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1.
Results of a 1‐year intensive monitoring of Vibrio bacteria, as thiosulphate citrate billar salt sucrose (TCBS) counts, in a hatchery for molluscs, are presented. Surface seawater, well seawater, tap water from a freshwater well, microalgae system, including pasteurized well seawater, f/2 medium, starter cultures of eight micro algal species, mass‐produced microalgae and compressed air were studied as possible sources of Vibrio. Additionally, recently collected broodstock of the catarina scallop Argopecten ventricosus (Sowerby II 1842) was also subjected for investigation for their possible role in discharging Vibrio during spawning. Efficiency of a cartridge–ultraviolet (UV)‐filtration system and of a steam gun employed for sterilizing tanks, hoses and utensils was also determined. Results indicated that Vibrio were present in surface seawater throughout the year. In well seawater these bacteria were only found during the first 5 months soon after construction of the well and before commencement of continuous operations, but not after this period. Vibrio was never detected in pasteurized well seawater, f/2 medium, starter cultures of microalgae and compressed air. However, mass‐produced microalgae contained Vibrio, possibly as a result of the use of contaminated tap water for washing and rinsing the fibreglass culture tanks. Scallop broodstock was found to be an important source of Vibrio in the hatchery. Biopsy on female gonads of live organisms demonstrated higher numbers of colony‐forming units than male gonads. At spawning, Vibrio was released into water, producing bacterial blooms in tanks after 24 h. The cartridge–UV‐filteration system was not sufficient to eliminate the bacteria from seawater, but the steam gun proved to be a good tool to eliminate Vibrio biofilms on tank walls or tools used in the hatchery. Some recommendations are given, which could be useful for other mollusc hatcheries.  相似文献   

2.
Different types and concentrations of probiotics were evaluated for their effects on growth, survival and enzyme activity of hatchery‐reared Nodipecten subnodosus spat. The treatments included (1) a mix of the microalgae Isochrysis galbana and Pavlova salina as the control group; (2) Diet 1 + a mix of Burkholderia cepacia and Pseudomonas aeruginosa; (3) Diet 1 + the commercial probiotic Epicin; and (4) Diet 1 + the commercial probiotic Bactosafe. Both commercial probiotics were tested at 3, 6 and 10 mg L−1. Scallops receiving Bactosafe and Epicin at 3 and 6 mg L−1 grew ~30% faster and larger than in the control group. Regardless of the treatment, survival at the end was 98.7%. There was no relation between the activity of catalase and superoxide dismutase; however, significantly lower catalase levels occurred at increasing doses of Epicin; significant higher catalase levels occurred in the control group and mix of bacilli. Compared with the control group, lysozyme levels were significantly higher with the Epicin and Bactosafe treatments (3 and 6 mg L−1). More research needs to be conducted with probiotics to determine their real effects on the activity of antioxidant enzymes. We expect that treated scallops will increase their performance at the field.  相似文献   

3.
We evaluated recruitment of larvae of catarina scallop, Argopecten ventricosus, in the area of Puerto Peñasco, NE Gulf of California. We moored artificial collectors in six sites from June 2007 to August 2008 and replaced them every 2 months. We used monthly (July 2002–September 2011) sea surface temperature (SST, °C) and surface chlorophyll‐a concentration (SSChl, mg m?3) Aqua/MODIS satellite data to describe seasonal environmental behaviour study area. Also, we recorded bottom temperature at each site every 4 h, and every 2 months measured sea surface salinity, temperature and dissolved oxygen. We used a repeated measures anova to evaluate differences in the number of recruited spat between main factors, and analysed the presence of multimodal spat shell size frequency distributions. Overall, spat recruitment was negatively correlated with seawater temperature and showed higher spat recruitment abundances throughout winter, which is the season with the highest surface chlorophyll a concentration. We estimated multimodal shell size frequency distributions characterized by more than one modal size. The natural collection of A. ventricosus spat on artificial collectors in the area can be successfully performed over a protracted period (November–December to May–June). Our results extend the area where collection of A. ventricosus spat can be successful.  相似文献   

