Identifying otolith subsampling strategies that are efficient and maintain data quality for stock assessments is imperative given limited resources to meet age estimation demands of managed fish stocks. My objective was to evaluate the performance of three different subsampling strategies for northern anchovy (Engraulis mordax): (1) fixed otolith subsampling, (2) proportional otolith subsampling with targeted supplemental sampling, and (3) hybrid otolith sampling for estimating age composition and proportions of individuals-at-age within length bins. Hybrid strategies generally performed better for all years compared to fixed and proportional strategies. The performance of subsampling strategies was less consistent among combinations of age and length bins for estimates of proportions of ages-at-length than for estimates of age composition, due in part to high variation in age-at-length that caused uncertainty in predicted ages from lengths.
Brittany D. Schwartzkopf (Tue,) studied this question.