Yangtze River Porpoise Scientific Expedition Diary: Meeting new friends in the old place, hello porpoise!

Produced by: Science Popularization China

Author: Zhou Shuo (Wuhan Baiji Conservation Foundation)

Producer: China Science Expo

On September 19, 2022, the Yangtze River finless porpoise scientific survey was officially launched. This survey is the fourth Yangtze River finless porpoise scientific survey after 2006, 2012 and 2017. It is also the first basin-wide species systematic survey after the implementation of the ten-year fishing ban in the Yangtze River. It is of great significance to the protection of Yangtze River finless porpoises and even the entire Yangtze River ecosystem.

September 21st was the third day of the Yangtze River dolphin survey.

Today I am going to Chenglingji, the place where I met "Qiqi" that year. This is also the day I look forward to most after I knew my scientific expedition schedule. Qiqi is our eternal love and pain, and we all miss it very much.

Baiji Dolphin - Qiqi

(Photo source: Wuhan Baiji Dolphin Conservation Foundation)

At about 8:00 p.m. on January 11, 1980, Liu Renjun, a researcher at the Institute of Hydrobiology, Chinese Academy of Sciences, received a call from the Chenglingji Aquatic Products Purchasing Station in Hunan Province, saying that four fishermen had caught a strange creature that looked like a fish but was not a fish, with a long and thin mouth and a smooth body. They could not catch it no matter how hard they tried. It was a live baiji dolphin. It was winter, with rain and snow, and the road was muddy and difficult to walk on. Liu Renjun and his team carried a stretcher and some veterinary drugs and traveled nearly 30 hours to bring Qiqi back to the baiji dolphin museum. From then on, this became Qiqi's final home.

Arriving at Chenglingji and seeing the busy water traffic, I was looking for a corner in a parallel time and space - the paradise where Qiqi and his friends used to play. Qiqi had a great fate with us. He lived in the Baiji Dolphin Museum for 22 years and 186 days and passed away on July 14, 2002. He was the last Baiji dolphin that humans could observe up close.

The junction of the Yangtze River Chenglingji and Dongting Lake

(Image source: provided by the author)

In order to find the trace of the baiji dolphin, the Institute of Hydrobiology of the Chinese Academy of Sciences organized a team of scientists from China, the United States, the United Kingdom, Switzerland, Japan, Germany, India and other countries to conduct the first large-scale scientific survey of Yangtze River dolphins in the Yangtze River in 2006. After 39 days and 3,400 kilometers, "Qiqi" never appeared in everyone's sight. In 2007, the baiji dolphin was determined to be "functionally extinct"! It has become an eternal pain for the Baiji Dolphin Museum and the world.

Research vessel 051

(Image source: provided by the author)

Today, Chenglingji has long lost the Baiji dolphin, and has become an important habitat for its neighbor, the Yangtze River finless porpoise. When approaching the waters of Chenglingji, the acoustic equipment began to warn, and those of us who were not on duty excitedly rushed to the deck, expecting the finless porpoise to appear in front of us. Everyone turned on the recording function of their mobile phones at the same time, quietly and excitedly waiting for the finless porpoise to come into sight. Within a few minutes, two finless porpoises came with the waves, and all the expedition members on the boat happily signaled to their partners next to them that the finless porpoise really appeared. The Yangtze River finless porpoise is a mammal that breathes with lungs. On average, it will float to the surface of the water every ten seconds or so, and we will see its shiny back exposed above the water. It was September, the season when young porpoises frequently appeared. We saw the little finless porpoises closely following their mothers, lying on their mothers' backs for a while, and then jumping off, rolling and tumbling in the water, which was very cute. I stood on the deck, staring at the front, not wanting to miss any dolphin in this area. At the junction of the Yangtze River and Dongting Lake, the captain slowed down the boat so that everyone could enjoy watching the dolphins.

Summary meeting after daily inspection

(Image source: provided by the author)

Due to the intensification of human activities, the population distribution of finless porpoises is fragmented. According to the scientific research data in 2017, there are nearly 110 finless porpoises living in Dongting Lake, which is the second largest water area for finless porpoises after Poyang Lake. With the implementation of the "Ten-Year Fishing Ban" in the Yangtze River and the "Yangtze River Protection Law", we hope that the number of finless porpoises in Dongting Lake and even the main stream of the Yangtze River will increase.

Collecting water samples

(Image source: provided by the author)

Before departure, we received theoretical and practical training in Wuhan. I was responsible for the water sampling and imaging assistance for this expedition. We will collect water samples in specific waters, use instruments on site to measure the pH value of the water samples, as well as water temperature, dissolved oxygen, and conductivity, and other data on biological information such as dander and feces of finless porpoises that may exist in the environment, and then take them to the laboratory for DNA testing. "eDNA" is known as the black technology of the Yangtze River finless porpoise scientific expedition. Its principle is to obtain information on the types of aquatic organisms remaining in the water samples through continuous sampling of water samples from the main stream of the Yangtze River. Based on information such as the distribution and relative density of finless porpoises in different waters, it is helpful to supplement the distribution information of the Yangtze River sections where the number of finless porpoises is very small, and confirm whether the finless porpoises are active there.

Visual and image recognition

(Image source: provided by the author)

There is also a pair of "clairvoyant eyes" on the side of the expedition ship. This rotating device is a newly attempted automatic image assistance system. With artificial intelligence AI recognition, it can help objectively record and analyze the number of Yangtze River porpoises in the river section where the ship passes. It can make up for the population estimation error caused by differences in observation ability of observation team members to a certain extent. For this scientific expedition, the fishery administration ship used in the investigation built a special observation platform. Visual work is very hard and consumes a lot of physical energy. Visual personnel rotate positions every half an hour. After the rotation, the team members rest in the cabin to ensure that they are energetic when on duty.

I am very excited to have such an important job opportunity after one year of working at Wuhan Baiji Conservation Foundation. In my daily work, I often draft some manuscripts on the protection of finless porpoises and the Yangtze River, and I have been looking forward to participating in the five-year scientific expedition team and experiencing the Yangtze River in the closest way. We are a group of "lonely brave men" who "will never regret" for the protection of finless porpoises. It is bound to be of great significance and precious to participate in the work of finless porpoise protection at close range.

During the scientific expedition, I saw the initial results of the Yangtze River protection. On both sides of the river are the honest people who "jointly protect the green water of the river", the conscientious government who "hold on to the green mountains and never let go", and the scientific researchers who "strive for self-improvement". When the spring breeze greens the south bank of the river again, it will be the beautiful China with beautiful mountains and clear waters and the return of the Yangtze River dolphins.

(Image source: provided by the author)