"Examination of Pallid Sturgeon Life-History Characteristics throughout the Missouri River Basin"

Organisms develop life history strategies to maximize fitness, thereby providing the best opportunity to contribute to future generations.  These life history strategies evolve as a result of individual responses (e.g., growth) to the environment or biotic interactions that occur within their realized niche.  We examined pallid sturgeon life history characteristics between isolated sub-populations from the Missouri River basin.  Growth information from mark-recapture data indicated that pallid sturgeon in the lower basin grew quickly at young ages and matured at a smaller size, whereas the opposite occurred in the upper basin.  Predicted ages from mark-recapture indicated that the age distribution was markedly different between areas.  Pallid sturgeon from the lower basin matured around age 7, had a maximum longevity of 30 years, and a mean life expectancy of 18.  Upper basin fish matured later (age-15), had a maximum longevity of 80 years, and a mean life expectancy of 45.  Furthermore, hatchery-reared pallid sturgeon originating from the upper basin and stocked into both the upper and lower basin at age-1 exhibited traits similar to their counterparts within the area they were stocked.  These results have important implications for understanding lifetime reproductive output and highlight important linkages between anthropogenic affects and population dynamics.