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The main aim of our experiments was to study the influence of colored light on juveniles of Carassius carassius, Perccottus glenii and Poecilia reticulata. The species of fish used for studies differ in their biotopes and feeding behavior. The results of experiments demonstrated that different species of fish can have different response to light quality. Thus crucian carp developed better by green light, rotan-by blue and green, guppy - by blue light. By red light the growth rate in all species decreased. The response in different species of fish to the light environment appears to be governed by changes in energy metabolism and hormone disproportionation.
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Influence of colored light on growth rate of juveniles of fish
A.B. Ruchin
Department of Biology, Mordovian State University, Bolshevistskaya str. 68, 430000, Saransk, Russia
(Phone: +7-8342-322637 Fax: +7-8342-324554; E-mail:
Accepted: January 24, 2005
Key words: colored light, growth rate, juveniles of fish
The main aim of our experiments was to study the influence of colored light on juveniles of Carassius
carassius, Perccottus glenii and Poecilia reticulata. The species of fish used for studies differ in their biotopes
and feeding behavior. The results of experiments demonstrated that different species of fish can have
different response to light quality. Thus crucian carp developed better by green light, rotan-by blue and
green, guppy - by blue light. By red light the growth rate in all species decreased. The response in different
species of fish to the light environment appears to be governed by changes in energy metabolism and
hormone disproportionation.
Spectral composition is a main characteristic of
light. In water light rays of different wavelength
pass to different depths depending on light
absorption and diffusion as well as on avail-
ability of admixtures and small organisms in a
water body. Most species of fish have
well-developed color sight, and are therefore
very sensi tive to colored light . For instant, the
survival rate of haddock larvae (Mellanogram-
mus aeglefinus L.) is higher with blu e and green
light (Downing 2002). The growth rate of silver
carp larvae (Hypophthalmichthys molitrix Val.)
and young carp (Cyprinus carpio L.) increased
with green light (Radenko and Alimov 1991;
Ruchin et al. 2002). Gaignon and co-workers
(Gaignon et al. 1993) revealed a negative effect
of yellow light on Na
-ATPase activity in
Atlantic salmon Salmo salar L. However, no
difference was detected in the growth rate of
Altantic salmon and haddock treated with col-
ored light (Stefansson, Hansen, 1989; Downing,
Materials and methods
During this study juveniles of three fish species were
maintained under different light conditions in 20 1
aquariums with water temperature (21±1°C), aer-
ation (oxygen content 7.0–7.5 mg/l) and flowage
(2 l/h). We studied species with biological and eco-
logical differences: (i) Crucian carps (Carassius
carassius L) living in benthonic layers of lentic
ponds, and mainly feeding on benthonic organism
(Olygochaeta, Chinomedae larvae etc.); (ii) rotans
(Perccottus glenii Dybowsky) living in middl e layers
of lentic ponds among thickets of water vegetation,
feeding omnivorously mainly on planktonic
organisms (Anostraca, Copepoda, Phyllopoda) and
perifiton (Gas-tropoda, Hemiptera, Coleoptera lar-
vae), as well as any other moving objects, juveniles
and amphibian larvae (Baklanov 2001); (iii) guppies
(Poecilia reticulata Peters) living in upper layers
of water bodies and eat feeding on organisms
(Insecta) which fall in the water and plankton
(Copepoda, Phyllopoda).
In our in vivo experiments we used juveniles
of crucian carp and rotan with an initial weight of
Fish Physiology and Biochemistry (2004) 30: 175–178 Ó Springer 2005
DOI 10.1007/s10695-005-1263-4
0.7–3 g and 0.065–1.0 g, respectively. They were
caught in a bottomo land pond. Guppy fry with an
initial weigh t of 12–50 mg were obtained from one
female fish for each series of experiments. In all cases
fish were acclimated to laboratory conditions for
15 days. We used luminescent lamps LB (Lisma
Ltd., Russia), and their spectrum was taken as the
control. During the experiment we scattered light
with the help of standard glass (Figure 1). In the
figure one can see that 80–85% of the light falls in a
narrow zone of spectrum; this zone is a symbol for
glass. Light intensity measured on water surface
after the passing of light through color filter was
100 lx in all modes. In our experiments light fell at a
vertical angle. In this case only 2% of light reflects
independently of wave length (Yavorsky and Detlaff
1981). After passing into water depths light was
absorbed and diffused, resulting in the reduction of
light intensity depending on spectral structure.
