"There is heaven above, and there is Suzhou and Hangzhou below. ”
Since ancient times, Hangzhou has been a land of abundance, and its food and beauty are innumerable.
And in Chun'an County, Hangzhou, there is a rich landThat was when the hydropower plant was builtIntercept the large and small lakes formed by the impoundment of water in the upper reaches of the Xin'an River, that is, the Xin'an River Reservoir, and these beautiful lakesThere are a total of 1078 islandsHence the nameQiandao Lake.
Qiandao Lake is not only famous for its clear water, but also for its beautiful sceneryIts water storage capacity is huge, at least 17.8 billion cubic meters.
The huge topography has also made nearly 100 species of fish homeAnd the artificially farmed fish is even more abundantFor example, grass carp, eel, herring and so on, it can be said that there is everything.
However, this resource-rich Qiandao Lake alsoThere are many dilemmas.
At the beginning, these schools of herring and grass carp were artificially cultivated to retain water.
What I didn't expect was that when these fish grew up, they brought two major problems to people:It is difficult to fish and stock.
Why is there such a problem in Qiandao Lake?
What did the original "water-retaining fish" protect?
Qiandao Lake is located in the Yangtze River Delta region, which belongs to the Qiantang River Basin, where water resources are abundant and abundant. And the completion of the Xin'an River Reservoir,It has provided a huge amount of water for Qiandao Lake and laid a solid foundation for the development of fisheries.
And the water area of Qiandao Lake is vastThe average water depth is more than 30 meters, and the deepest depth is more than 100 meters. The abundance of water supports the growth of a large number of phytoplankton, which provides ample natural bait for fish.
And the lake is rich in fishA total of 83 species of fish inhabit the areaIncluding silver carp, carp, whitebait and other economic fish, the variety is complete.
In addition to having a vast water environment,The inundation line of Qiandao Lake is also 1,400 kilometers high, the water level fluctuates by 9 meters, and there are many kinds of aquatic plantsIt is an ideal spawning environment for fish.
At the same time, the reservoir can also regulate the seasonal river water volume changes, ensuring the normal life of fish in different seasons. This provides a stable, high-quality living environment for fish.
In addition to the natural conditions, the fishery has also adopted scientific aquaculture management measures.
The fishery also has a special fish rearing pondFish fry are reared in large quantities to meet the breeding needs of the lake area.
The artificial cultivation of seedlings has become an important part of the development of fisheries. The fishery adopts scientific cultivation measures, controls the density, and strictly controls the nutrient ratio to ensure that the survival rate of fish fry is high.
They also regularly carry out disease control on the fry to avoid the loss of fish caused by the disease.
Strengthening disease control, controlling density, and improving varieties have improved yield and quality.
Fishermen have accumulated farming experience for generationsIt is also an important support for the development of fisheries.
It is the Thousand Island LakeThere are advantages such as abundant water, abundant bait, and complex environmentWith scientific fishery management, it also provides a unique advantage for the development of fishery, which is the Qiandao Lake becomesAn important part of the famous "fish store" in the country.
But asA large artificial lake,Qiandao Lake was not as vibrant as we thought it would be in the early days. On the contrary, it once faced serious water quality problems.
The reason is that the artificial lake is intercepted and impoundedThe ecosystem is completely destroyed, all kinds of algae and plankton are out of balance and overgrown in large numbers.
Especially since 2006,Disgusting blooms frequently occur in Qiandao LakeThe surface is covered in a thick layer of green algae and cyanobacteria, which smells foul. The water quality is deteriorating and the oxygen content is decreasing, posing a serious threat to the ecology of the entire lake.
In the face of severe water quality problems, the relevant departments are actively exploring ways to deal with them. After repeated arguments and tests, the concept of "governing the lake with fish" was put forward and implemented.
Can be over time,The original water-retaining fish program went awry, causing great pain to the fishermen.
Let's start with thatThe problem of difficult fishing.
Qiandao Lake covers an area of about 558 square kilometers, and the deepest water of the lake is more than 100 meters. This complex topography has caused great trouble to the fishing activities of fishermen.
It is recorded that in the 60s of the 20th century, in order to complete the task of fishing,A fishing team of 107 people has been set up in the Qiandao Lake Fishing Grounds. The size of the team,It can be seen that fishing is not easy.
Among them, there are 11 people in the transportation class, which can imagine the hardships of transportation. And it's even harder to catch fish.
The fishermen designed two types of gillnets, single and triple layersEquipped with 12 fishing boats, it is still difficult to catch live fish despite the strategy of encirclement and interception.
According to an old fisherman's recollection, once in the middle of fishing,The fish suddenly dispersedAs a result, the fishing fails, and it can be said that the fish are flexible and the fishing process is extremely complex.
