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1.
We used an up‐to‐date, a high accuracy CO2 manipulation system to investigate the sensitivity of organisms to CO2 acidification, rearing marine calcifiers under elevated CO2 in running water. We evaluated the effects of elevated partial pressures of carbon dioxide (pCO2) in seawater on larvae of the commercially important marine gastropod Ezo abalone Haliotis discus hannai. In larval Ezo abalone, no effect of exposure to <1100 μatm pCO2 seawater was observed in fertilization, malformation, or mortality rates until 15 h after fertilization. However, compared to control larvae in seawater (450 or 500 μatm pCO2), the fertilization rate and the hatching rate (15 h after fertilization) decreased with increased pCO2 exposure (1650 and 2150 μatm pCO2) and the malformation rate increased significantly, with the larval shell length being smaller 75 h after hatching. These results suggest that ocean acidification will potentially impact the marine population of Ezo abalone as a human food source in the future.  相似文献   

2.
Histo- and immunohistochemical techniques have recently been used to study the fibre type and myosin expression in fish muscle during development. In the present work, embryonic, larval and adult myosin isozymes (heavy and light chains) and parvalbumin isotypes were analyzed, from fertization to the adult stage, by polyacrylamide gel electrophoresis of barbel (Barbus barbus L.) trunk muscle extracts. The examined myosins display the sequential transitions from embryonic to larval and adult forms characteristic of higher vertebrates. They are characterized by specific heavy chains but their light chains differ only by the LC1/LC3 stoichiometry with LC3 exceeding LC1 after 10 days. Sarcoplasmic parvalbumins show considerable and unforeseen developmental transitions in their isotype distribution: the PA II isotype first appears after hatching and becomes the predominant form until the length reaches about 6 cm. One month after hatching, the amount of PA II then decreases and the synthesis of PA III and IV further increases to reach the typical adult pattern at a size of 18 cm. These observations show that the distribution of parvalbumin isotypes reflects the stage of development. It suggests a specific role for each isotype in relation to muscle activity. Microscopy illustrates the progressive development of somites, muscles cells, and myofibrils, which accelerates at hatching when movements increase.  相似文献   

3.
Larvae and early postlarvae of the ocean quahog, Arctica islandica, were reared under experimental hatchery conditions. Mature eggs were stripped from ripe adults and exposed to a dilute solution of ammonium hydroxide for various lengths of time prior to addition of stripped sperm. The larval clams were reared through settlement and metamorphosis using the Wells-Glancy (centrifuged, incubated seawater) method of algal culture and/or modifications of standard hatchery techniques developed by Loosanoff and Davis. Experimental cultures were maintained at various temperatures ranging from 8.5° to 14.5°C. At temperatures of approximately 13°C, the minimum time to settlement was 32 days, while settlement was not observed in a culture maintained between 8.5° and 10.0°C until approximately 55 days after fertilization. Larval growth rates were significantly lower in the culture maintained at 8.5–10.0°C than in cultures maintained at 11.0–14.5°C. An optical micrograph sequence of larval stages from the straight-hinge stage through metamorphosis is presented to facilitate identification of Arctica islandica specimens isolated from plankton samples. While various workers have reported exceedingly low growth rates of juvenile and adult Arctica, growth rates of larval Arctica appear to be fairly “typical” of rates encountered within the class Bivalvia.  相似文献   

4.
Abstract

There were strong correlations between soil pH and pHof water (R2 = 0.810) and total alkalinity (R2 = 0.724) in laboratory soil-water systems prepared with acidic rainwater and pond soil samples from Thailand. Moreover, water pH and total alkalinity were highly correlated (R2 = 0.987). Although soil carbonate concentration was not correlated with total alkalinity, there was a correlation between the product of soil carbonate and soil organic carbon and total alkalinity (R2 = 0.482). Other soil properties, exchange acidity, cation exchange capacity, base saturation, and total sulfur, were either not correlated or weakly correlated with total alkalinity. Total alkalinity did not exceed 20 mg/L except in systems with soils containing free carbonate. A method that estimates the amount of liming material needed to completely base-saturate bottom soils and provides an excess of carbonate, should be used in Thailand and other places. Calcitic agricultural limestone gave higher total alkalinity concentration in soil-water systems than dolomitic agricultural limestone. There usually would be no justification for selecting higher-priced dolomitic limestone for use in ponds.  相似文献   