Taking into account reflection, absorption and
scattering, light intensity on the bottoms of experi-
mental aquariums was: under control lamp
(lamp LB) ) 63.2 lx; by red light ) 66.8 lx; by
yellow ) 64.0 lx; by green ) 62.7 lx; by blue
) 58.3 lx. Due to the small depths of the aquariums
the decrease of light intensity was insignificant and
therefore we can claim that differences in the data we
obtained may be explained by spectral structure but
not by light intensity.
To study the effect of colored light on juveniles,
15–20 fishes were taken arbitrarily from four initial
groups. Every initial group included 150–200 fishes
of identical weight. Chosen fish were placed into
special aquariums. We carried out concurrent
experiments in two aquariums. In every set
experiments were replicated four times for fish
from four initial groups. At the beginning and at
the end of the experiment fishes were weighted to
within of 1 mg. Fish were fed with live feed
(Tubifex tubifex, Olygochaeta: Annelida) before
saturation 3 times daily.
Specific growth rates (SGR) in weight were
then calculated (Ricker 1979). Data were analyzed
by one-way ANOVA and t-test (P < 0.05). Data
are expressed as mean (SE) (Lakin 1990).
Results and discussion
During the study in the aquarium no death was
registered. It was revealed that the optimum mode
for cultivating juveniles of species is the shortwave
light mode (blue and/or green light). The response
of fish species to colored light was different
(Figure 2). For instant, with green light the growth
rate in crucian carp increased 42% compared to
the control group (P < 0.05). The growth rate was
slightly lower with yellow light. No pronounced
difference in growth was noticed with green and
yellow light, while with red light the growth rate
decreased 33 % compared to the control group.
As with crucian carp the maximal growth rate
in rotan occurred in both green and blue light
(Figure 2). On average, growth rate exceeded the
control by 21–23% with red and yellow light the
growth rate decreased 9% and 21% respectively,
and therefore is the effect of yellow light is more
negative. Blue spectral rays were optimum for the
cultivation of guppies, but with red light their
growth rate decreased 10%. There was no pro-
nounced difference in the growth rate of guppies
with green and blue light.
Thus the results of our studies demonstrate that
there are differences in response to different colored
zones in different species of fish. Some species such
as carp, crucian carp and silver carp grow well with
blue and green light (Radenko and Alimov 1991;
Ruchin et al. 2002 our data), the growth rate of
other species (guppy, whitefish) increases with blue
light (Radenko and Terent’ev 1998, our data), the
third (rotan) grow equally well with both green and
blue light. In spite of biological and ecological
differences, the study species have an almost iden-
tical response to colored light: i.e., they grow better
with blue-green light. However, there-are some
Figure 1. Light passing ratio of white luminescent lamp (LW-40)
and light filters, which were used for experiments.
exceptions. For instance, the growth rate in some
species (Atlantic salmon, haddock) is independent
of light wavelength (Stefanson and Hansen 1998;
Downing 2002).
What is the mechanism by which colored light
effects growth rate? The main role in this process is
played by the eyes and pineal organ, because only
they can detect colors (Levin and McNicol 1982;
Ekstrom and Meissl 1997). For instance, crucian
carps are able to detect colors at an early stage of
development. However, it is more difficult to dis-
tinguish blue and green colors than green and red,
i.e. if colors are more contrasting their detection is
more effective. Some authors (Rajaserkharan and
Chowdiah 1972; Reddy and Kote 1975) reported
that adult gambusias Gambusia affinis (Baird et
Gir.) eat mosquito larvae because they are golden
against a red and black background. In our
experiments it was noticed that carp juveniles eat
food more actively with green light than with red.
Proceeding from these facts the increase in growth
rate of some species may be explained by their
ability to detect colored feed and therefore their
increasing consumption.
However, the daily ratio of other fish is inde-
pendent of monochromatic light (Ruchin 2004). So
the results of our study may be explained by changes
in energy metabolism, hormone disproportionation
or by other biochemical an d physiological changes.
Detailed studies on influence of colored light are
lacking and at present we only have a hypothesis.
For instance, a negative effect of yellow light on
ATPases activity in Atlantic has been revealed
(Gaigon et al. 1993). In experiments with nile tilapia
it has been shown that after stress plasma cortisol
level was lower in fish treated with blue light than
that seen in fish treated with normal light (Volpatto
and Barreto 2001), i.e. blue light plays the role of an
antistress agent. As little work has been carried out
on the influence of spectrum on physiological
parameters of fish, we cannot draw any specific
conclusions and further studies in the given area are
This work was supported by the Grants from the
President of Russia (grant MK-1066.2003.04).
