FA-153, a 5-page illustrated fact sheet by Frank A. Chapman and Joel P. Van Eenennaam, describes a simple field and laboratory test used to assist in predicting ovulatory response in female sturgeon, which uses the egg size and position of the nucleus in the cytoplasm as indicators — the principle behind it, materials needed, biopsy procedure, and how to determine the egg polarization index. Published by the UF Department of Fisheries and Aquatic Sciences, December 2007.
http://edis.ifas.ufl.edu/FA153