Abstract

Fish migrate up and down streams for reproduction in both sea and freshwater ecosystems over their life cycle. Over the last decades, fish passages have been provided to mitigate the adverse impacts induced by barriers. However, what is the proper type of fish passage and how to guarantee the effectiveness of operation are still under discussion. In this paper, global and China's policies on fish passages are reviewed. The development and main contents of relevant instruments are analyzed. The similarities and differences between China and foreign countries are compared, and issues in the fish protection and fish passages' management in China are identified. The results show that global policies on fish passages varied from local governments to continents. The design, operation, and management of fish passages are popular throughout the world. Duplication of authorities' responsibilities is the most critical issue in China. The paper recommends implementing a plan of environmental protection at watershed scale, and strengthening the monitoring of fish passages' operation and management. Further development directions of policies on fish passages' management have been proposed. The paper may help facilitate national policies on fish passages by integrating the effective measures of global experience.

Introduction

Dams and reservoirs can be used to supply drinking water, generate hydroelectric power, increase the water supply for irrigation, provide recreational opportunities, and for flood control. Free-flowing rivers are dwindling fast throughout the world. Of the 177 large rivers of the world, only one-third are free flowing. Most rivers in China have been highly exploited except for some transboundary rivers (e.g., Nujiang River, Argun River, and Heilongjiang River) and tributaries (e.g., Chishui River). Water infrastructures have been greatly improved to benefit the development of local people in watersheds. The maintenance of natural hydrologic connectivity is particularly important for fish species that must migrate through river networks to complete their life cycle. Yet, in practice, connectivity in river networks has been a challenging property to measure and directly apply in conservation planning policy (Grantham, 2013; Wu & Chen, 2018). Barriers have influenced fish resources, natural flow regimes, structures, and functions of river ecosystems (Chang et al., 2008; Chen & Wu, 2019). Until now, the most effective way for indicating environmental impacts of barriers is to monitor fish species population. The disruption of river connectivity would prevent fish migration, and is caused by dam construction. A high dam would harm the life behavior and life cycle of fish species, such as reproduction, feeding, and overwintering. Furthermore, the water temperature stratification and releasing of water with low temperatures also have certain adverse impacts on fish spawning (Chen et al., 2013a, 2013b, 2017). Mitigation measures such as fish passages and fish stocks incorporated into the dam design would have effects. The fish passages would guarantee the life cycle of fish species, while protecting the transfer and exchange of materials, energies, and genes. Hence, this could protect the fish species by restoring fish migration passages (Gao & Chang, 2004).

Over the past years, improvement in fish passages has contributed to fish survival rates in many countries, especially the USA, UK, and Australia. Most fish passages were built according to the characteristics of regions, watersheds, and barriers. The effectiveness of fish passages has involved multi-disciplinary factors, such as ecology, technology, economy, and management. Structural or operational changes to fishways can improve the efficiency of fish passages, but there is often uncertainty regarding which improvement would be the most effective one (Keefer et al., 2014). Most research has focused on fish swimming ability and injury mechanism, numerical simulation of hydrological and hydraulics, fish passages' operation and monitoring all over the world (Cao et al., 2010; Zheng et al., 2010; Zheng & Han, 2013), while little research has been done for the improvement of design and fish passage policies. Research of fish passages in China originally began in the 1950s. Since then, river exploitation and mitigation measures have been proposed, ranging from net capturing, releasing and enhancement to the construction of fish passages, fish habitat protection and ecological operation (Chen et al., 2016a, 2016b). Greater and deeper understanding of fish passages' management underpinned more proper approaches from practice to scientific basis. Globally, previous research generally covered four areas: (1) review of fish passages' research and development, such as fishways development in the USA, Japan, and Scotland (Bai, 1978; Zheng, 1997; Ma, 2003), construction and operation of fish passages (Xing-yong & Jun, 2005; Hu et al., 2008; Bai et al., 2011; Chen et al., 2013a, 2013b), theoretical studies on the classification methods of fish passages (Zhou et al., 2011); (2) practice of fish passages' design and operation, such as the Yangtang fishway, Suwulong, Cuijiaying and Poyang Lake fish passages (Hu, 1980; Lin & Yang, 1984; Bai & Wu, 2011; Wang et al., 2013; Chang et al., 2016), the fish ladder test of Itaipu (Liu, 1995; Makrakis, 2007), fish passages' design of Niteba (Ma, 2003), fishways' design of Santo Antonio, Maddalena, etc. (Zhang et al., 2013); (3) hydrological and hydraulics characteristics of fish passages, such as the structural design of vertical slot fishways, the options for fish selection and biological characteristics (Quinn et al., 2008; Luo & Li, 2010; Sun & Zhang, 2012; Fang, 2014; Chang, 2015); (4) newly developed research on fish passages' monitoring and effective assessment, including the co-publication of Fish Channel Biology Design and Food and Agriculture Organization (FAO) Monitoring, the assessment of fish migration in Yangtang fishway, etc. (Jia, 2002; Tian & Jiang, 2013).

