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Federal Register / Vol. 86, No. 162 / Wednesday, August 25, 2021 / Proposed Rules Some Russian water-management agencies are now promoting flood control for property protection in the Amur floodplain, and Chinese institutions remain interested in future hydropower development as the much larger human population on their side of the river demands electricity Simonov 2016, not paginated. Construction of any dam on the Lower or lower Middle Amur main stem would be catastrophic for Amur sturgeon by hindering or preventing connectivity Simonov and Dahmer 2008, pp. 193196. The Khingansky-Taipinggou Dam, proposed for the Middle Amur, would have severe hydrological impacts on the river, creating a complete barrier to migrating fish Simonov and Egidarev 2018, pp. 9
10. Until recently, prevailing economic and social conditions made it unlikely that Chinese and Russian counterparts would agree to advance such a project in the next several years Simonov and Egidarev 2018, p. 10; however, recently thawing China-Russia relations Chen 2019, pp. 6264 could now lead to further discussion and construction of a main stem dam.
While the Amur itself remains freeflowing, approximately 100 dams dot its tributaries Simonov et al. 2019, p. 4.
Many of these are small and the impacts of smaller dams on Amur sturgeon are uncertain, but they more likely than not prevent connectivity along stretches of several tributaries and have likely contributed to the species decline.
Several tributaries also have larger dams; in all such cases, Amur sturgeon have been extirpated from these rivers due in large part to the inability of Amur sturgeon to pass over or around the dams. The Songhua River, a major tributary in the lower section of the Middle Amur, is interrupted by the Baishan, Hongshi, and Xiao Fengman dams GRanD 2019, not paginated;
Lehner et al. 2011, pp. 494502, which are approximately 150, 50, and 150 m tall, respectively. The Nierji Dam on the Nen River was built in 2006, after the Amur sturgeon was extirpated from this tributary Lehner et al. 2011; GRanD
2019, not paginated, but because it blocks the route taken by Nen River spawners, its presence would make any restoration efforts there difficult.
Farther upstream, the Zeya and Bureya Rivers are interrupted by dams built in 1975 and 2003, respectively GRanD 2019, not paginated; Simonov et al. 2019, p. 4; Lehner et al. 2011, pp.
494502. These two large hydroelectric dams are 115 and 140 m high Lehner et al. 2011, pp. 494502, and have the greatest ecological impacts of any of the dams in the Amur basin Simonov and Dahmer 2008, p. 191. They block Amur
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sturgeon migrations and destroyed downstream wetlands Simonov and Egivdarev 2008, p. 192, contributing substantially to the extirpation of the species from these rivers Koshelev et al.
2014a, pp. 1313, 1316; Krykhtin and Svirskii 1997, p. 237. Another dam downstream of the existing Bureya impoundment began operating in 2017
Simonov et al. 2019, p. 4 and its presence and effect on the river further limits the potential to restore sturgeon to the Bureya River by making yet a longer stretch of river inaccessible to Amur sturgeon.
Sturgeon are slower swimmers with large bodies; therefore, both fish elevators and fish ladders have been relatively ineffective at allowing sturgeon to transit around dams Billard and Lecointre 2001, p. 380. For the Amur sturgeon, fish passageways made to allow travel through or around dams must include resting pools between fast velocity runs and must be wider than the maximum tail-beat width during swimming Cai et al. 2013, p. 153.
However, we have no information indicating that such structures are built into dams in the Amur basin, and the best scientific and commercial information available shows that the Amur sturgeon is unable to traverse the larger existing dams constructed in the Amur basin, limiting its range to stretches of river below existing large dams and contributing to its decline.
Remaining available spawning grounds are substantially reduced compared to their historical extent.
Pollution Pollution of the Amur basin has likely contributed to the decline of the Amur sturgeon, given the volume and extent of pollution in the Amur basin, the susceptibility of the species to pollutants, and reports of large-scale fish kills in polluted river reaches Simonov and Dahmer 2008, pp. 47, 212236; Zhang 1985 cited in Zhuang et al. 2003, p. 38. Extensive human settlements, agriculture, and industry especially but not exclusively in Chinaall pollute the Amur River and its tributaries with petrochemicals, heavy metals, and persistent organic pollutants such as polychlorinated biphenyls PCBs Jiang et al. 2016, p. 537; Meng et al. 2016, pp. 15. Many Amur River fish, including the single Amur sturgeon sampled, contained copper, chromium, arsenic, and mercury Jiang et al. 2016, p. 540, table 2.
In the late 1990s and early 2000s, pollution in the Lower Amur was considered at an emergency level, and mass fish kills were not uncommon
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Erickson 2007, p. 30; Jen 2003, p. 3.
Sewage, domestic animal feces, pesticides, petrochemicals, heavy metals, and industrial pollutants including PCBs Jiang et al. 2016, p. 537;
Meng et al. 2016, pp. 15; Kondratyeva et al. 2012, p. 186, as well as eutrophication the process by which waters lose oxygen following extreme plant growth triggered by excessive nutrient inputs due to fertilizer runoff, all damaged the river basins ecosystems Erickson 2007, p. 30; Jen 2003, pp. 2
3.
In the Middle Amur analysis unit, the Zeya and Bureya catchments were substantially polluted with mercury, cadmium, and lead as of 2005
Kondrateva et al. 2013, p. 131. In addition, these two river basins are home to more than 30 reservoirs storing heavily polluted wastewater and mining residues. The potential for future failure of the smaller dams that contain these reservoirs and the consequent release of toxic pollutants into the river system poses a high risk to remaining habitats suitable for Amur sturgeon Simonov and Dahmer 2008, p. 191.
In 2001, 100 million mt 110 million t of wastewater containing 2,500 mt 2,800 t of organic chemicals, 80 mt 88
t of oil products, more than 1,000 mt 1,100 t of nitrogenous waste, and 2.5
mt 2.8 t of phenols were discharged into the Amur from Blagoveschensk, Russia at the boundary of the Middle and Upper Amur Simonov and Dahmer 2008, p. 2016. In the Upper Amur, including the Shilka, Amgun, and Argun Rivers, illegal gold mining causes sedimentation and turbidity, hampering sturgeon reproductive success Pacific Environment 2016, not paginated;
Egidarev and Simonov 2015, pp. 900, 906907.
Historically, the Songhua River in the Middle Amur has been the most contaminated tributary Kondratyeva et al. 2012, p. 185; the Amur sturgeon is extirpated from this river, very likely in part due to pollution Cai et al. 2013, p. 150; Simonov and Dahmer 2008, p.
129; Novomodny et al. 2004, p. 18. Two industrial accidents at Jilin City, China, contaminated the Songhua and eventually the Amur River, 1,000 km 600 miles downstream in 2005 and 2010. They released a combined 600 mt 660 t of methyl chloride, trimethyl chloride, nitrobenzene, benzene, aniline, chloroform, chlorobenzene, and other chemicals into the Songhua Kondratyeva et al. 2012, p. 186; The Guardian, November 25, 2005.
Concentrations of these chemicals were as high as 600 times the governmentaccepted levels Kondratyeva et al.
2012, p. 186 and were later detected in
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