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The potential benefits of ripe cultivated banana CV. Kluai Namwa (Musa sapientum Linn.) as a natural feed supplementation in practical diet on growth performance, feed utilization, innate immunity and disease resistance against Streptococcus agalactiae infection in hybrid tilapia (Oreochromis niloticus x O. mossambicus) were evaluated. Fish were fed with the test diet containing different levels of ripe cultivated banana (RCB) supplements (10, 30 and 50 g/kg diet) compared with the negative control and positive control diet for 60 days. Results showed that growth parameters, feed efficiency and lysozyme activity values in the positive control group (vitamins and minerals premix added) were significantly higher than the negative control group (without any premix supplements) but differences among the RCB supplementary diet group and the positive control group were not statistically significant. After challenged with Streptococcus agalactiae, the cumulative mortality of fish in the positive control group was lowest (0%), the percent survivals were 62.22%, 66.67%, 83.33% and 88.89% in the negative control, 10RCB, 30RCB, and 50RCB treatments, respectively. These results showed that the RCB supplementary diets had unaffected on growth performances and could be potential as an immunostimulant to improve fish health for red tilapia aquaculture.

The experimental work focused on 90 days culture of Heteropneustes fossilis in the 1000lit biofloc (T1T9×104, Bifidobacterium sp 176×103, Pseudomonas sp:9.5×103, Vibrio sp:742×103, Nitrifying bacteria:1.8×103. Moreover, water exchange of 20% in T1 & T2 tank and 50% in C tank required in every week.

This research aimed to evaluate the production performance of white shrimp Litopenaeus vannamei with super-intensive culture on different rearing densities. The research was conducted at PT. Dewi Laut Aquaculture, Cikelet, Garut, West Java. As many of 8 ponds were used and divided into 2 groups based on the stock density of shrimp, 550 ind/m2 and 650 ind/m2, and reared for 99 days. The results showed that super-intensive shrimp culture at the density of 550–650 ind/m2 potentially produced shrimp with average body weight ranged from 15.91–19.31 g, survival rate 62.67–87.95%, growth 0.16 to 0.20 g/day, FCR 1.35–1.66, and productivity reach 5.55–9.19 kg/m2. There were no significant differences between the two stocking densities in body weight, growth, and feed conversion performance, while ponds with higher rearing density had better survival and productivity than ponds with lower rearing density. L. vannamei cultured at a density of 650 ind/m2 produces the best performance and most feasible to be applied in super-intensive white shrimp cultivation. Keywords: Litopenaeus vannamei, super-intensive, high-density, production performance ABSTRAK Penelitian ini bertujuan untuk mengevaluasi kinerja produksi udang vaname pada sistem super- intensif dengan padat penebaran berbeda. Penelitian dilaksanakan di tambak PT. Dewi Laut Aquaculture, Cikelet, Garut, Jawa Barat, menggunakan 8 petak tambak. Tambak dibagi menjadi 2 kelompok, masing-masing 4 petak tambak dengan padat tebar udang 550 ekor/m2 dan 4 petak tambak lainnya dengan padat tebar 650 ekor/m2 dengan masa pemeliharaan 99 hari. Hasil penelitian menunjukkan bahwa budidaya udang vaname pada sistem super-intensif dengan padat tebar 550–650 ekor/m2 dapat menghasilkan udang dengan bobot rata-rata berkisar antara 15.91–19.31 g, sintasan 62.67–87.95%, pertumbuhan 0.16–0.20 g/hari, konversi pakan (FCR) 1.35–1.66, dan produktivitas mencapai 5.55–9.19 kg/m2. Tidak ada perbedaan nyata antara kedua padat penebaran pada kinerja bobot, pertumbuhan harian, dan FCR; sementara tambak dengan kepadatan tinggi memiliki nilai sintasan dan produktivitas yang lebih tinggi dari tambak dengan kepadatan rendah. Padat penebaran 650 ekor/m2 menghasilkan kinerja produksi terbaik dan paling layak untuk diaplikasikan dalam budidaya udang vaname super-intensif. Kata kunci : Litopenaeus vannamei, padat tebar tinggi, super-intensif, kinerja produksi

The objective of the present study was to assessment the growth performance and some non-specific immunological effects of growing fish Nile tilapia, Oreochromis niloticus in substrate based biofloc systems. This research was consisted of three types of biofloc systems in which bioflocs were produced by daily supplementation of three different carbon sources, i.e., T1 (only biofloc), T2 (biofloc + bamboo) and T3 (biofloc + nylon mat substrates) using wheat flour as carbon source along with control T4 (without biofloc and substrate) at an estimated C/N ratio of 15 and a control system without any organic carbon addition. Each biofloc system was stocked with 15 fingerlings (4.40 g±0.05) of O. niloticus for growth performance with each group consisted of four replicate aquarium tanks of 70 lit capacity that were reared for a period of 60 days. The present study illustrated the prospects of rearing Nile tilapia, Oreochromis niloticus” in a biofloc-based intensive culture tanks without affecting its survival and growth. It enhanced the fish growth and amplified the non-specific immune response and the antioxidant capability.

Rapid Biofloc® Technology (R-BFT) is a bio-augmentation protocol designed for biofloc. In this study, five production cycles were conducted to investigate the effect of R-BFT on water quality, and the performance of Litopenaeus vannamei reared on an industrial scale in comparison with a control group (C-SOP). Bacillus infantis was used to inoculate the R-BFT group at the start of each cycle, while the C-SOP was conditioned fortnightly with commercial probiotics following the standard operating procedure for intensive shrimp culture. The C/N balance was maintained at 15:1 in both treatments using molasses one hour after feeding. Zero-wastewater discharge was maintained throughout each cycle for the R-BFT group, while 20% water exchange was done in the C-SOP weekly. The result showed similarity in the mean values of temperature, pH, and salinity. However, phosphate concentration and biofloc volume were higher in the R-BFT compared to the control, while the reverse trend was observed for dissolved oxygen, nitrite, and ammonia. Although the final weight and weight gained were similar in the treatments, the quantity of feed fed per shrimp and feed conversion ratio were substantially reduced for the R-BFT (14.82 g and 1.52 respectively) compared to the C-SOP group (18.33 g and 2.49 respectively). Survival was significantly higher in the R-BFT (91%) compared to the C-SOP (66%), while the mean yield was 57% higher in the former compared to the latter. Thus, R-BFT substantially improved water quality and the zootechnical performance of L. vannamei under intensive culture.

