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1.
温度和密度对日本医蛭繁殖的影响 总被引：1，自引：0，他引：1
在实验室网箱中,研究温度(24±1)℃和(20±1℃)与密度(200尾/箱和100尾/箱)对平均体质量1g左右的日本医蛭Hirudo nipponia亲蛭交配率、减重率、产茧数量和体质量的影响,比较卵茧质量(0.05g、0.05~0.1g和0.1g)对孵出仔蛭数量的影响。结果表明:温度(24±1)℃、密度100尾/箱时亲蛭交配率(86±0.06)%和平均产茧量(0.87±0.14)枚/尾最高;亲蛭产茧后平均体质量下降(32.1±0.059)%;繁殖期间共收集卵茧870枚,孵化率87.47%;平均卵茧质量为(0.11±0.009)g(变化范围0.03g~0.25g);密度和温度对产茧量的影响极显著(P0.01),对卵茧平均质量和长短径的影响不显著(P0.05);(24±1)℃组亲蛭的产茧时间比(20±1)℃组缩短10~15d,单日卵茧最高收集量为43枚,(20±1)℃时单日最高收集量24枚;卵茧共孵出仔蛭5 648尾,随着卵茧质量增加产出的仔蛭数量和质量也增加。 相似文献
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阿鲁加姆锡兰蛭(Zeylanicobdella arugamensis)是重要的鱼类体外寄生虫,可感染30余种海水鱼类。阿鲁加姆锡兰蛭病在我国和东南亚多个国家的海水养殖鱼类中流行,严重时可导致鱼类大量死亡。为持续、稳定、足量地获得活体寄生虫,供防治鱼蛭病研究使用,本研究通过鱼蛭在体感染实验,建立了阿鲁加姆锡兰蛭的传代培养体系。研究结果证实,2种海水观赏鱼[棘颊雀鲷(Premnas biaculeatus)和白条双锯鱼(Amphiprion frenatus)]可作为宿主鱼,用于该鱼蛭的传代培养,且传9代后产生的子代仍具有很强的感染力。鱼蛭的生活史观察显示,该鱼蛭的生活史可分为卵茧孵化和幼蛭发育2个阶段。在水温为26℃、盐度为30的条件下,鱼蛭最短20 d即可完成其生活史。其中,卵茧孵化为幼蛭需要9 d,孵化率高达83.8%;幼蛭感染宿主、发育成熟并开始产卵茧最短需要11 d。本研究可为海水鱼蛭的生物学和鱼蛭病的防治研究提供技术支撑。 相似文献
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Margarete Mallasen Wagner Cotroni Valenti 《Journal of the World Aquaculture Society》2005,36(1):32-41
The effect of ammonia and pH levels on giant river prawn Macrobrachium rosenbergii larvae were evaluated to provide science-based information on safe levels of ammonia and pH for larviculture. Survival rate, developmental stage, and larval weight gain were determined for larvae kept in water with total ammonia (NH 4 -N)concentrations of 0, 1, 2, 4, and 8 mg\L and pH 7, 8, and 9. The trials were conducted in two phases: phase 1, larvae from stages I through VIII and phase 2, larvae from stage VIII until metamorphose. Oxygen consumption was determined for larvae in stages I and VIII at total ammonia concentrations of 0, 4, and 8 mg/L and pH 8. Survival rate up to stage VIII varied from 86 to 98% and did not differ for total ammonia concentrations in pH 7 and 8 and for 0 mg/L NH4 N in pH 9. Survival rate was significantly lower (0–20%) for total ammonia concentrations from 1 to 8 mg/L (0.43–3.41 mg/L of unionized ammonia) in pH 9. Larval stage indexes (7.9–8.0 range) and weight gain (1.572–2.931 mg range) of larvae at the end of phase 1 of the experiment did not differ for the different ammonia concentration solutions, but were significantly lower in pH 9. In phase 2, no parameter differed among treatments for pH 7 and 8; however there was total mortality at pH 9 until 96h. Respiration rates diminished when larvae were exposed to total ammonia concentrations of 4 and 8 mg/L (0.28 and 0.55 mg/L of unionized ammonia), but development remained unaltered. Therefore, M. rosenbergii larvae tolerate high levels of total ammonia, while toxicity depends primarily on unionized ammonia concentrations. In addition, alkaline pH (9) acted directly on the larvae, curbing development and causing severe mortality. Larval tolerance to high ammonia and pH levels decreases for the last zoeal stages. 相似文献
