end0skeletal: Paddlefish have been referred to as “primitive fish” because they have evolved with fe
end0skeletal: Paddlefish have been referred to as “primitive fish” because they have evolved with few morphological changes since the earliest fossil records of the Late Cretaceous, seventy to seventy-five million years ago. There are two living species, the American paddlefish, which is native to the Mississippi River basin, and the Chinese paddlefish, which is critically endangered. Paddlefish have electroreceptors on their rostrum (the paddle-shaped snout) which can detect weak electrical fields; this signals the presence of prey items. They have poorly developed eyes, and rely on their electroreceptors and other sensory pores covering their bodies for foraging.Paddlefish can live up to 30 years or more; females don’t reach sexual maturity until they are 7 to 10 years old. Their slow reproduction rate has made wild repopulation in China difficult, but since 1988, China imports approximately 4.5 million fertilized eggs and larvae every year from hatcheries in Russia and the United States to combat over fishing. -- source link