The effect of temperature and substrate on the growth, development and survival of larval white sturgeon

• Temperature and substrate during early-rearing of yolksac larvae significantly affected size.
• Rearing of yolksac larval white sturgeon in substrate improves growth both during yolsac phase and after.
• The interaction between substrate and temperature on sturgeon yolksac larvae has not been examined previously.
• Rearing in substrate increased survival of yolksac larval white sturgeon by 20 percent.
• Substrate-rearing affected the efficiency but not the rate at which yolk is absorbed after hatch.

White sturgeon yolk sac larvae (YSL) were reared at 13.5 and 17.5 °C with and without gravel substrate. Larvae reared within the gravel emerged from the substrate after 11–14 days (depending on temperature), and all larvae were subsequently fed in bare tanks until 46 days post hatch (dph). Temperature and substrate significantly affected size; at 46 dph, fish reared in gravel at 17.5 °C were the largest (288 ± 19 mg), while fish reared at 13.5 °C without gravel were the smallest (107 ± 3 mg). Yolk absorption rate did not differ between substrate treatments but was greater at 17.5 °C than at 13.5 °C. In contrast, yolk absorption efficiency was independent of temperature but was significantly greater in gravel-reared larvae. YSL reared in gravel also had more lipid vacuoles in their liver. Substrate and temperature significantly affected survival. Greatest survival (84.6% ± 0.6%) was achieved when YSL were reared in gravel at 13.5 °C, and survival was lowest (46.6% ± 0.6%) when larvae were reared without gravel at 17.5 °C. Understanding factors that affect growth and survival during early life history provides insight into factors affecting wild recruitment and should improve hatchery production.