We evaluated the relationship of stocking density to survival, growth performance and fin condition of European perch Perca fluviatilis with hand feeding and self-feeders. Hand-fed perch (body weight 19.1 ± 5.1 g and total length 107 ± 9 mm) were reared at 0.5, 1.0, 1.5 and 2.0 fish/L. Self-feeding perch (body weight 25.4 ± 3.9 g and total length 128 ± 7 mm) were reared at stocking densities of 0.6, 1.0 and 1.4 fish/L. Pond-reared perch served as a comparison group for fin damage assessment. We found no differences in survival rate among stocking densities with either feeding method. Hand-fed fish displayed the highest weight gain and SGR at stocking density of 0.5 fish/L. The self-feeding fish showed a non-linear association of weight gain with stocking density with the highest growth at 1.0 fish/L. Fin length was noticeably greater in pond-reared fish compared with RAS-reared fish regardless of feeding method. In both experiments, fin length relative to standard length showed a negative relationship with stocking density, with pectoral fins showing the greatest effect. Fin condition deteriorated with increasing stocking density, and growth was highest at 0.5 and 1.0 fish/L in hand-fed and self-feeding fish, respectively.

Lymphocystis disease, caused by the iridovirus lymphocystis disease virus (LCDV), is characterized by the appearance of tumour-like lesions on the skin of affected animals associated with several environmental factors and/or with stress due to the intensive culture conditions of fish farms. In a previous study, the genomes of a new LCDV species, LCDV-Sa, were detected, together with 2 previously unknown viruses, Sparus aurata papillomavirus 1 (SaPV1) and Sparus aurata polyomavirus 1 (SaPyV1). Gilthead seabream from 17 fish farms in Spain, Italy and Turkey were sampled between 2009 and 2015 to investigate the role of the newly described SaPV1 and SaPyV1 viruses in lymphocystis disease development. Our results show that in diseased fish, either or both of the new viruses are almost invariably detected together with LCDV (98%). In asymptomatic fish, these viruses were detected in a much lower percentage (28%) and mostly in concurrence with LCDV (24%). These data confirm the suspected association among the 3 different viruses during lymphocystis disease development in gilthead seabream and warrant future studies to establish their respective contributions.

Meeting of the three authors during the 2011 Midwest Fish and Wildlife Conference in Des Moines, Iowa, led to frequent communication that formed the basis for collaborating on the status of their respective production facilities. The operation techniques of the water reuse aquaculture system (RAS) facilities in Vermont and Iowa are compared and contrasted. Kelsey and Johnson present detailed descriptions of Walleye (Stizostedion vitreum) larviculture in innovative RASs at the fish culture facilities in Vermont and Iowa, respectively. Since 2011, intensive culture of Walleye fry/fingerlings has been conducted at the Ed Weed Fish Culture Station in Grand Isle, Vermont, with the goal of large-scale production from the facility’s program inception to supplement existing extensive pond culture efforts of fingerlings that are used for sports fishing restoration. Tank volumes of 1940 L are now used in a RAS dedicated exclusively for intensive Walleye culture. Proof-of-concept techniques have been applied with successive production years to duplicate identified advances related to feed and feeding rates as well as various rearing environment conditions. After two successive years of trials in four self-cleaning tanks (2018 and 2019), as of 2020 all tanks within the system are now self-cleaning, providing optimum rearing conditions. The feeding of blended feeds through the entire culture run has also been applied since 2017. Larviculture survivals from day 1 post hatch (1 dph) through 34 dph in excess of 60% are being achieved averaging 50 mm in length, providing recruitment to the fishery that can be documented.

The increase in overfishing and pollution in Patzcuaro Lake, Michoacan, Mexico, has generated a severe problem in the endemic species that live there; especially the Chirostoma estor estor that has been threatened. A computational model has been developed for the evaluation of water quality in freshwater intensive farming tanks to contribute to the conservation efforts of this species. The proposed model uses a fuzzy inference system weighted through a rule categorization process. Five parameters were selected for the analysis: dissolved oxygen, pH, temperature, total ammonia, and non-ionized ammonia, because they represent the primary set of parameters that affect the water quality and health of the species studied. The measurements were made on the Chirostoma farms, and different situations were studied to define weights of importance according to the situations of negative impact on water quality. The rules are maximized or minimized with those weights and then integrated into a final score (Chirostoma Water Quality Index (CWI). The CWI values have been compared with NSF and CCME. It is noted that the CWI values are more representative of the actual state of water quality for the Chirostoma estor estor. This is because the weighted fuzzy logic approach is sensitive to all parameters and can identify harmful situations by using the rules. CWI can be a useful tool for monitoring and managing the quality of tanks, as it provides helpful information to prioritize and maintain water quality, and this in turn favors the growth, reproduction, and preservation of the species.

Microalgae are a group of autotrophic microorganisms that live in marine, freshwater and soil ecosystems and produce organic substances in the process of photosynthesis. Due to their high metabolic flexibility, adaptation to various cultivation conditions as well as the possibility of rapid growth, the number of studies on their use as a source of biologically valuable products is growing rapidly. Currently, integrated technologies for the cultivation of microalgae aiming to isolate various biologically active substances from biomass to increase the profitability of algae production are being sought. To implement this kind of development, the high productivity of industrial cultivation systems must be accompanied by the ability to control the biosynthesis of biologically valuable compounds in conditions of intensive culture growth. The review considers the main factors (temperature, pH, component composition, etc.) that affect the biomass growth process and the biologically active substance synthesis in microalgae. The advantages and disadvantages of existing cultivation methods are outlined. An analysis of various methods for the isolation and overproduction of the main biologically active substances of microalgae (proteins, lipids, polysaccharides, pigments and vitamins) is presented and new technologies and approaches aimed at using microalgae as promising ingredients in value-added products are considered.

In aquaculture, the application of predictive techniques based on statistical-mathematical modeling allows not only to project and study individual growth trajectories, but also to evaluate the probable effect of external factors that would explain their behavior over time. This is the case of this work, which takes the above as a principle to demonstrate the effect of water temperature on the growth of the Pacific white shrimp Litopenaeus vannamei cultured in fresh water (0 mg L−1), using densities of 90, 120, 180, 230, 280 and 330 shrimp m−2. Shrimp were exposed to water temperature between 11.5 °C and 31.6 °C. Temperature effect was determined using a parameterized Gompertz growth model with experimental data from each initial culture density. The best shrimp productivity yield was obtained above 26 °C, and the least efficient was below 22 °C. Densities of 90–180 shrimp m−2 and 230–330 shrimp m−2 generated a maximum average size of 12.6 g and 8.8 g in 30 weeks, respectively. Here we present the implications of the effect of water temperature on the intensive culture of white shrimp with zero salinity (0 mg L−1) using these techniques from a predictive analytical approach.

