Disentangling conditional effects of multiple regime shifts on Atlantic cod productivity

• Published in: PLOS ONE
• Main Authors: Perälä, Tommi, Olsen, Esben M., Hutchings, Jeffrey A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Public Library of Science 2020
• Subjects: aikasarja-analyysi; kannanvaihtelut; bayesilainen menetelmä; ympäristötekijät; ilmastonmuutokset; kalakannat; turska; liikakalastus; atlantic cod; North Atlantic; North Atlantic oscillation
• Online Access: http://urn.fi/URN:NBN:fi:jyu-202012086979

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. peerReviewed