4.
Six experimental batches of Pacific oyster larvae, Crassostrea gigas Thunberg, were reared on a standard diet in the hatchery. After 8-12 days from fertilization, the larvae were separated into two to three size groups. These groups of larvae were then reared separately through to settlement. A sample was taken from each group when the larvae had reached the stage at which they were ready to settle for estimation of number, size and weight, and analysis of total lipid. All the spat that settled from each group were removed daily during the settlement period of 10-14 days. Selected samples of 1000 or more spat, collected from a single (day) settlement, were reared in standard hatchery upwelling systems for a further 30 days. Spatfall, as a percentage of the number of larvae in the group available to settle, was similar for all three groups of larvae, although it varied between experiments, and was positively correlated with the amount of lipid in the eyed larvae. The average spatfall, for all groups, was 44%. The dry and organic weights of spat that settled from the group of larvae that grew fastest were significantly greater than that for spat from the group with the slowest growth rate. Lipid content of the spat in the three groups was similar (9.3-12.4%). The spat that settled from the group of larvae that grew fastest also tended to be biggest after rearing in the hatchery for a further 30 days, but this result was not statistically significant. Spat from within the same group of larvae also grew to a similar size in this time, irrespective of whether they were collected during the first 3 days of settlement, or after a further 5 days. In practical terms, the results of these experiments show that it is cost-effective for hatchery operators to maintain batches of larvae for as long as settlement continues, to maximize the output of spat numbers without any danger of wasting resources by producing inferior quality or slower growing animals.  相似文献   

5.
Scallop Pecten maximus spat (1.3–2.1 mm shell height) from different settlement groups were transferred from hatchery to land‐based nursery at different ages and sizes. Chemical content, growth and survival were compared at transfer time and after 1 and 8 weeks of nursery growth. Growth was lowest and mortality highest in the first week after transfer. Mean shell height growth was 21.5–71.4 μm day?1 and ash‐free dry weight (AFDW) growth ?2.7 to 10.3 μg day?1. Spat from the first settlement group attained a larger size and weight than spat from larvae settled 3 days later, but had a lower daily growth rate (%). Keeping the late‐settled spat a longer time in the hatchery to reach a bigger size before transfer seemed not to improve subsequent nursery growth. Survival showed a large variation with mean survival ranging from 32% to 74%. A substantial reduction in lipid content was found after transfer to the nursery. Sterol content at transfer was the only lipid class correlating with survival in the nursery. Based on the results, it is justified that spat groups of different settlement age are included in production of 15‐mm great scallop spat if they are transferred from the hatchery at the same age.  相似文献   

6.
The results of a series of pilot-scale runs with P. mazatlanica larvae from 2004 through 2006 are reported. Preliminary runs in 2004 and 2005 used broodstock collected in summer, when massive spawning of wild populations naturally occurs. However, results of larval development were very poor and failed to produce spat in both years. In 2006, ripe broodstock were still collected in summer, but also in the spring time, based on the hypothesis that the gonads in this season were in better reproductive condition that in summer. Three larval runs were conducted in 2006: two in spring and one in summer. Larvae growth and survival greatly increased in both spring runs, ending with two successful productions of spat (∼ 20 × 103 and ∼ 100 × 103 juveniles). The summer larval run in 2006 failed again to produce spat. Additionally, the first run of April 2006 refers to an experiment that evaluated two different larval culture conditions: constant temperature (27 °C) and low stocking density (3-4 larvae ml− 1) versus variable temperature (24-28 °C) and high stocking density (8-9 larvae ml− 1). The first trial significantly increased larval survival and growth, which in turn resulted in greater numbers of settled spat, in comparison of the second trial, where survival, growth, and settlement of spat were significantly lower. Also in 2006, the quality of seawater used at the hatchery was evaluated with microbiological and chemical tests. The implication of these tests, together with results from all experiments are analyzed and discussed in terms of the potential development of large-scale hatchery cultivation of P. mazatlanica larvae in Mexico.  相似文献   

