American paddlefish
The American paddlefish is an ancient species of fish that has existed for approximately 125 million years, originating from the Cretaceous period. It is primarily found in the river systems of the Mississippi and Missouri Rivers, as well as in bayous, reservoirs, and lakes. Notable for its long, broad snout, which can reach up to two meters in length, the paddlefish uses this unique feature, likely equipped with sensitive taste buds and possible electrical sensory organs, to navigate and locate food in the water. The paddlefish primarily feeds on crustaceans and aquatic insect larvae, utilizing its large mouth to gulp water and filter food.
Typically, paddlefish can grow between five to seven feet long, with some reports indicating specimens reaching up to ten feet. Their spawning season spans from February in southern regions to May in northern areas, during which they gather in groups to release and fertilize eggs on clean gravel beds. Despite their long lifespan of up to 50 years, paddlefish face threats from overfishing, pollution, and habitat disruption. Additionally, their flesh is considered edible, resembling catfish, while their roe is harvested for caviar. Understanding the biology and ecology of the American paddlefish is essential for conservation efforts and sustainable management of their populations.
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American paddlefish
The American paddlefish is one of the oldest living species, dating back 125 million years to the Cretaceous period. They reside in rivers, reservoirs, bayous, and lakes and are rarely seen. They are named for their long, broad, flat snout, which may be one-third of their total length, or up to seven feet (two meters) long. The uses of the paddlefish's paddle are not known for certain, but it is most likely used to find food and to maintain balance.
Kingdom: Animalia
Phylum: Chordata
Class: FT.Osteichthyes
Order: Acipenseriformes
Family: Polyodontidae
Genus: Polyodon
Species: Spathula
The American paddlefish is a relative of the sturgeon and belongs to the same ancient order of fish. Because of this relationship and its unusually-shaped head, this fish has also been called the spoonbill sturgeon. Between the eyes of the paddlefish grows a large, paddle-shaped snout. The snout is broad, flat, and may be over two feet (60 centimeters) long, or one-third of the fish's overall length. Hundreds of sensitive taste buds cover the surfaces of the snout, which may help the fish find its food. It is not known for certain, but it is possible that the fish's snout has electrical sensory organs for detecting plankton in the water. It may also scoop and dig in the mud for food, or beat plants to stir small organisms from hiding. The paddle may also help stabilize, or balance, the fish's head as it swims and feeds.
Behind and on the underside of the paddle is a large, gaping mouth which gulps water and food as the fish swims. On either side of the head and behind the eyes is a large flap of skin called a gill cover which covers and protects the gills. As the fish swims, it also opens its gill covers so the water which enters its mouth may leave through these openings. The delicate network of gills removes oxygen from the water while the gill rakers filter food from the water into the throat. When the throat is full of crustaceans and aquatic insect larvae, the paddlefish swallows and then continues its nightly feeding. During the day it rests in deep pools.
Behind the gill covers is a pair of pectoral fins and a pair of pelvic fins, both on the fish's underside. Farther along the smooth-skinned, greenish or gray body of the paddlefish is one large anal fin (at the rear and on the bottom) and one rear dorsal fin (on the back). At the end of the fish's body is the large, two- lobed tail. The total length of the adult paddlefish ranges between five and seven feet (1 1/2 to 2 meters) long, but there are reports of paddlefish being 10 feet (three meters) long. Maximum weights are up to 175 pounds (80 kilograms), but the average is 40 pounds (18 kilograms).
American paddlefish live in the extensive river systems of the Mississippi and Missouri Rivers and their tributaries. They swim most frequently in the deep, slow-moving sections of these rivers where the water is fairly clear and gravel lines the bottom. Outside the main river systems, the fish may also inhabit bayous, reservoirs, and lakes. They spawn where there is plenty of clean gravel on which to lay and fertilize their eggs. If too much silt and sand cover the gravel, the fish find another place to spawn. Another they may find another place to spawn is dams' blocking the paths of their spawning runs. The spawning season for the American paddlefish lasts from February in the south to May in the north. During this time the fish, which normally live alone, gather on beds of gravel. After the females release their eggs into the water, the males fertilize the eggs. The eggs then sink to the bottom and stick to the place where they come to rest. Each female may release several hundred eggs. Five to ten days later, the young paddlefish hatch and begin scurrying about for food. Their paddles begin to appear after two to three weeks, and the young grow about one foot each year for the first couple years. They are able to spawn when they are seven to eight years old. The life span of American paddlefish is up to 50 years.
Some threats to the paddlefish are overfishing, pollution, and other human activity.
It is reported that the flesh of the American paddlefish tastes somewhat like catfish, and the eggs, or roe, of are a source of caviar.
Bibliography
Jerome, John. “Polyodon Spathula (American Paddlefish).” Animal Diversity Web, animaldiversity.org/accounts/Polyodon‗spathula/. Accessed 22 Mar. 2024.
“Paddlefish (Polyodon Spathula).” U.S. Fish and Wildlife Service, www.fws.gov/species/paddlefish-polyodon-spathula. Accessed 22 Mar. 2024.