Effects Of Tank Colour Research Articles

Effects of tank color on the growth, survival rate, stress response, and skin color of juvenile hybrid catfish (Clarias macrocephalus × Clarias gariepinus)

This study focused on the effects of tank color on the growth, survival rate, stress response, and skin color of juvenile hybrid catfish (Clarias macrocephalus × Clarias gariepinus) reared in tanks of 5 different colors (white, red, green, blue, and black). Experiments were performed in triplicate with a duration of 8 weeks. Growth performance, feed utilization efficiency, survival rates, stress levels (as indicated by hematocrit, blood glucose, and plasma cortisol levels), and skin color parameters were evaluated in this study. Fish reared in red tanks exhibited a significantly higher mean final body weight (FBW) (27.50 ± 0.26 g), greater weight gain (WG) (18.57 ± 0.30 g), and a higher specific growth rate (SGR) (2.08 ± 0.03% per day) than those reared in tanks of other colors (P < 0.05). In addition, fish reared in red tanks had the lowest mean feed conversion ratio (FCR) (1.23 ± 0.05), which was significantly different from those reared in green (1.86 ± 0.10), blue (1.88 ± 0.04), and black (1.88 ± 0.16) tanks (P < 0.05). Fish reared in red (95.55 ± 2.22%) and blue tanks (95.56 ± 4.44%) had higher survival rates (SR) than fish reared in white (93.33 ± 3.85%), green (84.44 ± 5.88%), and black (80.00 ± 3.85%) tanks. The survival rates of fish reared in red and blue tanks were significantly higher than those reared in black tanks (P < 0.05). The stress indicators revealed the highest levels of hematocrit for fish reared in green tanks (41.80 ± 2.26%), followed by those reared in black (37.86 ± 2.19%), blue (37.76 ± 4.24%), red (36.38 ± 2.39%), and white (31.06 ± 4.45%) tanks. Of these, the fish reared in green tanks had a significantly higher mean hematocrit level than those reared in white tanks (P < 0.05). The plasma cortisol levels of fish reared in red tanks (18.73 ± 4.48 nmol/L) were lower than those reared in tanks of other colors. The skin color of fish reared in white tanks was the lightest (grayish–brown and yellowish–white), followed by fish reared in red, green, blue, and black tanks, which had the darkest skin color (black). This study demonstrated that the lightness (L*) of the tank color had an effect on fish skin color (74%). The assessment of growth performance, feed utilization efficiency, survival rate, stress responses, and skin color indicated that red is the most appropriate tank color for rearing hybrid catfish.

Effect of tank colour on growth, survival, stress level, digestive enzymatic activities and body composition of snubnose pompano ( Trachinotus blochii Lacépède) larvae

Snubnose pompano (Trachinotus blochii, Lacépède) is a commercially important fish species that shows robust growth in captive environment. Tank colour is an important factor affecting the growth of fish larvae in aquaculture. Although the effect of tank colour has been studied in several fish species, it has not been studied in the snubnose pompano. We aimed to investigate how tank colour affects overall growth, survival, body composition, stress levels and digestive enzyme activities of snubnose pompano larvae at early larval stage and late larval stage. We noted that early–larval–stage larvae showed higher growth, crude protein contents and lower digestive enzyme activities when reared in blue and white tanks. Larvae showed low-stress levels when reared in grey and blue tanks. The same larvae showed low-survival and high-stress levels when reared in red tanks. The late–larval–stage larvae showed high growth and lipids, and low-digestive enzymes activities in white and yellow tanks. The larvae showed high-stress levels and low-ash contents when reared in red tanks. These differences are most likely due to the differences in light intensity inside tanks, which affects the ability of larvae to find and catch prey. Overall, our study sheds new light on cultivation conditions for snubnose pompano larvae. We recommend blue tanks for growing early–larval–stage larvae and white or yellow tanks for late-larval-stage larvae.