5.
为了解单一饵料或混合投喂对玉足海参(Holothuria leucospilota)幼体生长的影响,采用2种单胞藻(牟氏角毛藻、球等鞭金藻)和2种酵母(酿酒酵母、海洋红酵母)单一或组合搭配投喂玉足海参耳状幼体,测定并比较海参幼体的体长、胃宽、水体腔长、变态成活率等指标。试验结果显示：单一饵料组中,牟氏角毛藻对玉足海参幼体体长的生长及变态存活最有利,而球等鞭金藻对其脏器(胃、水体腔)的发育最有利;综合所有处理组的投喂效果看,混合投喂组比单一饵料组更有利于玉足海参幼体的生长和存活,其中酿酒酵母+海洋红酵母的混合投喂组合得到了最高的体长、胃宽和水体腔长特定生长率,牟氏角毛藻+海洋红酵母投喂组的变态成活率最高,变态发育速度最快。结果表明,在玉足海参幼体培养早期适合以混合酵母为主投喂,后期则可较多投喂牟氏角毛藻和海洋红酵母。  相似文献   

6.
The embryonic and larval development of black skirt tetra, Gymnocorymbus ternetzi, are described under controlled laboratory conditions. In addition, major histomorphological changes and the allometric growth patterns during larval development have been described. The laboratory‐reared broodstock, that is 1 year of age, were spawned. Hatching occurred 20–21 h after spawning at 24 ± 0.5°C. The cleavage was finished in 2 h and the early blastula stage occurred at 2:04 hours after spawning. The gastrulation started at 3:20 hours and 30% epiboly was observed at 3:34 hours after spawning. Eight‐somite stage was observed at 08:33 hours. And embryonic developmental stage was completed at 21 h after spawning. The newly hatched larvae were 1442 ± 14.3 μm in mean total length (TL). The mouth opened at 3 days after hatching (DAH). The yolk sac had been totally absorbed and the larvae started to swim actively within 3–4 days. Notochord flexion began at 11 DAH. The metamorphosis was completed and the larvae transformed into juveniles at 32 DAH. In this paper, the full developmental sequence from egg to juvenile of G. ternetzi is described for the first time.  相似文献   

7.
In order to derive the full benefits of ozonation technology for the destruction of toxic metabolites in shrimp grow-out ponds, strategies to supplement and control high alkalinity loss during ammonia oxidation in a model ozonation system were studied. Alkalinity loss and pH profiles were investigated in the ozonated model system containing artificial seawater and ammonia, and alkalinity compensation ability of supplements such as calcium carbonate-based limes, hydrated limes and sodium bicarbonate were evaluated. In some experiments, application of these supplements during ozonation were combined with other treatments like recarbonation (external CO2 supply). Results showed that calcium carbonate-based limes were not anymore effective for alkalinity supplementation when ozonation is applied to seawater containing ammonia. Although recarbonation improved the effectiveness of CaCO3 as an alkalinity supplement, application in large ozonated grow-out ponds were considered not practical. The effective alkalinity supplements for ozonated seawater containing ammonia were the more soluble materials, high purity sodium bicarbonate and hydrated lime applied at a proper dosage. Sodium bicarbonate and hydrated lime would be more appropriate alkalinity control strategies for in situ1 ozonated shrimp grow-out ponds; however, for application of hydrated lime, the problem of overdosage should be taken into consideration.  相似文献   

8.
A 3 × 2 factorial experiment was conducted to investigate the interaction between carbonate alkalinity and dietary α‐ketoglutarate (AKG) levels on the growth performance, antioxidant capacity and ammonia metabolization of Songpu mirror carp (Cyprinus carpio Songpu). Each diet (0%, 1% AKG) was randomly allotted to 0 mmol/L, 15 mmol/L, 30 mmol/L carbonate alkalinity groups with three replicate aquaria. The weight gain rate (WGR) significantly increased in the 1% AKG group and significantly decreased with increasing carbonate alkalinity (p < .05). Crude ash was significantly affected by the interaction between carbonate alkalinity and dietary AKG levels and significantly increased in the 1% AKG group (p < .05). A significant interaction between carbonate alkalinity and dietary AKG levels on superoxide dismutase (SOD) activities in hepatopancreas was observed (p < .05). The increasing carbonate alkalinities significantly decreased SOD activities in the hepatopancreas and foregut, catalase (CAT) activities in the hepatopancreas, foregut, midgut and hindgut and glutathione (GSH) contents in the hepatopancreas and foregut (p < .05). Despite AKG addition, the blood ammonia content still increased with increasing carbonate alkalinities. The gene expressions of AQP3, Rhag, Rhcg2 and Na+/K+‐ATPase (NKA) in the gills and glutamine synthase (GS) in the brain were significantly upregulated with increasing carbonate alkalinities (p < .05). In the 1% AKG group, GS gene expression significantly upregulated in the brains, whereas AQP3, Rhag, Rhcg2 and NKA gene expressions significantly downregulated in the gills (p < .05). In summary, the 1% AKG addition can enhance the gene expression of ammonia metabolization and improve the antioxidant capacity of Songpu mirror carp with chronic carbonate alkalinity stress.  相似文献   

