MEPS 543:257-271 (2016)  -  DOI: https://doi.org/10.3354/meps11557

Fine-scale foraging cues for African penguins in a highly variable marine environment

Rowen van Eeden1,*, Timothy Reid1, Peter G. Ryan1, Lorien Pichegru2,3

1DST-NRF Centre of Excellence at the Percy FitzPatrick Institute of African Ornithology, University of Cape Town, Rondebosch 7701, South Africa
2DST-NRF Centre of Excellence at the Percy FitzPatrick Institute of African Ornithology, Department of Zoology, Nelson Mandela Metropolitan University, Port Elizabeth 6031, South Africa
3Seabird Division, BirdLife South Africa, Randburg 2125, South Africa
*Corresponding author:

ABSTRACT: Breeding seabirds often need to locate prey in spatially confined search areas on short temporal scales. Ocean physical features such as thermoclines are used as foraging cues since they concentrate and thus increase the likelihood of locating prey. However, in highly variable environments, it is less well understood how these features act as foraging cues. African penguins Spheniscus demersus foraging in Algoa Bay, South Africa, were fitted with GPS-TD loggers to determine the cues they use to locate prey on fine temporal (<24 h) and spatial (<100 km) scales in a bay with changing thermal properties. African penguins showed a preference for cooler surface waters associated with upwelling, avoiding warm surface waters associated with the Agulhas Current. Thermocline presence and characteristics were an important foraging cue; penguins consistently foraged at and below the thermocline even though its depth and gradient shifted over time. Dive ascent and descent rates were quicker in the presence of thermoclines with strong gradients, which form a distinct separation between the warm upper mixed layer and the cooler lower layer. Foraging dives occurred predominantly below the thermocline, while search dives occurred around the thermocline depth. Penguins dived deeper in search of prey when there was no thermocline. Our results demonstrate that top predators can cope with highly variable environments by adjusting their search strategy to target environments suited to their main prey.


KEY WORDS: Foraging ecology · Thermocline variability · GPS tracking · Dive behaviour · Top predator


Full text in pdf format
Supplementary material 
Cite this article as: van Eeden R, Reid T, Ryan PG, Pichegru L (2016) Fine-scale foraging cues for African penguins in a highly variable marine environment. Mar Ecol Prog Ser 543:257-271. https://doi.org/10.3354/meps11557

Export citation
Mail this link - Contents Mailing Lists - RSS
- -