Groundfish biodiversity change in northeastern Pacific waters under projected warming and deoxygenation

Abstract

In the coming decades, warming and deoxygenation of marine waters are anticipated to result in shifts in the distribution and abundance of fishes, with consequences for the diversity and composition of fish communities. Here, we combine fisheries-independent trawl survey data spanning the west coast of the USA and Canada with high-resolution regional ocean models to make projections of how 34 groundfish species will be impacted by changes in temperature and oxygen in British Columbia (BC) and Washington. In this region, species that are projected to decrease in occurrence are roughly balanced by those that are projected to increase, resulting in considerable compositional turnover. Many, but not all, species are projected to shift to deeper depths as conditions warm, but low oxygen will limit how deep they can go. Thus, biodiversity will likely decrease in the shallowest waters (less than 100 m), where warming will be greatest, increase at mid-depths (100–600 m) as shallow species shift deeper, and decrease at depths where oxygen is limited (greater than 600 m). These results highlight the critical importance of accounting for the joint role of temperature, oxygen and depth when projecting the impacts of climate change on marine biodiversity. This article is part of the theme issue ‘Detecting and attributing the causes of biodiversity change: needs, gaps and solutions’.

More Than Marine Heatwaves: A New Regime of Heat, Acidity, and Low Oxygen Compound Extreme Events in the Gulf of Alaska

“…Rockfish living deeper along the Gulf of Alaska slope, such as adult thornyhead rockfish (Sebastolobus spp. ; 100-1,200 m), rougheye (S. aleutianus) and blackspotted (S. melanostictus) rockfish (300-500 m), and shortraker rockfish (S. borealis; 300-400 m), live in lower oxygen environments and are predicted to potentially move shallower (perhaps into warmer temperatures) if oxygen concentrations decrease further (Thompson et al, 2023). Lower pH could result in a decline of biomass or condition of deep-water corals, important habitat for juvenile Pacific Ocean perch (S. alutus) and numerous other commercially important rockfish.…”

Economic factors underlying biodiversity loss

“…Thompson et al . [ 6 ], for example, study the effect of climate change on the abundance of groundfish in northwestern Pacific waters, and Gregory et al . [ 7 ] identify climate change as a driver for changes in the range and abundance of a sample of European birds.…”

Detecting and attributing the causes of biodiversity change: needs, gaps and solutions

“…Thompson et al . [ 54 ] use fishery assessment and environmental data from trawl surveys to attribute factors that determine groundfish habitats on the west coast of North America. Subsequently, these attributions, including the effects of temperature and oxygen, are used to project future groundfish biodiversity change across space and water depth under the changing conditions predicted by ocean models.…”