[MARMAM] New Publication on Cuvier's beaked whales in Southern California

Erin Falcone EFalcone at cascadiaresearch.org
Tue Sep 8 14:40:35 PDT 2009


The following article has been published online in the journal Marine
Biology:

 

Falcone, E.A., G.S. Schorr, A.B. Douglas, J. Calambokidis, E. Henderson,
M.F. McKenna, J. Hildebrand, and D. Moretti. 2009. Sighting
characteristics and photo-identification of Cuvier's beaked whales
(Ziphius cavirostris) near San Clemente Island, California: a key area
for beaked whales and the military? Marine Biology doi:
10.1007/s00227-009-1289-8

 

Abstract   

 

The relationship between beaked whales and certain anthropogenic sounds
remains poorly understood and of great interest. Although Cuvier's
beaked whales (Ziphius cavirostris) are widely distributed, little is
known of their behavior and population structure throughout much of
their range. We conducted a series of five combined visual-acoustic
marine mammal surveys from 2006 to 2008 in the southern San Nicolas
Basin, a site of frequent naval activity off the southern California
coast, west of San Clemente Island. The study area was defined by a
1,800 km2 array of 88 bottom-mounted hydrophones at depths up to 1,850
m. The array was used to vector visual observers toward vocalizing
marine mammal species. Thirty-seven groups of Cuvier's beaked whales
were encountered during the study period. The overall encounter rate was
one group for every 21.0 h of survey effort, and was as high as one
group per 10.2 h of effort during the October 2007 survey. Whales were
encountered in the deepest portion of the study area, at a mean bottom
depth of 1,580 m (SD 138). The average group size was 3.8 individuals
(SD 2.4), which was higher than has been reported from other studies of
this species. Twenty-four groups were observed over multiple surfacings
(median = 4 surfacings, range 2-15). The mean encounter duration of
extended sightings was 104 min (SD 98, range 12-466 min) and the mean
distance moved over the course of sightings was 1.66 km (SD 1.56, range
0.08-6.65 km). Temporal surfacing patterns during extended encounters
were similar to dive behavior described from Cuvier's beaked whales
carrying time-depth recording tags. Seventy-eight photographic
identifications were made of 58 unique individuals, for an overall
resighting rate of 0.26. Whales were sighted on up to 4 days, with
duration from first to last sighting spanning 2-79 days. For those
whales sighted on subsequent days, the mean distance between subsequent
sightings was 8.6 km (SD 7.9). Individuals resighted over 2-3 days were
usually in association with previous group members. Approximately
one-third of groups contained more than one adult male, and many of the
repeated associations involved adult males. These observations suggest
the basin west of San Clemente Island may be an important region for
Cuvier's beaked whales, and also one which affords an unusual
opportunity to collect detailed data on this species. Given its status
as an active military range, it can also provide the ability to monitor
the behavior of individuals in the presence of naval sonar, a critical
step in the management of this and other beaked whale populations
worldwide.

 

The article can be accessed via the following link:
http://www.springerlink.com/openurl.asp?genre=article&id=doi:10.1007/s00
227-009-1289-8
<http://www.springerlink.com/openurl.asp?genre=article&id=doi:10.1007/s0
0227-009-1289-8&sa_campaign=Email/ACE/OF> 

 

For more information on this project, see also
http://www.cascadiaresearch.org/SCORE/SCOREMain.htm 

 

 

Erin Andrea Falcone

Cascadia Research

218 1/2 West 4th Ave.

Olympia, WA 98501

360-943-7325 (Office)

360-943-7026 (Fax)

efalcone at cascadiaresearch.org

www.cascadiaresearch.org

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