Insights into first feeding of newly-hatched paralarvae of the merobenthic octopus, Octopus tetricus

The commercial aquaculture of merobenthic octopus species is constrained by the inability to raise large numbers of paralarvae through their planktonic phase from hatching to juvenile. Knowledge on the early feeding behaviour and nutrition requirements of octopus paralarvae is critical for addressing this challenge. This study evaluates the food seizure behaviour of Octopus tetricus paralarvae at age 0–5 dph (days post-hatch) under different experimental conditions including, egg incubation method, tank colour, and live prey versus formulated food pellets. The percentage of paralarvae that attacked food items and the percentage of paralarvae that had at least one successful seizure at the age 0–5 dph were measured in relation to the experimental conditions. The number of attacks and successful seizures of food items by paralarvae was not affected by the egg incubation method, i.e., maternal grooming versus artificial incubator tank. A higher percentage of paralarvae performed attacks in black tanks (70 ± 8%) compared to grey tanks (44 ± 6%) with no differences to white tanks (58 ± 7%) when Artemia nauplii were supplied. However, no differences in the proportion of paralarvae with successful seizures were found among the three tested tank colours. A higher percentage of paralarvae attacked formulated food pellets (69 ± 6%) compared to Artemia nauplii (44 ± 6%) in grey tanks. An overall trend was observed of O. tetricus paralarvae having lower successful seizures at 0 dph that increased until 2 to 3 dph followed by a steep and continuously decline in success through until 5 dph. On average 31 ± 3% of paralarvae had at least one successful seizure of formulated food pellets in the first 5 min after the pellets were supplied compared to 4 ± 1% in the subsequent 10 min. In contrast, feeding on Artemia nauplii remained steady over the full 15 min experimental period. The results indicate that the effect of tank colour on feeding behaviour warrants further investigation as it affects the ability of the paralarvae to detect and attack potential food items. Moreover, the results demonstrate that artificial egg incubation did not have a negative effect on the feeding behaviour of paralarvae, and that formulated food pellets have the potential to be developed as an alternative to live prey for the culture of paralarvae of this species.

Effects of Tank Colour on Body Colour Intensity and Growth of Yellow Gourami Trichopodus trichopterus

Yellow gourami (Trichopodus trichopterus) is a species native to Southeast Asia and is famous as ornamental species. However, hobbyists and farmers encounter problems where its body colour easily becomes faded in captivity. Since colour enhancer pellets are expensive, an experiment was performed to determine whether tank colour can influence the body colour intensity and growth of T. trichopterus. Four different tank colours (white, yellow, blue and green) with five replicates were tested where fish were kept under natural lighting (outdoor) conditions for two months. The results demonstrated that fish reared in green coloured tank showed an increment in its colour intensity while fish reared in white tanks increased its body weight. It can be concluded that tank colour does affect the body colour intensity and weight of T. trichopterus. This study will help farmers and hobbyists to solve colour fading problem using a cheaper way.

Effect of tank colour on foraging capacity, growth and survival of milkfish (Chanos chanos) larvae

Larviculture of milkfish (Chanos chanos) associated with issues like larval deformity, mass mortalities which contribute in variable seed production. Effect of abiotic factors as rearing tank colour and illumination on larvae foraging behaviour, prey localization and ingestion were investigated to improvise milkfish larval rearing system. Reinforced Cement Concrete (RCC) tanks (capacity, 8 t; water salinity, 32 ppt) with three different background colors, white, blue and yellow were divided in five (05) treatment groups with triplicates, i.e. indoor white (T1/C), blue (T2), yellow (T3) color tanks with artificial illumination and semi outdoor blue (T4), yellow (T5) color tanks with solar illumination. Newly hatched milkfish larvae (tl., 3.4 mm) were stocked in the experimental tanks @ 2.5 no l−1 and apart from background colour and source of illumination uniform water quality and feeding regime were maintained in all treatments. Phytoplankton, Chlorella salina @ 103–104 cells ml−1 were maintained from 2 dph to 20 dph; Chlorella grown rotifers, Brachionus plicatilis (enriched with Nannochloropsis oculata paste) were provided @ 20–30 no ml−1 from 3 dph to 14 dph depending on the larval density. Artemia nauplii @ 0.5–1.0 no ml−1 was introduced from 15 dph. At the end of the experiment- 20 dph, highest (p < 0.05) larval survival (45 ± 5.63%) was achieved in tanks providing yellow background colour (T5) compared to control and other treatments. Larval growth (tl., 17.1 ± 1.37 mm) was also found to be highest (p < 0.05) in T5. Increased survival and growth of milkfish in T5 was synchronized with significantly higher (p < 0.05) specific growth rate (SGR), larval gut content relative to other treatments. Milkfish larvae being a day feeder did maximum foraging during 0700 h to 1600 h evident from decreeing prey abundance during that period and as a result positive correlation found between larval standard length and gut content. Larval visibility enhancement in solar illuminated yellow tank act synergistically to perform necessary foraging to acquire nutritional energy for metamorphosis to fry. Above phenomenon may not have occurred in other treatments except T5 and partially in T3. Solar illuminated yellow colour tanks significantly contribute towards mass scale seed production of milkfish.