Moreover, although schools of fish are frequent,But the fish that can be caught are limited. On the one hand, in order to protect the ecological environment, fishing must comply with the limits on the size and quantity of fishNeither juvenile nor large fish can be caught indiscriminately.
It is understood that the fish caught by fishermen must also be manually inspected and classifiedMake sure the small fish can be released safely. This undoubtedly increases the burden on fishermen.
On the other hand,Some fish are very cunning and live in the lake for many years and are well aware of their environment. As soon as they hear the sound of the boat, they can quickly escape from the fishing area.
It is said that the herring in Qiandao Lake is especially good at evading, living at the bottom of the lake at a depth of more than 110 meters all year round, and it is difficult to catch them.
Next, it is difficult to release fish. In order to maintain the ecological balance of Qiandao Lake, a large number of fish fry are released here every year. But the number of releases and the proportion of varieties,It's always been a problem.
It is understood that Qiandao Lake is released in one year600,000 kg of fry, mainly silver carp and bighead carp.
The problem is,Different fish species have different roles in algae control, and the proportion must be determined according to the water quality conditions.
For example, when there is too much cyanobacteria, the proportion of silver carp that eat algae should be increased. However, the exact amount of increase has not yet been determined.
Because the amount of fish in the lake cannot be counted,Catches can only be approximated by reference to previous years, but the accuracy of the estimates is questionable.
If the release strategy is wrong, it may lead to the exacerbation of the bloom problem. It can be seen that the work of releasing water is complex and arduous.
The difficulty of fishing and releasing fish in Qiandao Lake has always troubled fishermen and management departmentsSo what did the "water retention fish" plan pretend?
So-called"Fish to govern the lake",It is to raise some herbivorous fish in large quantities in the lake, and use their biological characteristics to purify the water body.
Among the four major fish, silver carp, grass carp and bighead carp feed on algae, and if there are enough of them, they can filter the lake water.
In addition, some small plankton, such as rotifers, nauplii larvae, earthworms, etc., are also important food for them**. These fish have a strong feeding capacity through a large intake of algaeIt effectively controls the state of algae growth imbalance.
It can be said thatThey are like "cleaners" in the lakeIt has helped to purify and improve the water quality and environment of Qiandao Lake.
In order to achieve "fish to govern the lake",Qiandao Lake has set up a number of fish farms in the lake area to cultivate these "water-retaining fish".
Unlike traditional farming, water quality is the first priority in farming, rather than simply fish production.
Farmers use green recycling farming technologyDo not add any chemical synthetic feed,Let the fish feed and grow in the lake according to their instincts.
This green farming model is cultivatedThe fish are sturdy and deliciousDue to the absence of contamination and hormone residues, it has received a good market response.
This batch of certified Qiandao Lake organic fish is warmly sought after by consumers for its pure natural taste, and it is also much higher than ordinary fish.
After years of persistent efforts,".The effect of "using fish to govern the lake" has begun to appear. The water quality of Qiandao Lake has improved significantly, the water transparency has increased, the surface bloom has receded, and the number of algae has decreased significantly.
At one time it became a lake"Pests".The algae, filtered by the fish system, returned to normal levels and the aquatic ecosystem returned to balance.
It can be said that through the innovative practice of "governing the lake with fish", Qiandao Lake not only retains the quality of valuable water resources, but also retains and enhances its brand value and environmental image in the market.
This concept of pursuing ecological balance and sustainable development enables the aquaculture industry in Qiandao Lake to develop economic benefits while protecting the ecological environment.
"Fish to govern the lake",The successful experience once again proves that man and nature can live in harmony and mutually beneficial. Fish need a good aquatic ecology, and water bodies also need fish to maintain the balance of the system.
Only when man and nature are in harmony and unity, and the economy is developed while protecting the environment, can sustainable development be achieved and a better future can be created.
The practice of Qiandao Lake has set an example for usIts model is worth replicating in more regions.
Man and nature should live in harmonyAnd we should also maintain a sense of reverence for nature, and in the ecological development, we must also make rational use of nature.
We should also be cautious about everything in nature and protect the ecology in the process of development. Nature's gifts are not always a godsend, and sometimes they are "devil's tricks." We also need to strengthen scientific research, deeply understand the laws of nature, and not blindly promote superficial prosperity.
The success of Qiandao Lake has yet to be tested by timeWe can't take unknown risks anywhere else. Development cannot be without a bottom line, and the ecological environment is the cornerstone of our survival.
Otherwise, the so-called gift could become a visitor to hell. We still have a long way to go, and we need to be cautious and rational and take into account the ecological balance in our development. We must not harm future generations because of small profits.