7.
不同来源海洋弧菌微生物被膜对厚壳贻贝稚贝附着的影响   总被引：3，自引：3，他引：0  
为探讨广泛存在于近海环境中海洋弧菌和贝类附着的相互作用关系,实验从自然微生物被膜和厚壳贻贝成体肠道内分离了海洋弧菌,测定其种属及亲缘性,调查了这些不同来源弧菌形成的微生物被膜与厚壳贻贝稚贝附着的调控作用。结果显示,测试弧菌形成的微生物被膜密度随着初始细菌密度的增加呈现不同程度的增加。源于自然微生物被膜和贻贝肠道内的10株弧菌均能显著促进厚壳贻贝稚贝的附着,不同菌株形成微生物被膜的诱导活性存在显著差异,附着率变化范围为17%~67%,其中稚贝在Vibrio sp.17微生物被膜上的附着率为67%±2%。微生物被膜对稚贝附着诱导活性与被膜密度呈显著相关性,其中弧菌V.crassostreae ECSMB14106的相关性系数最高,为0.8992。此外,微生物被膜的诱导活性与弧菌的来源无关。本实验初步探明了海洋弧菌对厚壳贻贝稚贝附着的影响,有助于进一步理解微生物被膜调控厚壳贻贝的附着分子机理。  相似文献   

8.
隋炜金  王鸿霞  刘保忠 《水产学报》2023,47(6):069413-069413
为研究文蛤育苗过程中幼虫病害及其主要致病菌,实验通过构建细菌16S rDNA克隆文库、病原菌分离纯化、人工感染和药敏实验等方法对育苗场发病的浮游期文蛤壳顶幼虫样品进行了系统分析。结果显示,发病的文蛤壳顶幼虫细菌群落多样性低,地中海弧菌占比高达75%以上,推断其可能为引发此次幼虫发病的主要致病菌。从发病幼虫的匀浆组织中分离获得该优势菌株,测序及系统发育鉴定为地中海弧菌。人工感染实验确定了其致病性,菌株US2-01在1.0×106 CFU/mL的菌液浓度下浸泡感染文蛤浮游幼虫,96 h累计死亡率为84%。药敏实验表明,地中海弧菌菌株US2-01在12种抗生素的测试中对常用的青霉素、氨苄西林、红霉素等抗生素具有一定的耐药性,对四环素和多西环素中度敏感,对头孢他啶、庆大霉素、卡那霉素等其余7种抗生素呈现高度敏感。本研究首次报道了地中海弧菌为文蛤浮游期幼虫致病的一种潜在病原,研究结果可为文蛤幼虫疾病研究及贝类苗种培育过程中的病害防控提供科学依据。  相似文献   

9.

The Catarina scallop Argopecten ventricosus is a highly valued resource. Although its hatchery spat production has already been reported, the effects of initial larval stocking density have never been reported for production purposes. This study evaluates A. ventricosus growth and survival in triplicate using three stocking densities: low (LD; 2 larvae mL?1), medium (MD; 4 larvae mL?1), and high (HD; 6 larvae mL?1). Three-day old larvae were reared in 18-L plastic carboy at 25.6?±?0.5 °C and fed with a microalgal blend of Isochrysis galbana and Chaetoceros calcitrans (1:1 cell number ratio) for 7 days, equivalent to 10 post-fertilization days (PFD). Higher specific growth rate was recorded at LD (15.8?±?0.2%) after 8 PFD of culture compared to MD (1.6?±?0.5%) and HD (4.1?±?1.8%) densities. The least time required for 60% of the larvae to reach the pediveliger stage was recorded at LD condition (10 PFD). Higher survival was recorded at HD (58.8?±?3.1%) at 8 PFD compared to MD (53.5?±?3.1%) and LD (43.9?±?3.0%). After 8 PFD, stocking density was highly related to larval growth and survival. To increase production and growth, and reduce the time required to reach pediveliger stage, stocking density should start with 6 larvae mL?1 and be reduced to 2 larvae mL?1 at 7 PFD.