The effect of tank colour on growth performance, stress response and carapace colour of juvenile swimming crab Portunus trituberculatus

Aquaculture ResearchVolume 50, Issue 9 p. 2735-2742 SHORT COMMUNICATION The effect of tank colour on growth performance, stress response and carapace colour of juvenile swimming crab Portunus trituberculatus Jiechi Wang, Jiechi Wang Key Laboratory of Applied Marine Biotechnology, Ningbo University, Chinese Ministry of Education, Ningbo, China Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture, Ningbo, ChinaSearch for more papers by this authorKewen Peng, Kewen Peng Key Laboratory of Applied Marine Biotechnology, Ningbo University, Chinese Ministry of Education, Ningbo, China Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture, Ningbo, ChinaSearch for more papers by this authorHuanda Lu, Huanda Lu Ningo Institute of Technology, Zhejiang Uninversity, Ningbo, ChinaSearch for more papers by this authorRonghua Li, Ronghua Li Key Laboratory of Applied Marine Biotechnology, Ningbo University, Chinese Ministry of Education, Ningbo, China Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture, Ningbo, ChinaSearch for more papers by this authorWeiwei Song, Weiwei Song Key Laboratory of Applied Marine Biotechnology, Ningbo University, Chinese Ministry of Education, Ningbo, China Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture, Ningbo, ChinaSearch for more papers by this authorLei Liu, Lei Liu orcid.org/0000-0002-8848-4008 Key Laboratory of Applied Marine Biotechnology, Ningbo University, Chinese Ministry of Education, Ningbo, China Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture, Ningbo, ChinaSearch for more papers by this authorHuan Wang, Huan Wang orcid.org/0000-0003-4256-021X Key Laboratory of Applied Marine Biotechnology, Ningbo University, Chinese Ministry of Education, Ningbo, China Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture, Ningbo, ChinaSearch for more papers by this authorChunlin Wang, Chunlin Wang orcid.org/0000-0002-4624-8381 Key Laboratory of Applied Marine Biotechnology, Ningbo University, Chinese Ministry of Education, Ningbo, China Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture, Ningbo, ChinaSearch for more papers by this authorCe Shi, Corresponding Author Ce Shi shice3210@126.com orcid.org/0000-0003-3274-3944 Key Laboratory of Applied Marine Biotechnology, Ningbo University, Chinese Ministry of Education, Ningbo, China Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture, Ningbo, China Correspondence Ce Shi, Key Laboratory of Applied Marine Biotechnology, Ningbo University, Chinese Ministry of Education, 818 Fenghua Road, Ningbo 315211, China. Email: shice3210@126.comSearch for more papers by this author Jiechi Wang, Jiechi Wang Key Laboratory of Applied Marine Biotechnology, Ningbo University, Chinese Ministry of Education, Ningbo, China Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture, Ningbo, ChinaSearch for more papers by this authorKewen Peng, Kewen Peng Key Laboratory of Applied Marine Biotechnology, Ningbo University, Chinese Ministry of Education, Ningbo, China Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture, Ningbo, ChinaSearch for more papers by this authorHuanda Lu, Huanda Lu Ningo Institute of Technology, Zhejiang Uninversity, Ningbo, ChinaSearch for more papers by this authorRonghua Li, Ronghua Li Key Laboratory of Applied Marine Biotechnology, Ningbo University, Chinese Ministry of Education, Ningbo, China Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture, Ningbo, ChinaSearch for more papers by this authorWeiwei Song, Weiwei Song Key Laboratory of Applied Marine Biotechnology, Ningbo University, Chinese Ministry of Education, Ningbo, China Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture, Ningbo, ChinaSearch for more papers by this authorLei Liu, Lei Liu orcid.org/0000-0002-8848-4008 Key Laboratory of Applied Marine Biotechnology, Ningbo University, Chinese Ministry of Education, Ningbo, China Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture, Ningbo, ChinaSearch for more papers by this authorHuan Wang, Huan Wang orcid.org/0000-0003-4256-021X Key Laboratory of Applied Marine Biotechnology, Ningbo University, Chinese Ministry of Education, Ningbo, China Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture, Ningbo, ChinaSearch for more papers by this authorChunlin Wang, Chunlin Wang orcid.org/0000-0002-4624-8381 Key Laboratory of Applied Marine Biotechnology, Ningbo University, Chinese Ministry of Education, Ningbo, China Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture, Ningbo, ChinaSearch for more papers by this authorCe Shi, Corresponding Author Ce Shi shice3210@126.com orcid.org/0000-0003-3274-3944 Key Laboratory of Applied Marine Biotechnology, Ningbo University, Chinese Ministry of Education, Ningbo, China Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture, Ningbo, China Correspondence Ce Shi, Key Laboratory of Applied Marine Biotechnology, Ningbo University, Chinese Ministry of Education, 818 Fenghua Road, Ningbo 315211, China. Email: shice3210@126.comSearch for more papers by this author First published: 26 June 2019 https://doi.org/10.1111/are.14224Citations: 6 Data Availability Statement: The data used to support the findings of this study are available from the corresponding author upon request. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume50, Issue9September 2019Pages 2735-2742 RelatedInformation

