•
FISHERIES RESEARCH BOARD OF CANADA .
Translation Series No. 2155
Stereotypes of the Volga sturgeon behaviour in the region of the Saratov hydro-electric power station, 'before and after the river regulation
by'L. K. Malinin, A. G. Poddubnyi •and,V. V. Gaiduk
Original title: ,Stereotipy povedeniya volzhskogo osetra v• raione saratovskoi GES dp i posle zaregulirovaniyà reki
From: Zoologicheskii Zhurnal (Zoological Journal), 50(6) : 847-857, 1971
Translated by the Translation Bureau( AM) Foreign - Languages.Division Department of the Secretary of State of Canada.
Department of the Environment Fisheries Research Board of Canada Biological Station St. Andrews, N. B. 19 72
27 Pages typescript ..-... • c\-176 :5— t. ■ • e• •f. ePARTMENT OF THE SECRETARY OF STATE SECRÉTARIAT D'ÉTAT
e ' TRANSLATION BUREAU BUREAU DES TRADUCTIONS • biULTILINGUAL SERVICES DIVISION DES SERVICES DIVISION MULTILINGUES
TRANSLATED FROM - TRADUCTION DE INTO - EN Rus Sian English
AUTHOR - AUTEUR .L.K. Malinin, A.G. Poddubnyi and V.V. Gaiduk
TITLE IN ENGLISH - TITRE ANGLAIS Stereotypes of the Volga sturgeon behaviour in the region of the Saratov Hydro-Electric Power Station before and afteithe regulation of the . river.
TITI.E IN FOREIGN LANGUAGE (TRANSLITERATE FOREIGN CHARACTERS) TITRE EN LANGUE ÉTRANGÉRE (TRANSCRIRE EN CARACTÈRES ROMAINS) Stereotipy povedeniya volzhskogo osetra v raione saratovskoi CES do i posle zaregulirovaniya reki
REFERENCE IN FOREIGN LANGUAGE (NAME OF BOOK OR PUBLICATION) IN FULL. TRANSLITERATE , FOREIGN CFIARACTERS, RÉFÉRENCE EN LANGUE ÉTRANGÉRE (NOM DU LIVRE OU PUBLICATION), AU COMPLET, TRANSCRIRE EN CARACTÈRES ROMAINS.
Zoologicheskii zhurnal
REFERENCE IN ENGLISH - RÉFÉRENCE EN ANGLAIS
Zoological Journal
PUBLISHER - ÉDITEUR PAGE NUMBERS IN ORIGINAL DATE OF PUBLICATION NUMÉROS DES PAGES DANS Academy of Sciences DATE DE PUBLICATION L'ORI GINAL of the USSR 847-857 YEAR ISSUE NO. VOLUME PLACE OF PUBLICATION A NNÉE NUMÉRO NUMBER OF TYPED PAGES LIEU DE PUBLICATION NOMBRE DE PAGES DACTYLOGRAPHIÉES Moscow 1971 50 6 27
RE.QUESTING DEPARTMENT TRANSLATION BUREAU NO. MINISTÉRE-CLIENT Environment NOTRE DOSSIER NO S-0443
BRANCH OR DIVISION Fisheries Board • TRANSLATOR (INITIALS) AM DIRECTION OU DIVISION Research TRADUCTEUR (INITIALES)
PERSON REQUESTING Dr. A.B. Stasko, St. Andrews, N.B. DEMANDÉ PAR UNEDITED *TRANSLATION • For information only YOURNUMBER VOTRE DOSSIER NO 769-18-14 TRADUCTION NON REVISEE Information seulement DATE OF REQUEST DATE DE LA DEMANDE April 28, 1972 MAY 2 5 1972
305-200.1 0-0 (REV. 2/68) 7030-21-028-0333 •eriPARTMENT OF THE SECRETARY OF STATE SECRÉTARJAT D'ÉTAT
. TRANSLATION BUREAU BUREAU DES TRADUCTiONS .t MULTILINGUAL SERVICES DIVISION DES SERVICES DIVISION MULTILINGUES
CLIENTS NO. DEPARTMENT DIVISION/BRANCH CITY NO DU CLIENT MMISTiRE DIVISION/DIRECTION VILLE 769-18-14 Envirbnment Fisheries Research Board St. Andrews, N. B. • BUREAU NO. • LANGUAGE TRANSLATOR (INITIALS) N ° DU BUREAU LANGUE TRADUCTEUR (INITIALES) S-0443 Russian . AM MAY 2 5 1 j72
Zoological Journal Vol. 50, No. 6, 1971 pp. 847-857 UNEDITED TRANSLATION • For informal-lon only STEREOTYPES OF THE VOLGA STURGEON BEHAVIOUR IN TRADUCTION NON REVISEF-THE REGION OF THE SARATOV HYDRO-ELECTRIC POWER Hoonation sedement STATION BEFORE AND AFTER THE REGULATION OF THE RIVER /p.847 *
L,K. Malinin, A.G. Poddubnyi and V.V. Gaidnk Institute of the Biology of Internal Waters, Academy of Sciences of the USSR (Borok of the Nekouzkii region of the Yaroslavskaya Oblast)
With the aid of ultrasonic transmitters studies were conducted of the tracks and rhythms of the movement of the Volga sturgeon. It was established that the main mass of the • migrating fish moves up the river near the river bed. The velocity , of the movement of the fish in sections with dif- ferent current velocities was determined. It was.established that the fish are most active in the morning and evening hours. On the basis of observations of the behaviour of the •fish in the vicinity of the hydro-electric dam, practical recommendations are proposed on increasing the effectiveness of the, work of the Saratov fish elevator.
