- About Us
- Contact Us
Physical characteristics - Early investigators once thought that the paddlefish used their snouts to dig vegetation from the bottom of lakes and rivers long ago, although today's investigators now know that they feed by filtering out zooplankton (Leptodora kindtii) organisms from the water, using filaments located on their gill arches called "gill rakers". While the fish is swimming throughout the water with its mouth open, the food is caught in these rakers which then the fish can digest. A recent study that has been conducted demonstrated that a paddlefish has electro sensory receptors in its rostrum that can detect some weak electrical fields suggesting that they use their rostrum as an antenna to detect zooplankton. Even though the rostrum seems to help the fish feed, it has been observed that fish with severely damaged or missing rostrums are able to feed and are just as healthy as other fish with them intact. The rostrum also helps the fish to feed by acting as a stabilizer. As the fish moves through the water with its mouth open, the rostrum creates lift, much like a wing of an airplane. This helps the fish by keeping its head in a steady position and helps it keep from diving to the bottom.
Caviar harvest - During the last century, paddlefish and sturgeon have stimulated the world stock trades with their eggs (roe), called caviar. Paddlefish and sturgeon are two of the most important fish for freshwater caviar. Paddlefish take many years before they are able to spawn. A female may take 9 to 10 years, when they are about 42 inches long, and males 7 years old and 40 inches long are able to spawn. When able to spawn, the female releases adhesive eggs randomly over the water bottom and abandons them. They are capable of producing over one-half million eggs a year, but they may not spawn every year.
Current threats - Due to the value of their eggs, paddlefish are a constant target for poachers, and they are subsequently a protected resource over a large part of their range. Additionally, in many of the 22 states that paddlefish reside, habitat destruction is causing their numbers to decrease more rapidly. Paddlefish need free flowing rivers that have shallow pools with sandy, rocky bottoms. These types of areas are perfect for their spawning. Water must also be at the right temperature for the fish to be capable of spawning. Since today's rivers are constantly being modified by the construction of dams, dredging, and excessive water removal for farming purposes, these types of areas are hard for the paddlefish to locate. In some areas, free flowing lakes with reservoirs are sometimes able to provide paddlefish with the right breeding habitat. One such area like this is the Missouri River-Lake Sakakawea system in North Dakota. This area is capable of producing good paddlefish numbers because it is a free flowing system with many good areas for paddlefish to spawn. Fishing for paddlefish in violation of local fishing regulations in some states is a felony.