The effect of tank colour on background preference, survival and development of larval swimming crab Portunus trituberculatus

The cultured swimming crab Portunus trituberculatus could be supplied out of season and achieve high-added value, leading to rapid development of P. trituberculatus culture industry. However, little knowledge is known in indoor seeding of swimming crab, creating a gap between seed supplies and farmer's demand. Optimizing background colour is essential for maximizing the larval performance of P. trituberculatus. The purpose of this study is to evaluate the colour preference of swimming crab larvae, and the effect of tank colour on survival, development and oxygen consumption rate from zoea I to megalopa. Tank colours evaluated were red, yellow, black, blue, green and white. A self-referent colour preference device was used to study colour preference of the larvae in 24 h. In the survival and development experiment newly hatched zoea I larvae were stocked into 1.4 L plastic culture tanks at an initial density of 100 individual L−1, fed with Artemia nauplii till they all metamorphosized to juvenile crab. Data indicated that >60% larvae of every stage had a significant preference to white background (P < .01), followed by red, blue and yellow. The larvae disliked green and black background. Surprisingly, in the survival and development experiment, the best larval performance was found in red and yellow tank (43.89 ± 2.22% and 42.30 ± 4.16%), while the larvae in white tank had the lowest final survival rate (19.78 ± 3.28%) (P < .01). The larvae also showed better synchronization in development in red (19.7 ± 1.1 d−1) and yellow (20.5 ± 1.2 d−1) tank than in black (22.1 ± 1.8 d−1), blue (22.6 ± 1.3 d−1), green (24.1 ± 1.7 d−1) and white tank (24.1 ± 1.7 d−1). The larvae cultured in white tank tended to swim on the bottom of the tank and had pale body colour. The larvae of all stages in blue tank had the highest oxygen consumption rate (P < .05), while those cultured in red and white had the lowest oxygen consumption rate (P < .05). The results indicated that the red and yellow are suitable background colour for larval P. trituberculatus, while white background may become a stressor and should be avoided.

Effects of tank color on the growth, stress responses, and skin color of snakeskin gourami (Trichogaster pectoralis)

The effects of tank color on the growth, stress responses, and skin color of snakeskin gourami (Trichogaster pectoralis) were investigated in this study. Fish with initial body weights of 5.03±0.00 g were reared in five experimental tank colors (white, red, green, blue, and black) for 8 weeks. Each tank color was tested in triplicate with an initial stocking density of 15 fish per tank. Fish were fed with commercial sinking pellets at 4% of the average body weight per day. Growth performance, feed utilization efficiency, stress indicators (hematocrit, blood glucose, plasma cortisol levels), and skin color parameters were investigated. The fish reared in blue tanks had a significantly higher average final body weight (9.73 ± 0.14 g) and significantly lower average feed conversion ratio (3.42 ± 0.12) than the fish reared in black tanks (P < 0.05). The fish reared in black tanks exhibited higher average hematocrit (36.63 ± 1.11%), blood glucose (48.33 ± 1.45 mg dL−1), and plasma cortisol (9.00 ± 0.56 μg dL−1) levels than those reared in the other tank colors. However, the blood glucose levels in only the fish reared in black tanks were significantly higher than those in the fish reared in the other tank colors. The fish skin color ranged from very pale (high skin lightness) in the white tanks to very dark (low skin lightness) in the black tanks, and 80% of the variation in skin lightness were explained by the tank lightness. The use of a blue tank resulted in normal skin color; hence, blue tanks will not affect the customer acceptance of the fish. Our study revealed that blue is the most appropriate tank color for culturing snakeskin gourami.

