Effects of light wavelength on growth and survival rate in juvenile Pacific bluefin tuna, Thunnus orientalis

The spectral sensitivity of the fish and the suitable light wavelength range for survival and growth performance of juvenile Pacific bluefin tuna (PBT) were investigated. The spectral sensitivity peak of PBT under photopic condition was observed between 449 and 503 nm, which corresponded to their natural habitat. The fish were reared in tanks irradiated continuously with 4 kinds of light emitting diodes (LEDs). The maximum wavelength of LEDs used for the rearing experiment were 460 nm (blue), 520 nm (green), 630 nm (red), and 450–680 nm (white). There was no notable difference in survival rate among fish in the four LED groups. However, the growth of juvenile PBT was lesser under red light compared to the green and white light wavelengths. These results suggest that PBT juveniles have low sensitivity to red light because the fish are rarely exposed to the red light wavelengths under natural ocean conditions. Thus, low sensitivity to red light negatively influenced the feeding behavior and growth of PBT juveniles.     

Snapper rest where they see best: visually mediated choice behaviour of Australasian snapper (Chrysophrys auratus)

The sensory physiology and behaviour of many fish species are strongly affected by light. This short study demonstrates that in the Australasian snapper (Chrysophrys auratus) absolute light intensity governs visual acuity and also guides preference behaviour, with fish choosing to ‘rest where they see best’. Use of the optomotor response to test visual acuity at four light intensities (0.01, 0.05, 1 and 3 μmol s^?1 m²), showed that visual acuity (measured as directional bias) was best at a light intensity of 0.05 μmol s^?1 m² (84.9% directional bias), but weakened at the highest and lowest light intensity (41.1 and 35.3%). When provided with a choice of the same four light environments fish also spent most time in the 0.05 μmol s^?1 m² light environment, while the highest and lowest intensity light environments were usually avoided. Acclimated light intensity (that is daytime light intensity of the home aquarium) was also 0.05 μmol s^?1 m²_. By selecting an environment where visual function is optimised, C. auratus are also optimising the ability to search for prey and to detect predators. The results are discussed with reference to habitat utilisation and thoughts for trawl fishing practices.     

不同波长光照对草履虫增殖的影响及其感光蛋白基因克隆的初步探究

目的研究不同波长光照对草履虫增殖的影响,克隆草履虫感光蛋白基因.方法以双小核草履虫 Paramecium aureli为研究对象,分别置于黄色光(578～592 nm)、蓝色光(446～464 nm)、红色光(620～760 nm)、白光和自然光下,每隔1 h随机抽样法显微观察并计数;RT-PCR克隆草履虫感光蛋白基因.结果不同波长光的照射下,与自然光比较,第1天黄光组草履虫增殖显著上升(P<0.01),蓝光组和红光组草履虫增殖受到不同程度的抑制(P<0.01, P<0.05),白光组无明显差异(P>0.05);第2天,蓝光组、红光组和白光组草履虫增殖仍受到抑制(P<0.01),黄光组作用不显著(P>0.05).黄光组和白光组草履虫总RNA作为模板,克隆出大小约500 bp的rhodopsin-like基因cDNA片段, 5个不同光照组均克隆出大小约195 bp的Long wave sensitive opsin-like 基因cDNA片段.结论黄色光显著地促进草履虫增殖,蓝色光和红色光抑制其增殖;黄光和白光能诱导草履虫rhodopsin-like基因表达;Long wave sensitive opsin-like 基因在草履虫有表达.     

Effects of various LED light spectra on circadian rhythm during starvation in the olive flounder (Paralichthys olivaceus)

In aquaculture, feeding is essential for the maintenance of metabolic processes and homoeostasis of fish. However, fasting acts as a stressor. In this study, we investigated the effect of circadian rhythm under various LED wavelengths [blue (460 nm), green (520 nm) and red (630 nm)] and two light intensities (0.3 and 0.6 W m^?2) over a 9-days period in the olive flounder (Paralichthys olivaceus). We analysed clock genes like period 2 (Per 2) and cryptochrome 1 (Cry 1), and serotonin and arylalkylamine-N-acetyltransferase 2 (AANAT 2), which control circadian rhythms. Per 2, Cry 1, serotonin and AANAT 2 were significantly decreased during the starvation period compared to the normal feeding group. Nevertheless, their levels increased in the groups exposed to green- and blue LED light during the experimental period. These results confirmed that green and blue wavelengths are effective in maintaining the circadian rhythm in olive flounder.     

