Considering The Future Of Gulf of Mexico Sturgeon Management In The Apalachicola and Suwannee Rivers

Populations of the threatened Gulf Sturgeon are slowly recovering, as impoundments and heavy water use exist within the subspecies’ riverine habitat. We used stochastic stock reduction analysis to compare Gulf Sturgeon abundance from 1897-2006 and the current capacities between the impounded Apalachicola River and the free-flowing Suwannee River (K= 2,708 and 10,704 age 4+ fish, 
respectively). Projections were made of future K using a scaled habitat index of discharge and river length, incorporating the Palmer Drought Sensitivity Index and constant per-capita water withdrawals, in the time periods of 2025-2049, 2050-2074, 2075-2099. Median K fell by 77% and 33% by 2099 in the Apalachicola and Suwannee, respectively. Simulating increased water use efficiency, i.e. future water withdrawals at 2007 levels, median K fell 49% and 20% from current K by 2099, in the Apalachicola and Suwannee, respectively. We simulated access to an additional
373 rkm of habitat above an impoundment. We found that median K improved to 219% above current K by 2049, 77% by 2074, and fell 9% by 2099. We estimate extending habitat will improve carrying capacity in Apalachicola River and significantly buffer against distribution-wide decreases in K from predicted drought and increased water withdrawals over the 60 years.