American paddlefish

A paddlefish ( Polyodon spathula )

The paddlefish ( Polyodon spathula ) is the only species of the monotypic genus Polyodon. The paddlefish ( Polyodontidae ) family is compared with the sister taxon sturgeon ( Acipenseridae ) and next to the genus Polyodon includes just another monotypic genus. His appearance differs quite strongly from that of the genuine sturgeon, which is why he was also originally considered a type of Süßwasserhai. He is about 1.5 to 2 meters tall.

The genus Polyodon has been known since the Upper Cretaceous and has long been described only fossil. Larvae of Polyodon spathula, however, were only discovered in 1932 on the banks of the Mississippi and have no frontal process. It is interesting that they still have small teeth that no longer have the adult specimens.

Appearance

The forehead is drawn out to a powerful extension. This flattened, flexible structure reaches about one-third of the total length of the fish. The completely unscaled skin may be covered with individual small bones grains, only the upper lobe of the unbalanced ( heterozerken ) caudal fin, there are some Ganoidschuppen.

Nutrition

The paddlefish feeds on small crustaceans and plankton, which he seiht with enlarged gill appendages from deep water.

Occurrence

The up to 1.80 meters long paddlefish was once widespread across the river basins of the Mississippi River. Dams, water pollution and overfishing have brought him to the brink of extinction, not least because the meat and the roe of the sturgeon spoons are considered very delicate. In recent decades, several projects were launched for commercial breed paddlefish in ponds.