1067-4136/04/3506- © 2004
Russian Journal of Ecology, Vol. 35, No. 6, 2004, pp. 383–388. Translated from Ekologiya, No. 6, 2004, pp. 430–435.
Original Russian Text Copyright © 2004 by Monakhov.
Population monitoring, ecological prognosis, and
rational management of game resources are impossible
without the assessment of game stocks in order to deter-
mine hunting quotas adequate to the age–sex popula-
tion structure. The approach universally accepted in
game management (and apparently the only feasible
approach today) is to assess the age structure of sam-
ples from a population of the species of interest and
extrapolate the results to the whole population. The cru-
cial role in this assessment belongs to the method for
identifying the age of each animal in the sample.
Many methods of age determination are known.
Some of them are applicable to many species (univer-
sal), whereas others have been developed for only a cer-
tain species. A more important aspect is that there are
descriptive methods (mostly approximate) and formal
methods based on measurements and calculations.
The essence of descriptive methods lies in the com-
parison of qualitative characters, which can provide for
only a rough estimation of animal age; measurements
and analysis of quantitative characters play a secondary
role. As a rule, these methods involve the use of a refer-
ence sample (a standard). For example, this concerns
the methods for determining the age of some mammals
from the degree of tooth wear (Kiris, 1937; Stroganov,
1937; Petrovskii, 1961; Stubbe, 1969; Mashkin and
Kolesnikov, 1990; Lobkov, 1999).
Formal methods, which are usually more accurate,
are based on calculations of qualitative characters and
morphometric procedures; i.e., they make use of
changes in organs, tissues, or structures that can be
measured, counted, or weighed. Parameters for deter-
mining animal age by such methods include, for exam-
ple, the weight of the eye lens (Pavlov and Smyshlyaev,
1968; Karpukhin and Karpukhina, 1971), the number
of spots on wings in hazel grouse (Gaidar and Zhitkov,
1974), body length (Novikov, 1953; Egorov, 1961;
Lobkov, 1999), and dimensional indices of the skull,
teeth, and bones (Tsygankov, 1955; Smirnov, 1960;
, 1966; Skaren, 1987).
Naturally, accuracy in assessing the age structure of
a sample depends on the accuracy of the method used
for identifying the age of the individuals comprising
this sample. This study deals with the assessment of the
age structure of sable populations (primarily for the
purposes of game management) and comparison of
results obtained by three methods of age determination.
MATERIAL AND METHODS
The samples of sables were collected by hunters in
four areas of the Transural region (
= 2150) and in the
Kizir River basin, the Western Sayan (
between 1976 and 1989. In that period, active studies
on the ecological structure of sable populations were
performed, and their results were used for calculating
population growth and planning rational sable hunting
in Sverdlovsk and Tyumen oblasts and Krasnoyarsk
Animal age was determined by three methods
employed consecutively (Grakov and Monakhov,
1981). In the course of initial processing (dissection),
Assessment of the Age Structure of Sable Samples
Using Three Methods of Age Determination
V. G. Monakhov
Institute of Plant and Animal Ecology, Ural Division, Russian Academy of Sciences,
ul. Vos’mogo Marta 202, Ekaterinburg, 620144 Russia
Received April 24, 2003
—The age structure of sable samples has been analyzed on the basis of parameters obtained by three
methods of age determination: by annual cementum layers (Klevezal, 1988), canine root canal width (Smirnov,
1960), and the degree of development of the mastication muscles and sagittal crest on the skull (Timofeev and
Nadeev, 1955). It has been found that the ﬁrst two methods produce similar results (
= 0.95) that are suitable
for use in the practice of monitoring and commercial game management. The third method is simpler but less
accurate and can be recommended only for the preliminary assessment of age ratios in populations. The results
of such assessment by the method proposed by Klevezal are sufﬁciently accurate for a detailed analysis of pop-
ulation structure and dynamics of its reproductive core, but this method is laborious and involves a complicated
histological procedure. When large samples are studied for the purposes of monitoring and management plan-
ning, the method proposed by Smirnov is preferable.
: methods of age determination, sable, population structure.