Marine Ecological Environment Protection

Marine Biological Resources Facing Degradation

Fishing industry is a kind of marine industry treating biological resources as its productive object. A lot of problems exist in activities of utilizing marine biological resources in our country, especially over development of fishing industry, marine pollution and coastal construction have largely degraded our marine biological resources, even worse some biological diversities have almost disappeared. As a result, the production has been reducing and fishing output been declining.

Some traditional economic fish diversities in China Sea have disappeared due to over-fishing activities. Take big yellow croaker as the example, during the period from 1950s' to 1970s', its annual yield was always above 100,000 tons, but at the beginning of 1980s' the output reduced to more than 60,000 tons, and in 1988 only 18.000 tons.

Caused by long-term over-fishing activities, the composition of marine fish diversity and its resource structure have been changed greatly. The amount of those traditional good-quality economic fishes positioning at higher levels of the food chain has been declining, while the amount of those lower-quality fishes as the food of those higher-quality ones is increasing. In addition, such fishes with low economic value like globe fishes and carangids as well as some shrimps and crabs have gradually become the main catching diversities.

Due to miniaturization and infancization of high-quality economic fish diversities, and due to fishing middle-level and high-level miniature fishes through fishing infant blue mackerel, scaled sardine, spotted sardine, as well as large amount of infant high-quality economic fishes. In addition, coastwise catching and offshore trawling also seriously damage the infants of key economic fish diversities. Fishing to the infants of the above mentioned fishes has also made serious damage to their diversity structure balance and affected the proportion of these fishes among fish diversities.. Furthermore, these activities also brought serious damage to the fishing industries. The declining of quantities of the fish diversities can also further affect coordinating development of the whole oceanic ecology. Some experts in this field believe that the declining of high-quality fish diversities in Bohai Bay is the main cause of the unstable and low output in China.

Our country has a vast marine area covering temperate zone, subtropical zone and tropical zone in the longitude direction, the coastal line is long and zigzag and the marine climate diversified. The ocean area is rich in marine biological resources and contains varieties of rare diversities such as whale, sea pig, seal, sea turtle, hawk-beaked turtle and lancelet. But their quantities in the sea has been sharply reduced for the reason of ineffective management and over killing. Some diversities have been nearly extincted.

We had a quite profound whale resource before, among baleen whales, we have humpback whale, blue whale, baleen whale and cachalot. With the world-wide declining of whale resources, we stopped killing whales since the 1970s'. At present we have fewer whale resource than before, which requires us to take necessary steps to recover the initial quantity.

Liaodong Bay of Bohai is the southeastern reproductive area of spotted seal in Western Pacific Ocean. There are usually more than one thousand seals coming here each winter to calve. But the quantity now has reduced to one or two hundred due to large scale killing over the past thirty years.

Sea pig was only found in the coastal areas of several countries and the revivers are even few, so it has been listed as one of the first class endangered animals by the United Nations. Since 1980s, with the increase of the quantity of motor fishing vessels on the sea, the residential environment has been destroyed more seriously, and some illegal activities such as catching fish by explosion, electricity and poison also kill some sea pigs, its quantity has been further declining.

In addition, some animals such as sea turtle and hawk-beaked turtle are also receiving threatening from over killing activities. It is said that some Southeast countries kill about 50,000 hawk-beaked turtles in South China Sea area.

We used to have some large-quantity biological diversities in China Sea area, the number of recorded diversities has exceeded 13,000, accounting for over one fourth of the total number of the world.

The coastal wet land of China is covered by mangroves and coriaceous plants. There are 36 varieties of plants belonging to mangrove plants, accounting for about 43% of the total in the world, of which there are eight kinds of mangroves, accounting for 47% of the total family in the world.

There are hundreds of birds living in the coastal line areas, coastal wet lands, islands and on the sea in China.

During the latest tens of years, China still has a certain amount for some fish diversities, but for some certain coastal areas, these diversities maybe nearly disappeared, this condition is especially serious in some areas such as ports and river mouths, of which the Bohai area is listed at the top.

Red Tide is happening more frequently than before in some main polluted areas along Chinese coastal line with extension of scale and duration of advent(the duration has been increased from one or two days to one week or even longer), the season of occurrence has also extended from only summer to spring and autumn. In addition, some new records have occurred in some sea areas of China in recent years.

Red tide is the signal of sea water quality degradation. The venom excreted by the red tide microorganisms not only lead to the death of some marine lives but also threaten the health of mankind through the food chain.

Reasons for Marine Biological Resources Degradation

1. Over-fishing to Marine Biological Resources

Bloody clam used to be always the main fishing resources of Bohai Bay, but its output has had a sharp decline due to over fishing in recent years.

With the continuous declining of some high-quality fish diversities, the object for fishing has become more and more concentrated on some certain fishes. As long as a certain kind of fish has some economic value, it will be fished centrally.

Further more, because some nets are used repetitively for many years and they are for some certain fishes, it caused the change of proportion of different fishes. When some fishes have been very hard to fish anymore, the fishermen will turn their object to some other fishes which are much easier to catch. So the ultimate result will be that more and more common high-quality fish diversities turn into rare ones. More seriously, it will also cause disappearance of low-quality fish diversities.

The pollution of environment in which lives live has decreased the quantities of many living diversities who cannot adapt themselves to the change, especially some important economic fishes, shrimps and shells are more sensitive to the harsh environment.

During the past tens of years, large scale activities of reclaiming land from the sea and making land by filling the sea have been executed in China. As a result, large area of beach for aquaculture and many natural spawning grounds of marine lives have disappeared, and imposed some serious negative influences on the marine biological resources of the surrounding areas.

River is the main path transporting materials needed by marine ecological system into the sea. But in recent years, the fresh water resources have become more and more scarce due to rapid development of coastal industries. In order to make up for the shortage of fresh water, many dams and floodgates have been built on the rivers, resulting in a sharp reduce of the quantity into the sea. As a result, the quantity of materials dumping into the sea have been declined, this condition will make the salinity of sea area of river mouth and offshore abnormal and further affect sound change of a series of marine ecological environment.