Effects of tank colour on feed intake, specific growth rate, growth efficiency and some physiological parameters of rainbow trout (Oncorhynchus mykiss Walbaum, 1792)

Effects of tank colour on feed intake, specific growth rate, growth efficiency and some physiological parameters of rainbow trout (<i>Oncorhynchus mykiss</i> Walbaum, 1792)

Effects of Tank Color on Growth Performance and Nitrogen Excretion of European Seabass (Dicentrarchus labrax) Juveniles

The present study investigated feed efficiency and growth performance of juvenile Seabass (Dicentrarchus labrax) cultured in tanks with different colors. Triplicate groups of experimental fish were distributed into 12 tanks, which showed four different tank colors, i.e. red, blue, green, and yellow. All the fish in the trial received the same diet for a period of 60 days. Forty fish with an average weight of 44 g were stocked in the tank. All experimental tanks were supplied with seawater of 22 ppt salinity with temperature ranging between 17–20 °C during the course of the experiment. Tank water volume in the experimental facility of the recirculating aquaculture system (RAS) was set to 40 L. The RAS system consisted of bio-filtration, UV filtration and gravel-mechanic filtration units. Results in the present study demonstrated that growth performance and feed utilization were affected by the tank colors tested in the trial. It is concluded that the selection of appropriate tank color might affect economic benefits in aquaculture facilities.

The effects of tank colour, live food enrichment and greenwater on the early onset of jaw malformation in striped trumpeter larvae

A high incidence of jaw malformation has hindered the production of quality striped trumpeter Latris lineata juveniles and has been correlated with walling behaviour in Artemia-fed larvae. In this study, striped trumpeter were reared from first feeding to 29days post-hatching (dph) in different coloured tanks (black or white), culture conditions (clear or greenwater) and fed different diets (enriched or non-enriched rotifers and Artemia), to examine behaviour, retinoid receptor gene expression and jaw malformation. The highest incidence and severity of jaw malformations occurred in clearwater and enriched diet treatments and were significantly more common in white (70±15%, mean±SD) than in black tanks (26±15%). In black tanks, jaw malformation was significantly more common in larvae fed enriched diets (18±14%) than in those fed non-enriched diets (8±8%) and in clearwater (19±14%) versus greenwater (7±6%). At the end of the rotifer feeding phase, larvae were significantly larger in black than white tanks, and longer in greenwater than in clearwater. In the Artemia feeding phase, larval growth was slowest and mortality was highest in non-enriched diet treatments. Larval length and survival were higher in black tanks and in enriched diet treatments, whilst survival was almost twice as high in greenwater (46±18%) than clearwater (26±13%). The average proportion of larvae walling over the duration of the experiment was higher in white than black tanks, and higher in enriched than non-enriched treatments, with lowest walling in greenwater. There was no consistent relationship between feed intake and jaw malformation. However, there was a significant positive correlation between walling and the incidence of jaw malformation at 29dph in larvae fed enriched diets. The expression pattern of three retinoid receptor genes indicated that live feed enrichment and stress could potentially perturb retinoic acid-associated pathways leading to skeletal abnormality. We found that the use of greenwater, black tanks and enriched live feeds is required for good growth, development, survival and final yield of striped trumpeter. The study emphasises the importance of reducing walling in the culture of oceanic larvae and may have direct application in the rearing of other marine fish with similar malformations.