Policies are more effective for fish passages' management than technical measures. Further study of policies on effective fish passages including laws and regulations should be paid more attention. Policies on fish passages in developed countries are earlier than those in developing countries. Britain demolished obstacles which blocked river flow as early as the 16th century. Germany passed the Prussian Fisheries Act related to the construction of fish passages in 1874. The first Federal Act to protect salmon migration was adopted by the US Congress in 1889. The USA reviewed relevant policies on fish passages, such as national policies on individual fishing quotas (National Research Council, 1999) and the relevant policies concluded. Although practice was also early in China, policies and scientific basis were not implemented in a timely fashion. The former State Environmental Protection Administration issued a Technical guide on environmental impact assessment of ecological water utilization for river, low temperature water and fish passages in water conservancy and hydropower construction projects (trial) in 2006. Since then, fish passages have been incorporated in most dam projects according to the guide. However, there are still some problems in implementation due to irregular fish passages' design, ineffective assessment of fish passages, which influences the main streams and tributaries of many migration passages. Most policy documents were made to manage fish passages according to regional fish species. Recently, policies have been adjusted, including streamlining administration and delegating power to the lower levels, environmental impact assessment (EIA) system reform, and environmental protection final acceptance. The Chinese Government stated that authorities should strengthen overall management in the whole process of implementation (Xu, 2016). With these innovations, it is necessary to learn of global policies on fish passages related to practical experiences in the management of dam projects and integrated watershed resource management. Through comparing and analyzing the similarities and differences of policies between China and other countries, issues reflecting insufficient practical applications in China should be identified and the implementation of fish passages to protect fish species be accessible. This research provides support for the legislation system of fish passages' design, operation, and management, and to protect national fish species.

Global policies on fish passages

Classification of instruments

Global policies on fish passages have been uneven (Table S1, available with the online version of this paper). The relevant legislations comprised mainly three parts: (1) guidelines for contracting parties, such as the global conventions issued by the United Nations (UN), the continental conventions issued by the European Union (EU), and the transboundary conventions signed by multiple countries; (2) guidelines which were implemented within a country, such as domestic laws and regulations, plans and actions; (3) guidelines for local governments, such as local management regulations, policy documents issued by local governments, local and sectoral standards or norms. Forty-nine documents of policies on fish passages were collected in total. Among them, 14 were international conventions, 33 were national acts and guidelines, and the other two were local guidelines. International conventions were issued mainly by the UN, EU, and International Union for Conservation of Nature (IUCN). National acts and guidelines were mainly issued by the USA, Canada, and Australia (Figure 1). The constraint force and contents varied from country to country, but all stipulated that fish passages were required to be constructed for barriers in which the migration passages were possibly influenced. The relevant policies of fish passages' design, operation and management generally existed in international conventions, state, and local instruments.

Fig. 1.

Global policies on fish passages.

Fig. 1.

Global policies on fish passages.

Legal binding constraints

International instruments

Countries that made commitments on fish passages must simultaneously adhere to the relevant instruments. International instruments are mainly directed at three parts of content, including: (1) common issues in the world such as the convention on the Conservation of Migratory Species of Wild Animals signed by the UN; (2) issues of transboundary rivers such as EU Water Framework Directive (WFD), Council of Europe Regulation (EC) No. 92/43 EEG; and (3) the treaties reached by multilateral agreements such as the Treaty of the Committee of Ministers of the Benelux Economic Union.

There is a long history in Europe of fisheries being held in the public domain and protected by the sovereign under common law for the benefits. The WFD focused on regional aquatic environment improvement, such as the protection of fish migration passages. The regulation which is generally binding on the signatories is critical to sustain migratory fish restoration. It is necessary to propose an international solution for most transboundary rivers in Europe. The countries involved all released related policy with their own national conditions based on the WFD. Although there are many differences in legislation among countries, they all observe the guidelines and agreements made by the EU. Relevant directives, laws, regulations, and policies are proposed to clarify the similarities concerning fish migration and the mechanisms of fish migration benefit from the implementation of the WFD. The regional policies based on international and national policies require to be carried out effectively by local authorities without the process of policy legitimation. With the increase of European funding for environmental protection, a growing number of European laws and regulations, not just the national or regional policies, have been implemented to restore fish migration passages.

