The other is the Chinese paddlefish (Psephurus gladius), which was declared extinct in 2022 following a 2019 recommendation;[6][7][8] the species has not been sighted in the Yangtze River Basin in China since 2003.

[11] The earliest known paddlefish is Protopsephurus, from the early Cretaceous (Aptian) of China, dating to around 120 million years ago.

Paddlefish populations have declined dramatically throughout their historic range as a result of overfishing, pollution, and the encroachment of human development, including the construction of dams that have blocked their seasonal upward migration to ancestral spawning grounds.

[12] Other detrimental effects include alterations of rivers which have changed natural flows resulting in the loss of spawning habitat and nursery areas.

Some common morphological characteristics of paddlefish include a spindle-shaped, smooth-skinned scaleless body, heterocercal tail, and small poorly developed eyes.

[19][20] However, the record would be broken an additional two times in 2020: On 28 June 2020, an Oklahoma man caught a 146 pound paddlefish in Keystone Lake, west of Tulsa.

Some reports incorrectly suggest that a damaged rostrum would render paddlefish less capable of foraging efficiently to maintain good health.

Attributable causes are overfishing, pollution, and the encroachment of human development, including the construction of dams which block their seasonal upward migration to ancestral spawning grounds.

Other detrimental effects include alterations of rivers which have changed the natural flow, and resulted in the loss of spawning habitat and nursery areas.

American paddlefish have been extirpated from much of their Northern peripheral range, including the Great Lakes and Canada, New York, Maryland and Pennsylvania.

[10][25] Research suggests they preferred to navigate the middle and lower layers of the water column, and occasionally swam into large lakes.

[7] Past attempts of artificial propagation for restoration purposes failed because of difficulties encountered in keeping captive fish alive.

[27] They have been found in several Gulf Slope drainages in medium to large rivers with long, deep sluggish pools, as well as in backwater lakes and bayous.

[14] Paddlefish migrate upstream to spawn, and prefer silt-free gravel bars that would otherwise be exposed to air, or covered by very shallow water were it not for the rises in the river from snow melt and annual spring rains that cause flooding.

Such improvements have led to successful practices in reservoir ranching and pond rearing, creating an increasing interest in the global market for paddlefish polyculture.

[36] Since that time, China imports approximately 4.5 million fertilized eggs and larvae every year from hatcheries in Russia, and the United States.

Some of the paddlefish are polycultured in carp ponds, and sold to restaurants while others are cultured for brood stock and caviar production.