Bicarbonate ions are the primary source of inorganic carbon for autotrophic organisms living in aquatic environments. In the present study, we evaluated the shortterm (hours) effects of sodium bicarbonate (NaHCO3) addition on the growth and photosynthetic efficiency of the green algae Chlorella sorokiniana (211/8k). Bicarbonate was added to nonaxenic cultures at concentrations of 1, 2, and 3 g L-1 leading to a significant increase in biomass especially at the highest salt concentration (3 g L-1) and also showing a bactericidal and bacteriostatic effect that helped to keep a reduced microbial load in the algal culture. Furthermore, bicarbonate stimulated the increase in cellular content of chlorophyll a, improving the photosynthetic performance of cells. Since microalgae of genus Chlorella spp. show great industrial potential for the production of biofuels, nutraceuticals, cosmetics, health, and dietary supplements and the use of bicarbonate as a source of inorganic carbon led to shortterm responses in Chlorella sorokiniana, this method represents a valid alternative not only to the insufflation of carbon dioxide for the intensive cultures but also for the production of potentially bioactive compounds in a short period.

In calanoid copepods, intensive culture is preferred, but currently, densities do not exceed a few adults per milliliter. Several explanations exist, but none have allowed increasing the density of adults. This study proposes a new explanation for the problem of adult density in intensive culture, using the copepod Parvocalanus crassirostris as a model. First: eggs (2 h old) were supplied to adults kept at 20 adults mL−1 in 1 L containers with and without microalgae; constant aeration was supplied to determine egg survival to damage caused by the adults. Different samples were taken up to 175 min. Second: A high-density spawning test (5–80 adults mL−1) was performed, using shallow depth (2.5 cm) and supersaturation level of oxygen for rapid egg separation and sufficient oxygen for adults, respectively. The SEP (egg female−1 day−1) and REP (egg mL−1 day−1) were determined. Third: two systems of continuous egg harvesting, filtration and sedimentation, were evaluated under a high density of adults culture (10 adults mL−1). The adults of P. crassirostris quickly damaged the eggs, but the presence of food reduces the damage caused. Adults presented high SEP up to 10 adults mL−1; however, REP increased significantly to more than 170 eggs mL−1 day-1 using densities of 20 and 30 adults mL−1 (p

This study provides a first evaluation of different hatchery culture methods for the giant clam Tridacna noae. Three culture methods (intensive, semi-intensive, and extensive) using two tank designs (60 L and 277 L) were successful in producing 30-day old T. noae juveniles. There was no statistically significant interaction between tank design and culture method when considering cumulative survival (P = 0.89) or antero-posterior growth (P = 0.20), and the two tank designs did not influence cumulative survival (P = 0.78) or antero-posterior growth (P = 0.81). Differences in cumulative survival among the extensive (0.027 ± 0.015%), semi-intensive (0.005 ± 0.002%), and intensive (0.004 ± 0.001%) culture methods were non-significant (P = 0.11). The mean antero-posterior measurements at 30 days post-fertilisation among intensive (583.57 ± 12.71 μm), semi-intensive (530.92 ± 11.02 μm), and extensive methods (541.67 ± 10.95 μm), were also non-significant (P = 0.05). Further analysis of survival among different developmental stages identified significantly greater survival of T. noae between the pediveliger and juvenile development stages within the extensive culture method. Our results show that extensive culture methods can achieve comparable hatchery production of T. noae to semi-intensive and intensive culture methods, which require additional managerial, infrastructural, and nutritional inputs.

Two experiments were conducted to quantify the dietary thiamin (experiment I) and pyridoxine (experiment II) requirements of fingerling Cirrhinus mrigala for 16 weeks. In experiment I, dietary thiamin requirement was determined by feeding seven casein–gelatin-based diets (400 g kg−1 CP; 18.69 kJ g−1 GE) with graded levels of thiamin (0, 0.5, 1, 2, 4, 8 and 16 mg kg−1 diet) to triplicate groups of fish (6.15 ± 0.37 cm; 1.89 ± 0.12 g). Fish fed diet with 2 mg kg−1 thiamin had highest specific growth rate (SGR), protein retention (PR), RNA/DNA ratio, haemoglobin (Hb), haematocrit (Hct), RBCs and best feed conversion ratio (FCR). However, highest liver thiamin concentration was recorded in fish fed 4 mg thiamin kg−1 diet. Broken-line analysis of SGR, PR and liver thiamin concentrations exhibited the thiamin requirement in the range of 1.79–3.34 mg kg−1 diet (0.096–0.179 μg thiamin kJ−1 gross energy). In experiment II, six casein–gelatin-based diets (400 g kg−1 CP; 18.69 kJ g−1 GE) containing graded levels of pyridoxine (0, 2, 4, 6, 8 and 10 mg kg−1 diet) were fed to triplicate groups of fish (6.35 ± 0.37 cm; 1.97 ± 0.12 g). Fish fed diet containing 6 mg kg−1 pyridoxine showed best SGR, FCR, PR, RNA/DNA ratio, Hb, Hct and RBCs, whereas maximum liver pyridoxine concentration was recorded in fish fed 8 mg kg−1 dietary pyridoxine. Broken-line analysis of SGR, PR and liver pyridoxine concentrations reflected the pyridoxine requirement from 5.63 to 8.61 mg kg−1 diet. Data generated during this study would be useful in formulating thiamin- and pyridoxine-balanced feeds for the intensive culture of this fish.

Woundfin Plagopterus argentissimus are a small, endangered cyprinid found solely in the Virgin River across Utah, Arizona, and Nevada. As of now, only three facilities culture Woundfin for conservation propagation purposes, but there is growing concern that current extensive culture protocols are not meeting the conservation recovery goals outlined in the Virgin River Resource Management and Recovery Program. The development of alternative rearing methodology, like effective intensive culture conditions, could help increase production to more effectively meet the conservation propagation needs for this species. Our goal was to assess the effect of different sex ratios and fish densities on reproductive success at indoor facilities. We measured fertilization success at three different sex ratios (1:1, 1:3, 1:5; female:male) and three different fish densities (0.05, 0.21, and 0.47 fish/L) in a laboratory setting. Sex ratio did not significantly affect fertilization success (P = 0.73). Fertilization was completely inhibited at a density of 0.05 fish/L, but there was no difference in fertilization success between the two other density treatments (P = 0.92). Our findings suggest that a density greater than 0.05 fish/L and a sex ratio of 1:1, 1:3, or 1:5 will likely enhance fertilization success. The results and conclusions of this paper provide valuable rearing information for the Virgin River Resource Management and Recovery Program and hatchery managers attempting to increase production of Woundfin in an intensive culture setting.

