The Power to Preserve the Personalities of Deep-Sea Fish: Deep-Sea Fish Resisting the Waves of Homogenization ─ Surprising Diversity Revealed by Global Analysis

1. Introduction: Challenging the Conventional Wisdom of "The Ocean is Already Homogenized"

Climate change, overfishing, invasive species—warnings that human activities are transforming the ocean into a singular "global aquarium" have become almost common knowledge over the past decade. However, according to a report by Phys.org introducing a paper published on July 9 in PLOS Climate, the world of demersal fish living on the seabed is not monolithic. Rather, in many marine areas, unique fish communities persist tenaciously.Phys.org

2. The Massive FISHGLOB Project and 175,000 Trawl Surveys

At the heart of this study is the international consortium FISHGLOB. The organization standardizes long-term data from over 70 scientific bottom trawl surveys (SBTS) worldwide, building an open platform that continues to expand.fondationbiodiversite.fr

The analysis covered 34 regions over 60 years, totaling 175,000 survey voyages, with data on 2,006 species and approximately 6.4 million individuals. Geographically, it is a "super collection" covering areas from the Arctic to the tropics, both the eastern and western Atlantic, the Pacific marginal seas, and the South American continental shelf.

3. "1/3 Homogenization, 1/3 Differentiation, the Rest Fluctuate"—The Surprising Picture Painted by the Numbers

• Progress of homogenization (decline in β diversity): 11 out of 34 regions

• Shift to differentiation (increase in β diversity): 11 out of 34 regions

• No significant trend/fluctuations year by year: 12 out of 34 regions

Compared to terrestrial and freshwater systems, it became clear that the "loss of regional uniqueness" is rather limited. For instance, while replacement by black sea bream and skates has progressed on the coastal shelves of the western Atlantic, off the coast of Portugal and Greenland, both old and new species coexist, increasing the uniqueness of the composition.Phys.org

4. Driver Analysis: The Key is "Water Temperature × Fishing Pressure"

Statistical models showed that the annual average bottom water temperature increase rate and **fishing pressure (annual total trawl time)** explain 45% of the changes in β diversity. In high-latitude areas where warming is moderate, curbing overfishing makes it easier for endemic species to recover, while in temperate to subtropical regions, high water temperatures push out native dominant species, promoting homogenization in some marine areas.

5. Three Discussion Points that Spread on Social Media

These posts were reposted over 2,300 times within 48 hours, being perceived as a **"not entirely pessimistic ocean story."**

6. Expert Comments: "Homogenization is Not the 'Default'"

• Dr. Zoë Kitchel (Lead Author)

  "Change is indeed rapid. However, seabed communities also have a 'resilience'."Phys.org

• Bastien Mérigot (FISHGLOB Project PI)

  "Data collaboration is the key to smart design of fisheries and protected areas in each region."fondationbiodiversite.fr

7. Implications for Conservation and Fisheries Management

1. From "Uniform Regulation" to "Segmented Adaptive Management"

2. Strengthening Monitoring in Warming Hotspots

3. Expansion of Data Sharing Platforms by Regional Fisheries Cooperatives

4. Introduction of "Resilience Indicators" in Rebuilding

8. Citizen Science and AI—The Next Frontier

If citizens take on ROV video analysis and eDNA monitoring along coasts, and AI supports real-time species identification, megadata like FISHGLOB will become even more robust. The accuracy of drawing "future β diversity maps" under warming scenarios will also improve dramatically.

9. Conclusion: "Preserving Uniqueness" Strengthens the Ocean

The resilience of seabed fish communities is greater than expected. However, in areas where warming and overfishing progress simultaneously, the speed at which their uniqueness is lost may accelerate. Preserving "uniqueness" itself becomes an insurance for ecosystem services—this large-scale analysis supports this fact with data. Depending on future policy and citizen science initiatives, the ocean still has a diverse future to choose from.