(Acipenser sinensis）.

Bian Shiqi1

Abstract

Often regarded as a "living fossil" or the "panda under the water", the Chinese Sturgeon is one of the rarest and most representative species in the Yangtze River. Despite its fame, no signs of natural spawning among the wild sturgeon population have been observed in recent years, highlighting the urgent need for an appropriate conservation program. This paper provides an overview of the population, lifestyles, and habitat characteristics of the Chinese Sturgeon by utilizing historical data, recent monitoring data, and existing research conducted by experts. Additionally, this paper evaluates the effectiveness of sturgeon stocking and artificial propagation at the molecular ecological level.

Key words: Acipenser sinensis; living Habits; endangerment; conservation biology; dilemma.

Introduction

The Chinese Sturgeon can be found in various regions of the Yangtze River, including the upper, middle, and lower reaches, as well as offshore waters, making it a significant representative of the river's aquatic ecosystem [1-3]. Protecting the Chinese Sturgeon involves multiple aspects, such as fisheries management, engineering projects, policy implementation, and the overall well-being of the Yangtze River and its coastal communities [4]. In this study, we aim to propose effective strategies and recommendations for the conservation of the Chinese sturgeon. Our approach includes a systematic analysis of the species' life history and habitat characteristics, an assessment of the impact of water-related projects and human activities in the Yangtze River, and an evaluation of the existing conservation measures in place. Furthermore, we examine the current challenges faced in the conservation efforts. It is crucial to recognize that the conservation of the Chinese sturgeon goes beyond the preservation of a single fish species. The outcomes of these conservation efforts have far-reaching implications for maintaining biodiversity and ensuring the ecological health of the entire Yangtze River system [5-8]. Therefore, our study aims to provide comprehensive and detailed recommendations that take into account the broader ecological and socio-economic considerations of the Yangtze River and its surrounding communities.

1.Population overview

The Chinese Sturgeon is a member of the family Acipenseridae in the order Acipenseriformeshe. Its lineage dates back approximately 140 million years to the Upper Cretaceous period, marking the end of the Mesozoic Era [10-13]. Exhibiting anadromous behaviors, the Chinese sturgeon can be found primarily in China, Japan, South Korea, North Korea, and the Lao People's Democratic Republic [11,13]. The highest concentration of Chinese Sturgeon populations is found below the mainstem of China's Yangtze River, from the Jinsha River to the estuary [9,12]. Although they can also be spotted in other waterways like the Gan, Xiang, Min, Qiantang, and Pearl Rivers, the Yangtze River remains the sole breeding ground for Chinese sturgeons [14-15].

In the 1970s, the Yangtze River was home to over 10,000 Chinese Sturgeons capable of reproduction [16]. However, following the closure of the Gezhouba Dam in the 1980s, their numbers plummeted dramatically to a mere 2,176 individuals [13]. By 2000, their population had dwindled even further to just 363 sturgeons, amounting to one-sixth of the population in the 1980s [17]. As of 2010, it was estimated that only 57 wild Chinese Sturgeons remained. The natural population of Chinese Sturgeon is facing an imminent threat, while the quality of the artificially preserved population is still a concern [11-13].

As a national treasure, the Chinese Sturgeon has been classified as a first-class protected animal in China and was included in the 1988 list of key protected wild animals. In 1996[10], the Chinese sturgeon was listed as an Endangered (EN) protected species by the International Union for Conservation of Nature (IUCN). A year later in 1997, it was designated as a key protection target by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Then in 2010, it was upgraded to a Critically Endangered (CR) protected species by the IUCN [7,15].

2. Living Habits

2.1 Anadromous behaviors

Chinese sturgeon is a typical anadromous migratory fish that thrives and nurtures itself in the coastal waters of China's continental shelf. Every year at the turn of spring and summer, Chinese sturgeons that reach sexual maturity will enter the seaport from the Yangtze River to start nearly 2 years of migration [6]. They travel upstream along the Yangtze River, and after more than a year's long journey arrive at their breeding sites: the upper zones of the Yangtze River and the Jinsha River band. After mating and spawning, Chinese sturgeons travel downstream back to the sea[11.14].