The study of fish behaviour and a . number of problems linked
to this question' (sensory reception, orientation, reaction to changes
in environmental factors) have been assuming greater and greater
:Translator's note: The number in the margin refers to the page number of the original text.'
505-200-I 0-31
7530-21-029-5332 ; $4
significance in recent years. Documented data on the behaviour of
fish in various ecological circumstances can be utilized in solving
many fishing industry problems: the construction of fish passages
and protective installations and the development of effective means
of attracting fish or repelling them off for the management of their
behaviour. The study of the routes and rhythm of movement of separate
individuals and their groups might aid fisheries in the selection
and deployment of fishing gear. Analysis of data on the magnitude of
movement activity, the visiting of various microbiotopes and the
reaction of fish to this or that change in environmental elements will
make it possible to determine the complex of conditions necessary for
• the successful existence of various species. There can be no doubt
also of the theoretical interest in this kind of research. With
their help comparative data can be derived on the methods and prin-
cipleâ of the orientation of animals in various environmental conditions,
on territorial groupings, their structure and so on.
Serving as material for this paper were the remote observations
of the behaviour of sturgeons in the region of the . Saratov Hydro-
electric Station (city of Balakovo), conducted in September, 1966
and August/September 1969 by the biotelemetric group of the Ichthyology
Laboratory of the Institute of the Biology.of Internal Waters, the • .
Academy of Sciences of the USSR. ••.,
MATERIALS AND METHODS
In the present study a method of remote observation was
employed which had been proven in previous telemetric studies (pod-
dubnyi, Spektor, Kidun, 1966).
The fish were tagged with ultrasonic transmitters weighing
not more than 30 g, and operating in the frequency range of 40-50
khz. Their range of operation was 2 km, and the duration of operation,
50-60 h.
The apparatus used Consisted of three units: display, ampli-
fication, and a trainable antenna, the receiving head of which was
lowered into the water to not less than 0.5 m, The display and ampli-
fication units were installed in launches from which the tracking was -
conducted. The receiving antenna was secured to the bow of the vessel
with aid of a swivelling device, enabling the training of the head /p.848
to any angle. The operator determined the relative bearing and
distance of the tagged fish and immediately fixed.the position of the fish
on a chart. As the fish moved the launches equipped with the receiving •
apparatus followed at a distance of 100-200 m. Atthe same time, •
Wherever the fish moved, the Parameters of the water -mass at various
depths were measured with the aid of a hydrokappameter developed for
this purpose.
Translator's note: Transliteration of the Russian term.
3 • 4 • 1
Number of tagged fish and time of observation
Area of observation Dates Number Duration Route of of fish h fish, km
M F
1. R. Volg,a in the region of the ,city of -i3alakovo 1-2.1X.1969 * 2-18 1-15 t! 21-30.VI11.1969 5-42 2-15'
2. Waters in vicinity i of Saratov HES dam; tail 23-30.V111.1969 12 4 7-31 1-12 bead 1-5:1X.1969 6 • 3 2-24 0.5-7
3. Saratov reservoir : 2-6.1X.1969 6 : 2 13-35 10-31
4. R. Volga in the region of the city of Perevolok 7-9.1X. 1969 6-29 5-18
Only large individuals (not less than 10 kg in weight) of the
Volga-Ozimov sturgeon were used in the experiments. The weight of
the transmitters used to tag the fish constituted not more than
0.2-0.3% of the weight of the fish body and the drag produced was
low. They were attached to the sturgeons with a strong soft wire
through holes made with a fine drill through two adjacent spinal bony
plates. Pond experiments (Poddubnyi, Spektor, 1969) indicated that,
immediately on release, fish so tagged perform chaotic movements and
behave in an agitated manner. However, a.fter only 15-25 min. their .<
behaviour is indistinguishable from the behaviour of control individuals.
