New research reveals that many commonly consumed fish species—including Atlantic cod, European eel, and common skate—are not only culinary favorites but also vital seabed engineers. These fish play a key ecological role through bioturbation, a process that stirs and reworks ocean sediments, significantly influencing carbon storage and overall marine biodiversity.
The study, published in Marine Environmental Research, was conducted by the Convex Seascape Survey, in collaboration with the University of Exeter. It marks the first comprehensive assessment of how fish contribute to seabed bioturbation in the UK’s shallow coastal waters.
🐟 What is Bioturbation and Why Does It Matter?
Bioturbation refers to the churning and reworking of sediments by living organisms, such as fish and invertebrates. This process is vital for:
- Storing organic carbon in seabed sediments
- Enhancing nutrient cycling
- Supporting healthy marine ecosystems
- Slowing the pace of climate change
“Ocean sediments are the world’s largest reservoir of organic carbon,” explains Mara Fischer, lead author and Ph.D. student at the University of Exeter. “Our findings show that fish are crucial to this natural carbon storage process, and they’ve been largely overlooked—until now.”
🐠 Fish as Ecosystem Engineers: Top Bioturbators Identified
Researchers assessed 185 fish species inhabiting the UK continental shelf, discovering that over half play an active role in seabed bioturbation. Of these, 120 species are commercially fished, posing ecological concerns.
The species were ranked using a “bioturbation impact score” based on behavior, size, and frequency of seabed interaction. Below are key highlights:
| Fish Species | Bioturbation Mode | Score (out of 125) | IUCN Status | Fishing Methods | Key Threats |
|---|---|---|---|---|---|
| Atlantic Cod | Vertical Excavator | 100 | Vulnerable | Trawling, Longlining | Overfishing, habitat loss |
| European Eel | Burrower | 100 | Critically Endangered | Fyke nets, traps | Climate change, disease |
| Common Skate | Lateral Excavator | 50 | Critically Endangered | Trawling (bycatch) | Slow reproduction |
| Black Seabream | Nest Builder | 36 | Least Concern | Bottom trawling | Spawning disruption |
| Red Gurnard | Sediment Sifter | 16 | Least Concern | Trawling | No fishing limits |
Did you know? The Atlantic cod, a favorite in fish and chips, is among the top bioturbators helping maintain seabed health—and it’s under threat from unsustainable fishing.
🌊 Climate, Conservation, and the Role of Fisheries
According to co-author Professor Callum Roberts, the largest and most impactful seabed-disturbing fish are also the most vulnerable to extinction.
“Species like halibut, skates, and cod—once abundant—have declined dramatically due to intensive fishing,” says Roberts. “These declines may trigger unpredictable changes in seabed ecosystem function and carbon storage capacity.”
The study also emphasizes that fishing activities, especially during spawning seasons, can destroy fish nests, eggs, and habitats—affecting both fish populations and their ecological roles.
🐚 Why This Study Matters: A New Perspective on Ocean Carbon
Fish have long been ignored in the context of ocean carbon sequestration, with most studies focusing on invertebrates. This new research provides the first quantifiable evidence of how fish directly contribute to carbon burial and seabed health.
“Anyone who snorkels or dives knows fish are constantly disturbing the seabed,” says co-author Julie Hawkins. “Yet their role in ocean carbon dynamics has been underestimated until now.”
🌍 About the Convex Seascape Survey
This study is part of the Convex Seascape Survey—a five-year global research project supported by the University of Exeter, the Blue Marine Foundation, and Convex Group Ltd. It aims to enhance our understanding of the ocean’s role in Earth’s carbon cycle and support more sustainable ocean management.