Stock-recruitment relationship

The form and parameter estimates of the relationship between parents (stock size) and offspring (recruitment) are highly influential in terms of developing biological reference points for purposes of bottom-line management of exploited populations. Although a large amount of research has been conducted on stock-recruitment dynamics to date, there remains much uncertainty surrounding the manner in which the stock-recruitment relationship is addressed in contemporary stock assessment models. Recent analyses indicate that estimates of the stock-recruitment relationship parameters are either highly uncertain, controlled by anomalies/outliers in the sample data, influenced by regime shifts and autocorrelation, or biased towards assuming little to no relationship between recruitment and stock abundance. For example, focused research on bias associated with estimation of steepness of the Beverton-Holt stock-recruitment model would greatly benefit overall, robust model development. Finally, standard stock-recruitment relationships are most appropriate for high-fecund species, but are less informative/more biased (to some degree) for low-fecund populations, which illustrates a critical need for such research on these more vulnerable species, such as sharks.