Spawning Ground of Tropical Eels

2016 ◽  
pp. 89-107 ◽  
Author(s):  
Takaomi Arai
Keyword(s):  
Spawning Ground ◽  
Tropical Eels

scholarly journals Optimization of the flow conditions in the spawning ground of the Chinese sturgeon (Acipenser sinensis) through Gezhouba Dam generating units

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Anyang Huang ◽  
Jinzhong Yao ◽  
Jiazhi Zhu ◽  
Xingchen Gao ◽  
Wei Jiang
Keyword(s):  
Spawning Ground ◽  
Chinese Sturgeon ◽  
Flow Conditions ◽  
Velocity Measurements ◽  
Acipenser Sinensis ◽  
Critically Endangered Species ◽  
Gezhouba Dam ◽  
Opening Mode ◽  
Suitable Area ◽  
Good Agreement

AbstractChinese sturgeon (Acipenser sinensis) is a critically endangered species, and waters downstream from Gezhouba Dam are the only known spawning ground. To optimize the velocity conditions in the spawning ground by controlling the opening mode of Gezhouba Dam generator units, a mathematical model of Chinese sturgeon spawning ground was established in FLOW-3D. The model was evaluated with velocity measurements, and the results were determined to be in good agreement. By inverting the 2016–2019 field monitoring results, the model shows that the preferred velocity range for Chinese sturgeon spawning is 0.6–1.5 m/s. Velocity fields of different opening modes of the generator units were simulated with identical discharge. The suitable-velocity area was maximal when all units of Dajiang Plant of Gezhouba Dam were open. For discharges below 12,000 m3/s, most of the area was suitable; for discharges above 12,000 m3/s, the suitable area rapidly decreased with increasing discharge. A comparison of suitable areas under high-flow showed that at discharges of 12,000–15,000 m3/s, opening 11–13 units on the left side was optimal. For discharges above 15,000 m3/s, all units should be open. We used these results to recommend a new operation scheme to support the conservation of Chinese sturgeon.

scholarly journals Does construction in the spawning ground improve the riverbed conditions making it suitable for spawning of the Ryukyu-ayu Plecoglossus altivelis ryukyuensis?

2020 ◽  
Vol 67 (4) ◽  
pp. 493-501
Author(s):  
Satoshi Awata ◽  
Tetsuya Tsuruta ◽  
Shin-ichiro Abe ◽  
Toshihiko Yonezawa ◽  
Kei’ichiro Iguchi
Keyword(s):  
Spawning Ground ◽  
Plecoglossus Altivelis ◽  
Plecoglossus Altivelis Ryukyuensis

Where is disciplinarity going? Meeting on the borderland

2011 ◽  
Vol 50 (3-4) ◽  
pp. 582-606 ◽  
Author(s):  
Anne Marcovich ◽  
Terry Shinn
Keyword(s):  
19Th Century ◽  
Scientific Knowledge ◽  
Scientific Discipline ◽  
Cognitive Structures ◽  
Spawning Ground ◽  
University System ◽  
The 19Th Century

This article analyzes the cognitive structures and dynamics of a form of scientific discipline that differs importantly both from the disciplinary format of the 19th-century university system, and from the profile proposed by much postmodern interdisciplinary (anti-disciplinary) discussion. This recent form of discipline, here termed the ‘new disciplinarity’, is a product of the increasing complexity of scientific knowledge and activity. The approach privileges cognition. It emphasizes the concepts of disciplinary referent, robust boundaries, ‘borderland’, combinatorials and projects. It suggests that the new disciplinarity is highly elastic and that it is a spawning-ground for new disciplines.

scholarly journals Degeneration of the olfactory epithelium in the Anguilid eels by hormone treatment

2019 ◽  
Vol 3 (2) ◽  
pp. 48-51
Author(s):  
Ching Fui Fui ◽  
Gunzo Kawamura ◽  
Kazuhiko Anraku ◽  
Bensan Ali ◽  
Nabilah Zieha Sikh Mohamad ◽  
...  
Keyword(s):  
Sexual Maturation ◽  
Side Effect ◽  
Hormone Treatment ◽  
Japanese Eel ◽  
Silver Eels ◽  
Olfactory Cells ◽  
Mucus Cells ◽  
Olfactory Cue ◽  
Olfactory Rosette ◽  
Tropical Eels

While the olfactory cue hypothesis has been proposed for spawning migration of silver eels, it has been shown that olfactory cells and associated mucus cells degenerate in male and female eels after hormonally induced sexual maturation. However, the degeneration of the olfactory organ could be a real event in the sequence of maturation, or may be an unnatural side effect of the hormone treatment itself. We morphologically and histologically examined the olfactory rosettes of hormone-untreated and hormone-treated (mixture of hCG and PG) giant mottled eel (Anguilla marmorata) and Japanese eel (A. japonica). The olfactory rosette from all the hormone-treated specimens significantly degenerated at various degeneration levels even in sexually immature specimens, indicating the side effect of the hormone-treatment. However, a sexually immature non-hormone treated female A. marmorata (87.4 cm TL, 199.4 g BW, at less advanced maturity) had slightly degenerated olfactory rosette. Further studies should focus on conducting natural degeneration of the olfactory rosette during the sexual maturation in tropical eels.

scholarly journals Case Study: Influence of Three Gorges Reservoir Impoundment on Hydrological Regime of the Acipenser sinensis Spawning Ground, Yangtze River, China

2021 ◽  
Vol 9 ◽  
Author(s):  
Yinjun Zhou ◽  
Zhijing Li ◽  
Shiming Yao ◽  
Miner Shan ◽  
Chao Guo
Keyword(s):  
Sediment Load ◽  
Hydrological Regime ◽  
Three Gorges ◽  
Spawning Ground ◽  
Chinese Sturgeon ◽  
The Three Gorges ◽  
Reservoir Impoundment ◽  
River Cross Section

After the construction of the Three Gorges Dam (TGD) in China, the downstream has been affected by the reduction in sediment discharge and regulation of flow processes, which have resulted in severe scouring and changes hydrological regime. Consequently, the spawning ground of Chinese sturgeon distributed along the downstream Yichang reach could be affected. This study examined the effects of TGD on the streamflow, sediment load and channel morphology downstream based on in situ measured data. Results showed that, after the impoundment of the TGD, sediment load at the downstream Yichang hydrological station decreased significantly, and the Yichang reach continued to be scoured. The distribution of erosion was uneven, and the scouring mainly occurred in the branching channels. The channel gradient and riverbed roughness increased with the erosion of the river cross section. After more than 10 years of erosion, the riverbed scouring and armouring in the Yichang reach was basically completed, thus we expected that the spawning grounds of Chinese sturgeon could be retain as the riverbed tends to be stable. The findings in this work have implications in the protection of the critically endangered Chinese sturgeon.

scholarly journals Fall Chinook Salmon Spawning Ground Surveys in the Snake River Basin Upriver of Lower Granite Dam, 2004 Annual Report.

2005 ◽  
Author(s):  
A.P. Garcia ◽  
S. Bradbury ◽  
B.D. Arnsberg ◽  
S.J. Rocklage ◽  
P.A. Groves
Keyword(s):  
River Basin ◽  
Chinook Salmon ◽  
Annual Report ◽  
Snake River ◽  
Spawning Ground
Sign in / Sign up

Export Citation Format

Share Document