Persisting Versus Relocating: Evidence That Marine Species Deploy Both Strategies in Compensation to Warming

Abstract

Marine species distributions reflect fundamental ecological interactions, and analyzing their patterns helps identify key drivers of change and enhances our understanding of shifting habitats and ecosystem responses. In response to ocean warming, marine species exhibit a range of accommodations, including tolerance to thermal changes and spatial redistribution. While distribution shifts have been extensively studied, concurrent changes in thermal exposure are less frequently assessed. To address this gap, bottom temperature and two measures of locational change associated with trawl survey catches made in the Northeast U.S. Continental Shelf ecosystem (NES) were analyzed. In one approach, location was characterized by depth, reasoning that change in depth would require a change in position. The other location index was computed by taking the sum of the along‐shelf distance and the distance from the coast, approximating a coordinate system reflecting geoposition within the NES. Median annual values for temperature and location were calculated over the period 1968–2022, and then for periods progressively trimmed by 5 years to evaluate potential differences between year blocks. Some species (15%–21%) showed a significant change in occupancy temperature and location simultaneously, indicating inefficient thermal tracking or temperature as less consequential. Most species showed increasing trends in bottom temperature or location indicators, revealing a general tendency for organisms to be found in warmer water over time or for movement of biomass towards the Northeast and further offshore, thus maintaining occupancy temperature. Management structures will face challenges from either accommodation strategy as patterns of local abundance and productivity change accordingly; incorporating predicted responses to thermal environments provides an improved understanding of future fisheries and ecosystem dynamics for management consideration.

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