Although damming in Asian rivers is common, policies on fish passages is sorely insufficient. In recent years, China has made increasing efforts regarding fish passages, river ecological restoration, and integrated watershed management. However, the findings on watershed research are obtained just through the model application of the USA, Europe, and Australia. The continental policies on fish passages are nonexistent in Africa, and only South Africa is concerned with fish migration and integrated watershed management. The African Water Resources Database (AWRD) developed by the Food and Agriculture Organization (FAO) has nested its own design tools under the analyzing framework based on GIS. This innovation is applied to the data detection of fisheries in inland rivers and fish passage design. There are no continental regulations on watershed management and fish passages in South America. Due to lack of data on river ecosystems and biological monitoring, most instruments of fish passages are based on land cover classification. However, policies on fish passages have been issued in Brazil.

National instruments

Developed countries such as the USA, Canada, and Japan have developed national policies on fish passages. There are mainly two federal agencies responsible for fish migration protection in the USA, including Division of Fisheries and Habitat Conservation (FHC) and the US Fish and Wildlife Service (FWS). National Oceanic and Atmospheric Administration (NOAA) is the former National Marine Fisheries Service (NMFS). FHC and FWS implement Habitat Conservation Plans (HCP) particularly to protect fish, wild animals, and critical habitat. NOAA is responsible for the conservation of marine living resources and their habitats. Instruments in the USA cover fisheries, water conservancy, energy as well as some national planning of fishways. For example, the US River and Coast Remediation Law clearly stipulates that any river or shoreline project obstructing fish must be constructed with adequate and effective fishways. The hydropower permit system stipulates that the permit will be supervised for the entire period after the permit is issued. The environmental protection measures are required by the national plan for establishing a nationwide fish-road decision support system, so that information on river hydraulic structures and the biological ecology of fish, recovery targets and priority protection sections can be collected. In practice, an extensive network of more than 170 radio receiving stations were used to document fine-scale passage efficiency of adult anadromous Pacific lamprey at Bonneville and the Dalles Dams in the lower Columbia River in the northwestern USA (Moser et al., 2002). Except for the monitoring, recent efforts to improve the survival of hydroelectric turbine-passed juvenile fish have explored modifications to both the operation and design of the turbines. Much of this research has been carried out by power producers in the Columbia River basin (US Army Corps of Engineers and the public utility districts), while the development policy of low impact turbines has been pursued on a national scale by the US Department of Energy (DOE) (Čada, 2001).

Regional instruments

Before local policies are established, international and national policies must be complete. Few regional policies were found in this study. The design and assessment of fish passages should take into account the basis of natural characteristics of rivers. Some regional instruments cannot come into force by policy legitimation, such as the exploitation plan of a river. Others could possibly be codified into law, such as the federal requirements or the plan of water management authorities. In this case, the Montana State Code of the USA has made provisions required in Volume 87; the Dutch Water Authority has put forward some goals related to fish migration; the federal states of Lower Saxony and North Rhine-Westphalia, located in Germany, also cooperated in legislating fish migration. With the passage of the Fishery Conservation and Management Act of 1976, Congress for the first time mandated a national program for the conservation and management of fishery resources, to be developed by eight regional fishery management councils and implemented by the Department of Commerce through the NMFS.

Contents of instruments

Laws and regulations

The implementation of legislation that aimed for fishery protection has existed for many years. In order to meet the requirements, many countries take actions to build fish passages and remove barriers in rivers. According to different national conditions, most countries have built fishways or other fish passages for fish migration. Britain's legislation and policies on removal of barriers for migratory fish were improved according to local issues, and were implemented as early as the 15th century. Fish migration protection of federal dams were required in the US Endangered Species Act. The Electricity Consumer Protection Act required that plant owners must take measures to protect special fish and wildlife before changing a river course. The licenses issued by the Fish and Wildlife Coordination Act required fish ladders to be built at dams. The Irish Fisheries Act required that fishways must be built when constructing weirs in order to ensure the migration of salmon. The Freshwater Fisheries Act required that all pipes, channels, or factories which were used to pump clean water should have fish screens to protect migratory fish like trout. This Act was made to guarantee that migratory fish could avoid piers and intakes safely and keep away from the shunt of rivers to the sea. The River Management Facilities Construction Order in Japan provides for building fishways to help fish run upstream.

Directives

As a guidance, WFD is expected to play a key role in improving regional aquatic environment protection including protection of fish migration passages. In England and Wales, the Salmon Action Plan aims to remove barriers to salmon migration in response to the directive of government ministers. No Net Loss (NNL) presents the ultimate goal of complementary measures for fish and their habitats. Fish passages at dams should guarantee the life cycle of target species, especially reproduction and migration. The hydropower relicensing in the USA ensures that migratory fish pass through hydraulic engineering facilities on time and safely.

