Reconstructing the decline of Atlantic Cod with the help of environmental variability in the Scotian Shelf of Canada

Abstract

Ignoring environmental variability can lead to imprecise and inaccurate estimates of abundance and their spatial distribution of organisms. Fully embracing environmental variability can improve precision and accuracy of estimates of abundance and distribution, especially when they can often be measured with lower costs. Using the example of Atlantic cod in the Scotian Shelf of the northwest Atlantic Ocean, we demonstrate the improved clarity of their historical population trends when such informative features are included. Further, the use of Bayesian spatiotemporal Conditional auto-regressive models substantially improves our ability to understand the role of ecosystem variability upon cod, even when samples are incomplete or missing. Finally, by decomposing biomass into number, weight and a Hurdle process to estimate habitat conditions, we can extract much more information on what has occurred in the past and make reasoned inference on processes. One-Sentence SummaryDeconstructing and reconstructing cod with environmental variability