Popular Fish Found to Play Crucial Role in Seabed Health and Climate Regulation.

A groundbreaking study by the Convex Seascape Survey has highlighted the crucial but previously underappreciated role of fish in maintaining the health of the seabed—an ecosystem vital for storing carbon and combating climate change. Published in the journal Marine Environmental Research, the study evaluates the influence of fish on bioturbation, the process of disturbing and reworking seabed sediments, and raises concerns over the vulnerability of many such species to commercial exploitation.

Led by University of Exeter Ph.D. student Mara Fischer, the research provides the first large-scale functional assessment of fish as bioturbators in shallow seas around the UK. While the role of invertebrates in sediment mixing is well documented, the contribution of fish has long been overlooked.

“Seabed sediments are the largest natural store of organic carbon on the planet,” said Fischer. “Understanding how bioturbation by fish affects this carbon storage is essential to grasping the ocean’s capacity to absorb greenhouse gases.”

The study assessed all fish species found on the UK continental shelf, identifying 185 species as contributing to bioturbation—120 of which are commercially fished. Among the top contributors were the Atlantic cod, Atlantic hagfish, and European eel, all of which scored highest in their bioturbation impact. Their activities—such as burrowing, nest-building, or sediment excavation—help regulate how carbon is buried in ocean sediments, thereby influencing global carbon cycles.

The European eel, with a bioturbation score of 100 out of 125, is classified as critically endangered. This burrowing species is considered a delicacy in various European and Asian cuisines but faces numerous threats, including habitat loss, pollution, disease, and overfishing.

Similarly, the Atlantic cod, another high scorer with a vertical excavating behavior, is marked as vulnerable by the IUCN. Popular in dishes like fish and chips or salted cod, the species has seen sharp declines due to trawling, longlining, and environmental degradation, esp

Other examples include the common skate (bioturbation score: 50), once common but now critically endangered due to overfishing and slow reproduction rates, and the black seabream, a nest builder with a score of 36, which is currently classified as least concern but is vulnerable during its spawning season.

Red gurnard, a sediment sifter with a lower bioturbation score of 16, is also increasingly targeted by fisheries despite the absence of EU management regulations for gurnard species. This raises concerns about potential overexploitation.

Professor Callum Roberts, a co-author from Exeter’s Center for Ecology and Conservation, stressed the broader implications: “Some of the most impactful sediment movers, like cod and halibut, are being fished to near extinction. The loss of these species could significantly alter how seabed ecosystems function.”

Julie Hawkins, another study contributor, emphasized the overlooked nature of fish-driven bioturbation: “Anyone who’s spent time underwater can see fish constantly reshaping the seabed. It’s remarkable this hasn’t been better studied before now.”

The Convex Seascape Survey, a collaboration between the University of Exeter, Blue Marine Foundation, and Convex Group Limited, is a five-year global initiative aiming to better understand the ocean’s role in the carbon cycle. This study is part of that effort, aiming to inform conservation policy and sustainable fishing practices.

As climate change accelerates, preserving the functionality of marine ecosystems—and the fish that help sustain them—may be more critical than previously realized.

Source:https://phys.org/news/2025-04-popularly-eaten-fish-key-seabed.html

This is non-financial/medical advice and made using AI so could be wrong.