Paddlefish
All about Paddlefish
What's In a Name?Common Name:
Paddlefish a.k.a. Spoonbill: from its snout that looks similar to that of a paddle.
Scientific Name:
Polyodon: (Polly´-oh-don) means "many toothed" in Greek spathula: (spat´-you-lah) from "spatula," referring to the shape of its snout.
Where Do They Live?
In Minnesota, paddlefish inhabit the lower St. Croix River (below Taylors Falls), the Mississippi River (below the Ford Dam), and the Minnesota River (below Mankato). They used to be more abundant and widely distributed, but today its numers are greatly reduced because of the construction of dams and flow prevention systems, pollution and past commercial harvest. Paddlefish prefer the open water of large rivers and riverine lakes (Lake Pepin and Lake St.Croix are examples) that are deep and wide.
How Big Do They Get?
The paddlefish rarely exceeds 50 lbs. in Minnesota, but farther south it has been known to exceed 150 lbs. and approach 7 feet in length. It is one of the largest freshwater fishes in North America. Paddlefish are long-lived. Individuals 20 years old are common, and some live 30 years or more.
What Do They Eat?
Given the large size of paddlefish you might expect that they eat large prey. However, they are planktivores--meaning they feed on microscopic plants and animals in the water column. They are the biggest planktivore in Minnesota. The paddlefish may use its long, paddle-like snout for locating food organisms. It feeds by swimming with its huge mouth open, straining water through its mouth and out its gills. The prey items are filtered out by its long gill rakers. In this way, it consumes huge amounts of plankton each day and grows to its enormous size.
What Eats Them?
Not much is known about the life history of young paddlefish and so we are not sure what eats them. Because of their great size, adult paddlefish have few predators. Paddlefish are heavily parasitized by lampreys (causing injury by attaching themselves to and feeding off the paddlefish). In the late 1800s and early 1900s, paddlefish were commercially fished for their meat and caviar (fish eggs). Overharvest and habitat destruction led to a drastic decline in their abundance. Today, paddlefish are protected from commercial and sport harvest in Minnesota.
"Cool Fact"
The paddlefish is a species of ancient origins. It is a member of an ancient family of freshwater fishes represented by only two living species.
Credits: Photograph by Konrad P. Schmidt. Text modified from Bell Museum of Natural History, Fishes of Minnesota Web site (Nicole Paulson & Jay T. Hatch authors)