TY - JOUR
T1 - Determinants of agonistic interactions in California sea lions
AU - Young, Julie K.
AU - González-Suárez, Manuela
AU - Gerber, Leah
N1 - Funding Information:
We thank the 2004–2006 Lobos Field Crews for field assistance. T. Atwood, T. Lalonde and J. Sabo provided statistical advice. Comments by S. Melin, B.A. Schulte and one anonymous reviewer considerably improved this manuscript. This work was supported by National Science Foundation, Grant No. 0347960 to L.R.G. and SEMARNAT (2006: Oficio num/SGPA/DGVS/03269; 2005: Oficio num/SGPA/ DGVS/05325; 2004: Oficio num/SGPA/DGVS/04160). All animal procedures meet Arizona State University Animal Care and Use Committee (07-918R) and SEMARNAT requirements.
PY - 2008/12/1
Y1 - 2008/12/1
N2 - California sea lions aggregate in high density colonies during the breeding season. Competition for space and mates results in agonistic interactions that may have long-term population consequences. We explored how demographic, behavioral, and environmental variables influence the rate of agonistic interactions in male and female California sea lions at three breeding colonies with varying population trends and distributed across a wide latitudinal gradient within the Gulf of California, Mexico. Our results indicate that male agonistic interactions are related to environmental and spatial parameters, whereas female interactions are related to male interactions, operational sex ratio (OSR) and environmental parameters. Most demographic and environmental parameters were inversely related to rates of agonistic interactions, with the exception of positive relationships between agonistic interactions and territory size for males and OSR for females. In addition, the highest overall rates of aggression were associated with a declining population. Our findings suggest agonistic interactions may be useful in assessing population dynamics, but additional research is needed to identify mechanistic relationships.
AB - California sea lions aggregate in high density colonies during the breeding season. Competition for space and mates results in agonistic interactions that may have long-term population consequences. We explored how demographic, behavioral, and environmental variables influence the rate of agonistic interactions in male and female California sea lions at three breeding colonies with varying population trends and distributed across a wide latitudinal gradient within the Gulf of California, Mexico. Our results indicate that male agonistic interactions are related to environmental and spatial parameters, whereas female interactions are related to male interactions, operational sex ratio (OSR) and environmental parameters. Most demographic and environmental parameters were inversely related to rates of agonistic interactions, with the exception of positive relationships between agonistic interactions and territory size for males and OSR for females. In addition, the highest overall rates of aggression were associated with a declining population. Our findings suggest agonistic interactions may be useful in assessing population dynamics, but additional research is needed to identify mechanistic relationships.
KW - Aggression
KW - Marine mammal
KW - Population ecology
KW - Population trend
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U2 - 10.1163/156853908786279646
DO - 10.1163/156853908786279646
M3 - Article
AN - SCOPUS:67249112549
VL - 145
SP - 1797
EP - 1810
JO - Behaviour
JF - Behaviour
SN - 0005-7959
IS - 12
ER -