O presente trabalho teve como objetivo avaliar o desempenho de alevinos de tilapia do Nilo, cultivados em tecnologia de bioflocos, utilizando diferentes densidades de inoculacao de Chlorella vulgaris. O delineamento experimental foi inteiramente casualizado, envolvendo o cultivo em sistema de bioflocos e quatro densidades de Chlorella vulgaris (0; 2,5; 5 e 10x104 cel mL-1), com quatro repeticoes cada. O trabalho teve duracao de 63 dias, sendo realizado em caixas com 40L de volume util, densidade de estocagem de 10 peixes por unidade experimental e peso medio inicial de aproximadamente 1,86 g. As variaveis de qualidade de agua nao apresentaram diferenca significativa entre os tratamentos, principalmente o nitrogenio da amonia total e do nitrito, que estiveram dentro do nivel aceitavel para o cultivo da especie. As variaveis de desempenho zootecnico nao foram afetadas pelas diferentes densidades de inoculacao da microalga, obtendo peso medio final de aproximadamente 21 g para os tratamentos e taxas de sobrevivencia superiores a 80%. Portanto para estas densidades de inoculacao da microalga Chlorella vulgaris, com frequencia semanal, nao apresentaram influencia no crescimento de alevinos de tilapia cultivada com bioflocos.

This work investigated survival and growth performance of male and female Potamon ebonyicum, at different Stocking Densities (SD) with 38% crude protein fish feed, in intensive culture system for six weeks. Experimental treatments were three in number viz., TI, TII and TIII. The TI contained only female, TII contained equal number of male and female, and TIII contained more females than male. The SD ranged from 1 crabT-1 to 3 CrabsT-1. All the male and female crabs survived first half (3 weeks) of the experimental period. Survival period of more than four weeks was recorded in the treatments with more than one female. Growth rates were insignificant and unevenly distributed. Yield was higher in the treatment with equal number of male and female than in the other ones. There was insignificant change in the growth rates as compared to records of previous investigations with the crab species. The narrow gap in the size of small ones, weight differential and their growth rates might assist aqua culturists to adapt SD and forecast yield in the freshwater crab. It could be suggested however that increment in the number of females during high density culture might enhance yield.

The aim of this study was to develop a commercial-scale biofloc-based tank system for shrimp culture in an efficient and environmental-friendly way. Eight independent and identical tanks (6 m/length × 6 m/width × 1 m/height, water volume of 30 m3) were randomly selected and prepared for the trial: four were from indoor and other four from outdoor. A complete production trial for super-intensive culture of L. vannamei was conducted under both indoor and outdoor environmental conditions simultaneously. In the trial, ten-day-old post-larvae of L. vannamei were stocked at a density of 580 ind m−3 and cultured for 13 weeks, obtaining survival rates of 82.7% and 81.3%, yields of 6.75 and 7.36 kg m−3, and FCRs of 1.32 and 1.25 under indoor and outdoor culture conditions, respectively. For producing one kg of shrimp, the usages of water, molasses and sodium carbonate were 210 L, 0.23 L and 0.27 kg under indoor condition and 217 L, 0.15 L and 0.19 kg under outdoor condition, respectively. Throughout the trial, the concentrations of both TAN and NO2−-N first increased and then decreased during the early to middle phases and then maintained below 1.0 mg L−1 until the end under both indoor and outdoor conditions. After mature bioflocs established in the culture water, diverse bacterial communities were detected from sampled bioflocs, with Shannon index significantly higher in outdoor than in indoor condition. Top eleven abundant phyla and top nine abundant genera of bacteria with relative abundance over 1% were all shared by both culture conditions, although most of them had significant differences in relative abundance between the two conditions. Notably, communities of nitrifying bacteria were detected in the bioflocs but with very low relative abundances under both culture conditions. Taken together, these results demonstrate the efficiency of a commercial-scale biofloc-based system for super-intensive culture of L. vannamei under limited water exchange. Moreover, the data suggest that the outdoor environmental conditions were more favorable in terms of production performance and inorganic nitrogen control of the system. Improved application of biofloc technology was also discussed and proposed for inorganic nitrogen control in intensive shrimp culture.

As the demand for fish increases and limitations are placed on water use, intensification in closed aquaculture systems could help to increase its sustainable production. The Amazon region stands out for its stable warm climate with fast-growing and resilient fish. This study evaluated the efficacy of two aeration regimes on intensive rearing of tambaqui, Colossoma macropomum, in six 46.4-m3 concrete-wall earthen bottom ponds, with no water exchange. Two aeration regimes were tested: (1) emergency aeration (EA), in which the aeration system was activated with dissolved oxygen (DO) levels below 3 mg L−1; (2) supplemental aeration (SA), with 8 h of aeration every night, and also during days with low solar radiation. Water quality, fish performance and health (haematological and parasitological indicators), aeration use and cost were assessed. Juveniles (44.39 ± 9.72 g, mean weight ± SD) were stocked in six concrete-wall ponds with earthen bottoms at 32,300 ha −1 and fed commercial feed (36–32% crude protein) for 17 weeks (122 days). Mean values of the water quality parameters showed no difference between treatments, but occurrences of hypoxia were significantly higher in SA (31 hypoxias with DO

A 16-week trial was carried out to evaluate an intensive culture system of Litopenaeus vannamei in commercial ponds with zero water exchange. Two management strategies were used: one with the addition of molasses (ML) and the second with commercial probiotic and molasses (PML), each with four replicates. Shrimp L. vannamei (2.09 ± 0.3 g) were stocked in 2.6 ha ponds without liners at a density of 98 shrimp m-2. The commercial probiotics used with molasses was a mixture of Bacillus spp. and Lactobacillus sp. After 16 weeks, no significant differences were found in mean dissolved oxygen, temperature, salinity, pH, total heterotrophic bacteria and zootechnical parameters (yield, FCR, survival and final weight) between the two management strategies. Total ammonia nitrogen concentration (53 to 69%) was the highest inorganic nitrogen compound. There were no significant differences between its concentrations in the two management strategies. The addition of molasses and probiotics are important management strategies for increased shrimp growth in an intensive system in ponds with zero water exchange, however, molasses is cheaper than the probiotics. Molasses inputs were based on a percentage of the daily feed allotments (by weight) and application rates of 30% of total daily feed in combination with commercial probiotics in intensive ponds without liners with zero water exchange was not sufficient to recycle all nitrogen waste with 10 HP ha-1.