Baklanov, M.A. 2001. Perccottus glenii Dyb. in water bodies in
Perm. Vestnik of Udmurtian University. Biology 5: 29–41(in
Figure 2. Average growth rate in juveniles under different wavelengths of incident light. * are marked authenticity of differences at
P < 0.05. Bars represent standard error (±SE) as means.
Downing, G. 2002. Impact of spectral composition on larval
haddock, Melanogrammus aeglefinus L., growth and sur-
vival. Aquacult. Intern. 33: 251–259.
Ekstrom, P. and Meissl, H. 1997. The pineal organ of teleost
fishes. Rev. Fish Biol. Fisheries 7: 199–284.
Gaingnon, I.L., Quemener, L. and Roux, A. 1993. Effects de la
diminution de la photoperiode sur la smoltification precoce
obtenue en environnement controle shez le saumon atlan-
tique (Salmo salar). Bull. francais de la peche et de la
piscicultur 66: 307–315.
Lakin, G.F. 1990. Biometry. Vysshaya shkola, Moscow (in
Levin, J. and McNicol, E. 1982. Color vision in fishes. Sci. Am.
246: 108–117.
Mecke, E. 1983. Absence of changes in colour discrimination
ability of goldfish when reared in monochromatic light. Ann.
Zool. Fenn. 20: 239–244 .
Radenko, V.N. and Alimov, I.A. 1991. The meaning of
temperature and light for the growth and survival of silver
carp Hipophthalmichthys molitrix larvae. Voprosy Ichthyo-
logii 34: 655–663 (in Russian).
Radenko, V.N. and Terent’ev, P.V. 1988. Effects of the different
regimen of the light on the effectiveness the rearing of the
Coregonus peled larvae. In: Biology of co-regonid fishes. pp.
216–225. Nauka, Moscow. (in Russian).
Rajaserkharan, P.T. and Chowdiah, B.N. 1972. Selective
feeding behaviour of Gambusia affinis. Oecologia 11: 79–
Reddy, R. and Kote, G. 1975. Predatory behavior of Gambusia
affinis in relation to different light colors. Physiol. Behav. 14:
Ricker W.E. 1979. In: Fish Physiology. Vol. III, pp. 677–743.
Edited by Randall D.J., Hoar W.S., Brett J.R. Academic
Press, New York.
Ruchin, A.B. 2004. The effect of light regime on feeding
intensity and growth rate in fishes. Hydrobiologichesky
Zhurn. (Kiev). 40: 48–52 (in Russian).
Ruchin, A.B., Vechkanov, V.S. and Kuznetsov, V.A. 2002.
Growth and feeding intensity of young carp Cyprinus carpio
under different constant and variable monochromatic illu-
minations. J. Ichthyol. 42: 191–199.
Stefansson, S.O. and Hansen, T. 1989. The effect of spectral
composition on growth and smoking in atlantic salmon
(Salmo salar) and subsequent growth in sea cages. Aqua-
culture 82: 155–162.
Volpato, G.L. and Barreto, R.E. 2001. Environmental blue
light prevents stress in the nile tilapia. Brazil J. Med. Biol.
Res. 34: 1041–1045.
Yavorsky, G.M. and Detlaff, A.A. 1981. Guide on physics.
Nauka, Moscow (in Russian).
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Des régimes artificiels de photopériode et de température permettent d'obtenir une smoltification précoce (dès l'automne), déphasée par rapport aux conditions naturelles prévalant lors du transfert en mer. On étudie ici l'effet de brusques diminutions de la photopériode associées au changement de spectre lumineux. En régime de photopériode et lumière artificielle (fournie par une ampoule à incandescence), après une augmentation de la photopériode sur 80 jours (soit le 18 août, J200 après la première prise d'aliment), un premier passage direct en situation de lumière naturelle en photopériode décroissante a été réalisé ; deux autres ont été effectués 11 jours et 35 jours plus tard. Afin de dissocier l'effet de la photopériode de celui du spectre lumineux, des lots de poissons ont été maintenus, d'une part, sous lumière du jour artificielle ("true lite") et régime de photopériode artificielle et, d'autre part, après transfert en photopériode naturelle décroissante, sous lumière jaune. On conclut que le type de spectre de lumière artificielle n'a pas d'effet sur la croissance, mais en a sur la smoltification ; qu'une diminution de la photophase à la suite d'une courte augmentation de photopériode telle que nous l'avons pratiquée ne permet pas, contrairement à une photophase constante, l'augmentation de la (Na+-K+)-ATPase.
