ABSTRACT. Mle lnvestlgated the foraging behaviour of king pengulns In relation to sea-surface temperature distribution over 3 years near the Crozet Archipelago, South Indlan Ocean. Wlthln their range there are 2 hydrographlc frontaI systems, whose seasonal patterns of productivity are predictable. These are the Polar Front and the Sub-Antarctic Front. During the austral summer the foraging range of breeding king pengulns was restricted to the Polar Frontal Zone, limlted to the south by the Polar Front and to the north by the Sub-Antarctic Front. Most b~r d s travelled towards the colder water situated south of Crozet, w h~l e other birds moved east to warmer water Blrds travelling south spent more time than expected in the coldest waters generally associated with the Polar Front. Birds travelling east reached the southern limit of the Sub-Antarctic Front (sea-surface temperature between 8 and 10°C). Within the Polar Frontal Zone birds differed In their foraging behaviour, with incubating birds remaining at sea for longer times and covering longer distances. During the incubation period, king penguins travelling south tended to spend their time in areas with a sea-surface temperature between 4 and 5°C. which coincide with the location of the Polar Front. Though these birds remained a t sea longer, they did not go any further south than birds hilv~ng a n egg ready to hatch or than birds in the brooding period, which appeared to travel more directly towards the Polar Front. As the breeding season progressed, the Polar Front moved further south, out of the range of the king penguins espcc~ally those with a newly hatched c h~c k that were limited in the amount of time that they could spend at sea. King penguins breeding a t Crozet may choose between 2 strategies, in w h~c h some blrds forage towards the SubAntarctic Front but most travel south towards the Polar Front.