The approach of fish carrying the transmitters to control fish did not
elicit any noticeable reactions in the ln-tter. It can be assumed that
ultrasonic vibrations of the selected frequency and intensity are not,
even if detected by the sturgeon, strong irritants, capable of having
an effect on its navigational capabilities or distorting its rhythm
of ,ectivity. The velocity of movement of the tagged and control
individuals was the same. After 10 days no deteoration could be
observed in the area of the drill holes in the spinal plates.
Post-tagging activity of the fish is very severely affected,
especially in high air temperatures, by prolonged periodà spent out of
the water during tagging. The period of shock and decreased activity
can, in these cases, last several hours. .For this reason, in all the
experiments, fish were kept in the water during tagging. Tagging of
each individual required not more than 1-2 min.
In the region of the Saratov Hydroelectric Station, which was
Under still construction, the first experiments in the study of the
rhythmics and Movement tracks of sturgeons were carried out in 1966,
before the regulation of the river. In 1969 studies of the behaviour
of the sturgeons were conducted at five points: in the section of the
river adjacent to the near-dam zone of the tail water, in the near-dam.
sections of the tail and head wat'er, in th. è Saratov reservoir, and in
the Volga in the region of the city of Perevolok. During the period
of these field observatiOns 58 experiments, 10 in 1966 and 48 in 1969, Ç
6
were carried out (see Table).
RESULTS AND OBSERVATIONS
Behaviour of sturgeons in river areas. The first river section
consisted of a 13 kilometre segment of the Volga river below the
section line of the Saratov 1-TES dam. Ilikaediately beyond the near-dam
zone the river breaks into two arms which flow around an island some
8 km in length. Both arms carry approximately the same volume of water and
have the same current velocity. Prior to the regulation of the river the right channel was used by shipping. The velocity of the
current at that time mas 0.4-0.8 'm/sec. After the erection of the dam
the velocity of the current and the level of the water began to vary
depending on the regime of water discharge through the dam, and ship-
ping now uses the left channel. The daily fluctuations of the water
level during the period of our work did not exceed 0.5 m. Normally
the minimum level occurred at 7-9 AM and the maximum at 6-10 PM. The
velocity of flow throughout the whole length of the arms is approx-
imately the same: at the surface 1.0-1.4 m/sec, near the bottom,
0.7-1.2 m/sec. The daily fluctuations of current velocity are not
high. Instead of a smooth merging of the two arms, a circular current
is formed. The water mass of the lift arm was more polluted in 1969,
and was characterized by a high electroconductivity and a low pH, The /p.849
electroconductivity of the water at the time of our studies in 1969 a 7
,
-3 was 0.15-0.17.10 1/ohm.cm, pH - 7.6 and temperature 19.2-20.6 ° .
- Released here on 1-2 September, 1966 were ten sturgeons
Which had been taken in the tail water of the Volga XXII Congress
of the CPSU dam, and transported to the study area in a Ship with
flow-through'fish tanks.
PlIC. 1. Tpaccbi Remnennsi oceTpoB B panoue r. Baaanona ,no (A) n noc.ie (B) 3aperyanponanun penn 1— nyl h pm 6, — 1t3a6aTbi; 1-111 — m ec ra hilt ycKa
Fig. 1. Tracks of the movement of sturgeons in the region of the city of Balakovo prior to (A) . and after (B) the regulation of the river. ' 1 - route of fish; 2 isobaths; I-III fish release points. 8
After release the sturgeon proceeded downstream for a time, apparently
as a result of a state of shock, but then they all, except for one
individual, began to move actively upstream (Fig. 1, A). Of the
nine sturgeons released 1.0-3.0 km below the island, three fish
ascended up the right arm and five up the left. In the right arm
the sturgeons moved upstream along the mainland bank, while in the
-left arm, where the river bed runs closer to the left
bank, along both slopes of the river bed . One fish
first moved along the slope of the left bank,
but later, under the high tension line, it moved across to the track
on the right bank. Above the island the sturgeons followed a narrow
strip along the right bank, above the 6-10 m isobaths. Individual
velocity of movement at various sections of the route varied from
5-37 m/min which, taking the head current into account, is equal to
50-80 m/min. As indicated in data presented below, the fish was most
active in the morning and evening hours:
Velocities of the movement of the sturgeons in the course of a day
Time of 0-2 2-4 4-6 6-8 8-10 10-12 12-14 14-16 16-18 18-20 20-22 22-24 day, h.