2.2 Life history

The life history of Chinese sturgeons commences in the freshwater spawning grounds. Juveniles hatch and reside in the shallow waters of the beaches, actively seeking nourishment. They undergo a transformation phase in the estuaries before finally reaching the vast expanse of the sea. After more than a decade, sexually mature sturgeons instinctively navigate their way to the mouth of the Yangtze River. During the summer months, they journey upstream, seeking the upstream spawning grounds for winter and adapting their migration patterns based on prevailing water conditions. In the subsequent fall, parent sturgeons return to the spawning grounds once again for natural reproduction [13]. For Chinese sturgeons, the ratio of their entire life history spent in freshwater versus seawater is 1:9 to the Yangtze River and the ocean. Every stage of their life cycle holds immense significance [3,6,11]. This comprehensive understanding of the Chinese sturgeon's life history sheds light on its incredible resilience and emphasizes the crucial importance of each phase it undergoes.

3. Reasons for endangerment

The endangerment of the Chinese sturgeon is the combined result of various factors, primarily including the following aspects:

3.1 Destruction of habitat

The development of water conservancy projects, including reservoir construction and river diversion, has significantly diminished the survival space available for the Chinese sturgeon, resulting in severe damage to its native habitat. Firstly, these projects have brought about notable alterations in the speed and direction of river currents, which are vital for the sturgeon's ecological balance. Secondly, reconstructions on siltation and river beds have caused a decline in the quality of habitats for the sturgeon. Furthermore, the construction process has introduced disturbances such as noise, vibration, and light pollution, significantly disrupting the sturgeon's biological life cycle. Additionally, the construction activities often involve extensive land exploitation and indiscriminate logging, further exacerbating the destruction of the Chinese sturgeon's habitat. Consequently, the loss of aquatic vegetation poses a significant threat to the species' survival [2, 4, 10, 17]. Moreover, global warming and alterations in precipitation patterns have led to shifts in the climatic and hydrological conditions within the sturgeon's habitat, presenting new challenges for its survival.
3.2 Overfishing

The significant decline in the Chinese sturgeon population can also be attributed to continuous periods of overfishing, haphazard harvesting, and illegal fishing by humans. These large-scale commercial fishing activities have had a detrimental impact on the Chinese sturgeon, leading to a continuous decline in their populations. Compounding this issue is the fact that the Chinese sturgeon has a prolonged growth rate and lengthy reproduction cycle, making it even more challenging for them to recover from the effects of overfishing [13].

3.3 Water pollution

Another major factor contributing to the endangerment of the Chinese sturgeon is water pollution. As industrialization and urbanization progress, substantial amounts of industrial wastewater, agricultural non-point source pollution, and domestic sewage are being discharged into water bodies without proper regulation. This has resulted in an alarming increase in the concentration of pollutants in the water, posing a serious threat to the survival of the Chinese sturgeon. Water pollution destroys the habitat of Chinese sturgeon, making it impossible for them to reproduce normally. The pollutants will also harm the physiological functions of the sturgeon, triggering diseases and damage to the immune system, which can directly threaten their survival. For instance, algae outbreaks triggered by water pollution can cause a shortage of oxygen in the water, adversely affecting the respiration and feeding processes of the sturgeon[18].

4. Measures to protect Chinese sturgeons

4.1 Engineering measures

In terms of engineering measures, combining the anadromous characteristics of Chinese sturgeon during the breeding period and the features of the dams can be utilized to rehabilitate existing spawning grounds of Chinese sturgeon [19]. Concurrently, enhancing the flow field and quality of the riverbed at existing Chinese sturgeon spawning grounds can improve the scale and effectiveness of natural breeding by increasing the reproduction capacity of these natural spawning grounds [20-22]. These measures will ensure the long-term survival of the Chinese sturgeon species.

4.2 Constructing fish passage

The barrier effect on the river caused by the construction of the Gezhouba Dam hydraulic hub is the most direct factor hindering the spawning and reproduction of Chinese sturgeon. To address this problem, constructing a fish passage project is the most practical and efficient measure [23-25]. This method is already widely employed worldwide. By using different water currents, fish are led through the fish inlet and to the upper reaches of the dam, which is referred to as constructing fish passage [17, 21, 26]. However, the effectiveness of this method depends on the level of design of overfishing engineering measures, such as whether the flow rate at the inlet can be appropriately controlled and whether the fish can recognize the induced flow. Presently, primary fish passage infrastructures include fish gates, fish lifts, fish boats, and other ancillary measures [27-30]. Implementation of these measures can mitigate the negative effects caused by the construction of the Gezhouba Dam hydraulic hub and help enhance the survival of the Chinese sturgeon species.

