"Release" and "Purdah" Release to the Yangtze River to swim after the waves [30 years of finless porpoise protection to fulfill a dream: from ex situ conservation to wild release of nature]

On the morning of April 4, four Yangtze finless porpoises (25 males and 4 female) were released into the Yangtze River in the Xinluo section of Shishou Swan Zhou and Honghu Lake in Hubei Province.

It is reported that this is the first time in China to try to "wild" the finless porpoise in the ex-situ reserve into the Yangtze River.

From relocation to "seed conservation" to returning to the Yangtze River to free "swimming", this step has been more than 30 years for domestic scientific researchers and management institutions.

Wearing a "vest"

"Jiangdi Live" grasps the movements of finless porpoises in real time

On April 4, in the Honghu Xinluo Section Reserve, two 25-year-old male finless porpoises happily rushed into the Yangtze River at the moment of release into the Yangtze River, wagging their tails, making a small arc, and disappearing from people's sight.

On the 25th, Wang Kexiong, a researcher at the Institute of Aquatic Sciences of the Chinese Academy of Sciences, introduced that in April 2021, as "advance team members", they moved from Tianwanzhou Old Road to Laowan Old Road and carried out adaptive training for two years (the image is called "wild training" or "rewilding").

Wang Kexiong said: "Our observation and analysis results show that these two finless porpoises have adapted well to the ecological environment of Laowan Gudao, have the ability to prey on and avoid sailing ships in the main stream of the Yangtze River, and the probability of survival in the main stream of the Yangtze River after release is very high." ”

Wang Kexiong said: "In order to achieve effective tracking of finless porpoises for a longer period of time, we put on special radio vests (radio signal transmitters) for finless porpoises, and adjusted the working time/interval time to save electricity, extend the tracking period, reduce the volume of equipment, and reduce the impact on the behavior of finless porpoises, so that the data obtained such as the porpoise movement route, behavior pattern and inhabiting waters are more representative." ”

On the afternoon of the 25th, the researchers received a signal from the finless porpoise, and then used a handheld antenna to track it, and found that the two finless porpoises released into the river stayed together, about 2 kilometers away from the release point.

In addition, researchers are also releasing porpoise waters, and have deployed a new RPCD real-time acoustic image monitoring and early warning platform, which is equivalent to laying out a "river bottom live broadcast" system to collect information on the location and number of finless porpoises, as well as their sounds and images, and effectively grasp their range of activities and living conditions.

Care for half a year

The keeper couldn't help but feed a few more fish

At 25:6 on the 30th, the sky was overcast, and Dr. Hao Yujiang, associate researcher of the Institute of Aquatic Sciences of the Chinese Academy of Sciences, observed the behavior of the two finless porpoises in the cage, and then accompanied them to the water and transported them to a temporary "soothing pond" with a diameter of 2.3 meters. He found that these two little guys were full of physical strength and very active.

As early as the 21st, he and the members of the research team came here to do a physical examination for them and observe their habits; Install acoustic monitoring equipment, design water starting, transportation, release plans and other release preparations.

On the afternoon of the 24th, the staff of the reserve and the researchers of the Institute of Aquatic Sciences of the Chinese Academy of Sciences conducted a comprehensive physical examination of the two finless porpoises that were about to be released, confirmed their health status and adapted to the release requirements, and then moved them into artificial cages.

At night, Ding Zeliang, a breeder who has been caring for finless porpoises here for 15 years, is full of reluctance to raise two finless porpoises for half a year.

At the end of 2022, in order to cope with the extreme arid climate, the two finless porpoises were transferred from the Tianwanzhou Old Road to a cage for half a year. They all have their own nicknames, which are the 2-year-old male "Fang" and the 13-year-old female "Purdah".

When he heard that small fish resources were abundant in the section of the river where the finless porpoise was released, he was a little relieved, "Now, I don't worry about the finless porpoise starving."

However, after the normal feeding at night, I couldn't help but add a few more small fish and added some vitamins to the fish, which was regarded as "adding meals" to the children who traveled far away. "Porpoises are smart, they recognize me! But it is good to release the Yangtze River, it is its home! ”

On the morning of the 25th, after starting from the base of the Tianwanzhou Ex-situ Reserve, the "release" and "boudoir" were transported to the river beach by a special water tank transport vehicle, and took a break in the "soothing pool" arranged in advance for 20 minutes, and then four people carried a special stretcher cloth to the waters of the Yangtze River ten meters away from the "soothing pool".

Unlike the two finless porpoises released in the Honghu Xinluo Reserve, the finless porpoises were supplemented by a "soft-release" field training process - they were first transferred to the natural waters of the Jiaozi River estuary in the Shishou River section to give them a buffer adaptation process.

This Yanjiang River, located on the bank of the Yangtze River and the sandbar on the river, is about 1 km long. It is similar to the geographical relationship between Tianxingzhou in Wuhan and the north bank of the Yangtze River, and also belongs to the natural Yangtze River waterway.