  相似文献   

10.
Larvae of Haliotis discus hannai were induced to settle and metamorphose by exposure to seawater supplemented with bromomethane. The settlement and metamorphosis of veliger larvae were observed with bromomethane concentrations of 300, 600, 900, 1200, 1500 ppm on the benthic diatom plates. The highest settlement and metamorphosis rates of larvae were observed in bromomethane concentrations of 600 ppm.

Abalone larvae were induced to settle and metamorphose by exposure to seawater supplemented with potassium chloride. The settlement and metamorphosis of veliger larvae was observed in potassium chloride concentrations of 14, 19, 24 and 29 mM on the benthic diatom plates. The highest settlement and metamorphosis rates of larvae were observed in potassium chloride concentrations of 14–19 mM.  相似文献   


11.
Harvesting practices of the clam Chionista fluctifraga show a decline in commercial size and densities, but no strategies have been developed to maintain clam beds. Aquaculture represents an alternative for preserving this resource. Adult clams from commercial grounds were used as broodstock. Conditioning, induction of spawning, cultivation of larvae, settlement of eyed larvae and nursing of postlarvae were performed in the hatchery for producing spat. Larvae and postlarvae were used to measure increase in shell height and data were fitted to exponential growth models. Spat were placed in floating trays and maintained in off‐bottom cultivation for 9 months. Samples of clams and tissues were collected monthly to measure absolute growth, shell height increase and a condition index. Larvae, postlarvae and juveniles showed exponential growth patterns. Mean shell height increased about 0.030 mm day?1 during larval and post‐larval stages and 0.049 mm day?1 during field cultivation. Pediveligers (height 215 ± 83 μm) entered metamorphosis at days 9–13 after fertilization, and postlarvae reached 3011.7 ± 325.5 μm (height) at day 60. After field cultivation, survival was about 95%; juvenile shell height was 20.6 ± 2.2 mm, and total weight was 5.3 ± 0.7 g. Growth rates were superior to natural conditions and the condition index was high throughout the study. Our results show that spat of C. fluctifraga can be produced in the hatchery, and that field production can be maintained in off‐bottom trays until reaching commercial size. Aquaculture activities for this species need to be established and evaluated.  相似文献   

12.
Phyllosoma larvae of the southern rock lobster, Jasus edwardsii, were cultured from egg to juvenile. For larvae reared from hatch to Stage III, survival was highest and bacterial contamination was lowest in seawater ozonated at low and moderate levels (400 and 500 mV oxidation-reduction potential, ORP). By contrast, at high ozonation (600 mV), all larvae suffered deformities at the moult to Stage II and terminally starved, while in unozonated water (about 300 mV), all larvae died at Stage III probably as a consequence of Vibrio bacteria proliferation. In a second experiment between Stages VI to VIII, larval survival was highest in ozonated water that had been filtered through activated charcoal and coral sand, compared to ozonated water with no filtration or filtered only through activated charcoal. Ozonated water with the combined filtration was used subsequently but there were ongoing deformities, so the level was progressively reduced from 400 mV at Stage VIII to 330 mV at Stage X, at which time ozonation was discontinued. Larvae were then cultured in unozonated water to metamorphosis of eight pueruli at 377 to 437 days after hatch, of which two survived to juvenile. Ozonation was thus effective up to Stage IX in improving culture water to minimise bacterial disease without problems of larval deformities.  相似文献   

13.
In the summer months, epizootics occurred regularly among larvae of Penaeus indicus (Milne Edwards) in a hatchery located at Narakkal near Cochin, India. The clinical signs of infected larvae were expansion of chromatophores. opaqueness of body with twisting and degeneration of appendages. Bacteria were isolated from the infected larvae. These bacteria had morphological, physiological and biochemical characteristics of the genus Vibrio, but these properties did not correspond with those of known Vibrio species. The Vibrio was most related to Vibrio campbellii according to DNA-hybridization experiments. By pathogenicity experiments, the present Vibrio isolate was proved to be pathogenic to larvae, postlarvae and adult shrimp. Shrimp larvae challenged by immersion showed significant mortalities. The bacterial isolate failed to produce the infection in adult shrimp after oral inoculation but it caused significant mortality in adults after intramuscular injection. LC50 and LD50 values of the Vibrio isolate were determined for larvae and adult shrimps, respectively, at different time intervals.  相似文献   

