Innovative Development of Fishery and Ecological Protection of Poyang Lake

, *,

1. Jiangxi Academy of Agricultural Sciences, Nanchang 330006, China; 2. Nanchang University, Nanchang 330031, China

InnovativeDevelopmentofFisheryandEcologicalProtectionofPoyangLake

XiaofengFU1,MingheXIAO1*,GuozhenFU2

1. Jiangxi Academy of Agricultural Sciences, Nanchang 330006, China; 2. Nanchang University, Nanchang 330031, China

Fishery is an essential part of economic and ecological civilization construction of Poyang Lake Ecological Economic Zone. Taking fishery development and ecological protection of Poyang Lake as research object, this paper elaborated the relation between fishery development and ecological protection from physiological characteristics and functions of fish species by the method of field survey and consulting related data. Finally, it came up with recommendations of increasing plagiognathops microlepis and Xenocypris davidi Bleeker and adopting and deepening healthy ecological and water body stratification. Besides, government organizations, local supervision authorities, scientific research institutions, and enterprise operating entities should jointly maintain and promote breakthrough mechanism for ecological balance of Poyang Lake water system.

Fishery, Innovative development, Poyang Lake, Ecological protection, Recommendations

1 Introduction

Covering an area more than 4000 km2, Poyang Lake is the largest fresh water lake in China. Connecting Gan, Fu, Xin, Rao, and Xiu rivers and hilly areas in upper reaches and Yangtze River in low reaches, Poyang Lake has drainage area up to 162 225 km2, accounting for 97.2% of the land area of whole Jiangxi Province[1]. Well-known for its lake resources and no eutrophication, Poyang Lake is also an essential wetland with world influence. With 30% of land area of Jiangxi Province, Poyang Lake Ecological Economic Zone feeds 50% population of Jiangxi Province and creates more than 60% of aggregate economic volume of Jiangxi Province[2], so Poyang Lake is nearly another name of Jiangxi Province. Functions of Poyang Lake are multiple. According to research findings, Poyang Lake has product production, economic and social, ecological and environmental, cultural and recreational, and political and diplomatic functions[3]. We believe that ecological function is the most important function of Poyang Lake and fully manifests characteristics of Poyang Lake, and also a decisive factor for sustainable development of Poyang Lake. Without ecological functions, other functions will become overshadowed. Therefore, protecting ecological environment of Poyang Lake and maintaining ecological balance of Poyang Lake are of strategic significance for better using resources of Poyang Lake and developing regional economy of Poyang Lake, as well as building beautiful Jiangxi Province. Ecology of Poyang Lake mainly takes the form of vast lake and wetland, therefore clear water is still major resource of Poyang Lake and also the source of vitality and wealth of Poyang Lake[4]. Using water better, adjusting water faster and managing water more effectively are essential guarantee for binging into play regional advantages of Poyang Lake to the utmost extent. In this process, fishery plays an essential role. Thus, building fishery ecology, managing fishery environment, enriching fishery resources, and changing resource advantage into economic advantage are essential parts of invigorating economy of Jiangxi Province and sticking to sustainable development road.

2 Ecological functions and challenges of Poyang Lake

2.1Giftedgeographicaladvantagesandconditions

2.1.1Poyang Lake has high quality water resources and biodiversity. Poyang Lake rises from surface runoff. With species are numerous in the whole year, Poyang Lake is an integral part of species resources of Yangtze River basin and plays a significant role in maintaining regional ecological balance and bio-diversity. Apart from numerous wintering migratory birds, fishery resources of Poyang Lake are abundant. As to natural fishery function, Poyang Lake provides habitats for fishes and shrimps. According to statistical data, there are more than 800 species of fresh water fishes in China, 400 species in Yangtze River water system and 205 species in Jiangxi Province, and fish species of Poyang Lake account for 17%, 34% and 66% of the above figures separately. In 122 fish species, commercial fishes account for a half, and Carassius auratus and carp yield accounts for nearly a half of fish catch. Besides, there are some rare aquatic animals in Poyang Lake, including rare aquatic animals at national protection level finless porpoise, Myxocyprinus asiaticus (Bleeker), and Acipenser sinensis[5].

2.1.2Station of migratory fishes. As one of two Yangtze River-connected lakes, Poyang Lake is the breeding and feeding place of migratory fishes, and plays an essential role in protection of fish resources and bio-diversity in Yangtze River. Especially in flood season, water level of Yangtze River rises sharply and water pours into Poyang Lake basin, which brings shoals of fishes and increases holding capacity of Poyang Lake biological population.

2.1.3Purifying eutrophicated water. As disclosed by some research institutions, microbial population of Poyang Lake has high bio-diversity, and there are microorganisms with high use of total nitrogen and function of purifying water environment[6]. In turn, such purified active water will provide rare ideal place for growth, breeding and habitat of fish community, promoting fishes and shrimps to multiply and survive, stabilize community and keep relatively pre-ecological characteristics.

