The Yangtze finless porpoise is the world’s only freshwater porpoise, inhabiting the Yangtze River in China. This unique status means it is recognized as a critically endangered species. With a population estimated at only 1,249 individuals in 2023, the species faces an uncertain future. The animal’s distinct facial expression has earned it the nickname “smiling angel.” This creature navigates a river ecosystem under immense pressure from human activity.
Physical Characteristics and Behavior
The Yangtze finless porpoise has a smooth, gray-skinned body that is stocky in build. A distinguishing feature is the absence of a true dorsal fin. Instead, it possesses a low, narrow ridge along its back that is covered in small, wart-like tubercles. Adults can reach lengths of up to 2 meters (6.5 feet) and weigh up to 72 kilograms.
This porpoise relies on a sophisticated form of echolocation to navigate and hunt in the murky waters of the Yangtze. Its diet consists mainly of small fish, crustaceans like shrimp, and mollusks. They are known to chase prey at high speeds, executing sharp turns and rapid accelerations. While often seen alone or in small groups, female porpoises give birth to a single calf in the spring or summer.
Habitat and Distribution
The geographic range of the Yangtze finless porpoise is limited to freshwater environments in China. Its population is concentrated in the middle and lower reaches of the Yangtze River. Beyond the main river channel, the porpoise also resides in two large, connected freshwater lakes: Poyang Lake and Dongting Lake. These lakes serve as important refuges for the species.
This habitat is also one of the world’s most developed and busiest rivers. The constant presence of human activity along the river creates a challenging environment for the porpoises. The species is not migratory, but its distribution can shift seasonally within this river system.
Threats to Survival
A major issue is illegal fishing and the use of harmful fishing gear. Porpoises frequently become entangled in fishing equipment such as rolling hooks and gillnets, which can lead to injury and drowning. This accidental capture, known as bycatch, has been a contributor to population decline.
Intense vessel traffic along the Yangtze presents another danger. The river is a major artery for shipping, and the high volume of boats and large ships creates a constant risk of collisions. These encounters can result in severe injuries or death from propeller strikes.
Habitat degradation poses a threat from multiple sources. Sand dredging, the large-scale removal of sand from the riverbed, destroys the physical environment the porpoises depend on. This practice disrupts the river’s ecosystem and has been linked to habitat loss. Pollution from industrial and agricultural runoff also contaminates the water, affecting the porpoises and their food sources.
The underwater environment of the Yangtze is filled with noise from the engines of countless vessels. This noise pollution directly interferes with the porpoise’s sensitive echolocation. This interference can impair their ability to communicate, hunt for food, and sense potential dangers in their surroundings.
Conservation Efforts
In-situ conservation efforts involve measures taken directly within the Yangtze River ecosystem. China has elevated the porpoise to the highest level of national protection, National First Grade Key Protected Wild Animal. A 10-year fishing ban was also implemented in the Yangtze River starting in 2021 to help fish stocks and porpoise populations recover.
Ex-situ conservation involves relocating porpoises to protected environments away from the threats of the main river. A success in this area is the Tian-e-Zhou Oxbow, a former section of the river channel that now serves as a semi-wild reserve. This protected oxbow lake provides a controlled environment where the porpoises can breed. The goal is to establish a healthy, breeding population as a safeguard against extinction.