4.3 Non-engineering measures

One crucial non-engineering measure is to expand the artificial breeding and releasing program. This involves artificially rearing broodstock, assisting in their spawning and hatching, and releasing the fry into the wild. Currently, this method is considered the most effective way to protect endangered fish species, including the Chinese sturgeon. To ensure the survival rate of Chinese sturgeon reproduction, it is recommended to conduct annual artificial breeding and release of at least 50,000 Chinese sturgeons [31-33]. Additionally, there is a need to enhance the assessment of the efficiency of artificial breeding and releasing.

4.4 Establishing real-time monitoring systems

While restoring and protecting individual Chinese sturgeon, it is also necessary to increase the monitoring of the aquatic ecological environment, parental fish cultivation, fry cultivation, migration environment, and population resources in the existing spawning grounds[25,34-36]. In particular, it is imperative to intensify monitoring of the gender and age ratio within the Chinese sturgeon community. In addition to this, the cultivation of parent fish and fry, the dynamic distribution of stocks, and the real-time situation of spawning grounds and migration paths should receive rigorous monitoring and evaluation [37].

4.5 Emphasis on ecological scheduling

 Based on an analysis of the spawning and reproduction habits of the Chinese sturgeon, it is evident that specific hydrological conditions are necessary for successful spawning. Therefore, by restoring the spawning grounds and manipulating the hydrological conditions, spawning and reproduction can be promoted. Furthermore, rational management of the Three Gorges Reservoir can compensate for the hydrological conditions required in the river section below the dam, thus safeguarding the natural spawning and reproduction of the Chinese sturgeon [27,38].

4.6 Enforcing government legislation

  Excluding the number of Chinese sturgeons that have been maliciously killed by humans, there are still hundreds of Chinese sturgeons that get accidentally injured every year despite the construction of protection stations along the Yangtze River[39-41]. They were often mistakenly caught by fishermen, injured by ship turmoils, and disabled by water pollution. It is thus reasonable to infer that the conservation efforts on Chinese sturgeons are inadequate and that the effects are unsatisfactory. To deal with this situation, the Government can regulate human behavior by establishing laws to prohibit fishing for a certain period, regulate navigation, and preserve water quality. These regulations can provide legal safeguards for the implementation of Chinese sturgeon conservation programs.

5 Discussion

5.1 Reasons for delays in conducting reproductive research

The artificial propagation of Chinese sturgeon has demonstrated success in previous years. Notably, in the 1970s, the Chongqing Institute of Fisheries achieved artificial fertilization of 114,000 eggs and produced over 1,300 seedlings. Subsequently, in 1978, there was another successful instance of artificial propagation [22]. In 2019, the Three Gorges Group Chinese Sturgeon Research Institute accomplished complete artificial propagation of the Chinese sturgeon. Moreover, during the first six months of of 2022, significant progress was made in the large-scale artificial breeding of Yangtze sturgeon [31]. The breakthrough in July 2022 with the development of artificial induction techniques for female nuclei of the Chinese sturgeon marked a significant milestone, enabling unisexual reproduction for the first time. This breakthrough holds immense importance for the long-term preservation of germplasm resources.

Despite these achievements, the slow progress in reproduction research can be attributed to several factors. One major obstacle is the prolonged lifespan and late sexual maturity of Chinese sturgeon, which necessitates a substantial amount of time and effort for artificial breeding research [37]. Furthermore, even minor adjustments in factors such as food supply, water temperature, water quality, and breeding space can yield entirely different research outcomes. Another challenge lies in the limited number of sturgeon groups available for cultivation, making it challenging to conduct comparative experiments in the field of Chinese sturgeon full artificial breeding technology. These factors collectively contribute to the sluggish pace of research on the complete artificial reproduction of Chinese sturgeon.

5.1.1Reproduction difficulties and loss of genetic diversity

Chinese sturgeon require a minimum of 16 years to reach sexual maturity, and the survival rate for their fry is alarmingly low. Despite releasing over 7 million individuals into the Yangtze River, only 1% have managed to survive [23, 37, 39]. Compounding the issue, sturgeon only spawn under specific conditions, particularly requiring mild temperatures. Unfortunately, human activities have led to the deterioration of the water ecosystem, resulting in the destruction of the sturgeon's migration path. Furthermore, the construction of dykes and hydroelectric power projects has had a negative impact on the ecological environment as well [40]. To address this problem, several measures need to be implemented, including reducing pollutant discharge, optimizing engineering project planning in the region, and establishing a monitoring system for fish migration.

