[MARMAM] New paper on sea lions and dolphins

Maddalena Bearzi mbearzi at earthlink.net
Thu Jun 29 10:25:35 PDT 2006


Dear Marmamers, 
 
The following paper on sea lions and dolphins was recently published:


Bearzi, M. 2006. CALIFORNIA SEA LIONS USE DOLPHINS TO LOCATE FOOD. Journal
of Mammalogy 87(3):606-617.
 
Abstract
 
  Aggregations by 3 species of dolphins (the bottlenose dolphin [Tursiops
truncatus], the short-beaked common dolphin [Delphinus delphis], and the
long-beaked common dolphin [Delphinus capensis]) and California sea lions
(Zalophus californianus) were investigated in Santa Monica Bay, California.
Groups were followed and observed during 201 boat-based surveys conducted in
1997­2001 documenting that sea lions were aggregated in 18.6% of the
sightings with bottlenose dolphins (150 bottlenose dolphin sightings) and in
45.9% of the sightings with 1 of the 2 species of common dolphins (98 common
dolphin sightings). Aggregations of bottlenose dolphins and sea lions were
observed in inshore (,500 m from shore) and offshore (.500 m) waters,
whereas common dolphins and sea lions were observed only in offshore waters.
These aggregations were often recorded feeding near escarpments and
submarine canyons, showing a striking preference for these bathymetric
features. The results show that sea lions spend a significant amount of time
following dolphins, sea lions initiate aggregation and departure from
dolphin schools, these aggregations occur more often than is expected by
chance, and no aggressive behavior between sea lions and dolphins was ever
observed at or near the surface. I argue that sea lions may take advantage
of the superior food-locating abilities of dolphins. This paper provides the
1st detailed description of mixed-species aggregations and habitat usage by
3 dolphin species and sea lions.

The paper is available through the journal¹s website:
http://www.asmjournals.org/perlserv/?request=get-pdf&doi=10.1644%2F04-MAMM-A
-115R4.1


Maddalena Bearzi, Ph.D.
Ocean Conservation Society, President
P.O. Box 12860
Marina del Rey, CA 90295 - USA
ph.310.8225205, fax 310.8225729
mbearzi at earthlink.net
http://www.oceanconservation.org



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