A century of invertebrate range extensions in the eastern North Pacific

We collated a database of poleward range extensions of marine invertebrates through a systematic literature review of peer-reviewed literature and reports from California Cooperative Oceanic Fisheries Investigations. We then analyzed the frequency and geographic distance of range extensions across the species and time in association with the El Niño Southern Oscillation and the 2014-2016 marine heatwave.

The final dataset comprises 63 species and 143 poleward range extensions. We found that the episodic range extension events are significantly associated with El Niño, and that further extensions occurred during stronger El Niño events. Twenty-two percent of the range extensions were during the 2014-2016 large marine heatwave—far more than in the years preceding or following it. Main Conclusions Our synthesis underscores that across many years and taxa, episodic poleward range extensions are not isolated curiosities but signals of how climate variability and warming can reshape coastal ecosystems. Gaining greater insight into short-term redistribution events and their interplay with long-term ecological change including range shifts is essential for forecasting long-term biogeographic change and for designing adaptive management strategies in a warming ocean. https://doi.org/10.32942/X2T94P Life Sciences marine, invertebrate, El Niño, range extension Published: 2025-11-06 01:56 Last Updated: 2025-11-06 01:56 CC-By Attribution-NonCommercial-NoDerivatives 4.0 International Conflict of interest statement: The authors have no competing interests. Data and Code Availability Statement: Data and code is available at https://github.com/jordanasevigny/ca-invert-shifts.git. Language: English