Rostrum Size of Paddlefish (Polyodon spathula)(Acipenseriformes: Polyodontidae) from the Mississippi Delta

Paddlefish rostra vary in size and shape suggesting existence of multiple morphotypes. Measurements for 118 adult paddlefish from a Mississippi delta river indicate that the rostrum becomes shorter, narrower, and straighter as a fish grows. Negative allometric growth of rostra, and high variation within size classes, may obscure existence of distinctive rostral morphotypes.