Scientific research surveys conducted in the previous years have revealed an alarming discrepancy in the male-to-female sex ratio of the Chinese sturgeon spawning population below Gezhouba Dam. The data shows that from 2003 to 2004, the ratio was approximately 6:1 [31], and in 2008, when scientific research fish were captured at the spawning site, the male-to-female ratio was close to 7:1 [32]. After 2008, the Ministry of Agriculture did not permit any further Chinese sturgeon scientific research fishery until 2015 [38]. In this year, however, no Chinese sturgeon parents were caught by the Yangtze River Fisheries Research Institute, making it impossible to obtain updated figures. Despite this lack of recent data, it can be inferred that the imbalance in the male-to-female ratio is continuing to rise based on the survival trend of the Chinese sturgeon population and their environment since 2008 [32, 35, 39].

5.1.2 Loss of genetic diversity

Genetic diversity serves as the foundation for both species diversity and ecosystem diversity. A species with a greater genetic diversity possesses a heightened capacity to adapt to external changes. Exploring the genetic diversity of Chinese sturgeon allows researchers to gain insight into its crucial role in the evolutionary history of fish, analyze its potential for evolution, and investigate its endangered status. Since the wild population of Chinese sturgeons has been on the verge of extinction, comprehending the genetic structure and diversity of this species becomes imperative for effective monitoring and conservation efforts [36,42].

5.2Modern biotechnology

The advancement of modern biotechnology has simplified the task of conserving the Chinese sturgeon. The utilization of various breeding methods serves as a valuable blueprint for achieving comprehensive artificial breeding of Chinese sturgeon in the future. Exploring alternative approaches like exogenous hormone induction holds promise in promoting the reproductive development of Chinese sturgeon [32-35,42,43]. As the technology for full artificial propagation of Chinese sturgeon continues to improve, there is potential to rescue the endangered wild population. 

In response to the problem of an imbalanced ratio of female to male Chinese sturgeons, scientists have put forward a potential solution. They have suggested a unique reproductive technique known as mono-female reproduction, or solitary reproduction, wherein the eggs can develop into viable individuals without being fertilized by normal sperm [42]. Essentially, this means that reproduction can occur solely with female sturgeons, eliminating the need for males. Additionally, another approach to address this issue involves the utilization of ultra-low temperature cryopreservation of Chinese Sturgeon sperm and subsequent insemination with frozen sperm. These alternative methods have the potential to partially alleviate the challenge posed by the disproportionate number of female sturgeons compared to males.

Molecular genetic markers have become a popular tool in studying the genetic diversity of organisms. These markers are generally not affected by environmental factors, and the polymorphisms can be found throughout the genome, making them widely distributed [31, 34, 44]. The results obtained from molecular-level biodiversity research are considered stable, reliable, and reproducible. Currently, the study of Chinese sturgeon DNA molecular genetic diversity primarily focuses on three types of markers: mitochondrial DNA (mtDNA), Randomly Amplified Polymorphic DNA (RAPD), and microsatellite markers [27-31, 37, 44]. These methods have been used to investigate the genetic diversity of Chinese sturgeon populations, providing valuable insights into the species' biology and evolution.

6. Conclusion

Given the current circumstances, it is crucial to prioritize the "Chinese sturgeon rescue action plan" as a guiding framework and urgently implement five key protection measures. Firstly, the implementation of the "land-sea-land" seeding project is vital to restore the biological characteristics of cultured Chinese sturgeons. Secondly, it is essential to strengthen restocking programs to replenish the sturgeon population. Thirdly, improving existing spawning conditions is necessary to facilitate natural reproduction. Moreover, efforts should be made to explore alternative natural spawning grounds. Lastly, restoring feeding grounds and other critical habitats must be undertaken. These protection measures require long-term commitment, spanning approximately 15 years, and involve safeguarding the sturgeonsfrom birth to breeding to achieve the restoration and continuity of the natural sturgeon population. The Chinese sturgeon, with its impressive body size, lengthy lifespan, and extensive migration patterns, holds great importance as the flagship species and umbrella species within the Yangtze River ecosystem. The successful conservation of the Chinese sturgeon is of significant significance in attaining harmonious coexistence between humans and nature while promoting the sustainable development of the Yangtze River Basin.

