Egg and Larval Development Index for Lake Sturgeon

We developed an index of egg and larval maturation for Lake Sturgeon Acipenser fulvescens to incrementally chart development over time. To evaluate the relationship between temperature and development rate, eggs and larvae from the Wolf River were incubated at four constant water temperatures. The time required for neural tube closure, hatch, and exogenous feeding were monitored. The number of hours from incubation to each development stage and mean water temperature were related by predictive exponential regression equations for neural tube closure (R-2 = 0.96), start hatch (R-2 = 0.97), end hatch (R-2 = 0.97), and exogenous feeding (R-2 = 0.99). Calculated hourly development was used to create an index capable of predicting specific daily development. Daily development from incubation to exogenous feeding ranged from 2.0% to 8.3% at 10 degrees C to 19.9 degrees C. This index was used to predict the rate of development of sturgeon eggs and larvae from the St. Lawrence River reared in water with varying temperatures. All development stages occurred within 24 h of the time predicted by the index. This index may be used to accurately predict and manipulate the progress of development and assist with the culture and management of Lake Sturgeon populations.