Body condition index of a pandalid shrimp, a novel method for assessing ocean shrimp populations

Assessing stocks of short-lived marine invertebrates is complex, yet highly valuable to fishery management. Knowledge of stock abundance prior to fishing has obvious advantages but is less attainable for shorter lived “recruitment fisheries”. The U.S. West Coast ocean shrimp ( Pandalus jordani) fishery relies on back calculation to understand stock abundance. Using 23 years of dockside biological sampling data (2001–2023), we show the relationship between body condition index (BCI) of ocean shrimp strongly relates to fishery catch per unit effort (CPUE: r = −0.86). For predicting seasonal abundance, we considered several factors (fishery CPUE, environmental conditions, predator levels); however, BCI showed the strongest correlation. We found BCI at season onset (April) to be the best predictor of annual catch. The strong connection of ocean shrimp population abundance to BCI may allow the variable’s use in predicting contemporaneous abundance. The potential uses of BCI include, (1) a simple preseason population abundance metric to aid seasonal catch expectations and, (2) use as a harvest control rule, both of which may be used to improve the sustainability of the ocean shrimp fishery.