Ontogeny of the Diving Behaviour of Juveniles

Research

My research focuses on the foraging ecology of Galapagos sea lion (Zalophus wollebaeki) and Galapagos fur seals (Arctocephalus galapagoensis). I am investigating the ecological niches of these animals and factors that shape their foraging strategies and habitat utilization such as environmental variation and ecological interactions. I am also interested in mechanisms that shape habitat preferences and utilisation.

One of the questions that I am addressing is the ontogeny of foraging in juvenile Galapagos sea lions and the factors that influence this development as this can have major implications for juvenile survival, reproduction and population dynamics. One of these factors is the extreme variability in marine productivity that is characteristic for the Galapagos Islands; another one is the effect of a competitor (the Galapagos fur seal).

Another set of questions deals with natal habitat preferences: Galapagos sea lions surprisingly segregate in two spatially close, but genetically and morphologically distinct clusters. I am investigating if juvenile foraging habitat and their foraging ontogeny differ between these two groups, which could explain the reproductive isolation via early learning of a specific habitat and foraging strategy.  

Approach

I am working in two different Galapagos sea lion colonies, one in the western and one in the central part of the archipelago. I am using stable isotope analysis and scat analysis to investigate trophic and dietary niche dimensions. I combine this information with GPS TDR (time depth recorder) data to link trophic information with diving strategies, activity patterns and habitat utilisation.

Background

I obtained my Diploma from the University of Hamburg, where I studied the distribution of male territories in relation to habitat features in the South African fur seal (Arctocephalus pussillus pussillus) in southwestern Namibia. I then moved on to study the foraging ecology of the Giant-striped mongoose (Galidictis grandidieri) in southwestern Madagascar for a year, before starting my PhD.