2.2Challengesandopportunities

2.2.1Challenges.

(i) Great changes of water body area. As a flooded lake of Yangtze River, Poyang Lake has the landscape of flood and low water occurs alternately. In rainy season and dry season, the biggest gap between largest area and smallest area of water body is up to 31 times, and water volume differs up to 80 times. Scarcity of water in dry season is a baffling problem influencing ecological environment of Poyang Lake. (ii) Degradation of water quality. Table 1 is Water Resources Bulletin of Jiangxi Province in 2005-2008, major polluted areas are Le’an River Estuary, Gan River South Estuary, Gan River Main Estuary, and major pollutants are total phosphorus and ammonia nitrogen.

Table1WaterResourcesBulletinofJiangxiProvincein2005-2008

Year2184km2waterareaPercentageofwaterbetterthanClassIII∥%PercentageofClassIIIwater∥%PercentageofwaterworsenthanClassIII∥%200558.832.38.9200657.824.317.92007ClassIIwater26.347.426.32008ClassIIandIIIwater63.836.1

Data source: website of Jiangxi Provincial Water Resources Department.

Compared with 2005, the gap between water better than Class III in 2006 and 2005 is only 1 percentage point, but the gap between water worse than Class III in 2006 and 2005 rises about one time; in 2007 and 2008, water worse than Class III increased at the rate of 10 percentage points year by year. (iii) Drop of water level. Due to drop of upstream water and influence of water storage of Three Gorges Project, low water level of Poyang Lake comes ahead of time and the duration is long, leading to relatively high total phosphorus and ammonia nitrogen in water of Poyang Lake. Taking Xingzi Station of Poyang Lake as representative, the highest level of 2006 was only 16.73 m, ranking the lowest fourth position since 1959. (iv) Serious damage of fishery resources. The annual yield of reeves shad was 440 tons, 475 tons, and 79 tons in the 1960s, the 1970s, and 1980s respectively; the yield of Coilia macrognathos Bleeker and Coilia brachygnathus (Shortjaw tapertail anchovy) was 1100 tons, 1358.5 tons and 550 tons in 1983, 1995, and 1998, showing a declining trend, especially in the later period, as shown in Fig. 1. The survey results of Macrobrachium nipponense population structure in 1998-2000 indicate that both the quantity and quality of shrimp population in Poyang Lake declined. There is conflict between forbidden fishing period and survival demand of fishermen in Poyang Lake from time to time, and the problem is becoming insurmountable.

Data source: Committee of Population, Resources and Environment of Jiangxi Provincial Jiangxi Political Consultative Conference, Jiangxi Provincial Department of Agriculture, Jiangxi Academy of Sciences. Report on Utilization and Protection of Poyang Lake Fishery Resources[EB/OL]. www.cnplph.com/sf_BB5C... 2011-11-23 (in Chinese).Fig.1 Curves for changes of yield of Coilia macrognathos Bleeker and shortjaw tapertail anchovy in the second half of the 20th century

2.2.2Opportunities. In December, 2009, National Development and Reform Commission issued thePlanforBuildingPoyangLakeEcologicalEconomicZone. The construction of Poyang Lake Ecological Economic Zone was integrated into the national development strategy. This will provide powerful strength for improving regional natural environment and developing economy. This plan calls for strengthening ecological functions and forbidding development and construction. Basic requirements are as follows: stabilize water quality and maintain wetland function, and improve habitat environment of migratory birds; regulate sand excavation, fishing, and breeding actions, strictly implement regulation on sand excavation, and comprehensively forbid aquaculture in net enclosure and fertilizer-derived aquaculture; carefully implement enclosure and grazing prohibition, and practically control spread of schistosomiasis; enhance prevention and control of tourist and ship pollution; protecting ecological environment is inevitable choice of human beings, and resource-saving development model and ecological environment with beautiful rivers and hills is becoming new competitive edge; fishery, as essential part of construction of Poyang Lake Ecological Economic Zone, will play a fundamental and important support role.

3 Ecological functions of fishery and ecological protection of Poyang Lake

3.1FunctionoffisheryinimprovingecologicalenvironmentofPoyangLakeAquatic ecosystem is one of the most important supports for the earth ecosystem. As important factor of aquatic ecosystem, fishery plays a greater and greater role in protecting and improving aquatic environment, expanding carbon sink, reducing carbon source, and maintaining aquatic ecological balance, and gradually receives higher and higher concern[7]. Fishery can promote green, healthy, and sustainable development of Poyang Lake.

