Paddlefish

Paddlefishes Temporal range: Barremian–Recent PreꞒ Ꞓ O S D C P T J K Pg N [1]
American paddlefish, Polyodon spathula
Chinese paddlefish, †Psephurus gladius
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Acipenseriformes
Suborder:	Acipenseroidei
Family:	Polyodontidae Bonaparte, 1838
Genera
Recent genera Polyodon †Psephurus Fossil genera †Crossopholis †Paleopsephurus †Parapsephurus[2] †Protopsephurus †Pugiopsephurus[2]

Paddlefish (family Polyodontidae) are a family of

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.^[13]

Morphology

Paddlefish as a group are one of the few organisms that retain a

The largest Chinese paddlefish on record measured 23 ft (7.0 m) in length, and was estimated to weigh a few thousand pounds.^[10] They commonly reached 9.8 ft (3.0 m) and 1,100 lb (500 kg).^[10][11][16] Although the American paddlefish is one of the largest freshwater fishes in North America, their recorded lengths and weights fall short in comparison to the larger Chinese paddlefish. American paddlefish commonly reach 5 ft (1.5 m) or more in length and can weigh more than 60 lb (27 kg). The largest American paddlefish on record was caught in 1916 in Okoboji Lake, Iowa.^[17] The fish was taken with a spear, and measured 7 ft 1 in (2.16 m) long and 45.5 in (1.16 m) in the girth.^[17] A report published by J. R. Harlan and E. B. Speaker in Iowa Fish and Fishing (1969) said the fish weighed over 198 lb (90 kg).^[18] The world record paddlefish caught on rod and reel weighed 144 lb (65 kg) and was 54.25 in (1.378 m) long. The fish was caught by Clinton Boldridge in a 5-acre pond in Atchison County, Kansas on May 5, 2004.^[19][20] However, the record would be broken an additional two times in 2020. On June 28, 2020, an Oklahoma man caught a 146-pounder in Keystone Lake, west of Tulsa. Later on July 23, 2020, the record was broken again when another Oklahoma man caught a 151-pound, nearly 6-foot long Paddlefish in the same lake.^[21]

Scientists once believed paddlefish used their rostrums to excavate bottom substrate,

Over the past half century, paddlefish populations have been on the decline. 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. There is growing concern about their populations in other states.

The Chinese paddlefish was considered

Paddlefish are long-lived, and sexually late maturing. Females do not begin spawning until they are six to twelve years old, some even as late as sixteen to eighteen years old. Males begin spawning around age four to seven, some as late as nine or ten years of age.[14]^[31][4] Paddlefish spawn in late spring provided the proper combination of events occur, including water flow, temperature, photoperiod, and availability of gravel substrates suitable for spawning. If all the conditions are not met, paddlefish will not spawn. Research suggests females do not spawn every year, rather they spawn every second or third year while males spawn more frequently, typically every year or every other year.^[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.

The advancements in biotechnology in paddlefish propagation and rearing of captive stock indicate significant improvements in reproduction success, adaptation and survival rates of paddlefish cultured for broodstock development and stock rehabilitation. Such improvements have led to successful practices in reservoir ranching and pond rearing, creating an increasing interest in the global market for paddlefish polyculture.[34]^[35]

In a cooperative scientific effort in the early 1970s between the US Fish & Wildlife Service and its former

In 1988, fertilized paddlefish eggs and larvae from Missouri hatcheries were first introduced into China.[37] 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. China has also exported paddlefish to Cuba, where they are farmed for caviar production.^[35]

Classification

There is one currently

Classification after Grande and Bemis (1991),[24] with Parapsephurus and Pugiopsephurus added after Hilton et al. (2023):^[2]

• Genus †Protopsephurus Lu, 1994 (Early Cretaceous, China)
  • Species †Protopsephurus liui Lu, 1994
• Genus †Pugiopsephurus Hilton et al., 2023 (Late Cretaceous, North America) (Incertae sedis)
  • Species †Pugiopsephurus inundatus Hilton et al., 2023
• Clade Polyodonti
  • Genus †Paleopsephurus MacAlpin, 1947 (Late Cretaceous, North America)
    • Species †Paleopsephurus wilsoni MacAlpin, 1947
  • Genus †Parapsephurus Hilton et al., 2023 (Late Cretaceous, North America)
    • Species †Parapsephurus willybemisi Hilton et al., 2023
  • Subfamily Polyodontinae
    • Genus †
      Psephurus Günther
      , 1873
      • †Psephurus gladius E. von Martens, 1862 Chinese paddlefish (extinct c. 2003)
    • Tribe Polyodontini
      • Genus †Crossopholis Cope, 1883 (Paleogene, North America)
        • Species †Crossopholis magnicaudatus Cope, 1883
      • Genus
        Polyodon Lacépède, 1797 (Paleocene
        -Recent, North America)
        • Polyodon spathula Walbaum, 1792 American paddlefish
        • †Polyodon tuberculata [Wikidata] Grande & Bemis, 1991

Relationships of the genera, after Grande et al. (2002).^[38]

References

External links

Wikimedia Commons has media related to Polyodontidae.

• One hour PBS documentary
• The Chinese Paddlefish Website – containing many photographs of Psepherus.
• images and movies of the paddlefish (Polyodon spathula) ARKive
• FishBase entry for Polyodontidae
• USGS UMESC Paddlefish Study
• Fisheries.org
• Paddlefish Fisheries Management
• Stochastic synchronization of electroreceptors in the paddlefish