Paddlefish, ancient and unique freshwater fish, captivate attention with their impressive size. Recognized by their distinctive paddle-shaped snouts and filter-feeding behavior, they are one of North America’s largest freshwater fish species.
Paddlefish Size and Growth
Adult paddlefish average around 1.5 meters (4.9 feet) in length and weigh about 27 kilograms (60 pounds). While some individuals can reach up to 2.13 meters (7 feet) and weigh as much as 91 kilograms (200 pounds), the average weight for most mature paddlefish often ranges between 4.5 to 6.8 kilograms (10 to 15 pounds).
Female paddlefish grow larger and have longer lifespans than males. Fish over 18 kilograms (40 pounds) are typically female, reaching ages of up to 40 years with an average age of 27 years. Males rarely exceed 18 kilograms (40 pounds) and have an average age of 20 years.
Paddlefish grow rapidly in their initial year, reaching lengths of 30 to 35 centimeters (12 to 14 inches), with some growing up to 50 centimeters (20 inches) under optimal conditions. As they mature, their growth rate decelerates, averaging about 5 centimeters (2 inches) per year by five years of age. They continue to grow throughout their extended lifespans, which can exceed 30 years, and may live for 50 years or longer.
Factors Influencing Paddlefish Size
Age is a primary determinant of paddlefish size, as they continue to grow throughout their long lives. Older individuals accumulate more mass and length over time. This extended lifespan allows for significant growth.
Habitat quality influences growth potential, with large, undisturbed river systems providing optimal conditions. Paddlefish in reservoir environments exhibit faster growth rates than those in riverine habitats, due to increased food availability and reduced water current, which minimizes metabolic expenditure. Conversely, habitat degradation and fragmentation, particularly from dams, can restrict movement and access to suitable areas, impacting growth.
Abundant zooplankton, their primary food source, is important for rapid growth. A plentiful supply allows paddlefish to gain up to 4.5 kilograms (10 pounds) annually during early life stages. Water temperature also affects their metabolism and feeding efficiency. An individual fish’s genetic makeup contributes to its growth potential, and environmental conditions can lead to size differences among populations.
Record-Breaking Paddlefish
Exceptional paddlefish catches highlight the species’ growth potential. A new world record was established on March 17, 2024, when Chad Williams landed a 74.7-kilogram (164-pound, 13-ounce) paddlefish from the Lake of the Ozarks in Missouri. This specimen surpassed a previous world record of 74.3 kilograms (164 pounds) caught in Oklahoma’s Keystone Lake in June 2021.
Historically, even larger paddlefish have been reported, including an 89.8-kilogram (198-pound) fish taken by a spearfisherman in Iowa in 1916. Some U.S. Fish & Wildlife Service accounts mention specimens exceeding 181 kilograms (400 pounds). Montana’s state record, set in 1973, stands at 64.6 kilograms (142.5 pounds).
The capture of such large paddlefish demonstrates the species’ capacity for great size. However, these record-breaking specimens are rare in modern times, partly due to habitat alterations and historical overfishing. Some of the largest recorded females are non-reproductive, suggesting they channel energy into somatic growth rather than egg production.