WHAT THE EVIDENCE SAYS
Fisheries monitoring from 1973 to 2025 found surface and bottom warming of about 1.25°C and 1.03°C per 50 years, respectively. Clarity increased and dissolved inorganic nitrogen fell especially in eastern areas. Bottom oxygen trends varied among sub-basins, increasing in some and declining or lacking a significant trend elsewhere.
WHY IT MATTERS / OUR READ
Clear water is not synonymous with a recovered ecosystem. Coastal plans must track nutrients, temperature, oxygen, hydrological exchange and fishery response at compatible scales instead of treating a single basin average as a verdict.
CAVEATS / UNCERTAINTY
Historical monitoring methods and station coverage changed. The study establishes observed trends, not unique causes of fishery decline or every oxygen change.
SOURCE
Onitsuka et al. · Journal of Oceanography · 53-year monitoring analysis
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