Groups of Atlantic salmon (Salmo salar) parr were reared under indoor light sources of different spectral composition. A control group was reared under outdoor light conditions. Growth rate was not significantly different among the indoor groups, whereas the outdoor group had a significantly lower growth rate.All groups developed the external appearance and experienced the reduced condition factor and increased salinity tolerance normally associated with the parr-smolt transformation. Fish from all groups were successfully acclimated to seawater in early May. The subsequent 6-month growth period in seawater did not reveal any differences in growth potential of fish from the different experimental groups. It was concluded that the parr-smolt transformation was completed under light sources of different spectral composition.
Discusses the evolution and function of photoreceptor cells in the retina of teleost (bony) fishes. Since violet and blue light are the colors most strongly absorbed by water, and green or yellow-green light becomes most dominant with depth, the rod and cone cells in each species of fish must adapt according to the depth at which the fish lives. Their rod cells are specially adapted for low-intensity illumination while the cone cells are associated with color vision and their better adaptation to bright light. Some saltwater fishes that live near the surface have 2 cone pigments, 1 to absorb green light and 1 to absorb blue light. The green light is absorbed when the fish looks upward while the blue light is absorbed when the fish looks downward. The broadest range of visual pigments is found in fish that live near the surface where the light is bright. Some species that are nocturnal or that live in the deep sea seldom encounter enough light to stimulate cone cells at all and so have no color vision. It is hypothesized that color vision, the ability to distinguish light on the basis of wavelength as well as intensity, evolved some time after 2-pigment visual systems were established. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Fish lengths have been measured in many different ways. The differences arise from choosing different reference points near the anterior end and near the posterior end of the fish, and from using different methods of making the measurement. Methods of making the measurement include using calipers; using a tape held along the curve of the body; laying the fish on a measuring board with the front end pressed against an upright piece; laying the fish on a board with a movable cross hair above it, attached to an indicator running along a scale. In theory, any combination of reference points and methods might be used, but practice is considerably more restricted. Some of the commoner combinations have special names; these are provided in the chapter, together with the reference points used. In addition to these methodological differences, length varies with the condition of the fish—for example, whether it is alive, recently killed, after rigor mortis has set in, or at different intervals of time after preservation in formalin or alcohol.
In a small-scale culture experiment, larval haddock, Melanogrammus aeglefinus L., were raised under various combinations of light quality [blue (470 nm), green (530 nm) or full-spectrum white light] and light intensity [low (0.3–0.4 µmol s−1 m−2) or high (1.7–1.9 µmol s−1 m−2)], and in total darkness (both fed, and starved). Larval growth (0.9% day−1 in standard length; 2.4% day−1 in body area) was not significantly different between any combination of coloured light. At the time of total mortality in the starved treatment, survival was significantly reduced under low intensity, full-spectrum white light (13%) vs. all other coloured light treatments (68%). Larvae raised under both continuous dark treatments (fed and starved) exhibited morphological changes associated with irreversible starvation (point-of-no-return). Lack of a pronounced effect of light quality on larval haddock growth probably results from a combination of plasticity in early larval vision, and enhanced encounter rates between larvae and prey at the relatively high prey densities used in aquaculture.
The pineal organ of teleost fish is a directly photosensory organ that contains photoreceptor cells similar to those of the retina. It conveys photoperiod information to the brain via neural pathways and by release of indoleamines, primarily melatonin, into the circulation. The photoreceptor cells respond to changes in ambient illumination with a gradual modulation of neurotransmission to second-order neurons that innervate various brain centres, and by modulation of indoleamine synthesis. Melatonin is produced rhythmically, and melatonin synthesis may be regulated either directly by ambient photoperiod, or by an endogenous circadian oscillator that is entrained by the photoperiod. During natural conditions, melatonin is produced at highest levels during the night. Although the pineal organ undoubtedly influences a variety of physiological parameters, as assessed by experimental removal of the pineal organ and/or administration of exogenous indoleamines, its role in any physiological situation is not clear cut. The effects of any interference with pineal functions appear to vary with the time of year and experimental photothermal regimes. There are strong indications that the pineal organ is one component in a central neural system that constitutes the photoperiod-responding system of the animal, i.e. the system that is responsible for correct timing of daily and seasonal physiological rhythms. It is important to envisage the pineal organ as a part of this system; it interacts with other photosensory structures (the retina, possibly extraretinal non-pineal photoreceptors) and circadian rhythm generators
The effects of different monochromatic light colors (wavelengths) on the feeding pattern and predatory efficiency of Gambusia affinis have been studied. Maximum predation of mosquito larvae by the fish is observed under red illumination (680 mμ). The different light colors do not alter the feeding pattern of the fish but markedly influence the predatory efficiency of the fish.