Premium
Accuracy and precision of age determination using growth layer groups for California sea lions ( Zalophus californianus ) with known ages
Author(s) -
Rust Lauren B.,
Danil Kerri,
Melin Sharon R.,
Wilkerson Brent
Publication year - 2019
Publication title -
marine mammal science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.723
H-Index - 78
eISSN - 1748-7692
pISSN - 0824-0469
DOI - 10.1111/mms.12605
Subject(s) - zalophus californianus , sea lion , age groups , domoic acid , demography , biology , zoology , ecology , sociology , biochemistry , toxin
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 <10 yr old. These findings support the validity of counting GLGs to estimate age for CSLs <10 yr old to within 1 yr of accuracy.