Aquaculture activities in coastal area potentially produced wastes which leads water pollution. In order to reduce pollution, the use of several bacteria is very promising. This study was aimed to determine the effectivity of commercial bacterial inocculants to reduce pollution in cultured water. Bacterial inocculant tested in this study was SN®, SB®, and the combination of both inocculants for water quality improvements in white shrimp (Litopenaeus vannamei) super intensive culture media. This study was conducting in two steps, namely (i) preliminary study and (ii) primary study. The preliminary study was aimed to determine the time required to add bacteria based on the total number of bacterial colonies. The result showed that total colonies number of media treated with addition of SN® and SB® were reached maximum within 2 days. The result of primary study showed that the combination of SN® and SB® showed best effect in maintaining water quality of the culture media. This combination are proven reduces ammonia by 96%, nitrite-N by 83%, and COD by 42%.

Chirostoma estor estor, commonly known as whitefish, is an important species that lives in some Mexican lakes and is endangered due to overexploitation. This work proposes a new computational model for water quality assessment in freshwater intensive culture tanks using fuzzy logic, and an Analytical Hierarchy Process (AHP). The most critical parameters for whitefish culture, namely dissolved oxygen, pH, temperature, total ammonia, and non-ionized ammonia, were measured. Using measurements from real cultured tanks, different situations were studied to define importance parameter weights. As a result, an index concerning good or bad water quality conditions was obtained. Chirostoma farms were assessed using the proposed index to detect potential undesirable situations, improving water management for a constant growth, reproduction and survival of this important fish.

Cannibalism is a major cause of mortality in the intensive culture of the spotted seatrout, Cynoscion nebulosus . Increased feeding frequency may reduce attacks on conspecifics and enhance growth due to less energy spent on aggression, or more efficient digestion of smaller ration parcels. The goal of this study was to examine the effects of feeding frequency on aggressive and cannibalistic behaviors in larval hatchery-reared spotted seatrout. Ten-day-old reared larvae stocked at 30 fish l − 1 were subjected to one of four feeding frequencies (every 1, 2, 4, or 8 h) for eight days by subdividing the total ration of enriched Artemia accordingly. Blocks of three replicate tanks per treatment were monitored from 2-h before feeding until 1-h after feeding via four video cameras. For each tank, two pre-selected 30 min segments starting 30 min before and 30 min after each feeding event were scored for the number of nips, chases, and captures (Type 1 cannibalism). Three main factors, Frequency, Day, and Time were significant for all three behaviors. Significant Frequency × Time interactions along with follow-up tests of interaction means indicated that the numbers of nips and chases were lower after feeding than before feeding for all but the most frequent (1-h) feeding frequency. The 2-h frequency treatment elicited the fewest aggressive and cannibalistic acts, likely reflecting the best balance between the opposing effects of ration size on satiation and feeding frequency on gut evacuation time. Specific growth rate (SGR) was relatively high and did not differ between the 2-h and conventional 8-h frequencies; but size heterogeneity was significantly higher for the 8-h frequency treatment.

American bullfrog (Lithobates catesbeianus) is the only species raised in Brazilian commercial frog farms, and the intensive culture of these animals has gained great popularity in Brazil over the past several years. Stress is one of the major obstacles in frog culture. To minimise this problem, the aim of the present study was to investigate the role of added vitamin C in the diet of American bullfrogs as an antistress factor through the assessment of plasma corticosterone, leucocyte levels and macrophage activation in animals raised in confinement. The experimental design was entirely randomised, with six treatments (supplementation of 0, 250, 500, 750, 1000 and 2000 mg of vitamin C/kg of feed) and four replications. The plasma corticosterone level, leucocyte level and macrophage activation were evaluated. It was concluded that vitamin C had no influence on the evaluated parameters due to the possible adaptation of the animals to life in captivity (domestication). The results of this research indicate that farmers should not increase the levels of vitamin C in commercial feeds because this would only enhance production costs.

Short-rotation intensive culture (SRIC) of willow (Salix spp.) or hybrid poplar (Populus spp.) is currently at a precommercial stage with a potential to be applied economically across important areas to produce lignocellulosic biomass and environmental services in Canada. A two-round Delphi survey was conducted among 50 experts to assess the future deployment of SRIC in this country. The total area in 10 years (2011 base year) was forecasted as 1330, 4100, and 11 400 ha under pessimistic, realistic, and optimistic scenarios, respectively. The deployment of SRIC in the next decade depends mainly on the development of the demand for SRIC biomass and services, that of production technologies, and the establishment of policies and programs promoting its application. In the short term, research and development (R&D) and policy initiatives should be funded or implemented by various stakeholders to facilitate the deployment of the system. On average, respondents deemed that the potential for long-term (20 years) deployment of SRIC in Canada was good. Some of the conclusions and the methodological approach of this study could apply to short-rotation woody crop systems and to agroforestry systems in Canada and elsewhere.

with four eye spots(E). C, Egg string divided into many capsules on the inner surface of abalone. D, Egg capsule containing developed larvae(L) and nurse eggs(→). SpeciesBodycolorPigmentationOccipital tentacleNotocaetae on chaetiger5Special notochaetae in posterior Palps chaetigersProstomiumInterchaetigersPygidium

Different culture methods may affect the intensive culture system of Pacific white shrimp (Litopenaeus vannamei) regarding water quality and growth and economic performance. This study evaluated the potential effects of three culture methods through cultivation of juvenile shrimps under consistent tank management conditions for 84 d. The three methods involved shrimp cultivation in different tanks, i.e., outdoor tanks with cement bottom (mode-C), greenhouse tanks with cement bottom (mode-G) and outdoor tanks with mud-substrate (mode-M). Results showed that water temperature was significantly higher in mode-G than that in mode-C (P 0.05), mode-M had significantly higher shrimp yield, survival rate and feed conversion rate (P < 0.05) than other modes. There were significant differences in revenue and net return among different treatments (P < 0.05). These demonstrated that the treatments of mode-G and mode-M were conductive to the intensive culture system of L. vannamei.

The descriptions of galls, or tumors, in red algae have been sparse. Ktzing (1865) observed possible galls of Bostrychia but only presented a drawing. Intensive culture observations of hundreds of specimens of the genus Bostrychia over many years have revealed that galls appeared in only a small subset of our unialgal cultures of B. kelanensis, Bostrychia moritziana/radicans, B. radicosa, B. simpliciuscula, and B. tenella and continued to be produced intermittently or continuously over many years in some cultures but were never seen in field specimens. Galls appeared as unorganized tissue found primarily on males and bisexuals, but occasionally on females and tetrasporophytes. The gall cells usually were less pigmented than neighboring tissue, but contained cells with fluorescent plastids and nuclei. The galls were not transferable to other potential hosts. Galls could be produced from gall-free tissue of cultures that originally had galls even after transfer to new culture dishes. Electon microscopy of galls on one isolate (3895) showed that virus-like particles are observed in some gall cells. It is possible that a virus is the causative agent of these galls.