Improved hatchery-rearing techniques for juvenile production of blue swimming crab, Portunus pelagicus (Linnaeus, 1758)

The effects of tank colour, larval stocking density, antibiotic administration and water exchange on survival and moulting of blue swimming crab, Portunus pelagicus, were determined. Circular 4-m3 experimental larval-rearing tanks were used in triplicate for all treatments. White, dark grey, blue and brown were tested as tank background colours. The stocking densities tested were 10, 20, 40, 60, 80 and 100 larvae L �1. The effect of oxytetracycline was estimated by comparing a treatment with oxytetracycline to a treatment without oxytetracycline administration. The daily water exchange rates tested were 0%, 25%, 50% and 100% of the tank volume. In all treatments, the larvae were fed with Artemia nauplii, rotifers and encapsulated Spirulina. The highest percentage survival was observed in the dark-grey tanks when the stocking density of larvae was 20 larvae L �1. No larva reached the juvenile crab size in white tanks. No significant difference in survival was found between treated and non-treated larvae with oxytetracycline when the daily water exchange rate was more than 50%.

Effects of colored light and tank color on growth indices and some physiological parameters of juvenile beluga (Huso huso)

International SturgeonResearch Institute, Guilan, IranSummaryThe influence of colored light and tank color was investigatedon growth performance (body weight, growth rate, carcasscomposition, etc.) and physiological status (blood and plasmaparameters) of beluga (Huso huso) juveniles. The study wasconducted using 64 specimens for colored light treatments withinitial weight 98.83 ± 1.42 (mean ± SE) g which were rearedunder white, red, green and blue light and using 80 specimensfor tank color treatments with initial weight 98.50 ±1.24 (mean ± SE) g which were reared in white, red, green,black and blue tanks, all for 12 weeks. Red light had asignificantly negative impact on beluga growth performance(in contrast with blue light) accompanied with reduced livertotal lipids and plasma albumin and elevated plasma cortisol,glucose, cholesterol and triglyceride (in contrast with the othertreatments). No significant effects of tank color were detectedon growth performance. Nevertheless, most of growth param-eters suggested a positive impact of black tank. Althoughplasma glucose levels in white tank were significantly higherthan the other tank colors, no significant effects of tank colorwere detected for the other physiological parameters. There-fore, based on the obtained results, blue light by establishingcomfort in beluga juveniles spelled increased growth perfor-mance and had positive significant effect on physiologicalconditions. Moreover, taking into consideration the consis-tency of all growth parameters among beluga juveniles rearedin black tanks, it is suggested that considerable results inregard to this treatment may be achieved if the rearing periodprolongs.IntroductionThe living fossil status of the lineage and the unusualmorphologic traits of sturgeons make the research on themscientifically valuable (Gardiner, 1984; Bemis et al., 1997).Caspian Sea is the habitat for the four commercial species ofsturgeon (Khodorevskaya et al., 1997) where their populationsare declining due to overfishing for meat and caviar produc-tion, habitat destruction, and environmental pollution (Billardand Lecointre, 2001). The beluga, Huso huso, is an importantcommercial species in the Caspian Sea and a good candidatefor aquaculture because of their fast growth, market price,propagation in captivity and high marketable value of theircaviar. In order to optimize the cultivation of this species,realizing its behavior and performance in culture conditions issubstantial. Among environmental factors that may influencefish performance in culture are colored light and tank color(Barton, 2002). The effects of colored light on disparate aspectsof fish physiology have been investigated such as growth,survival, neuro-hormonal system, reproduction, behavior andstress response (Head and Malison, 2000; Ruchin, 2001, 2004;Volpato and Barreto, 2001; Bayarri et al., 2002; Naor et al.,2003; Boulcott et al., 2005; Marchesan et al., 2005; Karak-atsouli et al., 2007, 2008). Each of the above studies has beenindicated that various light colors have relieved the physio-logical processes in different species. Hence, it is likely that thisspecies-specific quality relates to consistencies of fish visualstructure with its particular natural habitat traits. The effectsof tank color on different aspects of fish physiology have alsobeen investigated including growth performance, survival, skincolor and stress response (Papoutsoglou et al., 2000, 2005;Tamazouzt et al., 2000; Rotllant et al., 2003; Van der Salmet al., 2004; Jentoft et al., 2006; Strand et al., 2007). Thesestudies have indicated that reactions to tank color may varyaccording to fish species and life stage (Papoutsoglou et al.,2005). While light is easily adjusted in intensive indoor fishcultivation and it is possible to have tanks manufactured inany color, determining suitable light and tank color forfarming beluga is important for optimizing its production andcomfort. The present study aimed to investigate whethercolored light and tank color could affect beluga growthperformance and physiological status (blood and plasmaparameters). For this reason, fish were reared separately underwhite, red, green and blue light and in white, red, green, blackand blue tanks.Materials and methods