Velociy 10 10 13 27 27 12 11 27 33 28 13 10 m/min 9 r
In 1969 tagged sturgeons were released at the same points as
in 1966. Males averaging 103 cm in length predominated among the
released fish. The average length of the females was 116 cm. After
a short rest seven of the experimental sturgeons moved upstream, and
were followed to the dam of the HES. Of these only one (a male)
passed up the left arm, the remainder followed the right arm (Fig. 1,
B). Of interest is the fact that two of the sturgeons entered the
left channel, but after moving along it'for 1.0 and 3.5 km respectively,
they returned downstream to a distance of over 5 km, at which time one
individual crossed over to the right bank below the island and began
to ascend along the right bank, while the other continued downstream
for 20 km. Substantive differences in the tracks-passing up the right.
arm were not noted, all the sturgeons keeping to the main channel of
the river both during the day and at night. The greatest differences
in the tracks occurred on the approach to the island where eddies are
formed at the confluence of the tWo currents, and'under high tension
lines. The maxiMum velocity of individual fishyaried from 20-200
m/min. The average hourly velocity of six sturgeons in the right arm,
without taking the opposing current into account, was 9.1 m/min, and
in the left arm, 15.4 m/min. Thus, the speed made good by the fish
with respect to the bank was low. In fact, the movement velocities
themselves, taking the head on current into account, were relatively
high: 80-300 m/min, about 100 m/min on the average. 10
The movement velocity of individual fish varies within a wide
range. Normally the sturgeon moves upstream at maximum speed for
20-50 min, after which it decreases speed for 30-60 min and then
sometimes comes to a full stop. Rarely, the fish performs a number
of short sprints which are followed by a prolonged period at rest.
Prier to the regulation of the river the sturgeons moved upstream
along both channels, favouring the left. A totally different picture
was observed in 1969, when, out of seven fish, only one passed up
the left arm. As it has already been noted, the water of this arm
is more polluted, and, after the regulation of the river, it began
to be used heavily by shipping. .As observations have indicated
sturgeons react sharply to passing ships; either altering their
direction of movement or hiding on the bottom. It is likely that
these two factors served as the reasons for the changes in the move-
ment tracks of the fish. The relative velocity of movement of the
• fish in 1969 was 1 times less than 1966, while the actual velocity
(taking the current into account) was significantly greater, a fact
which is related to the increase in the velocity of the current after
regulation.
•The second river section in the region of the city of Perevolok
contains many islands, situated on both sides of the river channel of
the Volga, which lies along the right mainland bank, then flows around
a number of small islands, and returns again to the right bank. The 11
current velocity at the surface rarely exceeds 0.8-1.0 m/sec. The
electroconductivity of the water here is nearly the same as in the first
river section, while the température of the wa:ter is significantly
lower (17-17.7° ).
The . release of tagged fish. was carried out 1.0-2.0 km below
a group of islands, were the main flow separates from the right bank
.(Fig. 2).. Three males moved downstream immediately after release.
The velocity of movement downstream of these fish was considerably
higher than the velocity of the current. After five hours one
sturgeon ceased his downstream movement and began to move up the
river channel. Having moved 2 km upstream, it turned Sharply and
once more moved downstream. A female, released 1.0 km below the
islands, rested for several hours then slowly moved up the channel, /p.851
. and after 4.5 h, having moved 3.8 hm, itturned into a passage
between two islands where it stayed for 1.5 h. After this it moved
up to the very bank of one of the small islands, from where, after
period.of 2 h, it began to move downstream. Another two individuals
released in this section, following a 2-3 h ascent ; also moved down-
stream. Thus, all six of the individuals released moved downstream.
At first we believed that the movement downstream occurred as a result.
of fatigue or injury resulting from their transportation from the • .
vicinity of the city of Balakovo; where they were caught. But after - 12
.
...... "Lz------ ------ C==>
eve f
Fig, 2. Movement tracks of sturgeons in the region of the city of Perevolok. 1 - route of the fish; 2— main channel of the river.