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Clyde L. MacKenzie 《Aquaculture (Amsterdam, Netherlands)》1977,10(1):45-51
A single application of quicklime (calcium oxide), spread at a rate of 6.75 metric tons/ha, was used to prepare dormant oyster setting beds for spat production. Of 2 000 ha in Long Island Sound, Connecticut, U.S.A., 1200 ha had sufficient shells to cover at least 75% of the bottom. However, these shells had a continuous fouling organism layer that would prevent significant oyster setting. Many beds had predator populations of sea stars (Asterias forbesi) and oyster drills (Urosalpinx cinerea and Eupleura caudata). Quicklime cleans the shells by killing fouling organisms, and also controls sea stars and embryonic oyster drills.When the supply of clean shells for annual spreading on the setting beds is limited, use of the quicklime method prepares greater quantities of shells for possible oyster set. 相似文献
6.
比较有机孵化基质对宽体金线蛭卵茧孵化效果和不同开口饵料对苗种生长发育的影响。孵化基质分别为土壤、牛粪有机肥、蘑菇菌渣,开口饵料分别为螺蛳、漂螺。试验结果显示,蘑菇菌渣+土壤组卵茧孵化率高达98.89%,显著高于土壤组和蘑菇菌渣组(P<0.05);幼蛭各生长指标显著高于土壤组、蘑菇菌渣组、有机肥组及有机肥+土壤组(P<0.05);混合组幼蛭各生长指标均显著高于未添加土壤组(P<0.05)。5种不同孵化基质孵化率依次为蘑菇菌渣+土壤>土壤>有机肥+土壤>有机肥>蘑菇菌渣。不同开口饵料的试验比较发现,漂螺组幼蛭成活率为72.50%,显著高于螺蛳组和螺蛳+漂螺组(P<0.05),漂螺组和螺蛳+漂螺组幼蛭体质量显著高于螺蛳组(P<0.05)。生长效果依次为漂螺组>螺蛳+漂螺组>螺蛳组。试验结果表明,蘑菇菌渣可以作为宽体金线蛭卵茧孵化基质;无厣结构的漂螺更适宜作宽体金线蛭幼蛭的开口饵料。 相似文献
7.
《Journal Of Applied Aquaculture》2013,25(3-4):81-100
Hybrid striped bass larvae (striped bass, Morone saxatilis, ♀ x white bass, M. chrysops, ♂) are often stocked into fertile culture ponds. High rates of photosynthesis may result in elevated pH which can be lethal to fry and can affect the toxicity of ammonia. Six-hour static toxicity tests were performed on hybrid larvae of various ages to determine the toxicity of elevated pH and the effects of elevated pH on ammonia toxicity. Six-hour mortality threshold pH's with no measurable ammonia were estimated for various age larvae and found to be between pH's 9.8 and 10.2 for D2 (Dl is day of hatch), between 9.0 and 9.4 for D4, between 8.8 and 9.2 for D13, and between 9.2 and 9.4 for D20 fish. The addition of 0.7% NaCl had no effect on the toxicity of elevated pH to D2 or D4 fish but caused a significant reduction in the mortality of Dl3 and D20 fish exposed to high pH. The tolerance to elevated pH decreased as ammonia concentration increased. Sub-lethal un-ionized ammonia concentrations increased the toxicity of elevated pH, suggesting an interaction of pH and un-ionized ammonia toxicity. 相似文献
8.