Effects of tank colour and feed colour on growth and feed utilization of thinlip mullet (Liza ramada) larvae

The effects of aquarium background colour and feed colour on survival, growth rates and feed utilization efficiency of thinlip mullet (Liza ramada) larvae (0.035 g) were investigated in two experiments. In the aquarium background colour trial, 50 larvae were stocked in duplicates in 120 L glass aquaria filled with dechlorinated tap water. The outside walls and bottoms of each pair of the aquaria were covered with coloured paper sheets to achieve one of six colours (white, black, red, green, yellow and blue), while noncoloured aquaria served as a control. The fish were fed an experimental diet (35% crude protein) at a daily rate of 5% of their body weight (BW), twice a day for 8 weeks. The best growth rates, feed efficiency and survival were achieved in larvae reared in light-coloured aquaria (white, noncoloured and yellow). Fish performance was significantly retarded in larvae reared in dark-coloured aquaria (red, green, black and blue). Body composition was not significantly affected by aquarium colour. In a feed colour trial, duplicate groups of larvae (0.035 g) were stocked at 50 fish per 120 L aquarium and fed a test diet (35% crude protein) with six different colours [dark blue, red, yellow, light brown (control), light green and dark brown] at a daily rate of 5% BW, twice a day for 8 weeks. The best performance and survival were achieved in fish fed on dark-coloured diets (red, dark blue and dark brown). Light-coloured diets (yellow, light green and light brown) resulted in inferior performance. Body composition was not significantly affected by feed colour. These results suggest that light-coloured tanks should be used for rearing thinlip mullet, L. ramada larvae, while dark-coloured diets are more preferable to light-coloured diets.

The Effects of Tank Color and Light Intensity on Growth, Survival, and Stress Tolerance of White Seabass, Atractoscion nobilis, larvae

White seabass, Atractoscion nobilis, are important commercial and sport fish commonly found in Magdalena Bay, Baja California, Mexico to San Francisco Bay, California, USA (Thomas 1968). Adult white seabass inhabit the nearshore zone over rocky bottoms and kelp beds (Young 1973). White seabass can reach a size of 1.5 m and 38 kg (Miller and Lea 1972). Juveniles and young of the year are found in embayments and shallow water along the open coast (Allen and Franklin 1988a, b). White seabass are batch spawners typically spawning from April to August and congregate in rocky reef and kelp bed areas in the nearshore zone at this time (Thomas 1968). Eggs are approximately 1.3 mm in diameter and pelagic. Larvae are pelagic and are typical marine finfish larvae (Moser et al. 1983). Vision is important for feeding in most marine finfish larvae (Hunter 1980; Blaxter 1986). However, the eyes of marine finfish larvae at first feeding do not have illumination adaptation capability (Blaxter and Staines 1970; Neave 1984) and the development of the eye and visual acuity of white seabass, A. nobilis, is specifically known to be poor at first feeding (Margulies 1989). It is important to optimize environmental conditions in larviculture to facilitate feeding behavior (Tamazouzt et al. 2000). Maximization of feeding behavior should result in improved growth and survival (Downing and Litvak 1999b). Visually, this means maximizing contrast between food items and the environment making illumination in the larval rearing environment of primary importance. Illumination within a larval rearing tank can be affected by light source and intensity as well as tank color (Naas et al.

Effects of tank colour and light intensity on feed intake, growth rate and energy expenditure of juvenile Eurasian perch, Perca fluviatilis L.

Eurasian perch (Perca fluviatilis) is receiving increasing attention as a new species in freshwater aquaculture. Understanding perch behaviour and performance in culture is important to optimize the design and management of tanks, and other culture conditions. The objective of this study was to evaluate how different combinations of tank colour and light intensity affect the feed intake, growth and energy expenditure of juvenile perch. Feed intake, growth rate and energetic growth efficiency were measured using groups of perch exposed to different combinations of tank colour (white, grey or black) and light intensity (200 or 1100 lx). Six groups of six perch were exposed to each colour/light combination. The initial average weight (±SD) of the fish over all experimental rounds was 59.6 g (±6.6). Perch in white and grey tanks ate more than the perch in black tanks (P<0.05). Correspondingly, fish growth rates were higher in the white, than in the black tanks (P<0.05). Feed intake was also affected by an interaction between light intensity and tank colour (P<0.05). Feed intake increased from dark to light tanks only under low light conditions. The results indicate that the higher feed intake in lighter tanks was the result of increased feed visibility, probably due to the feed's higher contrast against the background colour of the tank. Energetic growth efficiency did not differ between treatments, indicating that none of the colour/light combinations was more stressful to the fish. It is concluded that both tank colour and light intensity are important factors to consider when optimizing the performance of perch in culture.

