Figuring out how salmon sperm adapt to edge past their competitors could shed valuable light on social dominance in many species.
Researchers don't know how these adjustments occur, or whether they alter a male's reproductive success.
Using a $345,000 Marsden Fund grant, Dr Patrice Rosengrave from the University of Otago will conduct social manipulation experiments using chinook salmon to try and work this out.
"Rapid adjustments in sperm quality has been seen in birds, fish and humans, but actually how those adjustments occur isn't really very well known," she said.
Dr Rosengrave says it's been shown that in some species, including salmon, the sperm of socially subordinate males swim faster, "so they're compensating for their social position by increasing their chances of fertilisation success".
Dr Rosengrave and her team will watch what happens when the social dominance of the male salmon changes, from dominant to subordinate and vice versa.
The researchers will move the fish between different social situations at a hatchery in Canterbury and cameras will record behavioural changes during these transitions.
Microscopes will be used to determine the changes salmon make to their sperm as a result.
Once the mechanisms of those changes have been worked out, the researchers will look at their effect on fertilisation success, by conducting competitive fertilisation experiments.
The results of the research could have implications for a broad range of species including humans, fish and birds.