Reference:

[1]Wei QW, Zhang J, Zhuang P et al. Biology, fisheries, and conservation of sturgeons and paddlefish in China. Environmen- tal Biology of Fishes, 1997, 48(1/2/3/4): 241-255．

[2] Wilcox BA. In situ conservation of genetic resources: determinants of minimum area requirements / / McNeely JA, Miller KR eds. National parks, conservation and development:   the role of protected areas in sustaining society. Washington: Smithsonian Institution Press, 1984:  639-647．

[3] Wang CY, Wei QW, Kynard B et al. Migrations and movements of adult Chinese sturgeon Acipenser sinensis in the Yangtze River, China. Journal of Fish Biology, 2012, 81( 2): 696-713．

[4] Alerstam T, Bckman J. Ecology of animal migration. Current Biology, 2018, 28( 17): R968-R972．

[5] Zhuang P, Kynard B, Zhang L et al. Ontogenetic behavior and migration of Chinese sturgeon Acipenser sinensis. Environ- mental Biology of Fishes, 2002, 65( 1): 83-97．

[6] Putman NF, Lohmann KJ, Putman EM et al. Evidence for geomagnetic imprinting as a homing mechanism in Pacific salm- on. Current Biology, 2013, 23(4): 312-316．

[7]  Holmlund CM, Hammer M. Ecosystem services generated by fish populations. Ecological Economics, 1999, 29 (2) : 253-268．[57] Van Eenennaam JP, Linares-Casenave J, Doroshov SI. Tank spawning of first generation domestic green sturgeon. Journal of Applied Ichthyology, 2012, 28( 4) : 505-511．

[8] Zhang H, Wei QW, Du H. A bedform morphology hypothesis for spawning areas of Chinese sturgeon. Environmental Biolo- gy of Fishes, 2009, 84( 2): 199-208．

[9] Boiko NE, Grigoryan RA, Chichachev AS. Olfactory imprinting in juveniles of Russian sturgeon, Acipenser guldenstadti. Journal of Evolutionary Biochemistry and Physiology, 1993, 29(5/6): 509-514．

[10] Wei FW. The value of ecosystem services from Giant panda reserves. Current Biology, 2018, 13( 2): 2174-2180．[58] Zhang H, Kang M, Wu JM et al. Increasing river temperature shifts impact the Yangtze ecosystem: Evidence from the en- dangered Chinese sturgeon. Animals, 2019, 9( 8): 583．

[11] Ireland SC, Beamesderfer RCP, Paragamian VL et  al. Success of hatchery-reared juvenile white sturgeon ( Acipenser transmontanus) following release in the Kootenai River, Idaho, USA. Journal of Applied Ichthyology, 2002, 18( 4 / 5 / 6) : 642-650．

[12] Ueda H. Physiological mechanisms of imprinting and homing migration of Pacific salmon / / Watabe S ed. Aqua-bioscience monographs. Tokyo: Terra Scientific Publishing Company, 2016: 1-27．

[13] Huang ZL, Wang LH. Yangtze dams increasingly threaten the survival of the Chinese sturgeon. Current Biology, 2018, 28( 22): 3640-3647．

[14] Wei K, Chen CS, Zhang XG et al. Review on olfactory organ and behavior in fish. Marine Fisheries, 2017, 39( 6): 723．

[15] Zhang H, Jaric I, Roberts DL et al．Extinction of one of the world's largest freshwater fishes: lessons for conserving the en- dangered Yangtze fauna. Science of the Total Environment, 2020, 710: 136242．

[16] Chebanov MS, Rosenthal H, Gessner J et al. Sturgeon hatchery practices and management for release guidelines / / Soto D ed. FAO fisheries and aquaculture technical paper. Rome: FAO, 2011: 570．

[17] Bemis WE, Kynard B. Sturgeon rivers:  an introduction to Acipenseriform biogeography and life history. Environmental Bi- ology of Fishes, 1997, 48( 1/2/3/4): 167-183．

[18] Khodorevskaya RP, Dovgopol GF, Zhuravleva OL et al. Present status of commercial stocks of sturgeons in the Caspian Seabasin / / Balon EK ed. Developments in Environmental Biology of Fishes. Berlin:  Springer, 1997, 17:  209-219．

[19] Chebanov MS, Karnaukhov GI, Galich EV et al. Hatchery stock enhancement and conservation of sturgeon, with an em- phasis on the Azov Sea populations. Journal of Applied Ichthyology, 2002, 18( 4/5/6): 463-469．