The rearing of astacid crayfishes under controlled conditions requires the addition of live zooplankton to basal dry diets. To investigate the possibility of minimizing the labor and costs involved in providing live feed, a 180-d experiment that focused on reducing the brine shrimp Artemia spp. supply period was carried out with stage 2 signal crayfish Pacifastacus leniusculus. From the onset of exogenous feeding, juvenile crayfish were fed a dry diet (formulated for salmonids) that was supplemented with live Artemia nauplii. Five treatments were implemented, varying the time at which the Artemia supplement was withdrawn (at days 80, 100, 120, or 160, or no withdrawal). No significant differences in survival, growth, or cheliped loss were found among groups throughout the trial. Survival rates at the end of the experiment (180 d) ranged from 62.3% to 66.7%, final carapace length averaged 20.6 mm, and final weight averaged 2.29 g. The results presented here indicate that juvenile astacid crayfishe...

Diel oxygen consumption patterns were determined in this study for California halibut ( Paralichthys californicus ) 3.2, 4.4, 6.2, 7.5, 9.2, 11.8, 12.8 and 14.2 g and between 110.5, 113.8, 115.7, 117.9, 120.1, 126.5, 132.4, 140.6, and 165.6 g held under farm-like conditions. The concept farm-like refers to a fish rearing condition as close as possible to a farming operation in terms of density, loading, and daily management. Open respirometries were performed in culture raceways during 24 h cycles while fish were growing from 3.2 g up to 165.6 g to determine hourly oxygen consumption rates by mass balance calculations. Fish were offered feed continuously during 12 h (within the 16 h light phase) resulting in maximum daily oxygen consumption rates that were between 1.2 and 1.5 times the mean daily values. A typical diel oxygen consumption pattern of the smaller group of fish tested (range between 3.2 and 14.2 g) had a peak during the feeding period, and relatively low and falling oxygen consumption after feeding was stopped. Oxygen consumption of the larger group of fish (range between 110.5 and 165.6 g) showed a less marked diel variation and did not change significantly after feed was distributed. In conclusion, diel oxygen consumption rates for California halibut reported here are key bioengineering parameters to be used when designing and sizing a rearing facility for the intensive culture of California halibut.

Condition of all fins was assessed in intensively cultured perch (n = 300) in comparison with control pond-reared perch (n = 30). Measurements of maximum fins length as well as a four point photographic scale were used. No damage to any fin was visually observed in the pond-reared group. The first dorsal fin showed the least damage in cultured perch with 93 % of fish demonstrating no erosion. The most affected were paired fins, with only 7 % and 2 % of pectoral and ventral fins, respectively, being non-eroded. No difference between culture systems was found in fin length for the first dorsal and the caudal fin. Pectoral, second dorsal, ventral, and anal fins of intensively cultured perch showed reductions up to 52, 49, 35, and 28 %, respectively. The relationship between fin lengths and standard body length (SL) were described for both groups (SL range 104–170 mm). Results of this study are discussed in relation to aesthetic, welfare and fish survival issues.

Shrimp farming is the most important mariculture industry on the west coast of South Korea. However, it has suffered from mass mortality due to viral disease outbreaks and coastal pollution due to water discharge. This study developed an intensive shrimp culture method for outdoor ponds, without wat...

The high rates of cannibalism which have been documented for H. americanus reared communally dictate that for a majority of the culture period the lobsters should be reared individually, in order to eliminate these losses. Criteria essential to the development of culture systems for the intensive rearing of lobsters and other cannibalistic crustacean species in individual holding compartments are considered. These include the necessity for holding large numbers of individuals in a minimal amount of space, delivery of oxygenated water evenly to each rearing compartment, and removal of wastes. Considerations of space utilization, capital construction costs, and associated components for automatic feeding, maintenance, and harvesting also are discussed.

Macrobrachium rosenbergii is under examination in various parts of the world as a potential culture animal. Unfortunately, M. rosenbergii does not aggregate and has been reported to be aggressive and cannibalistic. The suitability of the animal for intensive culture in closed systems has not been established. In this study experiments have been carried out on growth rate, molting frequency, and incidence of cannibalism among equal age grouped and isolated M. rosenbergii of different sex and size with and without shelters and with and without removal of the second periopods. In groups, more aggressive males and females grow faster than less aggressive males and females. In isolation, males, on the average, grow faster for a longer period and thus get bigger. Molting frequency does not appear to be directly related to growth rate, but rather growth rate is related to food consumption, regardless of the molting frequency. Comparing equal age animals of different size, small animals molt more frequently than large animals but grow more slowly. The incidence of cannibalism is high. Cannibalism invariably follows attacks made on animals undergoing molt. The larger an animal the greater the chance of a kill, but small animals will attack larger animals and two or more animals may attack a single animal. Shelters which can be defended can reduce the incidence of cannibalism.

In Taiwan, large acreages of suitable freshwater ponds, streams and dams, as well as irrigation canals used for culturing various freshwater fishes, are available to shift to freshwater prawn farming because of its proven good flavor, higher price and the established propagation and cultivation techniques. Since 1974, the number of stockable juveniles supplied by Tungkang Marine Laboratory (TML) and some private hatcheries has increased year by year from 110,580 to over 5,000,000 in 1978. Therefore, several culture patterns have been set up as demonstrations in TML and in the private farms consulted by TML. Extensive and intensive culture, polyculture with fishes, as well as river ranching, are discussed. The bottom choice of mud pond, sand pond, cement pond, and polyethylene sheet pond, and the food choice, mainly of egg custard, steamed rice, fish paste in early culture stage, with trash fish, cereals and prepared feed in late culture stage are summarized. The marketing system is discussed and an estimation of total production is made on updated investigation. A speedy solving of the listed local problems would lead to steady progress in freshwater prawn farming.

Common dentex larvae were reared using two culturing techniques, mesocosms and intensive rearing, to determine the principal culture parameters involved in the differences observed in growth, skeletal deformations and survival between the two rearing techniques. In growth, only dry weight of larvae of 40 days post-hatching (dph) from mesocosms was significantly higher than larvae from intensive rearing. Significant differences were observed in survival at 40 dph (6.58% in mesocosms and 1.58% in intensive rearing) and in the incidence of skeletal deformations, both for percentage of deformed larvae and for some deformation types such as those related to vertebral column and to the caudal complex. Initial larval density and initial prey density and quality are the factors suspected to affect growth and survival performance, while skeletal deformities might also be affected by tank hydrodynamics.