Convention and treaty

Section II of the Convention on the Protection of Migratory Species points out the importance of migratory fish species and requires proper measures, and migratory species which are endangered or subjected to the agreements are both listed separately in two appendixes. An EC treaty contributes to creating good conditions to protect fish species and their habitats in accordance with the EU's interests and to support the establishment of the European ecological network ‘Natura 2000’. The governments of member states are responsible for guaranteeing the life cycle of migratory species, the focus being on protecting migration passages and spawning areas in rivers where the phenomenon of running upstream or downstream to reproduce is particularly obvious. The Convention on the Conservation and Management of Highly Migratory Pacific Fish Stocks in the Western and Central Regions provided that coastal and fishing nations in the Pacific region are under an obligation to protect areas where there are highly migratory fish stocks and develop them appropriately. It is necessary to reduce persistent or irreversible pollution in the process of fishing as soon as possible. Furthermore, protecting the marine environment is critical for the diversity of living things and maintaining the integrity of marine ecosystems.

China's policies on fish passages

Classification of instruments

The environmental management system related to the planning, design, construction, and operation of fish passages has been continuously improved in China, and requires the government to implement it seriously. Relevant institutions and ministries have also issued a series of laws, regulations, and documents (Table S2, available online). Three laws issued by the Standing Committee of the National People's Congress (NPC), and 23 documents of guidelines and standards issued by the department of industry are included according to statistical results (Figure 2).

Fig. 2.

China's policies on fish passages.

Fig. 2.

China's policies on fish passages.

Policies and constraints

Most of China's instruments concerning fish passages were issued in the 2000s. There are three main periods in the development process of policies on fish passages, including: (1) emergence and legislation period, (2) consolidation and expansion period, and (3) improvement period.

Emergence and legislation period

This period is from 1970 to 2005. The first Water Law in China came into force in 1988 and was amended successively in 2002, 2009, and 2016. Article 27 of the Protection of Migratory Passages has never changed, that the construction unit should construct fish passages at permanent gate dams to protect migration passages. Also, bloat passages were required to be constructed for navigation, as well as wood passages to ensure that bamboo and wood can float downstream successfully. The ministries under the State Council should take remedial measures and make appropriate arrangements to protect hydrophilic biology, navigation, ensuring bamboos and wood can float downstream during operation and impoundment. All costs should be picked up by the construction unit. Laws and regulations such as Article 32 of the Fisheries Law, Article 13 of the Regulations on the Protection of Aquatic Resources Reproduction, Article 22 of Marine Environmental Management Regulations defined the legal status of fish passages, and made it necessary for them to be built legally. A sound legal system based on law enforcement is crucial to promote environmental protection. In 2005, the former State Environmental Protection Administration (SEPA) put a complete ban on disorderly low-level redundant development with strict environmental standards for 30 illegal construction projects according to the Law of Environmental Impact Assessment. During the 10th Five-Year Plan period, most of the 64 hydropower projects approved by the Ministry of Environmental Protection have constructed fishways. The Shiquanhe Hydroelectric Power Station is still at the design stage. The fish collection and transport system of Pengshui Hydroelectric Power Station has been put into trial operation.

Consolidation and expansion period

This period is from 2006 to 2015. During the 11th Five-Year Plan period, some instruments were successively issued by multiple ministries, such as the Opinions on Strengthening the Supervision and Administration of Environment Protection while Developing Resources, the Notice on Strengthening the Environmental Protection of Hydropower Construction and the Circular on Issuing Meeting Summary of Technical Policy Seminar about Water Environment and Aquatic Ecological Protection of Hydropower and Water Conservancy Projects. Since then, the industries have attached importance to ecological protection. However, the main measures to protect fish species were enhancement and releasing, net capturing beyond dams, etc. The development of fish passages did not become mature because of weak foundations and disagreements. Angu Hydroelectric Power Station in Dadu River was the only one out of 27 projects approved from 2006 to 2010. It is a combination of vertical seamed fishways and imitation natural channels to protect the fish. During the 12th Five-Year Plan, some instruments were examined and adopted successively, such as Measures for the Compilation and Implementation of Negative List of Industries in Key Ecological Functional Areas, Measures for the Appraisal and Examination of the Objectives of Ecological Civilization Construction, Opinions on Demarcating and Observing the Red Line of Ecological Protection and the 13th Five-Year Ecological Environment Protection Planning, which represented the improvement of laws and regulations. Ministry of Environmental Protection (MEP) and other ministries jointly issued a series of documents, such as the Circular on Further Strengthening the Work on Environmental Protection in Hydropower Construction, Circular on Further Strengthening the Management of Environmental Impact Assessment for Hydrophilic Biology Protection and Notice on Deepening Implementation of Ecological Environment Protection Measures for Hydropower Development, putting forward more stringent environmental management requirements. As well, other documents were issued to guide the ecological protection of hydropower, such as Water Conservancy and Hydropower Engineering Environmental Design Code, Water Conservancy and Hydropower Engineering Fishways Design Guideline. Benefiting from these documents, half of all the projects approved during the 12th Five-Year Plan built fishways along with all fish passages except for three expansion projects. In the late part of the 12th Five-Year Plan, a number of combined fish passages have also emerged, initially forming a fish protection system that integrates fish passages, enhancement and releasing, and habitat protection.