14.
We sought the source of gram-negative bacteria associated with giant freshwater prawns in a hatchery that was previously observed with severe mortality of prawn larvae during the sixth to seventh zoea stages. After thorough disinfection, the gram-negative bacterial microflora of broodstock, larvae, larval rearing tank (LRT) water, and other intake systems were examined for bacteria. Enterobacteriaceae and Vibrio were the major bacteria isolated from the larvae. The present study suggests that Enterobacteriaceae may be introduced via the broodstock and Vibrio via the LRT water.  相似文献   

15.
Northern scallop Argopecten purpuratus aquaculture relies on an efficient all year-round larval supply. Larvae are generally produced in closed aquaculture systems (CAS) using the batch techniques with periodical water changes. For instance, survival rates are greatly variable and can range from 0 to 80% making production of scallop larvae uncertain. The main goal of this study was to determine the feasibility of rearing scallop larvae in a recirculating aquacultural system (RAS), and secondarily to compare scallop larval growth rate and time length to reach the settling stage when reared with a traditional Chilean CAS technique and in a novel RAS technique in an industrial-like approach.Several batches of larvae were cultured in CAS and RAS. Larvae were fed on Isochrysis galbana cultured in 35-L tubular photobioreactors. Growth rates were significantly different (F11,2840 = 274.66; p < 0.001). All scallop larvae cultured in CAS showed lower growth rates ranging within 4.49 and 7.30 μm day?1 and protracted period of culture until settlement (at least 10 more culture days) than those reared in RAS (growth rates between 9.56 and 13.15 μm day?1). However, final survival (from D-larvae until settlement) of larvae reared in CAS showed higher values than those values recorded for larvae cultured on RAS. Higher growth rates observed in RAS could be attributed to a reduction in daily manipulation of the animals and/or more feed availability as well as higher temperatures and a steady state conditions in water quality. Even though, the reduction in time for rearing larvae until settlement in RAS was high, the comparison between systems is more significant in view of the reduction in make up seawater from 100% of system volume (CAS) to less than 10% of system volume (RAS). Therefore, RAS was independent from daily water quality variation from natural seawater by increasing water retention time, and with that improve water quality steady state conditions. Results of this research show that a more efficient use of water and heating systems than generally used in the Chilean hatchery industry is achievable. This is an important result since it could lead to significant reductions in the cost of operating a scallop hatchery, however further work is required to accurately compare the two systems (CAS and RAS). The main result from this research is that scallop larvae can be cultivated using recirculating aquaculture systems (RAS) as a method to increase production. The information reported in this paper will be useful for the improvement of scallop larvae culture techniques under controlled conditions.  相似文献   

16.
The European clam, Ruditapes decussatus is a species with high commercial importance in Portugal and other Southern European countries. However, the development of R. decussatus culture has been limited by the highly variable patterns of natural recruitment. The development of hatchery technology will provide an alternative source of spat. The effect of six nutritional regimes on the survival, growth and biochemical composition of R. decussatus larvae were evaluated, aiming to provide crucial information on its nutritional requirements. A holistic approach incorporating all physiological response showed that the bispecific diet I. aff galbana and C. calcitrans (60/40 cell μL?1) was the more adapted throughout larval development. Moreover, the monospecific diet I. aff galbana provided an overall good performance. Larvae cannot use C. calcitrans at early stages of development; however, the inclusion of these microalgae improved late larval development. The results obtained constitute an important first step in the hatchery R. decussatus larval nutrition and a prerequisite for future work on the improvement of larval development and the optimization of feeding practices that will maximize larvae yield and minimize cost in aquaculture hatcheries.  相似文献   