Effects of environmental colour on growth of Nile tilapia, Oreochromis niloticus (Linnaeus, 1758), maintained individually or in groups

Examined was the influence of different colours of light on the growth of adult Nile tilapia (Oreochromis niloticus) held either individually (initial size 12.8 ± 1.1 cm; 62.9 ± 15.6 g) or in groups (initial size 7.8 ± 0.8 cm; 17.2 ± 6.4 g). Various colours (blue 434.5 nm, violet 430.0 nm, red 609.7 nm, green 525.2 nm and yellow 545.2 nm) did not affect weight gain of fish held individually (initial to final weights: blue 62.5 ± 18.4 to 72.9 ± 16.0 g, violet 63.5 ± 17.8 to 78.0 ± 19.1 g, green 62.1 ± 13.0 to 72.9 ± 15.7 g, and yellow 60.4 ± 20.4 to 71.0 ± 21.1 g); red seemed to restrict growth (initial to final weights: 65.8 ± 13.3 to 71.8 ± 10.8 g). Final weight differences were observed among individuals in groups maintained under blue, violet, red and green light (smaller and larger fish: blue 13.2 ± 5.0 and 18.9 ± 7.0 g, violet 17.3 ± 5.2 and 23.8 ± 4.7 g, red 14.7 ± 3.3 and 23.9 ± 4.7 g, and green 19.4 ± 7.8 and 28.6 ± 8.1 g); however, under the yellow light there were no differences in final weights (smaller fish 19.1 ± 4.8 g; larger fish 26.2 ± 5.2 g). Under the red light, heterogeneity in growth was observed earlier than with the other colours. It is therefore suggested that the red colour might have some harmful effects on Nile tilapia growth, limiting weight gain when fish are individually maintained, and with weight differences increasing when fish are held in groups. On the other hand, the yellow light seems to be positive for Nile tilapia, as it appears not to affect individually‐held fish, but reduces variation in growth of group‐maintained fish, promoting growth homogeneity.     

Variation in response to artificial selection for light sensitivity in guppies (Poecilia reticulata)

We performed artificial selection on the visual system in guppies (Poecilia reticulata), using the optomotor reaction threshold as the selection criterion. Two lines were selected for increased sensitivity to blue light, two were selected for increased sensitivity to red light, and two were unselected controls. There was significant response to selection in all four selected lines and significant heritability for sensitivity. An examination of the spectral sensitivity function showed that the form of the response differed between the red and blue lines and among the red lines. Such divergence is likely because there are many different mechanisms allowing response to selection for spectral sensitivity. Diverse mechanisms allow a divergent response by different populations to the same selective pressures. Such a mechanism can promote diversity in vision and visual signals, and any multicomponent system where different components can respond to the same selective regime.     

Soybean (Glycine max L. Merr.) Sprouts Germinated under Red Light Irradiation Induce Disease Resistance against Bacterial Rotting Disease

Specific wavelengths of light can exert various physiological changes in plants, including effects on responses to disease incidence. To determine whether specific light wavelength had effects on rotting disease caused by Pseudomonas putida 229, soybean sprouts were germinated under a narrow range of wavelengths from light emitting diodes (LEDs), including red (650–660), far red (720–730) and blue (440–450 nm) or broad range of wavelength from daylight fluorescence bulbs. The controls were composed of soybean sprouts germinated in darkness. After germination under different conditions for 5 days, the soybean sprouts were inoculated with P. putida 229 and the disease incidence was observed for 5 days. The sprouts exposed to red light showed increased resistance against P. putida 229 relative to those grown under other conditions. Soybean sprouts germinated under red light accumulated high levels of salicylic acid (SA) accompanied with up-regulation of the biosynthetic gene ICS and the pathogenesis- related (PR) gene PR-1, indicating that the resistance was induced by the action of SA via de novo synthesis of SA in the soybean sprouts by red light irradiation. Taken together, these data suggest that only the narrow range of red light can induce disease resistance in soybean sprouts, regulated by the SA-dependent pathway via the de novo synthesis of SA and up-regulation of PR genes.     