Improvement period

This period is from 2015 until now. The occurrence of the Environmental Protection Act revised in 2015 represented the improvement of environmental laws. At the end of 2015, Circular on Issuing the List of Significant Changes in Construction Projects of Some Industries in EIA Management issued by MEP, stated significant changes on major environmental protection measures. For example, the guarantee for releasing eco-traffic discharge at a hub layout, fish passages, and the mitigation for water temperature stratification were required to be submitted to the EIA again. The notice document (Notice on the approval of construction environmental impact assessment documents about seven construction industry projects including specification of thermal power) pointed out that: ‘if projects have adverse impacts on habitats, species and resources, such as fish and other aquatic organisms' migration and habitats, measures should be proposed to protect habitat and migration passages, and enhancement and releasing’. Other notice documents (e.g., Notice on the issuance of construction projects completed environmental protection acceptance field inspection and points of examinations) stressed the fish passages' construction situation in the process of environmental protection acceptance field inspection of initial filling as well as the fish passages' operation effect in the stage of construction completion. Initial EIA documents are legal and available. Once a project had significant changes, the relevant EIA documents were required to be approved again to take effect. As a management system, EIA provides the strengthening of examination and approval in the earlier stage, implementation of the material stage, and the supervision aftermath, forming a whole process management in the full life circle of dam projects.

Contents of instruments

Laws

The main laws relating to fish passages in China are water law, fishery law, and EIA law, which guarantee the further control and mitigation of river barriers due to hydraulic structure. The dam owners should construct fish passages at permanent gate dams to protect migration passages of species such as fish, shrimp, and crab. All costs should be picked up by the construction unit. The main business competent departments are Ministry of Ecology and Environment (MEE), Ministry of Water Resources (MWR), and Ministry of Agriculture and Rural Affairs (MARA).

Regulations

Regulations relating to fish passages detail the implementing rules and protection planning of laws. Regulations such as Article 13 of the Regulations on the Reproduction Protection of Aquatic Resources and Article 22 of the Environmental Management Regulations on the Prevention and Control of Pollution Damage to the Marine Environment by the Coastal Construction Project stipulated the construction of fish passages in water conservancy projects. Fish passages were required to be constructed at dams to protect migration passages of fish species. For completed water conservancy projects, proper measures were required to be taken to protect fish migration and reproduction. Actions such as collection of fish fry by opening the sluice gate and seedling transplant would be taken after consultation between the aquatic department and water conservancy administrative department, according to water level and water quality. In addition, corresponding local implementing rules have also been issued. Article 22 of the Implementing Rules for the Protection of Fujian Aquatic Resources Reproduction required fishways and fish ladders to be constructed at dams, protecting fish migration and spawning. For hydraulic engineering projects that are in operation, fish rescue measures are required to be taken once they influence fish migration and spawning.

Specifications

To guide the implementation process, norms and guidelines are issued to make specific instruments on the fish passages' design and operation effects. Water Conservancy and Hydropower Engineering Fishways Design Guideline, Hydropower Project Fish Passages Design Specifications and Technical Guide of EIA for Water Conservancy and Hydroelectricity Engineering have defined the design of different fish passages. Some identified certain specific contents, such as the selection and layout of fishways, import and export of fishways, fishways' tank body design, induction facilities and other auxiliary facilities, fishways' operation and monitoring, etc.

Documents

Requirements regarding the protection of ecological environment have being enhanced continuously in China. Hence, a competent authority of industries led by MEP have issued a number of documents. Documents have been produced to improve the protection of river ecological environments, such as fish passages' design, operation, assessment, and compensation for fish protection. The notice document (Notice of reporting about fish culture in reservoir and multipurpose economic undertakings) produced by the State Council, approved and transmitted to the Ministry of Water Resources (MWR), Ministry of Finance (MOF), and State Aquatic Product General Bureau (SAPGB), mentioned effectively improving conditions, as soon as possible, in the case of fishways being cut off by barriers.