中华绒螯蟹温室育苗的水处理 总被引：6，自引：0，他引：6
通过对生物净化系统处理前后育苗水质指标变化情况的测定,初步探讨了生物净化系统在河蟹育苗过程中对水质的处理效果和应用价值。与传统的育苗工艺相比,应用生物净化系统有机物降解速度快,脱氮效果显著。ＣＯＤ、总氨氮的平均去除率分别为３３．２％,５５．５％。整个育苗过程ｐＨ稳定,溶氧丰富,池底无氧债和黑臭。 相似文献
9.
Yan Wang Wei L Wang Jian G Qin Xiao D Wang & Sheng B Zhu 《Aquaculture Research》2009,40(14):1634-1641
The effects of integrated combination and quicklime supplementation on growth and pearl yield of a freshwater mussel, Hyriopsis cumingii (Lea, 1852), were examined through a 137-day growout in land-based enclosures. The integrated combinations examined were either mussel, bighead carp and gibel carp or mussel and bighead carp. Each combination was treated either with or without quicklime supplementation. One half of the mussels in each enclosure were grafted with pieces of the mantle epithelium while the other half were not. During the experiment, gibel carp were fed formulated feed while the mussel and bighead carp were fed natural live food. Quicklime was regularly provided in the enclosures as calcium replenishment. The species composition in the integrated system significantly affected growth in shell size and wet weight of the mussels regardless of the graft and pearl yield, while no significant effects of quicklime supplementation were detected. Growth rates in shell size and wet weight of both grafted and non-grafted mussels and pearl yield were slightly higher in the enclosures with mussel, bighead carp and gibel carp than those with mussel and bighead carp, although these differences were not statistically significant. The non-grafted mussel exhibited faster growth in shell size and wet weight than the grafted mussel within the same treatment. Results of the present study indicate that species combination in an integrated system can affect growth and pearl yield of H. cumingii . The species combination of mussel, bighead carp and gibel carp is recommended for commercial H. cumingii farming. 相似文献
10.
Experiments were conducted to determine the performance of larval walleye (Stizostedion vitreum) reared in clear, 0.2 nephelometric turbidity units (NTU), and turbid water, 20 or 50 NTU, on formulated feed. Larvae were cultured for 21, 28, or 30 days posthatch in four trials with 3 or 4 replicate tanks per treatment (clear and turbid) in each trial. Duration of each trial was dependent on the arrival of newly hatched larvae for subsequent trials. The desired turbidity levels were obtained by pumping a solution of clay to the culture tanks every 20 (trial 1) or 30 min (trials 2, 3 and 4). Other than turbidity, all environmental conditions (dissolved oxygen, alkalinity, pH, total ammonia, un-ionized ammonia, nitrate, nitrite, chloride, and hardness) and rearing techniques were similar between treatments. Larvae were stocked at 20/L and fed formulated feed (Fry Feed Kyowa B-400 and B-700) every 3 to 7 min, 24 hours per day. Significant differences in feed acceptance and total length between larvae in the clear and turbid water were observed as early as 7d posthatch. Larvae in turbid water began eating the formulated diet one to two days before those in clear water. In all trials, survival, final length, and final weight of larvae reared in water of high turbidity were significantly greater than for larvae reared in clear water. Mean survival (±SE) for all four trials was 27.7 ± 5.6% in high turbidity water and 5.9 ± 1.3% in clear water. At the end of the trials, mean total length of the larvae reared in turbid water was at least 3.2mm (15%) greater than that in the clear water. Mean final weight of the larvae from turbid water was 2.25 times greater than larvae from clear water over the four trials. In two of the four trials, gas bladder inflation (GBI) of larvae reared in high turbidity was significantly greater than for fish reared in clear water, but the difference in GBI was not significant in the other two trials. In this study, performance of larval walleye was greatly enhanced by water with a turbidity of at least IS NTU. 相似文献
11.