Studies of fluorescence inDrosophila compound eyes: changes induced by intense light and vitamin A deprivation

Summary Ultraviolet light excites a red fluorescence fromDrosophila R1–6 rhabdomeres which is superimposed on a blue background emission. Metarhodopsin (M570) pigment generates some or all of the vitamin A dependent red emission. However, the excitation spectrum for red emission peaks in the UV. This suggests that the pigment which sensitizes R1–6's visual pigment to UV light (sensitizing pigment) absorbs the UV light, sensitizing metarhodopsin's fluorescence by energy transfer. Blue emission is neither from sensitizing pigment nor from visual pigment as shown by vitamin A deprivation studies.Very intense UV or blue stimulation causes these changes: (1) conversion of visual pigment into a fluorescent product; (2) destruction of this fluorescent product; (3) a decrease in the blue background fluorescence (even in vitamin A deprived flies); and (4) a permanent destruction of visual pigment and retinal degeneration. The first effect requires intensities 3 log units brighter than needed to interconvert rhodopsin and metarhodopsin 1/2 way to photoequilibrium. UV light is about 5 times as effective as blue light for the conversion of visual pigment into fluorescent product.     

Biochemical, histological and behavioural aspects of visual function during early development of rainbow trout

Retinal structure and concentration of retinoids involved in phototransduction changed during early development of rainbow trout Oncorhynchus mykiss , correlating with improvements in visual function. A test chamber was used to evaluate the presence of optokinetic or optomotor responses and to assess the functionality of the integrated cellular, physiological and biochemical components of the visual system. The results indicated that in rainbow trout optomotor responses start at 10 days post‐hatch, and demonstrated for the first time that increases in acuity, sensitivity to low light as well as in motion detection abilities occur from this stage until exogenous feeding starts. The structure of retinal cells such as cone ellipsoids increased in length as photopic visual acuity improved, and rod densities increased concurrently with improvements in scotopic thresholds (2·2 log₁₀ units). An increase in the concentrations of the chromophore all‐trans‐retinal correlated with improvements of all behavioural measures of visual function during the same developmental phase.     

The eye of the blue acara (Aequidens pulcher, Cichlidae) grows to compensate for defocus due to chromatic aberration

By rearing fish in various monochromatic illuminations we investigated (1) the potential for compensation of refractive error due to chromatic aberration, (2) the contributions of the chromatic channels to emmetropization, and (3) the role of color cues in the control of eye growth. Cichlid fish (Aequidens pulcher) were reared for 6 months (12 h light/12 h dark) in monochromatic lights (623.5, 534.1, 485.0 nm; spectral purity 5–10 nm). Light levels were isoirradiant at 1.1·10¹² quanta/s/cm². Two control groups were reared in white light with down-welling illuminances of 0.2 and 33 lx. Nasotemporal diameters (NTDs) of the eyes were measured in relation to lens size. Due to the oblique axis of highest acuity vision in cichlids, NTD is considered to be a more important dimension than axial length. Variances in NTD were equally small in all rearing groups. NTDs were enlarged with increasing wavelengths of the rearing lights with highly significant values over controls in the red-light group. The wavelength-dependent size of the eyes matched the changes in focal length due to longitudinal chromatic aberration. Complete recovery from eye enlargement was observed after fish reared in red light were exposed to a white light regime for 5 weeks. Small variances in NTD in all groups indicated stringent control of eye growth in the absence of color cues. The reversibility of the increase in NTD in fish reared in red light suggests that the eyes were emmetropized by visually guided mechanisms. Eye size in fish reared in white light was intermediate between the values expected if only blue-sensitive single or the red- and green-sensitive double cones contributed to the control of eye growth. This suggests that all chromatic channels participate in emmetropizing the fish eye.     

