ISSN 10674136, Russian Journal of Ecology, 2014, Vol. 45, No. 6, pp. 463–466. © Pleiades Publishing, Ltd., 2014.
Original Russian Text © A.R. Koporikov, V.D. Bogdanov, 2014, published in Ekologiya, 2014, No. 6, pp. 417–421.
The physiological state of the organism strongly
depends on environmental conditions. The idea that
environmental conditions affect the relative size of
internal organs (the method morphophysiological
indicators) was introduced by S.S. Shvarts as early as
the mid20th century (Shvarts, 1956, 1958; Smirnov
et al., 1972; etc.).
In contrast to most other freshwater fishes, burbot
deposits fat in the liver (Bull, 1928; Mittel’man, 1932)
and has a fat content of less than 1% in muscles
(Sorokin, 1976). Depending on the amount of accu
mulated fat, burbot liver can become several times as
large and shrink again. In our previous study
(Koporikov and Bogdanov, 2013) we analyzed changes in
the liver size of semianadromous burbot (
depending on the physiological state of the fish, feed
ing intensity, morphological aberrations, etc. In this
study we show that changes in liver size (i.e., accumu
lation of fat in the body) of semianadromous burbot in
the Ob River basin depends on the environmental
conditions of the open channel period (i.e., during the
summer phase of living in the floodplain).
The morphophysiological parameter characteriz
ing the relative liver weight is named the hepatoso
matic index. Determining this index makes it possible
to minimize measurement error in the assessment of
fat reserves in gadiform fishes, compared to the results
obtained using absolute parameters of liver size.
The purposes of this study were to reveal the envi
ronmental parameters that affect the relative body
conditions of burbot during the open channel period
and predict values of the hepatosomatic index of bur
bot spawners by calculating these values from parame
ters of the environment measured during the summer
period, when the fish live in the floodplain.
MATERIAL AND METHODS
The material was collected in 2000, 2004–2007,
and 2010–2012 (a total of 8 years) during the periods
of spring–summer foraging migration of burbot
upstream from the Gulf of Ob in the Ob River and
autumn foraging–prespawning migration upstream in
Ural tributaries of the Ob. The study area (Fig. 1)
included the lowermost segment of the Ob (Aksarka
village) and the Voikar River. The material was col
lected using various fishing gear: seines, stake and drift
nets, and hookandline gear. A total of 340 burbot
specimens were examined.
Values of the hepatosomatic index considerably
change in spawners in spring and summer during their
long (up to several thousand kilometers) anadromous
migration in the channel of the Ob, depending both on
the length of this migration and on particular environ
mental conditions in each part of the floodplain.
Using material collected in autumn from only one
spawning tributary (the Voikar River) made it possible
to assess the effect of environmental conditions on fat
accumulation during the open channel period more
precisely, since it excluded the effects of migration
length and differences in conditions encountered by
the fish in different parts of the floodplain. The envi
ronmental conditions were characterized by data pro
vided by the nearest weather station, situated in Muzhi
village, YamaloNenets autonomous okrug (33 km
from the mouth of the Voikar).
The Effect of Environmental Conditions of the Open Channel Period
on the Relative Body Condition of Semianadromous Burbot,
L. (Lotidae), in the Ob River
A. R. Koporikov and V. D. Bogdanov
Institute of Plant and Animal Ecology, Ural Branch, Russian Academy of Sciences,
ul. Vos’mogo Marta 202, Yekaterinburg, 620144 Russia
email: Koporikov@mail.ru; Bogdanov@ipae.uran.ru
Received December 6, 2013
—The results of longterm observations on changes in the relative body conditions of burbot (
L.) in the Lower Ob basin during the open channel period (June–September) are analyzed. Statistically
significant strong positive dependence of the hepatosomatic index of spawners on the maximum flood level
is revealed. An equation predicting the value of the hepatosomatic index of spawners from instrumentally
measurable environmental parameters is constructed.
: burbot, hepatosomatic index, environmental conditions, water levels, water temperature