Optimal harvest of shovelnose sturgeon (Scaphirhynchus platorynchus Rafinesque) in the Wabash River, Illinois
Whitehead, Amy L
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Shovelnose sturgeon (Scaphirhynchus platorynchus Rafinesque) are harvested in a modest caviar fishery from the Wabash River, Illinois. However, little is known about the status of the population or its ability to sustain a harvest. A Lefkovitch matrix model was constructed using available data to examine the population dynamics, while stochastic dynamic programming was utilized to determine the optimal harvest rate. Shovelnose sturgeon populations are susceptible to high juvenile and adult mortality, making them vulnerable to harvest. A maximum sustainable harvest rate of 2.7% of spawning adult females was predicted under two stock recruitment scenarios. This corresponded to low yields of roe, suggesting that a caviar harvest may not be economically viable at the optimum policy. Management policies should be conservative until more information is available on the population status of shovelnose sturgeon in the Wabash River.