(i) Function of controlling blue green algae with fishery and purifying water with fishery. Aristichthysnobilis and shellfishes take zooplankter and phytoplankton as foods, convert zooplankter and phytoplankton to fish protein and output to outside, and blue green algae can directly absorb nutrients in water body, effectively reduce nitrogen and phosphorus in water, and play the role of purifying water and restore water body. (ii) Function of restoring aquatic environment. Restoring aquatic ecology and improving aquatic environment are important approaches for promoting maintenance and restoration of resources. Restoration of aquatic ecological environment includes wetland ecological restoration with protecting water and grass resource as major part, enhancing self-purifying function of water area; building ecological aquaculture technical system; purifying large volume of excrement of aquaculture before discharging to river basin; reducing use of fishery drugs through effective ecological prevention and control technologies and precise feeding technologies, to control influence of diffused pollution on water. (iii) Function of carbon sink like carbon absorption and sequestration. This is also called carbon sink fishery. The carbon sink fishery refers to fishery production activities promoting aquatic organisms and storing carbon dioxide in water, reducing carbon dioxide concentration in atmosphere, and accordingly slowing down water acidizing and climate warming. At present, research findings indicate that such carbon sink is mainly manifested in marine organisms, namely, marine organisms absorbing biological carbon or green carbon. Reservoir ecological fishery is also a type of carbon sink fishery. The process of reservoir ecological fishery is as follows: surface run-off takes away larger portion of organic matters -> microorganisms are decomposed into nitrogen and phosphorus -> absorbed and used by algae and aquatic plants -> fishes gather nitrogen and phosphorus through eating various animals and plants -> taking way through fishing. Fishing is the most effective way of output of nitrogen and phosphorus. Therefore, we can draw lessons from these principles and study of reducing carbon content in Poyang Lake has significant value. (iv) Benign cycle of fish breeding in rice and fish breeding in lake. High efficient paddy field ecological cultivation and aquaculture technologies have advantages of vertical circulation, biological prevention and control, energy conservation and environmental protection, and high quality and high efficiency. Applying this technology in grain production and implementing ecological cultivation and aquaculture combination are effective approaches for solving the pesticide residue of grain, producing high quality organic rice, and raising economic, social and ecological benefits of paddy field[8]. Fishes live in water and have high quality for water quality. In reality, water quality and fish types of Poyang Lake complement each other. Poyang Lake provides foods and places for fishes, while fishes act as water cleaner and clean up microorganisms, algae, planktonic organisms, food residue, decayed organisms, prevent damage of blue green algae and improve water quality.

3.2NecessityandfeasibilityofecologicalprotectionforPoyangLakeDue to diffused pollution brought about by population growth and economic and social development, discharge of water conservancy and electricity, shipping and transportation, and urban domestic sewage and industrial and agricultural waste water, flow-in of river and lake pollutants, long-time extensive and predatory excessive fishing and sand excavation, ecological environment is constantly deteriorating and eutrophication index rose from 36 in 1987 to 51 in 2003. Poyang Lake has nitrogen and phosphorus condition for eutrophication and has the trend of gradual eutrophication. Blue green algae problem occurs frequently in Poyang Lake, the productivity of Poyang Lake declines gradually, and traditional commercial fish and shrimp resources also decline, the rare aquatic wild plants and animals are on the brink of extinction, and fishery resources and environment pressure is increasing, so it is urgent to change development and utilization model of traditional fishery resources. Since 1959, Jiangxi Province has launched natural environment, hydrology and climate, water level and sand, rainstorm and flood, water quality and water volume, and experiment research supervision and analysis evaluation work in Poyang Lake. Especially since 2007, Jiangxi Province started dynamic water quality monitoring of Poyang Lake, the scope expanded from 5000 km2to 25000 km2area, and monitoring stations rising from 21 to 50. And monitoring items added water level, flow rate, and flow velocity, and monitoring frequency increased to 12 times annually. Besides, it carried out dynamic water quality and volume monitoring at rivers above city level, made in-depth researches of factors restricting aquatic ecological environment and has made considerable achievements in water pollution accident investigation and supervision, water quality and volume monitoring in dry season, and collecting series of complete hydrological data. In addition, Jiangxi Province has completed fundamental researches inPlanofWaterResourcesProtectionofJiangxiProvince,WaterFunctionalZoningofJiangxiProvince,ComprehensivePlanforWaterResourcesofJiangxiProvince,CensusandRegistrationofSewageOutfallinJiangxiProvince,andSafetyGuaranteePlanforUrbanDrinkingWaterSourceofJiangxiProvince[9]. Poyang Lake ecological water conservancy projects in recent years also provide favorable ecological guarantee and reliable water resource guarantee for long-term sustainable development of Poyang Lake. All of these create excellent preconditions for controlling and protecting ecological environment of Poyang Lake.

