摘要：Length-frequency data can be quantified using proportional stock density and relative stock density indices. However, standardized length categories must be available for each fish species. Thus, we developed standard length categories for calculation of stock density indices for pallid sturgeon (Scaphirhynchus albus.) Based on the longest fish (1,638 mm fork length) that we could find in sampling records or from angler catches, we propose the following length categories: stock = 33 cm (13 in); quality = 63 cm (25 in); preferred = 84 cm (33 in); memorable = 104 cm (41 in); and trophy = 127 cm (50 in). Using these length categories, we then calculated the size structure indices for pallid sturgeon populations in which recruitment had been supplemented with hatchery-produced fish.