Diel cycles inHoplosternum littorale (Teleostei): entrainment of feeding activity by low intensity colored light

Synopsis Low intensity colored light is very often used to observe or manipulate fish during the scotophase. According to data on fish vision, most species can perceive these wavelengths of light since their cone pigments have maximum absorption peaks around 455, 530 and 625 nm. To test whetherHoplosternum littorale can detect low intensity red or blue light, we attempted to entrain feeding activity, known to be nocturnal and synchronized by the circadian light/dark alternation, to such light. Feeding activity was entrained with either red or blue light, indicating that these fish can perceive these lights. In all cases, the fish fed during the darker phase of the light cycle.     

Lighting environment predicts the relative abundance of male colour morphs in bluefin killifish (Lucania goodei) populations

Animal communication occurs when an animal emits a signal, the signal is transmitted through the environment, and then detected by the receiver. The environment in which signalling occurs should govern the efficacy of this process. In this study, I examine the relationship of lighting environment (light transmission and tree cover), location and the relative abundances of male colour morphs across seven drainages and 30 populations in the bluefin killifish, Lucania goodei. I found that males with blue anal fins were more common in populations with low transmission of ultraviolet (UV) and blue wavelengths. By contrast, males with red anal fins (and to a lesser extent, males with yellow anal fins) were more common in populations with high transmission of UV and blue wavelengths. High UV-blue light transmission should create a blue visual background and may make blue males less conspicuous and red males more conspicuous to conspecifics. Colour contrast with the visual background may be more important than total brightness of the colour pattern. These results indicate that natural selection for effective intraspecific communication drives the relative abundance of male colour morphs in different lighting habitats.     

不同光质对小球藻光自养培养积累油脂的影响

研究了5种光质对小球藻(Chlorella vulgaris)M209256生长和产油的影响。结果表明:蓝光为小球藻的最适生长和产油光质;与其他光质相比,蓝光培养的小球藻生物量和油脂含量均较高,为2.40×107个/mL和28%;红光培养的小球藻生长最慢且油脂含量最低,为1.32×107个/mL和15.13%,表现出明显的"红降"现象。在GCMS分析的基础上,对油脂甲酯化后的十六烷值进行评估,结果发现:蓝光的十六烷值最高;5种光质培养的小球藻所产油脂,甲酯十六烷值均在47以上。因此,小球藻油脂所制备的生物柴油具有较好的燃烧性能。     

The effect of strenuous exercise and beta-adrenergic blockade on the visual performance of juvenile rainbow trout,Oncorhynchus mykiss

It is hypothesised that the visual performance of rainbow trout, Oncorhynchus mykiss, will be impaired by strenuous exercise as a result of metabolic stress (blood lactacidosis) that activates the Root effect and limits the oxygen-carrying capacity of blood flowing to the eye. The ability to resolve high contrast objects on a moving background, as a measure of visual performance, was quantified pre- and post-exercise using the optomotor response. Strenuous exercise induced a metabolic acidosis (8.0 mmol l(-1) blood lactate) and a significant red cell swelling response but no change in the optomotor response threshold (120 min of arc) was observed. Beta-adrenergic blockade (propranolol) abolished post-exercise red cell swelling but optomotor response thresholds were still maintained at 120 min of arc despite a significant blood lactate load (7.8 mmol l(-1)). The choroid rete mirabile of the trout is extremely well developed (rete area:eye area = 0.39) and may maintain visual performance by ensuring a relatively direct supply of oxygen to the central regions of the avascular retina. Exercised fish under beta-adrenergic blockade exhibited an enhanced optomotor response at 240-300 min of arc. Assuming that these responses reflect "tunnel vision", adrenergic regulation of red cell function may preserve a high ocular PO(2) gradient that satisfies the oxygen demand of peripheral retinal cells.     