与太仓市毗邻的常熟市，结合农民专业合作社和家庭农场党组织建设全国试点工作，积极探索“行动支部+”新模式，全面提高农村一二三产业融合发展水平。常福街道中泾村先锋农业支部，以振兴农业生态园各项重点工作为行动方向，以推动“都市农业生态园”建设为行动目标，仅花卉种植项目的营业额就突破了3000万元。

4 Recommendations

4.1EnergeticallypopularizingecologicalaquaculturetechnologiesandbringingintofullplayenergysavingadvantagesoffisheryFirstly, fish species such as Plagiognathops microlepis and Xenocypris davidi Bleeker are ideal fishes for aquaculture. Plagiognathops microlepis seldom gets disease and its meat is fresh and delicious, so its economic value is high. Its food chain is short and it mainly eats bottom algae and scraps that other commercial fishes do not eat, so it has no food conflict with other fishes. Therefore, it is ideal fish species for aquaculture, it can improve water quality and increase economic benefits. Secondly, it is recommended to properly arrange net cages and factory-style intensive aquaculture. Thirdly, it is recommended to control aquaculture capacity and ensure water area carrying capacity. Stratification or vertical aquaculture is feasible. Stratification aquaculture means breeding different fish species at different water levels according to living habits and food feeding characteristics, to increase breeding intensity and per unit area yield through effectively using water body space and various natural baits. For example, Hypophthalmichthys nobilis and Hypophthalmichthys molitrix live in upper water level and are water-fertilizer favorite, and mainly eat planktonic organisms. Grass carps live in middle level and like clean water, and eat fresh water plants and other plant baits. Cirrhinus molitorella lives in bottom level, like clean water, and eat benthic such as conches and shells. Fourthly, it is strictly prohibited to use chemical fertilizer and organic fertilizer in lakes and reservoirs, and popularize fertilizer application through measuring water level.

4.2ChangingtointensiveaquaticproductprocessingmodelAquatic product processing trade concentration areas should continue to focus on processing strategy, introduce aquatic product processing enterprises with high content of science and technology, transform traditional aquatic product processing enterprises, consolidate aquatic product processing enterprises, colleges and universities, scientific research institutions, and logistics upstream and downstream extending industrial chain, to full explore deep value of fisher resources, satisfy growth demand of market, and reach demands of ecological balance, and cultivate a good many aircraft carrier type fisher group companies.

4.3Combiningimprovingpeople’slivelihoodandlimitingfishingIt is recommended to rapidly increase fishermen’s income combining construction of Poyang Lake control projects, arrange some fishermen to change to other industries, and reduce dependence of fishermen on fishery resources. Government should provide necessary subsidies for forbidden period, guide ecological tourism, encourage labors to do migrant work, increase percentage of non-fishery production in income of fishermen, and effectively reduce fishing intensity and alleviating resource pressure, to fundamentally solve livelihood problem of fishermen ane ensure sustainable use of fishery resources[10].

4.4Establishinglong-termmanagementmechanismFirstly, on the basis of existing fishery administration and wild plant and animal protection and management organizations, it is recommended to unite environmental protection departments to establish comprehensive management mechanism for Poyang Lake ecological resources, and reinforce bio-diversity protection and eco-system monitoring. Besides, it is recommended to establish a long-term mechanism with ecological protection fund input as major part, and cities, counties and townships taking responsibility. Government regulation and ecological cultural education and propaganda should be carried out at the same time, to form conscious and permanent awareness of whole people. Secondly, it is recommended to strengthen protection of fishery resources and aquatic living resources. It is recommended to change traditional autumn fishery by enclosing plate-shaped sublake. For example, it is recommended to save rare endangered fish species such as tetraodontidae, marbled eel, and Tenualosa reevesii, resolutely attack destructive fishing such as electrical fishing, blast fishing, and poison fishing, and advise and advocate correct consumption idea of citizens, to block the final gap. Specialized monitoring organizations cooperate with the masses, to prevent lawless persons to take advantage. It is recommended to develop lake side large-scale ecological aquaculture and processing industries, popularize Monopterus albus industrial model of Jinxian County and develop modern fishery technologies. Thirdly, it is recommended to take science and technology as support and jointly carry out fishery development and ecological protection of Poyang Lake. Jiangxi Province should consolidate related research resources of Poyang Lake, set up a platform for specialized domestic and international advanced Poyang Lake and wetland research institutions and academic exchange; strengthen construction of fry breeding bases; combine introduction and self breeding, especially fish species with great adjustment of lake ecology, good commodity performance, and high market value, such as Coilia ectenes Jordan et Seale and salangid; establish two-way dynamic change monitoring information network for fish species and lake, grasp dynamic data, to provide references for further researches, and provide powerful scientific basis and technological support for economic and social sustainable development of Poyang Lake area[11].

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November 20, 2015 Accepted: January 3, 2016

*Corresponding author. E-mail: 545112334@qq.com