Disentangling conditional effects of multiple regime shifts on Atlantic cod productivity.

Regime shifts are increasingly prevalent in the ecological literature. However, definitions vary and detection methods are still developing. Here, we employ a novel statistical algorithm based on the Bayesian online change-point detection framework to simultaneously identify shifts in the mean and (...

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Bibliographic Details
Published in:PLOS ONE
Main Authors: Tommi Perälä, Esben M Olsen, Jeffrey A Hutchings
Format: Article in Journal/Newspaper
Language:English
Published: Public Library of Science (PLoS) 2020
Subjects:
R
Q
Online Access:https://doi.org/10.1371/journal.pone.0237414
https://doaj.org/article/3e7a865dc4244117a32fbd77e084e831
Description
Summary:Regime shifts are increasingly prevalent in the ecological literature. However, definitions vary and detection methods are still developing. Here, we employ a novel statistical algorithm based on the Bayesian online change-point detection framework to simultaneously identify shifts in the mean and (or) variance of time series data. We detected multiple regime shifts in long-term (59-154 years) patterns of coastal Norwegian Atlantic cod (>70% decline) and putative drivers of cod productivity: North Atlantic Oscillation (NAO); sea-surface temperature; zooplankton abundance; fishing mortality (F). The consequences of an environmental or climate-related regime shift on cod productivity are accentuated when regime shifts coincide, fishing mortality is high, and populations are small. The analyses suggest that increasing F increasingly sensitized cod in the mid 1970s and late 1990s to regime shifts in NAO, zooplankton abundance, and water temperature. Our work underscores the necessity of accounting for human-induced mortality in regime shift analyses of marine ecosystems.