New Zealand Journal of Marine and Freshwater Research abstracts

---

Dusky dolphin (Lagenorhynchus obscurus) feeding tactics and multi-species associations

Robin L. Vaughn¹
Deborah E. Shelton¹ *
Lori L. Timm²
Leslie A. Watson¹ **
Bernd Würsig¹

¹ Marine Mammal Research Program
 Texas A&M University at Galveston
 5007 Ave. U
 Galveston, Texas 77551, United States
 email: vaughnrl@tamu.edu
² Department of Biology
 Liquid Life Laboratory
 750 S. Church Street
 West Chester University
 West Chester
 Pennsylvania 19383–2112, United States
*Present address: University of Arizona, Department of Ecology and Evolutionary Biology, P.O. Box 210088, Tucson, Arizona 85721, United States.
**Present address: Institute of Antarctic and South Ocean Studies, University of Tasmania, Private Bag 77, Hobart, Tasmania 7001, Australia.

Abstract In this study, monthly changes in dusky dolphin (Lagenorhynchus obscurus) feeding tactics and multi-species associations in Admiralty Bay and Current Basin, New Zealand were described from August to November 2005 and from May through August 2006. Concurrent changes in dusky dolphin abundance, prey characteristics, and locations of feeding bouts were examined. Data were collected during systematic surveys and focal follows of dolphin groups. During 335 dolphin feeding bouts (52 observed underwater), data were recorded on number of associated fur seal (Arctocephalus forsteri), seabirds, and sharks; dolphin behaviour; prey ball parameters; and locations. Dolphin feeding tactics, multi-species associations, and locations of feeding bouts were different from May through July than from August to November. From May through July, dolphins fed on mobile prey at depth; from August to November, they herded small schools of fish (including pilchard Sardinops neopilchardus) to the surface. Primarily shearwaters (Puffinus spp.) fed with dolphins from May through July; shearwaters, gannet (Morus serrator), gulls (Larus spp.), and fur seal frequently fed with dolphins from August to November. These intra-annual differences suggest that changes in prey species or behaviour influence dolphin feeding tactics, and influence which species benefit from feeding with dolphins.

Keywords Arctocephalus forsteri; feeding behaviour; foraging ecology; mixed species aggregations; seabirds; sharks

New Zealand Journal of Marine and Freshwater Research, 2007, Vol. 41: 391–400
0028–8330/07/4104–0391     © The Royal Society of New Zealand 2007
M07018; Online publication date 27 November 2007
Received 13 April 2007; accepted 24 October 2007

PDF file of entire paper: Print-quality (1367K) | screen-quality (502K)

---

This year's abstracts | Journal home page | All abstracts | Publishing home page