Fig. 3. Movements of the sturgeons in the near-dam zone of the tail water duang the day (A) and at night (B). 1 - route of the fish; 2 - isobaths. ,
1
a number of experiments in the region of the Kuibyshev Hydroelectric /p.852
Station, where the sturgeon were similarly slow moving, it became
clear that their movement downstream and decreased activity were 0 related to the temperature of the water, which was found to be 4-5 lower
he-re than in the vicinity of the Saratov HES. Observations were
carried out of wintering sturgeons which, in the fall, having attained
favorable places for wintering, cease their ascent until the spring
of the next year. The signal factor for the cessation of migration
is the temperature of the water. •
Behaviour of sturgeons in the near-dam zone of the tail water.
Observations of tagged sturgeons in the near-dam zone were carried
out during construction work on the dam and in the first year of the
operation of the fish elevator. The most complex bottom relief occurs
immediately below the dam. Many sections occur in which the river
bed level falls 1.5-3 m. The greatest depth (13-15 m) coincides with
the central part of near-dam zone. The simplest bottom relief occurs
in the section below the rock fill dam, where the river bed of the
Volga was located originally. Here the depth does not exceed 10-12 m.
At the time of these telemetric studies the dishcarge of
water was being carried out through the assemblies situated in the
left side of the dam. The direction and velocity of the flows during
this period, through the right side of the dam, where the fish elevator
is situated, did not depend on the working regime of the hydroelectric 14 station; but they varied strongly below the working assemblies. The highest current velocity here was recorded during the day (1.5-1.7 m/sec at the surface and 1.2-1.4 m/sec near the bottom).
Opposite the rock fill dam, at the location of the former bed of the river, a zone of circulating'current had been formed which had a velocity of up to 0.4-0.5 m/sec. The attractive current from the fish elevator, on the opening of its gates by 1.0-1.5 m, had an exit velocity of 0.54-0.71 m/sec near the bottom and 0.9 m/sec at the surface and could be traced for a distance of over 100 m. The param- -3 eters of the water mass (electroconductivity - 0.14-0.16.10 1/ohm.cm , pH 7 .3-7. 8 and temperature of the water - 19.8-20.2° ) . were homogen- eous throughout the entire mass of water.
Two groups of fish were studied in the near-dam zone of the tail water (Fig. 3): seven which had ascended to the dam from the down- stream end of the island and.ninè which were released in the near-dam zone. As was noted eatlier, of the seven fish which had arrived from downstream, six had passed up the right arm. Without decreasing their speed, and passing around the current from the HES • o the left, they . rapidly reached the.dam in the region of the fish elevator, where they began their first attempts to find the passage into the head water.
The time of the approach of the fish to the dam depended mainly on the. tiMe of their release. The sturgeon which had moved up the left arm to the vicinity of the dam, and two other individuals released from 15
the left bank, moved to the dam obliquely against the current. They
crossed the near-dam zone at an angle of 45-600 to the direction of
the main flow from the HES and also arrived in the vicinity of the
fish elevator.
All the individuals, both those which come up from downstream
and those released in the near-dam zone, displayed the greatest
movement activity in the first day. They performed frequent sprints
to the dam. After regular unsuccessful attempts to pass upward, the
current would carry the fish downstream to a distance of 100-300 m,
from where they would again move upstream (Fig. 4). On the second
day of their stay in the near-dam zone the number of attempts to pass
.upstream decreased significantly. On the third-fourth day the stur-
geons would leave the zone of the fish elevator for the former river
bed of the Volga below the rock fill dam.
Comparing the day and night movementtracks of the sturgeons
(Fig. 3) it can be noted that at night, the fish enters the left bank
part of the near-dam zone more frequently. This probably is related
to the decrease there of the velocity of the current with the decrease
in the work of the HES. Some of the individuals, after a number of
unsuccessful attempts to find the passage into the head water in the
right bank zone also moved to the central or left bank area of the
near-dam zone where the current is of significant velocity, in daytime.
Here they approached the dam with repeated sprints but would be ip.853
immediately carried downstream by the current. After some time these individuals would again appear in the right bank area of the near-
dam zone. Of the sixteen sturgeons under observation in the near-
dam zone, ten were to be found in the vicinity of the fish elevator
for a prolonged period of time,'while four fish entered the area
lelow the rock fill dam, which was located just beyond the fish
elevator. From here the fish, in the course of regular attempts to
pass upwards along the boundary of the current flowing from the HES,
invariably fell back into the section adjacent to the fish elevator.
Undoubtedly, it should be considered fortunate that the attractive
current from the fish .elevator shares a baundary with the main cur-
rent, the velocity of which is such that the fish attempts to pass
'around it and, following the boundary of the current, finds itself
in the right bank portion of the near-dam zone, where . the fish
eleVator is located. Nonetheless, none of the sixteen fish under
observation entered it, despite the fact that the majOrity of the
individuals passed literally . within several metres of the entrance.