9.
This study compared the growth of sea urchin Paracentrotus lividus larvae cultured using two different rearing methods: a variable method based on a variable amount of feed (microalgae) and seawater exchange (30% or 50%) established according to the phytoplankton concentration in the larval cultures and a fixed method characterized by a fixed amount of feed and seawater exchange. Three microalgae diets, Isochrysis sp. (Tahitian strain, T‐Iso), Chaetoceros gracilis and a 50:50 mixed diet, were tested with both rearing methods. Larval development and survival were assessed at the 6‐arm pluteus stage (P6), competence (Cp) and metamorphosis (Mt). Data showed that the variable method reduced the requirements for phytoplankton and seawater exchange. Indeed, through the optimization of feed rations, it was possible to reduce the production of debris and settled phytoplankton, minimizing the need for water exchanges. Higher larval survival resulted at Cp and Mt stages for those reared with the variable method as opposed to the fixed one. Survival and development were also influenced by the tested dietary treatments: at Mt stage, the mixed diet resulted in a higher larval survival (63.3 ± 8.9%) than T‐Iso (19.7 ± 12.1%) and C. gracilis (23.4 ± 15.1%) (P < 0.05). These results suggest that the use of the variable method improves the larval survival and development and also it reduces resource consumption (phytoplankton, seawater use and work effort), which in turn could potentially improve the hatchery production of P. lividus.  相似文献   

10.
This study aimed at evaluating the effects of two starvation modes (fasting‐feeding mode and feeding‐fasting mode) on survival, growth and development of mysis larvae of Exopalaemon carinicauda. It showed that food restriction significantly affected the survival, growth and development in both starvation modes. With the extension of initial starvation period, a significantly reduced survival rate during metamorphosis was observed. In the fasting‐feeding mode, the duration of metamorphosis was extended and the body lengths of the individuals, which experienced successful metamorphosis to the post‐larval stage 1, were much shorter. In the feeding‐fasting mode, the extension of initial feeding period led to dramatically increased survival rate and body lengths, while there was no significant difference in duration of metamorphosis of those groups that reached to post‐larval stage. The 50% point‐of‐no‐return and the 50% point‐of‐reserve‐saturation were 3.85 days and 4.81 days respectively. The results of this study indicate that E. carinicauda mysis have the ability to withstand or recover from relatively extended starvation, but to ensure the success of commercial seedling, timely and adequate feeding is necessary. The information obtained from this study could provide a basis to optimize the feeding schedule of artificial seedling of E. carinicauda.  相似文献   

11.
Seta  Tomofumi  Kurashima  Akira 《Fisheries Science》2021,87(3):365-370

The amphipod Sunamphitoe namhaensis grazes on seedlings of Sargassum horneri in culture. To exterminate S. namhaensis, we immersed them in seawater with dissolved carbon dioxide—a treatment used previously to remove copepods in cultures of abalone and sea cucumber. Experiments were conducted under different CO2 (aq) concentrations and for different lengths of time. Amphipod mortality was 100% following immersion in CO2 seawater with a CO2 (aq) concentration of 26,262 µmol/kg (pH 5.0) for 60 min. When algal seedlings were immersed in CO2 seawater under these same conditions, their survival rate and growth were not affected.

  相似文献   

12.
The cause of abnormal musculature on both sides of the same myotome in artificially cultured seven‐band grouper Epinephelus septemfasciatus (Thunberg) larvae remains unclear. We evaluated the effect of three factors: changes in temperature (between 22 and 24°C), disinfection with ozonated seawater (0.3 mg TROs L?1, 1 min), and hypoxia (22 or 14% saturation) during the early (20 h post‐fertilization, hpf) and mid‐ (24 hpf) somite stages on trunk muscular development in larval seven‐band grouper. The thermal regimes and disinfection with ozonated seawater had no effect on muscle development (P > 0.05, G‐test). In contrast, exposure to hypoxia during both the early and mid‐somite stages increased the incidence of abnormal musculature in the trunk (P < 0.01, G‐test). These larvae had abnormal musculature on both sides of the trunk. In addition, the number of abnormal myotomes differed among these larvae. Exposure in the early and mid‐somite stages resulted in the highest frequency of abnormalities in the 11th and 13th myotome respectively. Our results suggest that hypoxia during somitogenesis can lead to abnormal muscle development in the trunk of artificially cultured seven‐band grouper larva.  相似文献   