Other relevant documents also pointed out that it was necessary to guarantee normal protection facilities' operation of aquatic organisms. Proper fish passages were required in migration passages for fish which are endangered, specific, and of great potential economic value. Different types of fish passages were required according to the actual conditions. It is suitable for sluices and dams with low water head to build permanent fish passages, such as fishways, fish ladders, and fish locks. However, for high dams and large reservoirs, it is more advisable to build fish elevators equipped with fish pumps and fish boats, and achieve net capturing beyond dams artificially. Also emphasized is optimizing fish passages' operation management constantly through improving fish passages' design and construction based on monitoring and adaptive management. Subsequent documents have improved the standard of effect appraisal for passing fish. They require a full demonstration regarding the alternative types of fish passages, as well as the needs. More detailed and specific requirements to monitor the effect appraisal for passing fish have been proposed and different assessment contents identified according to various stages. The documents stress the fish passage construction situation within the process of environmental protection acceptance field inspection of initial filling, as well as the fish passages' operation effectiveness at the stage of construction completion.

Issues and challenges

Different countries have issued instruments related to fish passages in different development periods and various instruments have been issued based on specific economic background and technology. There are still some inadequacies in China concerning implementing fish passages' policies. Duplication of authorities' responsibilities is one of the most critical issues now. Mitigation measures have failed to achieve the expected effect due to duplication of authorities' functions. Fish resources protection demands great multi-agency coordination. MARA, MEP, and MWR are all responsible for fish species related issues. However, fish passages' construction and operation cannot proceed in an orderly way because of insufficient integrated management. MOA is generally responsible for the supervision management regarding the following aspects, including the protection and enhancement of key fishery resources, and the accountability on fishing. The fish passages' subordinate hub authority aims to control the facilities, mitigating the impact of barriers. MEP focuses on the impacts of human activities on fish, especially those rare and endangered endemic fish species. Dam activities were developed early in countries such as the USA and Canada. Such highly developed countries have meticulous procedures as well as mature systems for environmental permit approval and management in hydropower, whereas there are still some blank areas in environmental permit approval and management system in China. However, the protection system consisting mainly of fish passages, enhancement and releasing, and habitat protection is improving.

Regional and watershed integration of fish passages is the new challenge. The whole process management for fish passages has been guaranteed in China. However, regional and watershed integration in spatially and temporally is insufficient and relevant systems have not been developed in a timely fashion. Thus, cooperation is critical for issues such as river connectivity and the layout of fish protection facilities in fish passages' construction. Laws such as water laws and fisheries law are issued to supervise the fish passages. Recently, eight cascade dams in Xiangjiang River have been required to recover fish migration passages, which involve the protection of important fish species according to watershed fishery resources protection. However, only the fifth step dam (Tugu Pond) and the eighth step dam (Changsha) have constructed fishways. Even so, the effectiveness of fish passing would be influenced without good river connectivity.

Lessons from global fish passages' experience

From global policies on fish passages it can be concluded that the plan and design of watershed-scale fish passages is effective for restoring fish species' population. Policies on fish passage should be intensified to guide both regional and watershed exploitation. Hydropower development plans of main streams could be optimized according to their impacts on regional and watershed ecosystems. It is important to protect water ecosystems to sustain river connectivity through integrating the development and protection of both main streams and tributaries. Most importantly, habitat should be protected, particularly by implementing watershed environmental protection plan seriously. As well, it is necessary to make plans to restore riverine connectivity including upstream, midstream, downstream, and important tributaries. Also, considering the watershed connectivity as a precondition is significant when making watershed integrated and hydropower development plans. The benefits from technical measures such as fishways' construction should be proved for fish protection by those early projects that lack fish protection measures. Furthermore, strengthening discussion about the establishment of ecological compensation mechanisms is also important. If fishways' operation causes loss, there should be instruments to ensure reasonable compensation on electricity and water costs to relevant operations. Encouraging companies to take action actively has been successful. Reservoir regulation combined fish passages' operations contributes to integrated regulation. Moreover, that, combined with Green Small Hydropower assessment could form an effective guarantee mechanism.

Supervision over fish passages' construction and operation should be enhanced. It is necessary to implement supervision and regulatory mechanisms for full restoration of river connectivity and supervision by the main structure should be responsible for the fish passages' operation. As to the subject of direct liability, dam owners should cooperate and integrate supervision and regulatory mechanisms into their main work steadily. Long-term administrative measures about fish passages should be made to play a role post-EIA. There should be improvement to the fishways to meet the requirement of fish species through observation and monitoring. Relevant supervision ministries such as MWR, MEE, and the Department of Fisheries (DOF) should implement their responsibilities seriously to supervise fish passages' operation. The Plan-EIA, construction project EIA, project acceptance and post-EIA contributes together to promote fish passages' construction and operation. Fish passages' operation should be combined with integrated watershed management due to the construction and operation of cascade reservoirs.

