Yangtze finless porpoise facts for kids
Quick facts for kids Yangtze finless porpoise |
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| At the Chinese Academy of Sciences | |
| Conservation status | |
Scientific classification  |
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| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Artiodactyla |
| Infraorder: | Cetacea |
| Family: | Phocoenidae |
| Genus: | Neophocaena |
| Species: |
N. asiaeorientalis
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| Binomial name | |
| Neophocaena asiaeorientalis (Pilleri & Gihr, 1972)
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| Yangtze finless porpoise distribution | |
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The Yangtze finless porpoise (Neophocaena asiaeorientalis) is a special type of toothed whale. It belongs to the porpoise family. This amazing animal lives only in the Yangtze River in China. It is the only freshwater cetacean (a group that includes whales, dolphins, and porpoises) known in China. Another freshwater dolphin, the baiji, might have disappeared.
Sadly, the Yangtze finless porpoise is critically endangered. In 2023, scientists estimated only about 1,249 of these porpoises remained. They face many dangers, just like the baiji did. These threats include too much human activity on the Yangtze River. Things like illegal fishing, pollution, busy boat traffic, and dam building harm them. Because their numbers are dropping so fast, the Chinese government and conservation groups are working hard. They want to save this unique porpoise from disappearing forever.
Contents
Discovering the Yangtze Finless Porpoise
The Yangtze finless porpoise is a freshwater cetacean. This means it is a whale, dolphin, or porpoise that lives in fresh water. Finless porpoises first lived in salty ocean waters along the Indo-Pacific coast. Over time, some moved into the freshwater of the Yangtze River.
Scientists have studied these porpoises closely. They found that the East Asian finless porpoise and the Yangtze finless porpoise are different. They have not reproduced together for thousands of years. This means they are now considered separate species.
What is a Yangtze Finless Porpoise Called?
In Mandarin Chinese, people call this porpoise jiangtun. This name means "river piglet."
Physical Features of the Porpoise
A finless porpoise can grow up to about 2.3 meters (7.5 feet) long. They can weigh between 72 and 123 kilograms (159 to 271 pounds). Most adults are about 1.5 to 1.8 meters (5 to 6 feet) long. They usually weigh around 45 kilograms (100 pounds). Female porpoises are often a bit smaller than males.
Their flippers are curved and pointed. They are quite large, making up about 20% of their body length. The porpoise's body is thick in the middle. It gets thinner towards its tail. They generally look more slender than other porpoise types.
These cetaceans have a unique head shape. Their forehead is very steep, and they do not have a beak. Their neck bones are not joined together. This allows them to move their head freely. They have 15 to 22 pairs of teeth on both their upper and lower jaws.
The Dorsal Ridge: A Special Feature
As their name suggests, these porpoises do not have a dorsal fin. Instead, they have a flat back with a special "dorsal ridge." This ridge has rows of small, round bumps called tubercles.
Scientists have discovered that these tubercles are very useful. They act like sensory organs, helping the porpoise feel its surroundings. They also help the porpoise move smoothly through the water. The number of tubercle rows and the size of the ridge can differ. This depends on the specific type of finless porpoise and where it lives.
The Yangtze finless porpoise usually has a higher, narrower ridge. It has only 1 to 10 rows of tubercles. Other types, like the Indo-Pacific finless porpoise, have a wider ridge. They can have 10 to 25 rows of tubercles.
Porpoise Body Color
The color of a porpoise's body changes with its habitat and age. Baby Yangtze finless porpoises are usually dark gray or black. They become lighter gray after a few months. However, Indo-Pacific porpoises are born light-colored. They get darker as they grow older.
After a Yangtze finless porpoise passes away, its body usually turns black. It is also common to see lighter patches of color. These patches are often around their mouth and private areas. This coloring is easier to see when they are young.
Where the Porpoise Lives
The Yangtze finless porpoise lives in the main part of the Yangtze River. It also lives in lakes connected to the river. They only live in fresh water. This makes them different from other finless porpoises.
They often stay in shallow bay areas, swamps, and estuaries all year. They do not travel long distances. However, where they are found can change with the seasons. In winter, most are found in the middle and lower parts of the Yangtze River. They prefer warm or tropical climates.
What the Porpoise Eats
The diet of the Yangtze finless porpoise can change with the seasons. It depends on what fish are most common at that time. This suggests they are "opportunistic feeders." This means they eat whatever food is easiest to find. Some common fish they eat include Coilia brachygnathus, Pseudobrama simoni, Pelteobagrus nitidus, and Hemiculter bleekeri.
