Sperm traits dependent on body size in masu salmon Oncorhynchus masou

2015 ◽  
Vol 81 (5) ◽  
pp. 815-820 ◽  
Author(s):  
Toshiaki Yamamoto ◽  
Hatsuna Maruta ◽  
Tatsuya Suzuki ◽  
Shigeru Kitanishi
Keyword(s):  
Body Size ◽  
Masu Salmon ◽  
Oncorhynchus Masou ◽  
Sperm Traits ◽  
Masu Salmon Oncorhynchus Masou

Effects of timing of nest entry and body size on the fertilization success of alternative male reproductive phenotypes of masu salmon (Oncorhynchus masou)

2008 ◽  
Vol 86 (10) ◽  
pp. 1121-1130 ◽  
Author(s):  
M. Watanabe ◽  
S. Takamura ◽  
K. Maekawa
Keyword(s):  
Body Size ◽  
Parentage Analysis ◽  
Fertilization Success ◽  
Masu Salmon ◽  
Mature Male ◽  
Alternative Mating Tactics ◽  
Oncorhynchus Masou ◽  
Mating Tactics ◽  
Mature Male Parr ◽  
Masu Salmon Oncorhynchus Masou

Using a natural population of masu salmon ( Oncorhynchus masou (Brevoort, 1856)) in a stream of Shikaribetsu Lake, Hokkaido, Japan, we combined behavioural observations with genetic parentage analysis to explore the factors affecting fertilization success achieved by alternative mating tactics (fighting by large migratory males and sneaking by small mature male parr). Larger males gained priority access to females; migrant males do this by holding a guarding position near the nesting female and mature male parr do this by adopting sneaker behaviour and attending spawning groups. Status of mature male parr was related to success of nest entry but not to timing of nest entry, although the timing of nest entry influenced fertilization success of sneakers and ejaculation simultaneous with pair spawning was needed for fertilization by sneakers. The relative body size of each male who successfully spawned with a female is also likely to determine the proportion of eggs he fertilized because larger males have larger ejaculate. These results provide insight into factors relating to variation in fertilization success, how body size dimorphisms may be related to fitness, and evolution of alternative mating tactics.

Changes of serum growth hormone and vitellogenin levels during vitellogenesis in female masu salmon Oncorhynchus masou

2000 ◽  
Vol 66 (4) ◽  
pp. 789-791 ◽  
Author(s):  
Haruhisa Fukada ◽  
Naoshi Hiramatsu ◽  
Makiko Kitamura ◽  
Munetaka Shimizu ◽  
Akihiko Hara
Keyword(s):  
Growth Hormone ◽  
Masu Salmon ◽  
Oncorhynchus Masou ◽  
Serum Growth Hormone ◽  
Masu Salmon Oncorhynchus Masou
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