Influence of light colours on growth and stress response of pearl gourami <Emphasis Type="Italic">Trichopodus leerii</Emphasis> under laboratory conditions

This study aimed to investigate the influence of illumination with different light spectra on growth and stress response in pearl gourami Trichopodus leerii Bleeker, 1852. Fish (6.35 ± 0.43 cm, 5.69 ± 0.67 g) were reared in 8 glass aquaria each with 25 fish under one of four different lighting conditions: yellow (max 546 nm), red (max 605 nm), blue (max 470 nm) and white (control). Experiments lasted for 90 days. The stress response was evaluated by measuring cortisol levels. No significant effect was observed on final body weight, length and specific growth rate of fish. However, best values for these characteristics were achieved for fish reared under yellow light. A significant higher weight gain, condition factor was found in fish reared under yellow light compared with fish reared under blue or red light. In contrast, a lower final body weight, specific growth rate and weight gain were achieved for fish reared under red light. Feed conversion ratio was significantly lower in fish under yellow light compared with red or blue light. Stressed fish showed lower cortisol levels under yellow light compared with other light exposures. The study indicates that, pearl gourami grows better under yellow light and that yellow light lowers the stress-induced cortisol response.     

Green light stimulates somatic growth in the barfin flounder Verasper moseri

We examined the effects of different light wavelengths-blue, green, and red-on the somatic growth of the barfin flounder Verasper moseri, a flatfish. The light sources used were fluorescent lamps and a combination of daylight and fluorescent lamps that produced ambient light. These light sources were filtered using blue, green, or red filters. During the experiments, the fish were reared in indoor tanks with running seawater of natural temperature and fed with commercial pellets twice daily until satiety. The tanks were white in color. Fish were exposed to constant light emitted from the fluorescent lamps (9:15, light:dark; 08:00-17:00, light) for 14 weeks from October or September to January or to ambient light with a 14-week natural photoperiod from September to December. The wavelengths that were filtered from the fluorescent lamp light modified the growth of the fish, i.e., fish reared under green or blue light exhibited a greater total length (TL; P<0.01) and body weight (BW; P<0.01) than those reared under red light. In contrast, in the case of fish exposed to filtered ambient light, fish reared under green light exhibited a greater TL (P<0.01) and BW (P<0.01) than fish exposed to other wavelengths-blue-, red-, and nonfiltered ambient light. Our results indicate that flounder growth was modified by certain wavelengths, namely, green and red light, which had growth-stimulating and growth-inhibiting effects, respectively.     

VISUAL ACUITY AND ILLUMINATION IN DIFFERENT SPECTRAL REGIONS

The relation between visual acuity and illumination was measured in red and blue light, using a broken circle or C and a grating as test objects. The red light data fall on single continuous curves representing pure cone vision. The blue light data fall on two distinct curves with a transition at about 0.03 photons. Values below this intensity represent pure rod vision. Those immediately above represent the cooperative activity of rods and cones, and yield higher visual acuities than either. Pure cone vision in this intensity region is given by central fixation (C test object). All the rest of the values above this transition region represent pure cone vision. In blue light the rod data with the C lie about 1.5 log units lower on the intensity axis (cone scale) than they do in white light, while with the grating they lie about 1.0 log unit lower than in white light. Both the pure rod and cone data with the C test object are precisely described by one form of the stationary state equation. With the grating test object and a non-limiting pupil, the pure rod and cone data are described by another form of the same equation in which the curve is half as steep. The introduction of a small pupil, which limits maximum visual acuity, makes the relation between visual acuity and illumination appear steeper. Determinations of maximum visual acuities under a variety of conditions show that for the grating the pupil has to be larger, the longer the wavelength of the light, in order for the pupil not to be the limiting factor. Similar measurements with the C show that when intensity discrimination at the retina is experimentally made the limiting factor in resolution, visual acuity is improved by conditions designed to increase image contrast. However, intensity discrimination cannot be the limiting factor for the ordinary test object resolution because the conditions designed to improve image contrast do not improve maximum visual acuity, while those which reduce image contrast do not produce proportional reductions of visual acuity.     