We examined the effect of light regime on daily egg harvest ( EH , eggs tank − 1 d − 1 ), and 48-h egg hatching success ( HS , %) by Acartia tonsa (Copepoda: Calanoida) in intensive 130-l cultures. Since this copepod produces more eggs during darkness than in the light, we tested whether EH could be increased by utilizing unnatural light regimes. Egg harvests were between 0.85 to 1.20 million eggs culture − 1 wk − 1 and mean EH was not significantly different among tanks maintained at 3 h:3 h, 4 h:4 h, 6 h:6 h and 12 h:12 h light:dark. HS was not significantly different for eggs produced in the different light regimes and incubated at 12 h:12 h. In a second experiment, cohorts were reared (from nauplii) in constant darkness (D) and constant light (L) and eggs produced in each cohort were incubated in darkness (D–D, L–D) or light (D–L, L–L). Mean(± SE) HS was significantly different among the treatments, increased with increasing light exposure, and equal to 3.7(1.1), 32.2(15.1), 38.3(0.8) and 52.2(16.5)% for D–D, L–D, D–L and L–L treatments, respectively. These and published data were combined to generate an equation predicting 48-h HS for eggs produced and incubated at photoperiods between 0.5 and 24 h. Our experiments indicated that light can be an important factor affecting the success of intensive cultures of A. tonsa and that copepod culture protocols should include information on light regimes used during rearing and incubation of eggs.

[The effect of stocking density on the growth and survival of Astacus leptodactylus juveniles was evaluated. Newly hatched third instars of A. leptodactylus with an average total length of 11.4 mm (TL) and an average weight of 22.4 mg were stocked in 0.14 m 2 tanks in a recirculation system at 50, 100, and 200 specimens/m 2 and reared for 120 days at 22.8°C. Crayfish growth was inversely correlated with density. The mean final weights for the crayfish were 1.26, 1.16, and 0.91 g for crayfish densities of 50, 100, and 200/m 2 , respectively. Survival of the crayfish was also affected by stocking density; it decreased as initial stocking density increased. The proportion of lost chelipeds was also found to be dependent on the stocking density and increased with increasing stocking density. The differences in the proportion of crayfish with cheliped injuries among animals stocked at 50/m 2 , 100/m 2 , and 200/m 2 were found to be 7.1%, 16%, and 29%, respectively. The yield was directly related to density ( P 2 = 0.95). No evidence was found for feed conversion ratio (FCR) being affected by density. Astacus leptodactylus had a normal length distribution of 11-12 mm at the beginning of the experiment. However, at the end of the experiment, the length distribution varied among animals in the three density treatments. At the densities of 100/m 2 and 200/m 2 , animals had a final length range of 16-40 mm TL, showing a distinct peak at 21-25 mm TL; however, at the density of 50/m 2 , the animals had a final length range of 16-41 mm TL with a distinct peak at 26-30 mm TL. In addition, the implications of the above findings for optimal intensive culture conditions for juvenile Astacus leptodactylus are discussed. L'effet de la densite de stockage sur la croissance et la survie des juveniles d' Astacus leptodactylus a ete evalue. Des troisiemes stades nouvellement eclos d' A. leptodactylus d'une longueur totale moyenne de 11,4 mm (TL) et d'un poids moyen de 22,4 mg ont ete stockes dans des bacs de 0,14 m 2 pourvus d'un systeme de recirculation, a des densites de 50, 100 et 200 specimens/m 2 et eleves pendant 120 jours a 22,8°C. La croissance des ecrevisses etait inversement correlee a la densite. Les poids moyens finaux des ecrevisses etaient de 1,26, 1,16 et 0,91 g a des densites de 50, 100 et 200/m 2 , respectivement. La survie etait egalement affectee par la densite de stockage; elle diminuait avec l'augmentation de la densite initiale de stockage. La proportion de chelipedes perdus dependait egalement de la densite de stockage et augmentait en meme temps que la densite de stockage. La difference dans la proportion d'ecrevisses ayant des blessures aux chelipedes par rapport aux animaux stockes a 50/m 2 , 100m 2 et 200/m 2 etait de 7,1%, 16% et 29%, respectivement. Le rendement etait en relation directe avec la densite ( P 2 = 0,95). Il n'a pas ete mis en evidence que le rapport de conversion de la nourriture (FCR) soit affecte par la densite. Au debut de l'experimentation, Astacus leptodactylus presentait une distribution de longueur normale de 11-12 mm. Cependant, a la fin de l'experimentation, la distribution de longueur variait dans les trois densites testees. Aux densites de 100/m 2 et 200/m 2 , les animaux avaient, a la fin de l'experimentation, une longueur de 16-40 mm TL, avec un pic net a 21-25 mm TL; mais, a la densite de 50/m 2 , leur longueur finale etait de 16-41 mm TL, avec un pic net a 26-30 mm TL. Les implications de ces resultats pour determiner les conditions optimales de culture intensive des juveniles d' Astacus leptodactylus sont discutees. , The effect of stocking density on the growth and survival of Astacus leptodactylus juveniles was evaluated. Newly hatched third instars of A. leptodactylus with an average total length of 11.4 mm (TL) and an average weight of 22.4 mg were stocked in 0.14 m 2 tanks in a recirculation system at 50, 100, and 200 specimens/m 2 and reared for 120 days at 22.8°C. Crayfish growth was inversely correlated with density. The mean final weights for the crayfish were 1.26, 1.16, and 0.91 g for crayfish densities of 50, 100, and 200/m 2 , respectively. Survival of the crayfish was also affected by stocking density; it decreased as initial stocking density increased. The proportion of lost chelipeds was also found to be dependent on the stocking density and increased with increasing stocking density. The differences in the proportion of crayfish with cheliped injuries among animals stocked at 50/m 2 , 100/m 2 , and 200/m 2 were found to be 7.1%, 16%, and 29%, respectively. The yield was directly related to density ( P 2 = 0.95). No evidence was found for feed conversion ratio (FCR) being affected by density. Astacus leptodactylus had a normal length distribution of 11-12 mm at the beginning of the experiment. However, at the end of the experiment, the length distribution varied among animals in the three density treatments. At the densities of 100/m 2 and 200/m 2 , animals had a final length range of 16-40 mm TL, showing a distinct peak at 21-25 mm TL; however, at the density of 50/m 2 , the animals had a final length range of 16-41 mm TL with a distinct peak at 26-30 mm TL. In addition, the implications of the above findings for optimal intensive culture conditions for juvenile Astacus leptodactylus are discussed. L'effet de la densite de stockage sur la croissance et la survie des juveniles d' Astacus leptodactylus a ete evalue. Des troisiemes stades nouvellement eclos d' A. leptodactylus d'une longueur totale moyenne de 11,4 mm (TL) et d'un poids moyen de 22,4 mg ont ete stockes dans des bacs de 0,14 m 2 pourvus d'un systeme de recirculation, a des densites de 50, 100 et 200 specimens/m 2 et eleves pendant 120 jours a 22,8°C. La croissance des ecrevisses etait inversement correlee a la densite. Les poids moyens finaux des ecrevisses etaient de 1,26, 1,16 et 0,91 g a des densites de 50, 100 et 200/m 2 , respectivement. La survie etait egalement affectee par la densite de stockage; elle diminuait avec l'augmentation de la densite initiale de stockage. La proportion de chelipedes perdus dependait egalement de la densite de stockage et augmentait en meme temps que la densite de stockage. La difference dans la proportion d'ecrevisses ayant des blessures aux chelipedes par rapport aux animaux stockes a 50/m 2 , 100m 2 et 200/m 2 etait de 7,1%, 16% et 29%, respectivement. Le rendement etait en relation directe avec la densite ( P 2 = 0,95). Il n'a pas ete mis en evidence que le rapport de conversion de la nourriture (FCR) soit affecte par la densite. Au debut de l'experimentation, Astacus leptodactylus presentait une distribution de longueur normale de 11-12 mm. Cependant, a la fin de l'experimentation, la distribution de longueur variait dans les trois densites testees. Aux densites de 100/m 2 et 200/m 2 , les animaux avaient, a la fin de l'experimentation, une longueur de 16-40 mm TL, avec un pic net a 21-25 mm TL; mais, a la densite de 50/m 2 , leur longueur finale etait de 16-41 mm TL, avec un pic net a 26-30 mm TL. Les implications de ces resultats pour determiner les conditions optimales de culture intensive des juveniles d' Astacus leptodactylus sont discutees. ]