At the time of the observations in the vicinity of the fish elevator,
construction and assembly work was being carried out, generating many
noises. Undoubtedly, this, to some extent, affected the behaviour of
the tagged sturgeons. A repelling influence, apparently, was also
• exerted by the sharp change in illumination at the entrance to the
fish elevator, especially on sunny days, when the high concrete walls
of the flume made for dark shadows in its interior. • . , 17
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o› • 0 FL- (-C 0 J_D Ti cr) 75 - Q.) el Q) zo 50 -
'Fig. 4. Changes in the movement velocity of Sturgeons in the river (1) and in the mear-dam zone of the tail water (2).
Behaviour of stur:eons in the near-dam zone of the head water.
The area of the head water is bounded on the right by the main bank,
and on the left, by the dike of the outer harbour. The width of the
reservoir at this point is 2.3-4.0 km. The greatest depths (27-30 m)
. occur in the main channel and in separate depressions opposite to the
dam of the HES. The direction of flow and the pattern of velocities
here is quite complex and is determined in the main by the relief of
the bottom and the magnitude of discharge of water into the tail
water.' Besides this, the surface current depends to a great extent
upon the wind. The main flow of water moves along the 'former river
bed with a velocity of 0.15-0.30 m/sec. The temperature of the water
during the study period was 19.3-19.6 ° . Electroconductivity and pH 18
were the same as in the near-dam zone of the tail water.
In the head water nine sturgeons were under observation, four
having been released from the fish elevatOr, and five fish, at various
points of the near-dam zone (Fig. 5). The attachment of the trans-
mitters to the fish in the chamber of the fish elevator was carried
out on completion of sluicing, while in other places, the tagging of
the fish was carried out right on board the ship, in the live fish
tank. Three sturgeons, existing •from the fish elevator, immediately
headed upstream, moved around the rock fill dam and came out below
the right bank. One sturgeon from the fish elevator turned to the
dam of the HES where it stayed for more than 40 h, until the charge
of the transmitter was depleted. Of the five fish released from the
ship, four fish moved upstream, and one descended to.the dam. The
tracks of the fish proceeding upstream can be conditionally separated
into-three variants. Three individuals passed along.the right bank Ip.854
close to the river channel part of the reservoir, following the 10-15 m
isobath (1st. variant). Two sturgeons tracked upstream parallel to
•the river bed, but along its left bank slope (2nd; variant). At a .
_distance of 3.5-4. -0 km from the dam, these fish turned to the river
bed and passed along it some distance further. The other two individuals,
• after 5-7 hours of confused and slow movements in the vicinity of • .
left bank dike, slowly passed upstream and at a-distance of 5 km from
the dam also turned into the river bed (3rd. variant). 19
Fig. 5. Movements of the sturgeons in the near-dam zone of the head water. I-III - main variants of the movement tracks of the fish; 1 - route of the fish; 2 - isobaths.
Thus, significant divergence of the tracks is to be observed only in the immediate vicinity of the dam. The highest movement velo- cities were observed for the sturgeons on the track of the 1st. variant.
Their average velocity consisted of 18 m/min (not allowing for the head current). The fish, moving along the track of the 2nd, variant, had a movement velocity of 11.2 m/min, and along the 3rd, variant track, 5,7 m/min, In the near-dam zone the females were less active, the duration of resting without movement being almost 1 times longer than for the males (on the average - 1.5 and 2.8 h). No differences were noted in the daytime and nightime tracks of the sturgeons.
The results of the. studies indicated that the sturgeons exiting from the fish elevator relatively easily and rapidly reach the river . bed part of the reservoir where their main 'movement tracks were located prior to the regulation of the river. The routes of the fish released 20
in the left bank zone of the near-dam area-turned out to be consid- erably more complex, while the speed of their movement upstream was much lower, which is to be explained by their complex orientational situation.
Behaviour of sturgeon in the Saratov reservoir. In the reser- voir, the studies were carried out in a section 20 km in length, adjacent to the near-dam zone of the head water. The width of the reservoir here is 5-6 km in places. The river bed is .situated under the right mainland bank. The depth over the river bed is up to 30 m, and over the flood lands, not more than 20 m. Along the river channel there is a constant current of Up to 0.3-0.4 m/sec velocity. The figures for temperature, electroconductivity and pH do not differ significantly from those of the near-dam zone. The electroconductivity of the water in the river channel is higher than that of the water over the flood lands. A temperature layer occurs at a depth of 13-15 m.
