Paddlefish

Paddlefishes (family Polyodontidae) are bizarre-looking primitive ray-finned fishes whose snouts are greatly elongated, about 1/2 the length of the rest of the body. There are only two living species.

The Mississippi paddlefish Polyodon spathula lives in the slow-flowing waters of the Mississippi River system, feeding on zooplankton by straining them through gill rakers[?]. It may grow to 220 cm and weigh up to 100 kg. Its snout is not only long, but flattened into a paddle shape, thus the name; its purpose is still unclear. Once common throughout the Midwest, overfishing (both the meat and roe[?] are desirable) and river alteration have caused major population declines.

The Chinese swordfish Psephurus gladius lives in the Yangtze River. 3-meter specimens weighing 300 kg have been recorded; the reports of 7-meter fish are doubtful.

External links

• FishBase entry for Polyodontidae (http://www.fishbase.org/Summary/FamilySummary.cfm?ID=33)
• USGS UMESC Paddlefish Study (http://www.umesc.usgs.gov/aquatic/fish/paddlefish/main)