Effect of Light Quality on Stomatal Opening in Leaves of Xanthium strumarium L

Flux response curves were determined at 16 wavelengths of light for the conductance for water vapor of the lower epidermis of detached leaves of Xanthium strumarium L. An action spectrum of stomatal opening resulted in which blue light (wavelengths between 430 and 460 nanometers) was nearly ten times more effective than red light (wavelengths between 630 and 680 nanometers) in producing a conductance of 15 centimoles per square meter per second. Stomata responded only slightly to green light. An action spectrum of stomatal responses to red light corresponded to that of CO₂ assimilation; the inhibitors of photosynthetic electron transport, cyanazine (2-chloro-4[1-cyano-1-methylethylamino]-6-ethylamino-s-triazine) and 3-(3,4-dichlorophenyl)-1,1-dimethylurea, eliminated the response to red light. This indicates that light absorption by chlorophyll is the cause of stomatal sensitivity to red light. Determination of flux response curves on leaves in the normal position (upper epidermis facing the light) or in the inverted position (lower epidermis facing the light) led to the conclusion that the photoreceptors for blue as well as for red light are located on or near the surfaces of the leaves; presumably they are in the guard cells themselves.     

Ontogenetic improvement of visual function in the medaka Oryzias latipes based on an optomotor testing system for larval and adult fish

We developed a system for evaluation of visual function in larval and adult fish. Both optomotor (swimming) and optokinetic (eye movement) responses were monitored and recorded using a system of rotating stripes. The system allowed manipulation of factors such as width of the stripes used, rotation speed of the striped drum, and light illuminance levels within both the scotopic and photopic ranges. Precise control of these factors allowed quantitative measurements of visual acuity and motion detection. Using this apparatus, we tested the hypothesis that significant posthatch ontogenetic improvements in visual function occur in the medaka Oryzias latipes, and also that this species shows significant in ovo neuronal development. Significant improvements in the acuity angle alpha (ability to discriminate detail) were observed from approximately 5 degrees at hatch to 1 degree in the oldest adult stages. In addition, we measured a significant improvement in flicker fusion thresholds (motion detection skills) between larval and adult life stages within both the scotopic and photopic ranges of light illuminance. Ranges of flicker fusion thresholds (X±SD) at log I=1.96 (photopic) varied from 37.2±1.6 cycles/s in young adults to 18.6±1.6 cycles/s in young larvae 10 days posthatch. At log I=−2.54 (scotopic), flicker fusion thresholds varied from 5.8±0.7 cycles/s in young adults to 1.7±0.4 cycles/s in young larvae 10 days posthatch. Light sensitivity increased approximately 2.9 log units from early hatched larval stages to adults. The demonstrated ontogenetic improvements in visual function probably enable the fish to explore new resources, thereby enlarging their fundamental niche.Copyright 2002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved .     

Ultraviolet and violet light: attractive orientation cues for the Indian meal moth, Plodia interpunctella

The Indian meal moth (IMM), Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae), engages in long-distance or foraging flights in the twilight hours of the scotophase when blue light dominates the irradiance spectrum of the sky. We tested the hypothesis that IMM uses wavelengths of visible blue/violet light as orientation cues that trigger phototactic responses. In four-choice laboratory experiments, blue light (400–475 nm) was significantly more effective than green (475–600 nm), orange (575–700 nm), or red (590–800 nm) light in attracting males and mated females. In subsequent experiments that tested light emitting diodes (LEDs) emitting peak wavelengths in the blue/violet-light range, the 405-nm 'violet' LED was significantly more effective than the 435-, 450-, or 470-nm 'blue' LED in attracting males as well as virgin and mated females. In electroretinogram recordings, the 405-nm wavelength elicited significantly stronger receptor potentials from female and male eyes than the 350-nm (UV) wavelength, and in a behavioral experiment it significantly enhanced the known attractiveness of UV light. Equal attraction of IMMs to 405-nm LEDs at 600–700 µW/cm² with or without UV light, and significantly stronger attraction to a 405-nm LED than to a 350-nm LED at maximum light intensities, suggest that the deployment of violet instead of UV light could become one of several management tactics for control of IMMs.