Distribution and demographics of marine mammals in SOCAL through photoidentification, genetics, and satellite telemetry

Loading...
Thumbnail Image
Authors
Falcone, Erin A.
Schorr, Gregory S.
Subjects
Marine mammals
cetaceans
satellite tagging
location data
diving data
fin whales
Southern California Bight
SOAR
SCORE
Cuvier's breaked whales
photo-identification
Advisors
Date of Issue
2014-12
Date
December 2014
Publisher
Monterey, California. Naval Postgraduate School
Language
Abstract
This report summarizes data collected during small-vessel surveys for cetaceans in the Southern California Bight (SCB), with a focus on the Southern California Offshore Range Complex (SCORE), from June 2010-January 2014. Detailed annual progress reports were prepared after each survey year through 2013 and are available online through the Naval Postgraduate School. This final report emphasizes analyses that combine data across study years, particularly with respect to two focal species: Cuvier's beaked (Ziphius cavirostris, Zc) and fin (Balaenoptera physalus, Bp) whales. 18 cetacean species were encountered in surveys based at SCORE, and several previously documented seasonal trends in species occurrence were confirmed. Bp were sighted in every month surveyed, Zc in all but one, suggesting both are present year-round. Preliminary mark-recapture abundance estimates from photo-identification data suggest both species have local populations in the low hundreds. Both photo-identification and telemetry data suggest Zc exhibit a degree of basin-specific site fidelity within the SCB. Many Bp also appear to preferentially remain within the SCB year-round, with increased use of nearshore waters in fall and winter. A subset of 688 hours of Zc diving behavior from periods without Mid-Frequency Active Sonar use in the area showed that the behavior of these whales was similar to that of the larger dataset (including sonar exposure), and confirms previous observations that Zc here appear to forage less often than whales in other regions, and that sonar exposure is unlikely to be the primary driver of these regional differences, though some exposures may cause foraging disruption. Future research will seek to further elucidate the relationship between behavioral patterns and sonar use in the area.
Type
Technical Report
Description
Series/Report No
Department
Oceanography
Identifiers
NPS Report Number
NPS-OC-14-005CR
Sponsors
CNO(N45), Washington, D.C.
Funder
Cascadia Research Collective and supported under NPS Grant N00244-10-1-0050
Format
Citation
Distribution Statement
Approved for public release; distribution is unlimited.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.