Jana Jeglinski (University of Glasgow) and Markus Horning (Oregon State University) both studied the diving behaviour of Galapagos fur seals (Arctocephalus galapagoensis) during PhDs conducted twenty years apart. Although the technology changed in the intervening years, baseline data recording how long and how deep these seals’ dive provide a unique opportunity to compare their diving behaviour across time.
Galapagos fur seals are the smallest species of pinnipeds and one of two species endemic to the Galapagos, thus the only truly tropical seals. What is truly fascinating about this species is their ability to live in a highly productive, yet also highly variable environment where access to food can be severely limited, both in space and time. The prey of these small seals which includes myctophids and bathylagids or ‘lantern fishes”, as well as squid, are accessible only at night when they migrate nearer to the surface and within the seal’s diving range. This migration is influenced by the lunar cycle and the abundance and distribution of these prey are strongly tied to upwelling events, when nutrient-rich deep, cold water rises to the surface.
In this exciting collaboration, Jana and Markus will seek to gain a broad-scale understanding of the diving behaviour of these seals in a fluctuating environment.
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Interested in learning more? Check out these papers by Markus and Jana.
Horning M, Trillmich F (1997) Ontogeny of Diving Behaviour in the Galapagos Fur Seal. Behaviour 134: 1211-1257.
Horning M, Trillmich F (1997) Development of Hemoglobin, Hematocrit and Erythrocyte Values in Galápagos Fur Seals. Marine Mammal Science 13(1): 100-113.
Horning M, Trillmich F (1999) Lunar cycles in diel prey migrations exert stronger effect on diving of juveniles than adult Galápagos fur seals. Proceedings of the Royal Society B-266 (1424): 1127-1132.
Horning M (2012) Constraint lines and performance envelopes in behavioral physiology: the case of the aerobic dive limit. Frontiers in Physiology 3:381. Open Access: http://journal.frontiersin.org/Journal/10.3389/fphys.2012.00381/full
Jeglinski JWE, Goetz KT, Werner C, Costa DP, Trillmich F. (2013) Same size–same niche? Foraging niche separation between sympatric juvenile Galapagos sea lions and adult Galapagos fur seals. Journal of Animal Ecology 82 (3), 694-706
Villegas-Amtmann S, Jeglinski JWE, Costa DP, Robinson PW, Trillmich F. Individual foraging strategies reveal niche overlap between endangered Galapagos pinnipeds. 2013. PLoS ONE 8 (8), e70748
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