Diving for food: a switch of foraging strategy of dusky dolphins in Argentina

During winter, dusky dolphins ( Lagenorhynchus obscurus ) were observed in coordinated diving apparently in a feeding activity, contrasting with the surface feeding observed during summer. The aim of this work consisted in analyzing the diving activity as an alternative foraging strategy in Argentin...

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Bibliographic Details
Published in:Journal of ethology 2012-09, Vol.30 (3), p.361-367
Main Authors: Degrati, Mariana, Dans, Silvana L., Garaffo, Griselda V., Crespo, Enrique A.
Format: Article
Language:English
Subjects:
Animal Ecology
Behavioral Sciences
Biological and medical sciences
Biomedical and Life Sciences
Cetacea
Evolutionary Biology
Fundamental and applied biological sciences. Psychology
Lagenorhynchus obscurus
Life Sciences
Mammalia
Marine
Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution
Zoology
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Summary:During winter, dusky dolphins ( Lagenorhynchus obscurus ) were observed in coordinated diving apparently in a feeding activity, contrasting with the surface feeding observed during summer. The aim of this work consisted in analyzing the diving activity as an alternative foraging strategy in Argentine dusky dolphins, based on sequential analysis. The study area was Golfo Nuevo, located in Northern Patagonia, Argentina. Random transects were surveyed by a research boat from 2001 to 2007. During behavioral sampling, group members were observed continuously and the predominant activity was recorded at 2-min intervals. Six predominant activities were identified. Each 2-min interval was classified according to the activity at the previous interval (preceding activity), the activity at the interval (following activity), and the season (cold or warm). Z scores were calculated and then used to construct sequence diagrams. An association between diving and milling behavior was observed. This could be another foraging tactics different to the surface foraging sequences and this could be related with the distribution or abundance of preys.
ISSN:0289-0771
1439-5444
DOI:10.1007/s10164-012-0333-1