Reproductive investment patterns, sperm characteristics, and seminal plasma physiology in alternative reproductive tactics of Chinook salmon (Oncorhynchus tshawytscha)

Reproductive investment patterns and comparison of sperm quality in the presence and absence of ovarian fluid in alternative reproductive tactics of masu salmon, Oncorhynchus masou.

In most teleost fish species, sperm competition is a key factor in determining male reproductive success, leading to selection on males to increase their reproductive investment in gonads and ejaculate competitiveness. In this study, reproductive investment patterns were assayed by examining the relative investment in gonads and sperm quality metrics (in river water and in the presence of ovari...

Tactic-specific benefits of polyandry in Chinook salmon Oncorhynchus tshawytscha.

This study examined whether polyandrous female Chinook salmon Oncorhynchus tshawytscha obtain benefits compared with monandrous females through an increase in hatching success. Both of the alternative reproductive tactics present in male O. tshawytscha (large hooknoses and small, precocious jacks) were used, such that eggs were either fertilized by a single male (from each tactic) or multiple m...

Proteomic Analysis of Chinook Salmon (Oncorhynchus tshawytscha) Ovarian Fluid

The ovarian, or coelomic, fluid that is released with the egg mass of many fishes is increasingly found to play an important role in several biological processes crucial for reproductive success. These include maintenance of oocyte fertility and developmental competence, prolonging of sperm motility, and enhancing sperm swimming speed. Here we examined if and how the proteome of chinook salmon ...

Ejaculate Allocation and Sperm Competition in Alternative Reproductive Tactics of Salmon and Trout: Implications for Aquaculture

Sneaker “jack” males outcompete dominant “hooknose” males under sperm competition in Chinook salmon (Oncorhynchus tshawytscha)

In a variety of taxa, males deploy alternative reproductive tactics to secure fertilizations. In many species, small "sneaker" males attempt to steal fertilizations while avoiding encounters with larger, more aggressive, dominant males. Sneaker males usually face a number of disadvantages, including reduced access to females and the higher likelihood that upon ejaculation, their sperm face comp...