Porpoise Behavior and Communication
Yangtze finless porpoises are usually shy. They do not often come to the water's surface if people are nearby. They are most active when they are eating. They spend most of their time near river banks or where two waterways meet.
These porpoises usually travel in small groups. A group might have three to six individuals. However, groups of 20 have been seen. Studies show they often make one long dive, then two shorter ones. Longer dives are more common during the day. In the Yangtze River, they are known to leap out of the water. They also perform "tail stands," where they balance on their tails. At night, they tend to sleep and are less active.
One interesting behavior, though not fully confirmed, is mothers carrying their babies on their backs. Another unique thing about these porpoises is how they communicate. Most dolphins use whistles. But these porpoises use echolocation. They send out ultrasonic pulses to find their way and talk to each other.
Conservation Status and Efforts
After the Yangtze river dolphin likely disappeared, the Chinese government gave the finless porpoise special protection. It is now a National First Grade Key Protected Wild Animal. This is the highest level of protection by law. This means it is illegal to harm a porpoise.
However, the porpoise population is still decreasing quickly. This is due to less food, pollution, and ship movements. Scientists worry there is a high chance it could disappear in the future. Underwater noise pollution also threatens them. If noise levels in the water are too high, it makes it harder for them to survive. Global conservation groups like the World Wildlife Fund and IUCN are working with China. They want to ensure the porpoise's survival.
Threats to the Porpoise
Fishing Dangers
Accidental capture by fishermen is a problem for the Yangtze finless porpoise. This is called bycatch. Illegal fishing and dangerous gear, like gillnets, are common in the Yangtze River. Porpoises often live in the same areas where gillnets are used. This makes them very likely to get tangled and drown.
However, recent studies suggest that fewer porpoises are dying from bycatch now. This is because the porpoise population itself has become smaller. So, gillnetting might not be the main reason for their decline anymore.
River Development Impacts
More boat traffic, pollution, and damage to the river's natural areas have caused the population to drop. More boats mean porpoises can be hit by propellers. Boat noise can also make it hard for them to communicate. It can also interfere with their biosonar, which they use to find food and move around. Deaths from boat collisions have increased a lot recently.
Widespread sand mining in the river and lake beds also harms the porpoises. It destroys their homes and food sources. This problem is very serious in Dongting and Poyang Lakes. Many people and factories live along the river. They release a lot of waste into the water. While not fully proven, some porpoises have died from harmful chemicals like pesticides in the water. This happened in Dongting Lake in April 2004.
Dams also greatly affect the river and lake environments. They block porpoises from moving between the river and connected lakes. Dams also affect the fish that porpoises eat. The Three Gorges Dam has changed the Yangtze River. Building the Poyang Lake Dam could severely harm the remaining porpoise population.
Protecting the Yangtze Finless Porpoise
In 2014, about 505 porpoises lived in the main Yangtze River. Their numbers were especially low in Ezhou and Zhenjiang. Even though they are protected, their population decline has sped up. From 2006 to 2012, the porpoise population dropped by more than half. A 2012 survey by the World Wildlife Fund showed a decline rate of 13.7% per year. By 2017, the number in the Yangtze had increased to 1,012. Thanks to ongoing protection efforts, porpoises have been seen again in places like Nantong.
The huge growth of Chinese industry since 1990 has caused many problems. It led to more shipping, pollution, and environmental damage. This includes building dams and illegal fishing. To protect the species, China's Ministry of Agriculture gave it the highest protection status. This makes it illegal to harm a porpoise.
The Tian-e-Zhou Oxbow Nature Reserve has worked for many years to protect these porpoises. This reserve is supported by the Chinese government, the World Wildlife Fund, and others. It successfully increased its porpoise population from five to forty over 25 years. By 2017, there were 80 individuals there. This was close to the reserve's maximum capacity of 100.
The Chinese Academy of Sciences' Wuhan Institute of Hydrobiology works with the World Wildlife Fund. They are trying to secure the future for this porpoise. They have moved five porpoises to another safe area, the He-wang-miao oxbow.
Five protected natural reserves have been created. These are in areas where many porpoises live or where many have died. In these reserves, harmful fishing gear and patrolling are banned. Scientists are also studying porpoise biology. This helps them with special conservation methods, like breeding porpoises in captivity. The Baiji Dolphinarium was set up in 1992. It allows scientists to study porpoise behavior and biology. They learn about things like how hormones change during breeding season.
The first Yangtze finless porpoise born in captivity arrived on July 5, 2005. This happened at the Baiji Dolphinarium in Wuhan. Scientists have also mapped the porpoise's entire genetic code. This helps them understand its genetic health. It also helps manage the population. This research showed increased risks to the species' genetic health.