Conclusion

The development of river exploitation in China is prospering and the impacts of barriers will exist for a long time. It is popular in China to construct fishways in order to guarantee fish migration from obstructions. However, operational effectiveness has reduced. For one thing, the fishways' design and construction involved many uncorrelated subjects, such as biology, hydrology, and engineering. Also, relevant research on fish habits, fishway operational mode and its monitoring are insufficient.

As both the fishways' design and management demand multi- and interdisciplinary participation, improvement of the system is merited. We recommend making fish protection programs and completing the communicating system among departments and administrative regions, forming a professional group consisting of the DOF, eco-environment, and water conservancy, then measures could be taken to improve the design, operation, and maintenance of fish passages. The original idea of fish protection would be encouraged to innovate by this group, strengthening research and practice. As well, it is necessary to implement monitoring and appraisal regarding the effectiveness of fish passing. Then, managers would take responsibility to transform the unapproved fishways and generalize the use of those effective fishways.

Acknowledgments

This study was funded by National Key Research and Development Program of China [No. 2016YFE0102400], Scientific Research Foundation for Youth Innovation Project of Appraisal Center for Environment and Engineering, Ministry of Ecology and Environment.

References

References
Bai
S.
, (
1978
).
Fishways in Japan. Shuili Shuiyun Keji Qingbao (05), 78–87
.
Bai
Y.
&
Wu
Y.
, (
2011
).
Study on the fish passages facilities construction scheme for Poyang Lake Water Control Project
.
China Institute of Water Resources and Hydropower Research
9
(
04
),
279
282
.
Bai
Y.
,
Guo
J.
&
Wu
Y.
, (
2011
).
Analysis of the design, construction and operation of typical fish passages in overseas projects
.
Journal of China Institute of Water Resources and Hydropower Research
9
(
02
),
116
120
.
Cao
Q.
,
Yang
W.
&
Zhou
L.
, (
2010
).
Review on study of fishery facilities at home and abroad
.
Journal of Yangtze River Scientific Research Institute
27
(
05
),
39
43
.
Chang
Y.
, (
2015
).
Study on the Key Technologies of Fish Passage for a Hydropower Station
.
Zhejiang Gongshang University
, Hangzhou, p.
109
.
Chang
J.
,
Chen
Y.
,
Gao
Y.
,
Zhu
B.
&
Qiao
Y.
, (
2008
).
Impacts of hydropower and water conservancy projects and mitigation measures on fish resource
. In:
Chinese Hydraulic Engineering Society 2008 Annual Conference
,
Hainan, China
, p.
12
.
Chang
Y.
,
Tan
Q.
,
Zhang
Y.
,
Jin
Y.
&
Li
X.
, (
2016
).
Preliminary study on fish passages facility comparison in Suwalong Hydropower Station
.
Water Power
42
(
07
),
8
11
.
Chen
K.
,
Ge
H.
,
Guo
J.
&
Tao
J.
, (
2013a
).
Study on the situation analysis of fish passages and the key issues of adaptive management in China
.
Journal of Hydroecology
34
(
04
),
1
6
.
Chen
K.
,
Chang
Z.
,
Cao
X.
&
Ge
H.
, (
2013b
).
Status and prospects of fish pass construction in China
.
Journal of Hydraulic Engineering
43
(
2
),
6
.
Chen
A.
,
Sui
X.
,
Liao
W.
&
Chen
K.
, (
2016a
).
Review study on instream ecological base flow in China
.
Joumal of China Institute of Water Resources and Hydropower Research
14
(
06
),
401
411
.
Chen
A.
,
Sui
X.
,
Wang
D.
,
Liao
W.
,
Ge
H.
&
Tao
J.
, (
2016b
).
Landscape and avifauna changes as an indicator of Yellow River Delta Wetland restoration
.
Ecological Engineering
86
,
162
173
.
Chen
A.
,
Wu
M.
,
Chen
K.
,
Sun
Z.
,
Shen
C.
&
Wang
P.
, (
2017
).
Main issues in environmental protection research and practice of water conservancy and hydropower projects in China
.
Water Science and Engineering
4
(
9
),
312
323
.
Fang
M.
, (
2014
).
Swimming Capability of Several Cyprinid and Assessment of Vertical Slot Fishways Based on Simulation
.