[20] Chebanov MS, Galich EV. Sturgeon hatchery manual / / Soto D ed. FAO fisheries and aquaculture technical paper. Rome: FAO, 2011: 558．

[21] Sulak KJ, Randall M. Understanding sturgeon life history:  enigmas, myths, and insights from scientific studies. Journal of Applied Ichthyology, 2002, 18( 4/5/6): 519-528．

[22] Du H, Wei QW, Zhang H et al. Changes of bottom substrate characteristics in spawning ground of Chinese sturgeon down- stream the Gezhouba dam from impounding of three gorge reservoir. Acta Ecologica Sinica, 2015, 35( 9): 3124-3131. [杜浩, 危起伟, 张辉等. 三峡蓄水以来葛洲坝下中华鲟产卵场河床质特征变化. 生态学报, 2015, 35 (9) : 3124-3131.]

[23] Huang ZL, Wang LH. Did the gonads of the Chinese sturgeon below the Gezhouba Dam degenerate seriously?  J Lake Sci, 32( 4): 915-923. DOI:  10．18307 / 2020. 0402. [黄真理, 王鲁海. 葛洲坝下中华鲟性腺退化严重吗?  湖泊科学, 2020, 32( 4): 915-923.]

[24] Liu JY, Wei QW, Chen XH et al. Reproductive biology and artificial propagation of Acipenser sinensis below Gezhouba Dam. Chinese Journal of Applied Ecology, 2007, 18( 6): 1397-1402. [刘鉴毅, 危起伟, 陈细华等. 葛洲坝下中华鲟繁殖生物学特性及其人工繁殖效果. 应用生态学报, 2007, 18( 6): 1397-1402.]

[25] Wei QW, Du H, Zhang H eds. Conservation biology of Chinese sturgeon ( Acipenser sinensis) . Beijing: Science Press, 2019. [危起伟, 杜浩, 张辉等. 中华鲟保护生物学. 北京:  科学出版社, 2019.]

[26] Wei QW. Reproductive behavioral ecology of Chinese sturgeon ( Acipenser sinensis Gray)  with its stock assessment [Disser-tation] . Wuhan:  Institute of Hydrobiology, Chinese Academy of Science, 2003. [危起伟. 中华鲟繁殖行为生态学与资源评估[学位论文] . 武汉: 中国科学院水生生物研究所, 2003.]

[27] Wang LH, Huang ZL．What is actually the main cause for the survival crisis of Chinese sturgeon?  J Lake Sci, 2020, 32 (4): 924-940. [王鲁海, 黄真理. 中华鲟(Acipenser sinensis)  生存危机的主因到底是什么? 湖泊科学, 2020, 32 ( 4): 924-940.]

[28] Xie P. Can we save the disappearing sturgeons in the Yangtze River? J Lake Sci, 2020, 32 ( 4): 899-914. DOI: 10. 18307 / 2020．0401. [谢平. 我们能拯救长江中正在消逝的鲟鱼吗?  湖泊科学, 2020, 32( 4): 899-914.]

[29] Pan JH, Liu CH. Morphological comparison of sturgeons in Changjiang and Zhujiang rivers. Journal of South China Normal University:  Natural Science Edition, 1986, ( 2): 35-39. [潘炯华, 刘成汉. 长江及珠江鲟鱼形态特征的初步比较. 华南师范大学学报:  自然科学版, 1986, ( 2): 35-39.]

[30] Yangtze Aquatic Resources Survey Group of Sichuan Province ed. The biology of the sturgeons and paddlefish in the Yan- gtze river and their artificial propagation. Chengdu:  Sichuan Scientific and Technical Publishing House, 1988. [四川省长江水产资源调查组. 长江鲟鱼类生物学及人工繁殖研究. 成都: 四川科学技术出版社, 1988.]

[31] Watanabe Y, Wei QW, Yang DG et al. Swimming behavior in relation to buoyancy in an open swimbladder fish, the Chi- nese sturgeon. Journal of Zoology, 2008, 275( 4): 381-390．

[32]  Zhuang P. Ontogenetic behavior of sturgeons ( Acipenseridae)   with comments on evolutionary and practical significance[Dissertation] . Wuhan:  Institute of Hydrobiology, Chinese Academy of Science, 1999. [庄平. 鲟科鱼类个体发育行为生态学及其在进化与实践上的意义[学位论文] . 武汉: 中国科学院水生生物研究所, 1999.]