17.
The objective of this study was to understand the microbial flora associated with the hatchery system of giant fresh water prawn, Macrobrachium rosenbergii during an entire rearing cycle. Bacteriological and physico-chemical analysis was done for different samples of water, larvae, and Artemia. The total bacterial load in well water, seawater and inlet water varied from 101 to 105 cfu ml− 1 with higher counts seen in larval rearing tank (LRT) water. The Vibrio count ranged between 101 to 103 cfu ml− 1. Larval samples harboured a bacterial load of 106 to 107 cfu/10 larvae. The bacterial load in Artemia hatching water ranged from 4.90 × 104 to 5.63 × 106 cfu ml− 1 while Artemia had a load ranging from 1.08 × 107 to 2.09 × 109 cfu g− 1. Vibrio count in the LRT water ranged from 101-103 cfu ml− 1 while the count in larvae ranged from 102 to 104 cfu/10 larvae. The bacterial genera were predominantly Gram-negative and comprised of Aeromonas spp., Pseudomonas spp., Vibrio spp. and Bacillus spp. and non-spore formers (NSF) were the dominant Gram-positive bacteria. This study documents the bacterial flora associated with Macrobrachium hatchery system during a regular normal run. Knowledge of the qualitative and quantitative aspects of bacterial flora in the hatchery would help to understand disturbances, if any, brought about during disease outbreaks.  相似文献   

18.
We present here the first laboratory study on the effects of pharmacologically active compounds on the larval metamorphosis of the New Zealand geoduck, Panopea zelandica (Quoy and Gaimard, 1835). Two batches of competent hatchery‐reared larvae were exposed to acetylcholine chloride, epinephrine hydrochloride and excess potassium ions in the form of KCl and K2SO4. None of the tested chemicals increased the proportion of metamorphosed geoducks, and in some cases, the chemical caused significant mortality, despite having been used extensively with other species, such as mussels and oysters. This might indicate that geoduck larval physiology and development differs from other bivalves. Geoducks may have evolved distinct chemoreceptor patterns that facilitate metamorphosis under environmentally favourable conditions for subtidal soft sediment habitats suitable for burrowing. Thus, further research is needed to identify alternative cues (e.g. conspecific adults, sediment characteristics and surface biofilm) and understand their role in settlement and metamorphosis. This information will aid the design of reseeding methods and contribute to the development of reliable hatchery production of geoduck spat.  相似文献   

19.
To understand the influence the environment and associated genotype by environment interactions will exert on future silver-lip pearl oyster (Pinctada maxima) selective breeding programs, this study assessed the relative performance in four shell growth traits of spat from five full-sib families, when spat were communally reared at different salinities (29, 34 and 40 ppt), food availability (high, medium and low), food quality (high, medium and low), and in a hatchery vs. ocean environment for 43 days.Rearing environment was found to influence growth expression, with significant differences evident when oysters were grown at different salinities in the ocean instead of hatchery, or when fed algae of differing nutritional quality. As indicated by MANOVA, family comparative growth performances were also altered when the environment changed, with significant environment by family interactions apparent in the food quality, food availability and hatchery vs. ocean rearing treatments. Changes in salinity, however, did not affect relevant family performances.These results indicate that growth and relative family performance in P. maxima may change dependent on local environmental conditions and that genotype by environment effects may need to be considered in breeding programs for this species.  相似文献   

20.
The effect of temperature on the development, growth, survival and settlement of Perna viridis was studied under controlled conditions to provide information needed for the development of commercial hatchery technology for green mussel P. viridis. Total mortality of the larvae occurred after 24 h at temperatures of 33°C and 35°C. At 24°C, larvae took longer to settle than at temperatures of 27°C, 29°C and 31°C. For optimum larval development (8–13 h), growth (17.2±0.84 μm day–1) and survival (55.2±0.84%), a hatchery rearing temperature of 31°C is required. For settlement no significant difference was seen between the percentage settlement at 29°C (49.3±3.34%) and 31°C (45.8±1.76%). However, the process of settlement began and ended earlier at 29°C (from 15 to 18 days) than at 31°C (from 18 to 20 days). Thus for larval settlement a temperature of 29°C is recommended.  相似文献   

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