Theses and Dissertations Collection

Recent surveys suggest that the population of White Sturgeon Acipenser transmontanus in the Sacramento-San Joaquin River basin (SSJ) is declining. Probable reasons for the decline include overharvest and habitat degradation, compounded by poor recruitment during recent droughts. Despite the importance and status of White Sturgeon, knowledge of their population dynamics in the SSJ remains incomplete and additional information is warranted to develop an effective management and conservation plan. The purpose of this research was to establish baseline demographics for White Sturgeon in the SSJ and evaluate possible influences of water management characteristics (i.e., discharge, temperature) on growth. Information from this thesis will provide insight on the population-level responses under different management scenarios. Overall, White Sturgeon in the SSJ experienced higher rates of mortality and growth than other populations. Additionally, growth has increased since the 1980s. Thermal and hydrological variables had little influence on growth of juvenile White Sturgeon, suggesting that annual growth may be affected by other abiotic and biotic factors. Model projections, in conjunction with demographic information, indicated that White Sturgeon in the SSJ are likely exploited to an excessive degree. Under current conditions, the population will continue to decrease. Low levels of exploitation (i.e., < 3%) will be required to prevent growth and recruitment overfishing of White Sturgeon in the SSJ.