Forecasting fishery performance for northern shrimp (Pandalus borealis) on the Labrador Shelf (NAFO Divisions 2HJ)

Abstract

The physical environment of the ocean is believed to have a major influence on pandalid shrimp populations and there are numerous studies that incorporate environmental variables to predict and forecast landings from the fishery and/or resource abundance. Cause-and-effect mechanisms are not clearly understood in many instances but the predictive nature of the relationships provides a potentially powerful forecasting tool. Meaningful indicators of the prospects for shrimp stocks that support valuable commercial fisheries are necessary in a comprehensive stock assessment process. In this paper, a time-series analysis is used to estimate a predictive model for standardized annual catch rates (an abundance index) in a shrimp fishing area off the mid Labrador coast (NAFO Div. 2HJ). Environmental data (annual winter ice cover) are incorporated in a transfer function to improve predictions of catch rates and facilitate their forecasting. Results support the hypothesis that cold conditions, which result in more extensive ice cover, are favourable for the northern shrimp (Pandalus borealis) at early life-history stages. Predictions of annual catch rates fit the observed values well in most cases and a catch-rate forecast for several years is provided. Possible functional mechanisms are discussed.