Simple Calibration of Spawner Biomass and Survey Biomass for South African Sardine and Anchovy

The Operational Management Procedures for South African sardine and anchovy are empirical, using hydro-acoustic survey estimates of abundance as key inputs into the Harvest Control Rules. This document provides a simple means to compare these November survey estimates of total biomass against the model estimated spawning biomass. Risk thresholds for OMP 18 will be based on historical spawning biomass levels (Cox et al. 2017).