Dabry's sturgeon (''Acipenser dabryanus''), also known as the Yangtze sturgeon, Chiangjiang sturgeon and river sturgeon, is a species of fish in the
sturgeon
Sturgeon is the common name for the 27 species of fish belonging to the family Acipenseridae. The earliest sturgeon fossils date to the Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretace ...
family,
Acipenseridae
Sturgeon is the common name for the 27 species of fish belonging to the family Acipenseridae. The earliest sturgeon fossils date to the Late Cretaceous, and are descended from other, earlier acipenseriform fish, which date back to the Early ...
.
[Zhuang, P., et al. (1997)]
Biology and life history of Dabry's sturgeon, ''Acipenser dabryanus'', in the Yangtze River.
''Environmental Biology of Fishes'' 48(1-4), 257-64. It is
endemic
Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...
to
China
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
and today restricted to the
Yangtze River
The Yangtze or Yangzi ( or ; ) is the longest list of rivers of Asia, river in Asia, the list of rivers by length, third-longest in the world, and the longest in the world to flow entirely within one country. It rises at Jari Hill in th ...
basin,
but was also recorded from the
Yellow River
The Yellow River or Huang He (Chinese: , Standard Beijing Mandarin, Mandarin: ''Huáng hé'' ) is the second-longest river in China, after the Yangtze River, and the List of rivers by length, sixth-longest river system in the world at th ...
basin in the past.
It was a
food fish
Food is any substance consumed by an organism for nutritional support. Food is usually of plant, animal, or fungal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals. The substance is ingest ...
of commercial importance. Its populations declined drastically, and since 1988, it was designated
an endangered species on the Chinese Red List in Category I and commercial harvest was banned.
It has been officially declared extinct in the wild
A species that is extinct in the wild (EW) is one that has been categorized by the International Union for Conservation of Nature as known only by living members kept in captivity or as a naturalized population outside its historic range due ...
by the IUCN
The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...
as of July 21, 2022.
Appearance
This sturgeon has been known to reach in length, but it is usually much smaller.[Froese, R. and D. Pauly. (Eds.]
''Acipenser dabryanus''.
FishBase. 2011. Its body is blue-gray above and yellowish white on the belly, with five rows of scutes. The head is triangular and the snout is long with the mouth located on the underside. There are two pairs of barbels.[Gao, X., et al. (2009)]
Threatened fishes of the world: ''Acipenser dabryanus'' Duméril, 1869.
''Environmental Biology of Fishes'' 85(2), 117-18.
Behavior
The fish lives in slow-moving river waters over substrates of sand and mud. It feeds on aquatic plant
Aquatic plants are plants that have adapted to living in aquatic environments (saltwater or freshwater). They are also referred to as hydrophytes or macrophytes to distinguish them from algae and other microphytes. A macrophyte is a plant that ...
s, invertebrates, and small fish. This species is potamodromous, taking part in a migration, but never leaving fresh water.[ It ]spawns
Spawn is the eggs and sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of releasing the eggs and sperm, and the act of both sexes is called spawning. Most aquatic animals, except for aquat ...
in the upper Yangtze, mainly during March and April, and sometimes around November and December. Males spawn each year, but most females do not. The female produces 57,000 to 102,000 eggs.[
]
Conservation status
This was once a common fish in the Yangtze system.[ It was known from the main river and some of its larger ]tributaries
A tributary, or affluent, is a stream or river that flows into a larger stream or main stem (or parent) river or a lake. A tributary does not flow directly into a sea or ocean. Tributaries and the main stem river drain the surrounding drainage b ...
, as well as some lakes attached to the system. By the late 20th century, it was extirpated from the lower river and limited to the upper reaches in Sichuan
Sichuan (; zh, c=, labels=no, ; zh, p=Sìchuān; alternatively romanized as Szechuan or Szechwan; formerly also referred to as "West China" or "Western China" by Protestant missions) is a province in Southwest China occupying most of the ...
. The main causes of its drastic decline include overfishing
Overfishing is the removal of a species of fish (i.e. fishing) from a body of water at a rate greater than that the species can replenish its population naturally (i.e. the overexploitation of the fishery's existing fish stock), resulting in th ...
, including the overharvesting of juveniles. The construction of dam
A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, a ...
s, notably the Gezhouba Dam
The Gezhouba Dam or Gezhouba Water Control Project () on the Yangtze River is located in the western suburbs of Yichang, in central China's Hubei province. One of the largest run-of-the-river dams, it sits several kilometers upstream from downtow ...
and Three Gorges Dam, blocked the movement of the fish along the river, restricting it to the upper reaches. It also caused habitat fragmentation
Habitat fragmentation describes the emergence of discontinuities (fragmentation) in an organism's preferred environment (habitat), causing population fragmentation and ecosystem decay. Causes of habitat fragmentation include geological processes ...
and degradation. Increased development and deforestation
Deforestation or forest clearance is the removal of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. The most concentrated d ...
on land near the river has increased pollution
Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the ...
from wastewater and runoff
Runoff, run-off or RUNOFF may refer to:
* RUNOFF, the first computer text-formatting program
* Runoff or run-off, another name for bleed, printing that lies beyond the edges to which a printed sheet is trimmed
* Runoff or run-off, a stock market ...
. The Yangtze basin is and was its main range, but it has also been found in the Yellow River basin, with the last records in the 1960s.[
The fish has been bred in captivity since the 1970s. Thousands of individuals have been released into the Yangtze basin, but are apparently not breeding. Nevertheless, this restocking may be the only effort preventing the ]extinction
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...
of the species.
See also
* List of endangered and protected species of China
The endangered species of China may include any wildlife species designated for protection by the national government of China or listed as endangered by international organizations such as the Convention on International Trade in Endangered Sp ...
* Chinese sturgeon
The Chinese sturgeon (''Acipenser sinensis''; ) is a critically endangered member of the family Acipenseridae in the order Acipenseriformes. Historically, this anadromous fish was found in China, Japan, and the Korean Peninsula, but it has b ...
(''Acipenser sinensis'')
* Chinese paddlefish (''Psephurus gladius'')
References
{{Portal bar, Fish, Animals, Biology, China
Acipenser
Critically endangered fish
Critically endangered fauna of Asia
Endemic fauna of China
Fish described in 1869
Freshwater fish of China
Species endangered by damming
Taxonomy articles created by Polbot
Yangtze River