At both ends of the Yanjiang River, through the barrier net, on the one hand, to prevent human encroachment such as boats, on the other hand, to ensure their safety, researchers will continue to track and observe, if they can fish and eat normally, have the ability to avoid sailing ships, they will be released into the main stream of the Yangtze River at the right time.

Ex-situ "seed preservation"

The number of finless porpoises stopped falling and rebounded

Ex-situ conservation of the Yangtze finless porpoise has lasted for more than 30 years. It stems from the protection of another flagship species of the Yangtze River, the baiji dolphin.

Subsequently, Chinese scientists pioneered the ex situ conservation of the Yangtze finless porpoise. As a result, some "oxbow lakes" in the old road of the Yangtze River were targeted by researchers. Blocking both ends can provide a place for porpoises to "preserve" ex situ.

In 1990, the first five Yangtze finless porpoises were successfully relocated to Tian'ezhou Old Road.

In 1992, the State Council approved the establishment of the first domestic cetacean ex situ reserve in the Yangtze River Old Road, Shishou Tianwanzhou, our province.

Hao Yujiang introduced that since the ex-situ protection of finless porpoises in the ancient road of the Yangtze River in Shishou Tianwanzhou, from the initial 5 to 2010 in 30, to 2015 in 60, now increased to 100...

In addition, Tianwanzhou has also become an important source of finless porpoise, and has successively exported 49 finless porpoises to Jiangxi, Anhui and other nature reserves and scientific research institutions in the province, plus 2 released this time, so there are 65 inhabited in the road, and Tianwanzhou Reserve has become a successful model of ex situ conservation of small cetaceans in the world.

Looking at the Yangtze River Basin, a survey by the Ministry of Agriculture and Rural Affairs shows that the number of Yangtze finless porpoises reached 2022,1249 in <>, which for the first time achieved a halt to decline and rebound, and the continuous decline of the population was curbed.

Among them, the role of in situ protection and ex situ conservation is obvious. At present, China has established 8 in-situ protected areas such as Hubei Honghu and Anhui Tongling, and 5 ex situ protected areas or bases such as Hubei Shishou, Hubei Jianli/Hunan Huarong.

Hao Yujiang said that at present, the population of these ex situ reserves is about 150, and all of them can reproduce naturally, and more than 15 finless porpoises are born every year.

Similarly, in terms of captive breeding and breeding protection, the Institute of Aquatic Sciences of the Chinese Academy of Sciences has long realized artificial breeding; On July 7 last year, the artificially bred offspring "Taotao" and the finless porpoise "Fukujiu" gave birth to the second generation of finless porpoise "F6C9". Because it is the first time to broadcast the finless porpoise litter online, this little guy has become a "little Internet celebrity" after being born, and is loved by people.

The Institute of Aquatic Sciences is building a new Yangtze River porpoise house with a storage capacity of 640 cubic meters, hoping to provide a "marriage room" and "delivery room" with wider water and more advanced facilities for the finless porpoise to "give birth to children".

There are more finless porpoises

Only then will we have the confidence to "release back into the Yangtze River"

As an aquatic mammal, the Yangtze finless porpoise can only be sexually mature at the age of 5, and can only begin to participate in reproduction at the age of 6-7, with a gestation period of about one year, a lactation period of about one year, and a baby per litter, and female finless porpoises can only conceive a few litters in their lifetime, so the population proliferation recovery is slow.

In recent years, the ecological environment of the Yangtze River has been continuously improved, which has promoted the restoration of the habitat of the Yangtze finless porpoise. The policy of large-scale protection of the Yangtze River and the "ten-year ban on fishing" has created a good opportunity for the recovery of fish resources in the Yangtze River.

When the environment is good and food is available, the wild population of finless porpoises that call the river their home can continue to recover. The results of the 2022 Yangtze finless porpoise scientific expedition prove that the growth potential of the Yangtze finless porpoise population has initially emerged.

With the steady growth of the finless porpoise population, we have the confidence to "release some finless porpoises that have been trained in rewilding" into the Yangtze River.

Some members of the public want to know whether these finless porpoises released into the Yangtze River are "their own family" or "gregarious" with other wild populations in the Yangtze River.

In this regard, experts say that this possibility exists, and continuous observation is required to know their whereabouts.

In recent years, the Yangtze finless porpoise has appeared intensively in Wuhan waters, and this newspaper has reported it many times. Among them, the section from Jinkou to Parrot Zhou of the Yangtze River and the section from Yangluo to Huanggang Tuanfeng in Xinzhou are the two main porpoise spots in Wuhan.

If the released finless porpoises join them victoriously, then increase the number of finless porpoises in the Wuhan River section, so that the citizens' "dolphin viewing in the city" will become a beautiful thing.

Text/Reporter Jin Wenbing Correspondent Zhao Hui Deng Xiaojun