Age, Growth, and Mortality of Shovelnose Sturgeon in the Lower Mississippi River

Abstract

Two hundred of 295 shovelnose sturgeon Scaphirhynchus platorynchus captured in the Mississippi River near Rosedale and Vicksburg, Mississippi, were aged by examining sectioned pectoral fin rays. Ages ranged from 2 to 16 years, and the annual mortality was 20% for ages 7 and greater. The weight (W, g), to fork length (FL, mm) relation was W = 0.000001257 FL3.174 (R2 = 0.87). The von Bertalanffy growth equation for fork length was FL = 730(1 − e−0.213(t+0.972)); the equation for weight was W = 1,604(1 − e−0.148(t−1.841)). Mortality and mean length at age were less than has been reported for upper Mississippi River populations of shovelnose sturgeon. Knowledge of causes of mortality of shovelnose sturgeon may have applications in management of the sympatric pallid sturgeon Scaphirhynchus albus.