Field Science Center for Northern Biosphere, Hokkaido University, N9 W9, Sapporo 060-0809, Japan.
J Fish Biol. 2010 Jul;77(1):162-8. doi: 10.1111/j.1095-8649.2010.02667.x.
This study examined whether dominant migratory males (adopting fighter tactics) of the masu salmon Oncorhynchus masou would more aggressively attack large mature male parr (adopting sneaker tactics) as large mature male parr are expected to have the potential to cause a greater decrease in fertilization success. The frequency of aggressive behaviour was not related to the body size of males, and it increased with the frequency of interactions with mature male parr. The fertilization success of mature male parr was much lower than migratory males, and no relationship was observed between fertilization success and aggressive behaviour. The low fertilization success of mature male parr, despite infrequent aggressive behaviour by migratory males, indicates that there might be little benefit for migratory males to attack mature male parr more aggressively according to their body size.
本研究考察了成熟的大型雄鱼（采用偷袭策略）是否会更积极地攻击洄游雄鱼（采用斗士策略），因为成熟的大型雄鱼有可能对受精成功率造成更大的影响。攻击行为的频率与雄鱼的体型大小无关，而是随着与成熟雄鱼的互动频率增加而增加。成熟雄鱼的受精成功率远低于洄游雄鱼，且未观察到受精成功率与攻击行为之间存在相关性。尽管洄游雄鱼的攻击行为不频繁，但成熟雄鱼的受精成功率仍然较低，这表明根据体型大小，洄游雄鱼更积极地攻击成熟雄鱼的好处可能不大。
