Low reproductive success in territorial male Antarctic fur seals (Arctocephalus gazella) suggests the existence of alternative mating strategies

Microsatellites were used to conduct an analysis of paternity of Antarctic fur seals (Arctocephalus gazella) from Bird Island, South Georgia. At most, only 28% of pups at our study site could be assigned a father, even though the majority (similar to 90%) of candidate males within this colony were s ampled. The behavioural and genetic evidence from this study suggests that a number of alternative mating strategies may exist within this fur seal po pulation. Holding a land-based territory conferred an advantage to male rep roductive success. However, this advantage was much smaller than expected f rom behavioural observations. At least 70% of fur seal pups born at our stu dy site in a given year are not fathered by males who held a territory or w ere observed copulating with females in the previous year, implying that th ere exists a pool of males that seldom venture ashore at this site. To expl ain this discrepancy we suggest that female choice is an integral component of the Antarctic fur seal mating system and that aquatic mating may play a much larger role in the Antarctic fur seal than previously thought.