The high prevalence (80–100%) of the marine leech Zeylanicobdella arugamensis (De Silva) on cage‐cultured Asian sea bass Lates calcarifer (Bloch) led us to investigate the percentage of juvenile leeches hatched from deposited cocoons, survival of juvenile and adult marine leeches at different salinity and temperature. The results showed that the hatching percentage of juvenile leeches was highest at salinity of 30 ppt (32.5 ± 2.8%) followed by 20 ppt (18.0 ± 4.3%) and 10 ppt (12.1 ± 1.4%), respectively. It was found that the adult and juvenile leeches could live up to an average range of 4–7 days at salinity ranging from 10 to 40 ppt. The juvenile leeches were able to hatch at temperature ranging from 25 to 35 °C but unable to hatch at 40 °C. The survival period of adult and juvenile leeches ranged from 11 to 16 days at 25 °C, which was comparatively longer than 5–13 days and 10 h – 5 days at 27–30 °C and 35–40 °C, respectively. The study provided the information on the physical parameters of salinity and temperature which are most optimal for the marine leech Z. arugamensis to propagate. 相似文献
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Yolk-sac larvae and starved larvae of Clarias gariepinus (Burchell 1822), reared at 28°C, were predominantly ammonotelic, but urea excretion contributed about 19±7% to the total nitrogen excretion. Exogenously feeding larvae of C. gariepinus were mainly ammonotelic until 180-205 h post fertilization, but from then on the relative urea excretion stabilized at 44±13%. The contents of total free amino acids (FAA) and ammonia in C. gariepinus peaked around complete yolk absorption. During the first period after hatching 64% of the FAA and 60% of the total ammonia were located in the yolk compartment. The body compartment contained the highest amount of FAA and total ammonia at the end of the yolk-sac period (65 and 77%, respectively). The amount of nitrogen originating from catabolism of amino acids was balanced within 6% by the excreted sum of ammonia and urea. The high degree of ureotelism in C. gariepinus larvae may constitute an adaptive mechanism to a habitat of temporal water shortage. 相似文献
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W Rietschel 《Tier?rztliche Praxis》1989,17(2):189-193
The occurrence of sand fleas (Tunga penetrans) in a reservation in the north of French Guyana is described. The parasite is found on dogs, Europeans and children of the local Indian tribes. Infections in man are supported by a big population of stray dogs as well as by the local cottage construction. Due to the simultaneous efficiency against the larvae of Dermatobia hominis lvermectin is only of limited suitability for the treatment of tungiasis in dogs. In man single parasites can be removed with a splinter forceps. In dogs footbathing with 0.2% Neguvon has shown to be effective. On long term a reduction of the stray dog population is recommended. 相似文献
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M. SAAVEDRA P. POUSÃO-FERREIRA M. YÚFERA M.T. DINIS & L.E.C. CONCEIÇÃO 《Aquaculture Nutrition》2009,15(5):517-524
Fish larvae present high amino acid requirements due to their high growth rate. Maximizing this growth rate depends on providing a balanced amino acid diet which can fulfil larval amino acid nutritional needs. In this study, two experimental microencapsulated casein diets were tested: one presenting a balanced amino acid profile and another presenting an unbalanced amino acid profile. A control diet, live feed based, was also tested. Trials were performed with larvae from 1 to 25 days after hatching (DAH). Microencapsulated diets were introduced at 8 DAH in co-feeding with live feed and at 15 DAH larvae were fed the microencapsulated diets alone. Results showed a higher survival for the control group (8.6 ± 1.3% versus 4.2 ± 0.6% and 3.2 ± 1.8%) although dry weight and growth were similar in all treatments. The proportion of deformed larvae as well as the ammonia excretion was lower in the group fed a balanced diet than in the unbalanced or control groups (38.3% deformed larvae in control, 30% in larvae fed unbalanced diet and 20% on balanced diet group). Furthermore, larvae fed the microencapsulated diets presented higher docosahexaenoic acid and arachidonic acid levels. This study demonstrates that dietary amino acid profile may play an important role in larval quality. It also shows that balanced microencapsulated diets may improve some of the performance criteria, such as skeletal deformities, compared to live feeds. 相似文献
18.