China Three Gorges University
, Yichang, p.
81
.
Gao
Y.
&
Chang
J.
, (
2004
).
Significance of fish passage on fish resources
. In:
Chinese Society for Oceanology and Limnology 2004 Annual Conference
,
Chongqing, China
, p.
2
.
Grantham
T. E.
, (
2013
).
Use of hydraulic modelling to assess passage flow connectivity for salmon in streams
.
River Research and Applications
29
(
2
),
250
267
.
Hu
N.
, (
1980
).
Yangtang Fishway
.
Hunan Provincial Water Resources Department, Changsha
.
Hu
W.
,
Han
D.
,
Gao
Y.
&
Chang
J.
, (
2008
).
Restoration of fish migration: practice of foreign countries and strategies of China
.
Resources and Environment in the Yangtze Basin
17
(
06
),
898
903
.
Jia
J. S.
, (
2002
).
Fishways: biological basis, design criteria and monitoring: foreword
.
Bulletin Français de la Pêche et de la Pisciculture
364
(
Suppl. S
),
3
207
.
Keefer
M. L.
,
Caudill
C. C.
&
Moser
M. L.
, (
2014
).
Fishway bottleneck relief models: a case study using radio-tagged Pacific lampreys
.
Transactions of the American Fisheries Society
143
(
4
),
1049
1060
.
Lin
Q.
&
Yang
C.
, (
1984
).
Introduction of Yangtang fishway
.
Journal of Nanjing Hydraulic Research Institute
6
(
04
),
67
72
.
Liu
Y.
, (
1995
).
Fish ladder experiment in Itaipu
.
Express Water Resources & Hydropower Information
16
(
01
),
28
29
.
Luo
X.
&
Li
J.
, (
2010
).
Study on structure and hydraulic characteristics of vertical-slot fishway
.
Journal of Yangtze River Scientific Research Institute
27
(
10
),
50
54
.
Ma
Y.
, (
2003
).
Fish passage in lower granite
.
Express Water Resources & Hydropower Information
24
(
02
),
22
.
Makrakis
S. A. C. A.
, (
2007
).
The Canal da Piracema at Itaipu Dam as a fish pass system
.
Neotropical Ichthyology
5
,
185
195
.
National Research Council
(
1999
).
Sharing the Fish: Toward A National Policy on Individual Fishing Quotas
.
National Academies Press
,
Washington, DC
,
USA
.
Quinn
S.
,
Moradkhani
H.
,
Sillars
D.
&
Smith
T
, . (
2008
).
Lessons from fish passage waterways in Oregon and factors for improving their construction
. In:
World Environmental and Water Resources Congress
,
Honolulu, Hawaii
, pp.
1
11
.
Sun
S.
&
Zhang
G.
, (
2012
).
Environment-friendly fishway in close-to-nature types
.
Journal of China Institute of Water Resources and Hydropower Research
10
(
01
),
41
47
.
Tian
Z.
&
Jiang
G.
, (
2013
).
Research and practice on the restoration of fish migration channels in European rivers
.
Journal of Hydroecology
34
(
04
),
10
13
.
Wang
K.
,
Liu
S.
,
Duan
X.
,
Sun
M.
,
Ye
C.
&
Chen
D.
, (
2013
).
Fishway effect of Cuijiaying navigation-power junction project
.
Transactions of the Chinese Society of Agricultural Engineering
29
(
03
),
184
189
.
Xing-Yong
W.
&
Jun
G.
, (
2005
).
Brief review on research and construction of fish-ways at home and abroad
.
Journal of China Institute of Water Resources and Hydropower Research
3
(
3
),
222
228
.
Xu
L.
, (
2016
).
Challenges and suggestions on environmental impact assessment based on new situation of environment protection
.
Journal of Environmental Management College of China
26
(
1
),
7
10
.
Zhang
H.
,
Kynard
B.
,
Junho
R.
,
Du
H.
&
Wei
Q.
, (
2013
).
Implications from the design and consruction of Santo Antonio fishway in the Madeira River in the Amazon Basin
.
Journal of Hydroecology
34
(
04
),
95
100
.
Zheng
Y.
, (
1997
).
Fishways in Scotland
.
Express Water Resources & Hydropower Information
28
(
08
),
28
30
.
Zheng
J.
&
Han
D.
, (
2013
).
Review on the development of high-head fish passage facilities and its enlightenment to China
.
Journal of Hydroecology
34
(
04
),
76
79
.
Zheng
J.
,
Han
D.
,
Hu
W.
,
Wang
X.
&
Zhang
X.
, (
2010
).
Fish swimming performance related to fishway design
.
Journal of Hydroecology
3
(
05
),
104
110
.
Zhou
P.
,
Zhou
Y.
&
Yao
B.
, (
2011
).
Status and development of fish passage in hydropower and water conservancy projects
.
Water Resources Development & Management
22
(
07
),
40
43
.

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