Chinese paddlefish

## Psephurus

The Chinese paddlefish, or *Psephurus*, is a presumably extinct genus of paddlefish that lived in Asia, unanimously declared extinct in 2019.

## Description

The Chinese paddlefish has a notable white underbelly, a grey head and body, with it's fins, snout and other locations are a pinkish red. A defined white ridge extends from the middle of the body down to the caudal fin. Their dorsal and anal fins sit far down their bodies. The titular paddle has a triangle profile, which does not flatten; opposed to the rectangular flattened fins of their American counterparts. The paddle is narrowed and pointed, reaching about one third of the total body length. The Chinese paddlefish has small eyes. The jaws are protrusible, with many small pointed teeth. The tail fin is heterocercal, with a well-developed caudal lobe. Like many other Acipenseriformes, the skeleton is cartilaginous and the body is smooth and largely lacks scales, except for small scales on the caudal and peduncle fin. When reaching sexual maturity, an individual weighs about 25 kilograms (55 pounds), and by age seven or eight, was 2 meters (6 feet 7 inches) long. Anecdotal reports place some individuals at 500 kilograms (1100 pounds) in weight and 7 meters (23 feet long), some telling of Chinese paddlefish several thousand pounds in weight. Little research is done on the maximum size of the Chinese paddlefish, due to the species endangered nature and little sightings, though a size of 3 meters (10 feet) long and 300 kilograms (660 pounds) in weight is generally a more accepted average.

## History

### Taxonomy

The Chinese paddlefish was first classified as a species of *Polyodon* in 1862 by Eduard von Martens. From there, it was classified further to a new monotypic genus, *Psephurus* by Albert Günther in 1873. Then, the fish was given the name *Polyodon angustifolium* in 1862 by Johann Jakob Kaup, now considered a junior synonym of *P. gladius*.

### Conservation

The Chinese paddlefish has been included as a first-level protected animal in China since 1983, and on the CITES Appendix II since 1998. The last individual spotted alive was in 2003, with anecdotes of a dead individual in 2007. Since 2019, the fish was published on, reported extinct. However, their status last updated June 2020. The last record of Chinese paddlefish dates back to the 1960s, although declines noticed between the 13th and 19th century. Significant declines in the Yangtze basin (primary range), although continuing capture of individuals around 25 tonnes continued since the 1970s. Small groupings of paddlefish were found in the 1980s (like a group of 32 caught in 1985), with immature seen as soon as 1995.

Since 2000, two confirmed individuals have been caught. One, a 3.3 meter (11 feet) long and 117 kilogram (258 pounds) in weight female caught in Nanjing in 2002. The second, a 3.52 meter (11.5 feet) long and 160 kilogram (352 pounds) in weight female accidentally caught at Yibin, Sichuan on January 24, 2003 by fisherman Liu Longhua. Although the first died despite lifesaving attempt and the latter, radio-tagged and released, however stopped functioning after 12 hours.

A search conducted on the Yangtze basin between 2006 and 2008 conducted by the Chinese Academy of Fisheries Science failed to catch any individuals, however two likely individuals were identified via hydroacoustic signals. Very small populations may survive, but many officials consider the Chinese paddlefish extinct. The 2019, the study points that the species is likely extinct due to extensive capture expeditions between 2017 and 2018 failed, authors placing the extinction date between 2005 and 2010, functionally extinct by 1993.

### Extinction

The Chinese paddlefish was thought to have gone extinct due to overfishing and critical habitat loss. Young schooled, easily caught by traditional methods. This reduced sustainability in viable populations. Additionally, dams such as the Gezhouba Dam and the Three Gorges Dam locked populations from one-another and prevented spawning. The authors of the 2019 paper recommended the IUCN to reclassify the Chinese paddlefish as Extinct. Co-author and professor Wei Qiwei of the Yangtze River Fisheries Research Institute reported the Chinese paddlefish's extinction on CCTV.

## Biology

### Distribution

The Chinese paddlefish was native to the Yangtze River and the accompanying estuary at the East China Sea. The species is also historically known from the Yellow River basin and estuary at the Yellow Sea, which connects to the Yangtze River by the Grand Canal.

### Ecology

The Chinese paddlefish starts off it's life at the lower sections of the Yangtze, which includes the brackish estuary, migrating upstream into major tributaries, spawning. This starts in Spring, mid-March through early April. The fish primarily swam in large rivers, sometimes moving into large lakes. Because of their anadromous nature, mature specimens are often found coastal of the East China and Yellow Seas, tides sometimes carrying individuals into the lower Qiantang and Yangjian rivers

Chinese paddlefish are often solitary and occupying the mid/lower water column. Chinese paddlefish are noted strong swimmers. Unlike the American paddlefish that is planktivorous, the Chinese paddlefish is mostly piscivorous. Notable medium/small fishes and aquatic life include; *Coilia, Coreius, Rhinogobio, Gobius*, Bagrids, Bothids, shrimp and crab. The American paddlefish can likely use electroreceptors on their snouts to detect prey, and the Chinese paddlefish can likely do the same. However, due to rarity and possible extinction, no testing on this theory has been done.

## Etymology

The Chinese paddlefish, known as elephant fish (象魚; xiàngyú), due to the fishes rostrum resembling an elephant's trunk, is sometimes recorded in Classical Chinese (鮪; wěi-fish). When used in a more poetic stance, it is referred to as the "Giant Panda of the Rivers" due to it's protection and rarity. The genus name derives of the Greek "pseph" (pebble) and "phoreus" (bearer of), which combines to "psepharos" (gloomy/cloudy one).

## References

https://en.wikipedia.org/wiki/Chinese\_paddlefish