LAUREN B. RUST ,
1 The Marine Mammal Center, 2000 Bunker Road, Sausalito,
California 94965, U.S.A.; KERRI DANIL, Southwest Fisheries Science Center,
NMFS, NOAA, 8901 La Jolla Shores Drive, La Jolla, California 92037, U.S.A.;
SHARON R. MELIN, Alaska Fisheries Science Center, NMFS, NOAA, 7600 Sand
Point Way N.E., Building 4, Seattle, Washington 98115, U.S.A.; BRENT WILKERSON,
Department of Biological Sciences, University of Washington, Seattle, Washington
98195, U.S.A.
MARINE MAMMAL SCIENCE, 35(4): 1355–1368 (2019)
© 2019 Society for Marine Mammalogy
DOI: 10.1111/mms.12605
Abstract
Age determination from counts of growth
layer groups (GLGs) in tooth dentine is a common method for aging marine
mammals. Using known-aged animals, we validated this method for acid etched
teeth of California sea lions (CSLs), Zalophus
californianus. Between 1991 and 2013, the upper left canine (n=33) was collected opportunistically
during necropsy from animals tagged or branded as pups that later died.
Overall, 55%-61% of age estimates by GLG counting were within 1 yr of the known-age
in the sample of 1-30 yr old CSLs. Accuracy of age estimates was found to be
dependent on age of the CSLs, however. 71%-79% of age estimates were within 1 yr
of the known-age in CSLs less than 10 yr old. These findings support the validity of
counting GLGs to estimate age for CSLs less than 10 yr old to within one year
of accuracy.
For copies of the full PDF, please email: laurenbeddiarust@gmail.com