A New Spatial Ecosystem-Based Surplus Production Model for Northern Shrimp in Shrimp Fishing Areas 4 to 6

Abstract

Although one of the most economically important stocks in Canadian waters, Northern Shrimp (Pandalus borealis) in shrimp fishing areas (SFAs) 4-6 currently lack a population model to predict how fishing pressure and changing environmental conditions may affect future shrimp abundance. We tested various surplus production models that included potential predictors, such as predator density, bottom temperature, large-scale climatic conditions, plankton, patterns in recruitment, and fishing pressure to assess their ability to predict annual changes in Northern Shrimp biomass density. A spatially-explicit, lag-1 autoregressive surplus production model that included Atlantic Cod (Gadus morhua) density, alternate predator (Greenland Halibut Reinhardtius hippoglossoides and Redfish-Sebastes spp.) density, North Atlantic oscillation (NAO) index, and Northern Shrimp biomass as predictors was found to be the best model. This model represents a step forward for assessing Northern Shrimp in SFAs 4-6, but as with any modelling, caution is warranted when applying it outside the range of ecosystem conditions already observed and ongoing evaluations of its efficacy will be required.