Severe offshore pollution may leave no fish to eat in 30 years

“If we want fish to eat in 30 years, protecting the marine ecological environment has already become an important and urgent task at present.” On the 27th, the academic exchange conference on “marine and limnological ecological security under global change,” hosted by the Chinese Society for Oceanology and Limnology, was held in Nanjing, where many experts and scholars from across the country gathered together to diagnose problems and offer suggestions for protecting the ecological security of our country's oceans and lakes.

10,000 kilometers of coastline already artificialized

“At present, we have already discovered 120,000 species of marine life, but it is estimated that marine life may number as many as 1 million species, so 90% of marine life is still unknown to us. A fuller understanding of the deep sea and open ocean is of extraordinary significance to humanity.” Sun Song, chairman of the Chinese Society for Oceanology and Limnology and director of the Institute of Oceanology of the Chinese Academy of Sciences, said in his introduction that at present, the frequent occurrence of marine ecological disasters, the decline of marine biological resources, and other major problems facing marine ecosystems are all closely related to changes in marine biodiversity.

According to the disclosure in the 2011 “China Ocean Development Report,” coastal port development and port-side industries are basically formed by reclamation, “creating a situation of blind competition for shoreline and low-value use.” “At present, nearly 10,000 kilometers of China's 18,000 kilometers of coastline have already been artificialized, and artificialized coastline exceeds half.” Artificial aquaculture, land reclamation from the sea, and dense heavy chemical industries have placed a heavy burden on the ocean. Sun Song said that our country is carrying out systematic research on the mechanisms of eutrophication and harmful red tides, and that in the future relevant research should be carried out on the mechanisms of jellyfish outbreaks, which is also a global issue. In recent years, the increase in the number of jellyfish in our country's offshore waters has posed a great threat to the security of marine ecosystems. Because of the special position of jellyfish in marine ecosystems, once jellyfish become a dominant species in marine ecosystems, the structure and function of the entire marine ecosystem will undergo fundamental changes. Once such a pattern is formed, it will be very difficult to restore, and the key is to take corresponding measures to avoid the formation of such an irreversible situation. Sun Song believes: “We should not only pay attention to changes in marine biodiversity, but also to changes in species and changes in functional groups, such as the imbalance of ecosystems caused by the replacement of forage organisms in many sea areas by gelatinous organisms such as jellyfish. Whether marine ecosystems will therefore undergo structural changes and thereby affect their service functions to humanity, all these issues should be given great attention.”

⟦NL> Offshore pollution doubled in ten years

The internationally authoritative journal Science once published an article by a research team led by Canadian scientists, pointing out that overfishing and pollution are accelerating the destruction of the marine ecological environment, and that if the current rate continues, by 2048, these harvested populations will completely collapse and lose their harvesting value, and people will have no fish to eat.

What is the actual situation? Jin Xianshi, director of the Yellow Sea Fisheries Research Institute of the Chinese Academy of Fishery Sciences, said in his introduction that at present, overfishing, reclamation, environmental pollution and climate change have indeed had a serious impact on our country's marine ecological environment. Relevant data show that pollution in our country's coastal waters is relatively severe, and the trend of deterioration in the health of coastal marine ecosystems has not yet been fundamentally alleviated, mainly manifested in water eutrophication and nutrient imbalance, degradation of estuarine spawning grounds, loss or alteration of living environments, and abnormal biological community structure. Pollution of the marine ecological environment has had a relatively serious impact on fisheries. According to official monitoring data, over the past 10 years, the scope of pollution in China's offshore waters has nearly doubled, red tides occur more than 60 times each year, and important ecosystems such as mangroves, coral reefs and wetlands have respectively lost 73%, 80% and 57%. In Zhejiang, on the coast of the East China Sea, one third of the province's sea areas have become zones where benthic organisms are extinct. The Yellow Sea and Bohai Sea fishing grounds, Zhoushan fishing ground, South China Sea coastal fishing ground and Beibu Gulf fishing ground, the “four major fishing grounds,” have exhausted their resources and exist in name only.

“In the 1990s, our country became the first country in the world whose aquaculture output exceeded its catch output. Protecting the marine ecological environment has already become an important and urgent task at present.” Jin Xianshi said.

We must value the ocean as much as the moon landing

“The deep sea and open ocean are an important part of the Earth's climate system, and their movement processes play an important regulatory role in the Earth's climate, water cycle and biogeochemical cycles.” Wu Lixin, an academician of Ocean University of China, said in his introduction that over the past more than half a century, more than 90% of the heat increase in the climate system has been absorbed by the ocean, so the deep sea and open ocean have to a great extent slowed and delayed the rate of global warming. However, the absorption of heat by the deep sea and open ocean has changed their heat and freshwater balance, causing profound changes in their dynamic processes as well, thereby having an important impact on the marine environment, climate, and especially extreme climate events.

In recent years, Wu Lixin's team has deployed nearly 50 sets of subsurface moorings in the South China Sea to observe ocean internal waves, mixing and deep flow processes, and this technology is relatively advanced internationally. Wu Lixin said that as our country develops oil and gas fields, combustible ice and deep-sea diving in the East China Sea and South China Sea, research on ocean dynamic processes not only plays an important role in national security, marine resource development and marine environmental protection, but is also increasingly closely linked with people's daily lives.

“Ocean climate change is different from that on land. We can predict climate change one or two years in advance, and can even issue early warnings.” Wu Lixin said that studying ocean dynamic processes and sea-air energy exchange can improve the level of typhoon disaster prediction. At present, they are promoting a “Transparent Ocean” research program like the “moon landing project,” establishing a prediction system to predict the spatiotemporal changes of the marine environment, climate and resources over a specific future period, paving the way for our country to move toward the deep sea and open ocean.