Streamside rearing facilities (SRFs) have been widely advocated in the Great Lakes basin as the preferred method of culturing Lake Sturgeon in situations where restoration goals to enhance or repatriate populations can be met by stocking. However, over the past decade, targeted stocking goals have been difficult to achieve due in large part to low survival and low growth during early life periods. This study examined three specific early life periods encountered during streamside operation (egg, free-embryo, and larval) and aimed to quantify the effects of different methodologies on the body size and survival of lake sturgeon in a SRF. Information collected during the egg period provides insight regarding the use of different egg chemotherapeutants, de-adhesion and incubation procedures, as well as the documentation of microbial community composition on lake sturgeon egg surfaces. Among egg chemotherapeutants utilized in streamside hatcheries, hydrogen peroxide showed higher mean proportional survival compared to formalin and the control (although results were not statistically significant). Additionally, chemotherapeutants may have selected for microbial communities that have been determined in other studies to be pathogenic. The effects of de-adhesion and incubation on lake sturgeon eggs were quantified using egg survival, egg oxygen consumption rate, and body size as response variables. Results revealed that these variables, except egg survival, did not vary significantly among de-adhesion and incubation treatments. Microbial community composition data suggest de-adhesion and incubation techniques affect the bacterial community composition on the egg surface which may provide insight into mechanisms responsible for differences detected in survival. At the free-embryo period, the effects of rearing density and family on body size and survival in association with dissolved oxygen concentration were quantified to the time of emergence. A significant density and family effect on free-embryo body size at emergence was documented. Feeding regimes, as well as the effects of different weekly prophylactic chemotherapeutants were quantified during the larval period. Results from feeding regime studies revealed significant differences in body size as a function of feeding frequency in hatchery-produced larvae to 30 days post-exogenous feeding. In addition, using hatchery-produced as well as wild-caught larvae, significant differences in body size and survival as a function of alternate food types were documented. Results from the weekly prophylactic chemotherapeutant study revealed a significant treatment effect on the survival of young-of-year lake sturgeon at 49 days post-exogenous feeding. This investigation at multiple life periods highlights methods that improve survival and growth, as well as serves as a tool for the development of standard operating procedures for SRFs geared to enhance current production and recovery of the Great Lakes Lake Sturgeon.
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