Effect of tank colour on Artemia ingestion, growth and survival in cultured early juvenile pot-bellied seahorses ( Hippocampus abdominalis)

The effect of the background (tank) colour on feeding activity, growth and survival of early juvenile seahorses Hippocampus abdominalis was investigated in two experiments. In experiment one, two sets of background colour (Set 1: Clear, white, red, blue, black; Set 2: Clear, white, yellow, orange, green) were used to quantify short-term Artemia ingestion in 42-day-old fish, and 7-day-old fish (Set 1 only). No statistical difference was observed between data. In the second experiment 3-day-old seahorses were cultured over 6 weeks in one of six coloured tanks (clear, white, yellow, red, blue, black) in a temperature and photoperiod controlled recirculation system to determine the effect of the background colour on growth, survival and conditioning to tank colour. At the end of the experiment there were no significant differences between any of the parameters tested. Early juvenile seahorses under the described experimental conditions were able to feed, grow and survive in a similar manner in any of the tank colours tested. Seahorses did not appear to display any conditioning to the tank colour in which they were cultured.

Effects of tank colour and prey density on first feeding of the spotted sand bass Paralabrax maculatofasciatus (Steindachner) larvae

Effects of tank colour and prey density on first feeding of the spotted sand bass Paralabrax maculatofasciatus (Steindachner) larvae

Effects of tank color on melanin-concentrating hormone levels in the brain, pituitary gland, and plasma of the barfin flounder as revealed by a newly developed time-resolved fluoroimmunoassay

A pleuronectiform fish, the barfin flounder Verasper moseri, reared in a white tank had a smaller ratio of pigmented area of the skin on non-eyed side, grew faster, and had greater melanin-concentrating hormone (MCH)-immunoreactive cell bodies and MCH gene expression in the brain than in the black tank, indicating that synthesis and release of MCH are higher in fish from a white tank. In the present study, a time-resolved fluoroimmunoassay for MCH was developed. MCH levels were assessed in the brain, pituitary gland, and plasma of barfin flounders reared in a white or black tank. A competitive assay using two antibodies was performed among secondary antibodies in the solid phase, MCH antibodies, samples, and europium-labeled MCH. Displacement curves of serially diluted extracts (brain, pituitary gland, and plasma) of the barfin flounder paralleled that of the MCH standard. MCH levels in the brain and plasma were higher in fish reared in the white tank for 5 months than in the black tank. These results suggest that synthesis and secretion of MCH are enhanced with the white background and that MCH is involved in both somatic growth and the skin pigmentation in the barfin flounder.

Effects of tank colour on larval survival and development of mud crab Scylla serrata (Forskal)

Hatchery culture of mud crabs has not yet achieved commercial viability despite decades of research efforts. Further research is therefore needed to better understand larval culture requirements of the crab. Based on anecdotal observations, an experiment was carried out to test whether the background colour of the culture vessel affected larval culture success. Newly hatched larvae of Scylla serrata were reared in culture vessels of five colours, i.e., black, dark green, maroon, sky blue and white. Larval survival and development were monitored daily until all of them either moulted to the first crab stage or died. The results showed clear effects of background colour on larval survival. A general tendency of higher larval survival in darker-coloured backgrounds was evident. In particular, overall zoeal survival for larvae reared in black vessels was significantly higher than those reared in white ones. Background colour also appeared to affect larval development. Larvae reared in darker backgrounds generally had shorter development times and more synchronized moulting. A significant delay in zoeal development was observed in larvae reared in white vessels. Dark backgrounds possibly facilitated more efficient feeding, reduced settlement of larvae at the bottom of the vessels as well as minimized stress. This result appears to be the first to demonstrate that background colour can significantly affect larval survival and development of a crustacean species.