[33] Huang ZL, Wang LH. The Chinese sturgeon (Acipenser sinensis)   conservation—Introspection, reform and innovation. J Lake Sci, 2020, 32( 5): 1320-1332. DOI:  10．18307 / 2020．0510. [黄真理, 王鲁海. 长江中华鲟( Acipenser sinensis) 保护—反思、改革和创新. 湖泊科学, 2020, 32( 5): 1320-1332.]

[34] Wang CY. Migrations for reproduction of Chinese sturgeon (  Acipenser sinensis) and its habitat selections in the Yangtze River [Dissertation] . Wuhan:  Huazhong Agricultural University, 2012. [王成友. 长江中华鲟生殖洄游和栖息地选择[学位论文] . 武汉:  华中农业大学, 2012.]

[35] Duan XJ, Wang XL, Xu XB et al. Main problems and Countermeasures of ecological protection along the Yangtze River coastline. Resources and Environment in the Yangtze Basin, 2019, 28( 11): 2641-2648. [段学军, 王晓龙, 徐昔保等．长江岸线生态保护的重大问题及对策建议. 长江流域资源与环境, 2019, 28( 11): 2641-2648.]

[36] Sun HL, Wang D, Wu YY et al. Analysis for the effect of hydropower and water conservancy engineering on basin eco-en- vironment in the upper Yangtze River. Environmental Protection, 2017, 45( 15): 37-40. [孙宏亮, 王东, 吴悦颖等. 长江上游水能资源开发对生态环境的影响分析. 环境保护, 2017, 45( 15): 37-40.]

[37] Zhang JQ, Liu JS. Saving Chinese sturgeon and protecting the live river-the Yangtze River:  A record of '99 Restocking e- vent of Chinese sturgeon with 100, 000 fingerlings. China Fisheries, 2000, ( 1): 58-59. [张嘉秋, 刘晋生. 拯救中华鲟保护生命河———'99 十万中华鲟苗世纪放流活动纪实. 中国水产, 2000, ( 1): 58-59.]

[38] Luo J, Du H, Wei QW et al. Reproductive biology of an artificial population of endangered Chinese sturgeon (Acipenser sinensis) . Journal of Fishery Sciences of China, 2020, 27( 3): 269-276. [罗江, 杜浩, 危起伟等. 濒危中华鲟人工群体的繁殖生物学. 中国水产科学, 2020, 27( 3): 269-276.]

[39] Liu JY, Wei QW, Du H et al. Studies on promoted key technologies in artificial propagation of Chinese sturgeon. Journal of Economic Animal, 2006, 10( 2): 96-100. [刘鉴毅, 危起伟, 杜浩等. 中华鲟人工繁殖关键技术的改进效果研究．经济动物学报, 2006, 10( 2): 96-100.]

[40] Wei QW, Li LX, Du H et al. Research on technology for controlled propagation of cultured Chinese sturgeon (Acipenser sinensis) . Journal of Fishery Sciences of China, 2013, 20( 1): 1-11. [危起伟, 李罗新, 杜浩等. 中华鲟全人工繁殖技术研究. 中国水产科学, 2013, 20( 1): 1-11.]

[41] Chang JB, Cao WX. History and prospect of conservation on Chinese Sturgeon in the Yangtze River. Acta Hydrobiologica Sinica, 1999, 23( 6): 712-720. [常剑波, 曹文宣. 中华鲟物种保护的历史与前景. 水生生物学报, 1999, 23( 6) : 712-720.]

[42] Yu WG, Xia ZQ, Yu GR et al. Water temperature variation in Three-Gorges Reservoir and its influences on procreation of Chinese sturgeons. Journal of Hohai University:  Natural Sciences, 2007, 35( 1): 92-95. [余文公, 夏自强, 于国荣等．三峡水库水温变化及其对中华鲟繁殖的影响. 河海大学学报:  自然科学版, 2007, 35( 1): 92-95.]

[43] Yang DG, Wei QW, Chen XH et al. Hydrological Status of the spawning ground of Acipenser sinensis underneath the Gezhouba Dam and its relationship with the spawning runs. Acta Ecologica Sinica, 2007, 27( 3): 862-868

[44] Zhu B, Zhou F, Cao H et al. Analysis of genetic variation in the Chinese sturgeon, Acipenser sinensis:  estimating the con- tribution of artificially produced larvae in a wild population. Journal of Applied Ichthyology, 2002, 18(4/5/6): 301-306．