Apparent Problems and Potential Solutions for Production of Fingerling Striped Bass,Morone saxatilis
《Journal Of Applied Aquaculture》2013,25(3-4):101-118
Data on production of fingerling striped bass, Morone saxatilis, in 103 ponds at 17 hatcheries in 1988 were related to information on management practices and water qualities. Production was highly variable, with a median of 50,000/ha. No survival was evident in 12% of ponds; numbers harvested exceeded 250,000/ ha in 5% of ponds. Best survival resulted when larvae were stocked within 2 days after pond filling was started and at hatcheries with relatively low application rates of fertilizers during the prestocking interval. No survival was evident in ponds with pH >9.0 in the week after stocking. High pH's and probably toxic concentrations of un-ionized ammonia were related to water being in ponds for too long prior to stocking and to high applications of fertilizers. Examination of samples of larvae collected at stocking and the week after stocking documented a problem with swim bladder inflation. When larvae were stocked at D5 or D6 (Dl is day of hatch), inflation success averaged 91%: when stocked at ≥D7. inflation success averaged 60%. Measures proposed to improve production include: (1) Stock larvae prior to the critical period of swim bladder inflation(D4-D5). (2) Start filling ponds as close to stocking as is feasible (filling can be completed after stocking). (3) If the concentration of available nitrogen is low, apply no more than 300 µg/L of nitrogen in the prestocking interval. (4) Add phosphorus as needed, but avoid pH>8.5 until larvae are D14. 相似文献
19.
地衣芽孢杆菌De在优质草鱼养殖中的应用研究 总被引：8，自引：0，他引：8
运用综合对比分析法探讨了地衣芽孢杆菌Bacillus licheniformis De在优质草鱼（Ctenopharyngodon idellus）养殖中的应用效果,其评价指标分别为成活率、水体pH、透明度、溶解氧及水中氨氮、硝酸盐浓度等。结果表明,施用地衣芽孢杆菌De可在一定程度上使水体环境和养殖生产性能得到优化,提高养殖草鱼的成活率,显著降低水体透明度及水中氨氮、硝酸盐含量（P〈0．05）,使水体pH、溶解氧有利于草鱼的生长。其中施菌组较对照组的成活率、水体pH、溶解氧分别提高了3．2％、3．9％、25．5％,而水体透明度、氨氮及亚硝氮浓度则分别降低了38．5％、74．6％、69．3％。 相似文献
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Piotr Gomułka Daniel Żarski Krzysztof Kupren Sławomir Krejszeff Katarzyna Targońska Dariusz Kucharczyk 《Aquaculture International》2014,22(1):225-233
Acute ammonia toxicity was investigated in four developmental stages of the juvenile ide, Leuciscus idus: 1, 10, 20 and 30 days after the first feeding. Mean (±SD) total length of the larvae was 8.5 ± 0.3, 15.7 ± 0.7, 23.0 ± 2.0 and 29.7 ± 2.0 mm, and standard weight was 1.6 ± 0.3, 9.2 ± 5.5, 94.9 ± 31.0 and 196.0 ± 31.7 mg, respectively. The larvae used for toxicity tests were reared in the experimental, closed recirculating system. Groups of fishes (n from 7 to 10; in respect of fish size) were exposed to the ammonium chloride solutions in 1-L glass units. Water temperature was 25 ± 0.1 °C for both the rearing and the toxicity tests. pH was not adjusted and ranged between 8.4 and 8.7. The ammonium chloride solutions were renewed every 12 h. At the same time, dead larvae were counted and removed, and the pH and temperature measurements were taken. Each acute toxicity test duration was 96 h, and lethal concentration LC1, LC50 and LC99 values were calculated for 24, 48, 72 and 96 h. The susceptibility of the ide larvae to ammonia decreased linearly with age up to 20th day and surprisingly increased during the next 10 days. The LC50 (48 h) values ranged from 0.27 mg L?1 of unionized ammonia nitrogen for 1 day after the first feeding (AFF) larvae to 1.42 mg L?1 at day 20 after first feeding. The LC50 (48 h) for 30 days AFF was as high as 0.67 mg L?1. The critical level of the unionized ammonia nitrogen for ide larvae was suggested as 0.21 mg L?1. 相似文献