Observations were carried out of sturgeons which had ascended from the near-dam zone, and of two individuals which had been released
4 km above the dam. As has already been noted, all the sturgeons
.existing from the near-dam zone moved to the river channel. Their
further movement took place only in the river bed portion of the reservoir.
The velocity of movement varied from 15 tà 35 m/min, and was 20.1 m/min •
on the average. • 21
DISCUSSION OF RESULTS
The parental stock of the sturgeons, in the majority of cases when moving up the river, find themselves in current velocities of 0.7-0.9 m/sec. In the face of this, their cruising speeds are maintained for periods of 20-50 min, after which the movement of fish noticeably decreases. On encountering currents of higher . velocity the sturgeons do not move directly upstream, but usually cross the flow at an angle of 45-60. 0 .
In the reservoir, where the velocity of the current is relatively low, the fish avoid slow-flowing sections. Their cruising speed here is maintained for periods of up to 2 or 3 h. Undoubtedly, this is due to the influence of the velocity of the flow: at lower velocities of flow a lower energy expenditure is required to move against it. Where the current flow is high (over 1.0 m/sec) the sturgeons frequently stop to rest, and move up the river in long sprints, while in the reservoir, where the current velocity is rarely over 0.4 m/sec, the movement of the fish is more even and without prolonged stops. Only in sections with a complex bottom relief and complex or weak current do the fish decrease their speed of movement for a prolonged time.
Where there is a gradual increase in the velocity of current flow the relative velocity of the fish decreases somewhat. A decrease in the velocity of the fish, and sometimes its direction as well, was
Me, elicited by sharp alterations in the direction of the flow or on the
presence of eddy currents. Finding themselves in an area of eddies
or circulatory flow, the sturgeons sprint in various directions to
find the right direction. On existing such an area the fish moves
to the river, bed and sharply increases its speed.
Both in the river and in the reservoir the movement tracks
of the sturgeons are surprisingly uniform and lie only along the
river channel of the body of water. Departures from the main channel
were observed only in areas where there were various disorienting or
repelling factors: artificially induced electromagnetic fields, complex
currents or their total absence and so on. All this indicates that
in stable flow conditions, one of the main and the most reliable
orienting influences is the. bottom relief.
Comparison of the behaviour of the fish in various ecological
circumstances enables the assuffiption that in the navigating complex
of the sturgeon there are two methods of orientation: by bottom relief and by current. These factors of the environment are utilized also by other anadromous species: the sockeye and chinook salmon (Johnson,
1960), as well as the non-anadromous fish: bream, zander, burbot and pike (Malinin, 1970; Poddubnyi, 1970). The average daily movement velocity of the sturgeons is not high. For the region of the Saratov
HES it consisted of 0.54 (river Volga) and 1.2 km/h (Saratov reservoir), that is in one day the sturgeon will move, on the average, 13-29 km.
In the region of volgograd the daily average upstream movement of the parental stock is somewhat higher - 24-36 km/day (Poddubnyi, 1971). 23 .•
The activity of the fish is not the same during the course
of a daY. A series of'curves are presented in Fig. 6' which shows
the changes of hourly average speeds of fish movement (not taking
head currents into account) in various sections of the river and
the reservoir in a 24-hour period. It is impossible not to note that
this characteristic is specific for the various areas where the
studies were carried out. The first curve reflects the daily vari-
. ations of hourly average movement speeds Of sturgeons, which had
approached the dam from the downstream end of the island on 23-27 -
August, 1969. As was noted above, six individuals followed similar
tracks along the right arm. Ali the sturgeons displayed a heightened /p.856
activity during the morning (4-7 AM), midday (11 AM to 1 PM) and
evening (7-9 PM) hours. A thmall increase in the speed of movement
occurred at night (12 PM-2 AM). During the 'course of a 24-hour period
the discharge of water and, it follows, the velocity of the current
.changed insignificantly; usually at night, from 11 PM to 6-7 AM, the
velocity of the current decreased somewhat. In the study area the
decrease in the discharge of water is not immediately reflected in
the flow velocity but rather after a period of 1.0-2.0 h. The
night increase of the movement velocity of the fish occurs exactly
at the time of the decrease in the velocitY of the current flow. In
the region of the city of Perevolok the movement activity of the
sturgeon has an entirely different . pattern (2nd. curve). Here"a •
sharp decrease in the movement velocity at night is seen. Undoubtedly,
to some extent, the activity of these fish is affected by their • te. • * 24
movement downstream. On the other hand., the arrival of discharge
wave from the upstream Kuibyshev HES which results in an increase
in the current velocity, is delayed by almost a day and a half,
and the time of approach of this wave coincides the increase of the movement activity.r- 30F •
9 n rtr 1 Ln - L. r{1• le =1 {P --- Lr r- e -ru ,1 1 , a s 12 IS 18 21 Z« -0 E a 4-r I tï 0 1 1 1 1 1 e 3 6 " 12 15 21 24( 2g z :0 tn f
g 3 8 9 /5 18 21 ze Time of day, h
Fig. 6. Average hourly movement speeds'of sturgeons in the course of the day (for explanation see text).
