Dive strategies and foraging effort in the Australasian gannet Morus serrator revealed by underwater videography

Abstract

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 442:255-261 (2011) - DOI: https://doi.org/10.3354/meps09458 Dive strategies and foraging effort in the Australasian gannet Morus serrator revealed by underwater videography Gabriel E. Machovsky Capuska1,2,* , Robin L. Vaughn3, Bernd Würsig3, Gadi Katzir4,5, David Raubenheimer1,2 1Nutritional Ecology Research Group, Institute of Natural Sciences, Massey University, Private Bag 102 904 North Shore MSC, Auckland, New Zealand 2Coastal-Marine Research Group, Institute of Natural Sciences, Massey University, Private Bag 102 904 North Shore MSC, Auckland, New Zealand 3Department of Marine Biology, Texas A&M University at Galveston, 200 Seawolf Parkway, Galveston, Texas 77553, USA 4Department of Marine Biology, University of Haifa, Mount Carmel, Haifa 31905, Israel 5Department of Evolutionary and Environmental Biology, University of Haifa, Mount Carmel, Haifa 31905, Israel *Email: g.machovsky@massey.ac.nz ABSTRACT: Gannets are specialist plunge divers that perform short and shallow V-shaped dives and long and deep U-shaped dives in pursuit of pelagic fish and squid. We used underwater videography to examine the patterns of behaviour and relative success rates of V- and U-shaped dives in Australasian gannets. A significantly greater proportion of U-shaped dives were associated with successful prey capture than V-shaped dives (95% vs. 43%, respectively). The maximum number of prey captured per dive by the gannets was higher than previously reported, reaching up to 5 fish in a single U-shaped dive. However, V-shaped dives were more efficient in terms of grams of prey captured per time spent underwater in successful dives. In contrast, a population-level comparison of the mass of fish captured per total time spent underwater (i.e. including unsuccessful dives) suggested that the 2 dive profiles were equally efficient. We also found that gannets adjusted their dive shape in relation to the depth of their prey rather than prey type, as previously hypothesized. Further studies are needed to understand decisions made by gannets while plunge diving in complex marine environments. KEY WORDS: Gannets · Morus serrator · Dive shape · Prey capture success · Decision making · Multispecies feeding associations Full text in pdf format PreviousNextCite this article as: Machovsky Capuska GE, Vaughn RL, Würsig B, Katzir G, Raubenheimer D (2011) Dive strategies and foraging effort in the Australasian gannet Morus serrator revealed by underwater videography. Mar Ecol Prog Ser 442:255-261. https://doi.org/10.3354/meps09458 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 442. Online publication date: December 05, 2011 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2011 Inter-Research.