lower reaches of the Jinsha River, with high fish biodiversity. In order to efficiently carry out the ecological protection and restoration work of the Heishui River, in 2014, Three Gorges Group signed a framework agreement with Liangshan Prefecture, Sichuan Province for the protection of fish habitats in the Heishui River, and immediately launched the "Heishui River Fish Habitat Ecological Restoration Project". In 2020, the first phase of the restoration project, including the demolition of the Laomu River dam, the construction of the Songxin fishway, and the restoration of habitats in the reduced water section, was completed. According to the evaluation conclusion of the first phase of the project, the overall habitat quality of protected fish such as the Qikou split belly fish and the short whiskered split belly fish in the Heishui River has been improving year by year after restoration. However, the overall flow velocity of the river is low and the flow state is slow, making it difficult to stimulate the reproduction of split belly fish that prefer to lay eggs in shallow rapids. Moreover, no natural spawning phenomenon of split belly fish was found in the monitoring of fish in the main and tributaries of the Heishui River from 2020 to 2023. In view of this, in May 2023, the Center for Biological Diversity launched the "Life History Tracking and Physical Habitat Simulation Research on the spawning grounds of Fishes in the Heishui River" project, which is one of the key research contents of the project.

The picture shows cracked belly fish eggs found in sandy and gravel substrates

In January 2024, the project team of the Biodiversity Center officially conducted a "natural spawning experiment of split belly fish" in Xiaohe, Xingfu Town, a tributary of the Heishui River. By selecting local river sections for simulation and transformation of split belly fish spawning habitats, and using methods such as three-dimensional high-precision trajectory positioning (VPS) of fish and underwater video monitoring, controlled river sections of split belly fish trajectory tracking and natural spawning experiments were carried out. On January 27th, significant progress was made in the experiment. The project team used underwater cameras and shore cameras to record the phenomenon of split belly fish naturally laying eggs in multiple locations in the experimental river channel, and found split belly fish eggs in the sandy and rocky substrate. The natural reproduction of split belly fish in the wild was successfully achieved, and its natural reproduction behavior process was analyzed. In addition, the project team obtained the activity trajectory of the natural reproduction process of the split belly fish and the physical habitat characteristics parameters of the spawning ground by conducting sonar marking tracking, drone measurement, underwater terrain and flow field measurement, and other work.

The picture shows the naturally spawning split belly fish in the experimental river channel

The successful implementation of this experiment effectively fills the gap in the biological and biomimetic research of target protected fish species in the existing habitat restoration work of the Heishui River, and is of great significance for the construction of the ecological testing ground for fish species in the upper reaches of the Yangtze River in the Heishui River. Next, the Biodiversity Center will carry out this experiment in depth and complete the analysis and evaluation work as soon as possible, summarize the effectiveness and shortcomings, and form a replicable and scalable fish habitat simulation technology model based on this, which will be promoted to other fish habitat restoration projects in the upper reaches of the Yangtze River.

Author: Li Bo, Ye Zi/Image supplier: Li Bo/Reviewer: Yang Yuanjin

Transferred from: CSRI Chinese sturgeon