China's marine ecological protection and restoration efforts yielded preliminary results, with overall marine conditions remaining stable and localized improvements observed last year, according to a bulletin released on Monday by the Ministry of Natural Resources.

Coral reefs, seagrass beds, mangroves and island ecosystems remained in good condition, the ministry said in its 2025 bulletin on China's marine ecological early warning and monitoring.

Released to mark the 18th World Oceans Day, the bulletin drew on monitoring data from 14 standard offshore transects, 1,579 monitoring stations, 126 typical ecosystem areas and 350 islands across China's jurisdictional waters.

The report showed that biodiversity indicators for plankton and large benthic organisms in nearshore waters remained consistent with the five-year average. Surface seawater salinity, pH levels, inorganic nitrogen concentrations and dissolved oxygen levels in bottom waters also remained close to the 10-year average.

According to the bulletin, key bays and estuaries maintained stable biological community structures, with no significant shifts in dominant species groups. Sediment conditions remained sound, although localized eutrophication persisted in some areas.

The bulletin also warned of marine ecological risks linked in part to global climate change. Last summer, nearshore surface water temperatures in China were 0.7 C above the long-term average.

Although both the frequency and affected area of red tides declined compared with the 10-year average, risks from Ulva prolifera, or green tides, localized biological outbreaks and estuarine hypoxia remain, it said.

The ministry also released the second batch of its marine data open-sharing catalog on Monday, providing data support for marine economic development, disaster prevention and mitigation, resource exploitation and scientific research.

Building on 37 data products included in the first batch released in June 2024, the updated catalog adds 10 global three-dimensional ocean datasets covering temperature, salinity, currents, waves and atmospheric pressure, as well as seven new statistical analysis products for global marine hydrological and meteorological data.

Since the first catalog was published, marine data services have been accessed more than 600,000 times by more than 100 government departments, research institutes and maritime enterprises, delivering more than 600 million data records, the ministry said.

China's marine monitoring capacity has expanded significantly in recent years, forming an integrated observation network that combines coastal stations, radar systems, buoys, research vessels, drones and satellite remote sensing.

The outline of the 15th Five-Year Plan (2026-30) calls for enhancing the protection and sustainable use of marine resources and accelerating the building of a maritime power.

In line with the plan, the ministry said it will continue advancing marine ecological protection and restoration, using high-level environmental protection to support the high-quality development of the marine economy.

limenghan@chinadaily.com.cn