Sperm allocation in semelparous salmonid species

2014 Fiscal Year Final Research Report

• Project/Area Number: 25840163
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Ecology/Environment
• Research Institution: Nihon University
• Principal Investigator: MAKIGUCHI Yuya 日本大学, 生物資源科学部, 助教 (00584153)
• Project Period (FY): 2013-04-01 – 2015-03-31
• Keywords: サケ / バイオロギング / 繁殖行動 / 配偶者選択

Outline of Final Research Achievements

We investigated sperm economy in semelparous salmonid species, chum salmon. We developed a method for determining the amount of sperm in milt and collecting volume of sperm released during spawns of the salmon using acceleration dataloggers and condoms. We also examined relationship between volume of sperm released and body size of paired female.
The time length in vibration of trunk musculature at the moment of sperm release was positively correlated with the amount of sperm ejaculated, which indicated that the length of time in vibration at the moment of sperm release can be an indicator of the amount of sperm released. The vibration time at the moment of sperm release was positively correlated with a relative body size of paired female and was also negatively correlated with a body size of male. These results indicate that male salmon can allocate their sperm expenditure in accordance with paired female body size.

Free Research Field

行動生態学