13.
This study was carried out to test the effect of triiodothyronine (T3) on the growth and survival of larval striped bass (Morone saxatilis). Growth and survival of striped bass held in 5 ppt seawater and treated with various doses of T3 were measured beginning at 5 and 16 days after hatching. Body content of T3 was measured by radioimmunoassay. T3 dissolved in the 5 ppt seawater was taken up by larval striped bass in a dose-dependent manner, and affected the growth and survival of the fish. At 5 days after hatching, T3 at 100 ng ml–1 and 50 ng ml–1 retarded the growth of larval striped bass and caused a lower survival rate than T3 at 25 ng ml–1 or the control treatment. At 16 days after hatching, T3 at 100 ng ml–1 retarded the growth of larval fish and caused a higher mortality. T3 at 10 ng ml–1 and 1 ng ml–1 did not show any effect on either survival or growth. Body content of T3 returns to control levels within days following end of treatment. The results indicate that exogenous T3 can be detrimental to the growth and survival of larval striped bass.  相似文献   

14.
This work aimed at assessing the role of salinity in the dissolution rates of CaCO3, discussing its implications for aquaculture liming. A simplified formula of artificial seawater without HCO3? was initially prepared. Four batches of 10 L of diluted artificial seawater (salinity = 3.3 g/L) without HCO3? were prepared. Sixteen Erlenmeyer flasks were filled up with 2 L each of the diluted artificial seawater without HCO3?. Besides, 16 other 2,000‐ml Erlenmeyer flasks were filled up with 2 L of distilled water (freshwater). The experimental treatments were formed by applying increasing amounts of analytical‐grade sodium bicarbonate (NaHCO3) upon brackish water and freshwater. Accordingly, four initial levels of total alkalinity (TA) have been set up as follows: 4–6, 33–35, 62–63 and 120–122 mg/L. Next, approximately one gram of analytical‐grade calcium carbonate (CaCO3) was applied onto each flask. Water's pH, TA and calcium concentration were determined weekly over a 7‐week period, by appropriate methods. For a same initial TA, TA increase over time after CaCO3 application was lower in the brackish water flasks than in the freshwater ones. This was especially clear for moderate (63 mg/L) and high (120 mg/L) alkalinities. It was concluded that brackish and saline waters used for aquaculture would only benefit from CaCO3 liming if their alkalinities were lower than 60–80 mg/L.  相似文献   

15.
Ocean acidification, resulted from high level of carbon dioxide (CO2) dissolved in seawater, may disturb the physiology of fish in many ways. However, it is unclear how acidification may impact the growth rate and/or growth hormones of marine fish. In this study, we exposed juvenile orange‐spotted groupers (Epinephelus coioides) to seawater of different levels of acidification: a condition predicted by the Intergovernmental Panel on Climate Change (pH 7.8–8.0), and a more extreme condition (pH 7.4–7.6) that may occur in coastal waters in the near future. After 6 weeks of exposure, the growth rates of fish in pH 7.4–7.6 were less than those raised in control water (pH 8.1–8.3). Furthermore, exposure at pH 7.4–7.6 increased blood pCO2 and HCO3? significantly; exposure at pH 7.8–8.0, meanwhile, did not affect acid–base chemistry. Moreover, exposure to pH 7.4–7.6 resulted in lower levels of hepatic igf1 (insulin‐like growth factor I) mRNA, but did not affect levels of pituitary gh (growth hormone) or hypothalamus psst2 and psst3 (prepro‐somatostatin II and III). The results show that highly acidified seawater suppresses growth of juvenile grouper, which may be a consequence of reduced levels of IGF‐1, but not due to diminished growth hormone release.  相似文献   