This study was conducted to determine oxygen consumption level of white shrimp (Litopenaeus vannamei) and the model of oxygen management in intensive culture pond. Shrimp in weight of 5 gram were maintained in 20 liter of water in density 6 tails/container. Water quality was measured every 2 hours for 6 hours. Other experiments were done using shrimp in weight of 8, 10, 12 and 15 gram per tail, in density 4 tails/container. The results of study showed that oxygen consumption levels of white shrimp was higher after feeding than before feeding. Oxygen consumption levels of smaller shrimp were higher than that of bigger shrimp. Regression model of oxygen consumption levels before and after feeding were linear. Correlation between oxygen consumption and shrimp weight reached 92.5%. Keywords: white shrimp, Litopenaeus vannamei, oxygen, respiration, intensive pond ABSTRAK Penelitian ini dilakukan untuk mengetahui tingkat konsumsi oksigen udang vaname (Litopenaeus vannamei) dan model pengelolaan oksigen pada tambak intensif. Udang dengan bobot sekitar 5 gram dimasukkan ke dalam wadah tertutup berukuran 20 liter dengan kepadatan 6 ekor/wadah. Kualitas air diukur setiap 2 jam selama 6 jam. Perlakuan tersebut juga dilakukan pada udang dengan kelompok berat 8, 10, 12 dan 15 gram, dengan kepadatan 4 ekor/wadah. Hasil penelitian menunjukkan bahwa tingkat konsumsi oksigen udang vaname sesudah makan relatif lebih tinggi daripada sebelumnya. Tingkat konsumsi oksigen udang ukuran kecil relatif lebih tinggi daripada yang berukuran lebih besar. Model persamaan regresi tingkat konsumsi oksigen pada udang yang tepat sebelum dan sesudah makan adalah linear. Korelasi antara konsumsi oksigen dengan bobot udang mencapai 92,5%. Kata kunci: vaname, Litopenaeus vannamei, oksigen, respirasi, tambak intensif

Experimental research on production of plantlents from fragments of thallus of the alga Gelidium were carried out. The best results on development of plantlets without rhizoids were achieved with cultivation of fragments of subapical parts of the plant. Thus, the average growth rate of plantlets in the last for 4 weeks of rearing was 6.7 ± 1.2% a day. Gelidium plantlets with rhizoids were grown from the top branches of plants in an intensively stirred culture with shading of the lower parts of the branches. It is suggested to use the same method for obtaining planting material during bottom rearing of Gelidium in the sea as that for intensive culture in tanks.

The least chub Iotichthys phlegethontis is a diminutive and rare cyprinid endemic to the Bonneville Basin of Utah. As part of a species recovery effort, aquaculture techniques were investigated. Three experiments are summarized here: Two compared silt substrate and no substrate, and one evaluated the effect of three different densities on growth and survival. The substrate experiments were an attempt to compare extensive versus intensive culture. In the first test, growth of 4–7-month-old least chub in outdoor aquaria containing 2–3 cm of silt substrate was significantly higher than that of fish in indoor or outdoor aquaria with no substrate. Survival was unaffected by substrate treatment. In another test using fry that had just hatched, mortality rates were significantly higher in the aquaria treatment (mean ± SD = 95.3 ± 2.3%) than in the silt substrate treatment (45.3 ± 23.1%; P = 0.009). Final length was also significantly higher in the simulated ponds (mean ± SD = 10.2 ± 1.2 mm) than in the ...

The influence of tank wall color and up-welling water flow on growth and survival of Eurasian perch larvae (Perca fluviatilis) was tested in an intensive culture system. Newly hatched larvae were fed Artemia nauplii, later combined with dry feed, and reared for 5 wk in either black tanks with up-welling water flow or in gray tanks with or without up-welling water flow. The perch larvae grew significantly faster in black tanks than in gray tanks regardless of water flow. Two weeks after hatching, a significantly higher mean weight was shown in larvae reared in black tanks compared to larvae reared in gray tanks with up-welling water flow, and after 4 wk, the mean weight was significantly higher than in both of the other treatments. The difference in growth was further enhanced during the last week of the experiment, and the final mean weights were 51.1 ± 1.9 mg in black tanks with up-welling water flow, 23.8 ± 2.1 mg in gray tanks with up-welling water flow, and 23.7 ± 2.2 mg in gray tanks without up-welling water flow. The cumulative mortality at the end of the experiment averaged 75% in all treatment groups. Taken together, the enhanced growth of Eurasian perch larvae in black tanks could be explained by high prey contrast and increased prey consumption. Up-welling water flow had no impact on growth and survival of the perch larvae in gray tanks, indicating that the availability and consumption of the prey were independent of water movement.