The 3rd. curve shows the changes of the movement speed of
sixteen sturgeons in the near-dam zone of the tail water. It is notice,
able that the speeds of movement here are somewhat lower than those
which were observed in the first section of the river and less variable
during the course of the day. The morning and evening activity peaks
are not expressed as clearly. It is likely that the forced cessation
of migratory movement distorts the rhythm of activity. Besides this,
it is necessary to take into account that the speeds of flow in the 25
channels of the right and left arms vary insignificantly ( 10.2 m/sec),
while in the near-dam zone the range of changes of the current velocity
reaches i0.5-0•6 m/sec. This, naturally, distorts the trend of the
curves of movement activity. In the head water a similar picture is
seen (4th curve). In the first place here, in all liklihood, a com-
plex orientation situation exerts itself: a decreased current velocity
and a complex-bottom relief. Entering the river channel the fish
increases speed of movement sharply, and the rhythm of its movement
activity resembles that of the first river section (5th curve).
On the whole, in sections where orientation conditions are
straightforward, the tracks of migrating sturgeons are typical of the
daily rhythms of movement activity of the majority fish of the tem-
perate latitudes. In localdties however, which have sharn variations
in the combination of environmental factors utilized by the fish for
its navigational purposes, this typical picture suffers substantive
changes. To the causal factors of these changes, linked in the fish
with loss orientation, fright or physical impossibility of continuing
the movement, first place should be ascribed, on the basis of the
.studies carried out, to changes in the direction and velocity of
current flow and the relief of the river bottom.
The approach of the sturgeons to the near-dam zone of the
Saratov HES takes place mainly in the right arme Proceeding from this,
the location of the Saratov fish elevator can be regarded as fortunate, ;,d • e' 26
since the main mass of fish, following the boundary of the current
from the HES, falls relatively easily into the section adjacent to
the fish elevator, which increases the probability of its entry into
the latter. However, here no account is taken of the orientation of
sturgeons by bottom landmarks. As the telemetric observations have
indicated, the migrating sturgeon quite clearly selects the river
,bed sections, following their edges. For this reason, undoubtedly,
the construction of a bottom directing dike would increase the pos-
sibility of the entry of the fish into the fish elevator. The
sturgeons found in the area of the fish elevator may be repelled by
the sharp alteration in illumination at its entrance..
In connection with differences in flow, the optimum velocity
of the current for a migrating sturgeon in the various . parts of the
body of water is not the same. For this reason, in selecting the most
effective velocity for the attractive stream of a fish elevator due
account should be taken not only of the peculiarities of the reaction
' of the sturgeon to the current, but also of the hydraulics of the whole
region adjacent to the fish elevator.
. LITERATURE /13:857
1. MALININ L.K., 1970. Employment of ultrasonic transmitters for . and pike in the Rybinsk reservoir. Information Bulletin tagging bream of the Institute of the Biology of Internal Waters, the Academy of Sciences of the USSR, 7: 49-54.
2. PODDUBNYI A.G., 1971. Ecological topography of the populations of fish in reservoirs. 1-312, Publishing house "Nauka", Moscow-Leningrad.
M 27
3. PODDUBNYI A.G., SPEKTOR Yu. I., 1967. Study of the migrational behaviour of sturgeon in the vicinity of dams by the biotelemetric me thod. Collected articles "Questions of Bionics", 596, Publishing house "Nauka", Moscow.
4. PODDUBNYI A.G., SPEKTOR Yu. I., KINDUN S.M., 1966. Results of the first experiments in tracking sturgeon carrying electronic tags. Questions of icthyology, 6, 4(41): 725-735.
5. . JOHSON J.H., 1960. Sonic tracking of 'adult Salmon at Bonneville Dam, 1957. Fish. Bull, U.S., 60, 2: 471-484.