16.
采用静态毒理学方法研究了不同碳酸盐碱度(3.5,5,6.5,8 mmol/L)胁迫对脊尾白虾(Exopalaemon carinicauda)生存、生长、繁殖及免疫酶活性的影响。结果表明,碳酸盐碱度对脊尾白虾的96 h LC_(50)值为8.73 mmol/L(p H约为9.15);脊尾白虾的死亡率、特定生长率、抱卵率、孵化率、性腺发育及变态幼体成活率随碱度的上升而降低,3.5 mmol/L的低碳酸盐碱度对脊尾白虾生长繁殖影响不显著(P≥0.05),高于该碱度则会显著降低其生长及繁殖能力(P0.05);随着碳酸盐碱度胁迫时间的增加,各碱度胁迫组脊尾白虾鳃和肝胰腺中的免疫酶活性均呈先升高后降低的变化趋势。研究结果表明,脊尾白虾具有较高的碳酸盐碱度耐受性,碳酸盐碱度为3.5 mmol/L时对生长和繁殖影响不显著,高于5 mmol/L时影响显著;高碳酸盐碱度胁迫下脊尾白虾可以通过调节免疫酶的活性更好地适应高碱环境。  相似文献   

17.
Whole-animal thyroxine (T4) and 3,5,3′-triiodothyronine (T3) levels were measured in larval and juvenile striped bass, Morone saxatilis, reared for 10 days at one of three levels of salinity (equivalent to fresh water (FW), one-third seawater (1/3 SW), and seawater (SW) and two temperatures (15°C and 20°C). The striped bass were pre-metamorphic larvae, metamorphic larvae or juveniles. The short-term effects of seawater on plasma T4 levels of juvenile striped bass were also measured. Higher salinities increased T4 levels in premetamorphic larvae. In metamorphic larvae, SW and 1/3 SW increased T4 levels and SW increased T3 levels at 20°C. This response was eliminated in those at 15°C. Whole-animal thyroid hormone content was unaffected by salinity or temperature in juvenile striped bass, although significant fluctuations in plasma T4 levels occurred in those transferred to 1/3 SW and SW. The thyroid axis of striped bass responds to salinity and temperature as early as in the pre-metamorphic stage. Thyroid hormones may mediate the beneficial effects of salinity on larval striped bass growth and survival.  相似文献   

18.
The effects of glycopeptides, prepared from pearl oyster Pinctada fucata, on embryonic development, larval and juvenile growth and adult non‐specific immunity of P. fucata were investigated in this study. Glycopeptides had a pronounced stimulatory effect on embryonic development and larval and juvenile growth of P. fucata. enhancing with increased glycopeptide concentrations. All of haemocytes, phagocytosis, aggregation, serum microbiostatic activity and bacteriocidal activity all showed significant increases after 60‐day feeding, relative to unfed controls. The major conclusion is that glycopeptides had a pronounced stimulatory effect on the non‐specific immunity of pearl oysters.  相似文献   

19.
This study investigates the effects of embryonic exposure to two different antioxidants on growth and development in fish. Zebrafish (Danio rerio) embryos (100 per group) were exposed to lipoic acid (LA, 6–12 μM) or ascorbic acid (AA, 100–200 μM) and the hatching rate, standard lengths (SL) at hatching, development and growth post‐hatching monitored. The SLs at hatching were increased (P<0.05) in both antioxidant‐exposed groups relative to the controls, with no effect on yolk reserves. This enhanced development persisted up to 15 days post hatching. At hatching, cell proliferation rates (P<0.0005) and basic fibroblast growth factor (P<0.001), were greater in the antioxidant‐exposed fish than in the controls (0 μM antioxidant); no oxidative DNA damage was detected (P>0.05). Activity of the endogenous antioxidant enzyme superoxide dismutase was greater (P<0.001) in LA‐treated fish than in the controls. The results suggest that embryonic treatment of zebrafish with LA or AA during embryogenesis enhanced cell proliferation, leading to increased somatic growth in the larval stages, persisting into the juvenile stage. The findings support the treatment of embryonic fish with antioxidants for enhanced results in aquaculture.  相似文献   

20.
Morphological changes in the embryos, egg size and development, incubation period and morphological structures of newly hatched zoea of three mud crab Scylla species were determined. The three species exhibited similar embryonic development composed of 10 stages. The mean egg diameter of Scylla serrata was significantly larger (P<0.05) at the prehatch stage. The mean egg diameters of Scylla tranquebarica and Scylla olivacea were similar (P>0.05). The incubation period was the longest in S. serrata and the shortest in S. olivacea. There was a positive relationship between egg size and larval size, as S. serrata exhibited the largest egg size and first zoea. However, no correlation was detected between egg size at prehatch and lengths of the morphological structures of the newly hatched zoea. The three species exhibited similar lengths of cephalic structures, but S. olivacea had significantly shorter (P<0.05) abdominal structures. The duration of spawning from ablation was the shortest in S. tranquebarica and the longest in S. olivacea. The study is relevant to aquaculture and fisheries management of Scylla species.  相似文献   

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