Composite per-Recruits: Metrics for Deriving Biological Reference Points of Data-Poor Stocks

Most exploited aquatic populations lack the fishery selectivity and life-history information by age needed to develop age-based harvest control rules (HCRs). This study relies on stage-structured life-history and fishery characteristics inherent in delay-difference models to propose a suite of Composite (age-aggregated) Yield-Per-Recruit (CYPR) models, Composite Spawning Stock-per-Recruit (CSSR) models, and Composite Spawning Potential Ratios (CSPRs); and suggests the related, conventional-like biological reference points (BRPs). These BRPs may prove useful in devising HCRs, especially for data-poor stocks. CYPR, CSSR, and CSPR use fishing mortality as a control variable and inputs on growth and natural mortality and, occasionally, can include stage-specific selectivity and maturity. Their application to the U.S. Atlantic bluefish (Pomatomus saltatrix) and the U.S. Gulf of Mexico blue crab (Callinectes sapidus) indicate that some of the related fishing mortality-based BRPs are consistent with the current fishing mortality rates producing the maximum sustainable yield for these stocks as estimated using full assessment models.