American paddlefish
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| iMississippi Paddlefish | ||||||||||||||
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| Polyodon spathula (Walbaum in Artedi, 1792) |
The American Paddlefish, Polyodon spathula, also called the Mississippi Paddlefish or Spoonbill, lives in slow-flowing waters of the Mississippi River drainage system. This large freshwater fish may grow to 220 cm (7 ft) and weigh up to 100 kg (220 lbs). The paddlefish takes its common and scientific names from its distinctive snout, which is greatly elongated and flattened into a paddle shape. The American Paddlefish is believed to use sensitive electroreceptors on its paddle to detect prey, as well as to navigate while migrating to specific spawning sites. The paddlefish feeds primarily on zooplankton which it filters from the water using enlarged gill rakers.
Once common throughout the Midwest, overfishing has caused major population declines, as both the meat and roe of the paddlefish are desirable as food. River alteration is also a major factor in the decline of paddlefish populations, as dams and other manmade obstacles prevent the fish from reaching places they once occurred in. Until about 1900 the paddlefish was also found in the Great Lakes, as well as in river systems in adjacent U.S. states and Canadian provinces. Invasive species such as zebra mussels have reduced the number of zooplankton in the Great Lakes to such low levels that any paddlefish reintroduction program seems unlikely to succeed. Recently, examples of paddlefish were spotted in the Danube river. It has still not been confirmed whether these fished escaped from Romanian or Bulgarian fish farms during the 2006 European floods, or whether they were let into the Danube earlier and matured in the river.
The American Paddlefish is a popular sport fish in states that retain sufficient populations. Since they are filter-feeders, paddlefish will not accept bait or lures and must be caught by snagging. Several states, including Missouri, have enacted stocking programs for these fish in reservoirs where the resident populations were low or nonexistent, or in areas where historical populations are no longer naturally sustainable.
Polyodon spathula is one of two living species of Paddlefish.
[edit] References
- Grady (2004). Polyodon spathula. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 11 May 2006. Database entry includes a lengthy justification of why this species is vulnerable
- Polyodon spathula (TSN 161088). Integrated Taxonomic Information System. Accessed on 30 January 2006.
- "Polyodon spathula". FishBase. Ed. Ranier Froese and Daniel Pauly. 10 2005 version. N.p.: FishBase, 2005.
