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1.
A Keramat Amirkolaie 《Aquaculture Research》2008,40(1):112-117
Artificial rearing of fry has been introduced as an alternative to supply fry and juvenile sturgeon in order to restock the depleted sturgeon population in the Caspian Sea. The aim of this study is to assess the feed selection characteristics of sturgeon (Acipenser persicus) fry during the period in which they stay in earthen ponds before being released into the river. Sturgeon fry weighing around 150 mg were introduced into five almost similar‐sized earthen ponds. The ponds were enriched with fertilizer to supply natural food for the fries. A weekly sample of six specimens was collected from each pond during the 5 weeks of the experiment. All collected fish were weighed and then dissected for inspection of the stomach and the intestine content. The overall stomach content measured from 150 fish showed that around 74% of the stomach content was composed of chironomids and the rest was daphnia and cyclops. At the beginning of the study (first 2 weeks), sturgeon fry feed more on daphnia and cyclops; this trend, however, reversed in the last 2 weeks of the study. In conclusion, sturgeon fry feed on three prey groups—chironomids, daphnia and cyclops—during their lifespan in earthen pond. Feeding on chironomids larvae increased with sturgeon fry size. 相似文献
2.
In Hong Kong, chironomid larvae are grown on chicken manure. The larvae are used in large quantities as live food for aquarium fish and carnivorous fish fry in fish culture. In this survey, the culture technique and yield of chironomid farming were studied. The technique is simple: at temperatures of 15–30°C the yield is about 140 kg in a 675 m2 field per cycle of 50 days. Since a large quantity of chicken manure, about 1440 kg, is consumed in each cycle, and there is also the possibility of using other farm wastes to grow chironomid larvae, this highly profitable chironomid farming may be developed to reduce the problem of stream pollution due to the farm wastes. 相似文献
3.
美洲鲥仔、稚、幼鱼的形态发育与生长特征 总被引：4，自引：0，他引：4
通过对美洲鲥(Alosa sapidissima)仔、稚、幼各发育期的连续取样,系统观察了仔、稚、幼各期的形态变化及生长发育特征.结果显示:在水温(20±1)℃下,初孵仔鱼全长(6.75±0.60)mm;2日龄仔鱼即开口摄食,进入混合营养期;4 日龄仔鱼卵黄囊吸收完毕进人晚期仔鱼阶段,完全依靠外源物质获取能量,主要以鳔室、脊椎形成及各鳍的分化与形成为主要标志;培育至36 d,仔鱼鳃盖后缘及脊椎骨两侧线有少量鳞片状突起,标志美洲鲥结束仔鱼期进入稚鱼期;培育至65 d,仔鱼身上鳞片基本长出,腹膜闭合,美洲鲥完成变态成为幼鱼.仔鱼培育期间,除了严格控制培育水温在(20±1)℃外,2日龄仔鱼开口后就应及时投喂轮虫类开口饵料,密度为5～10 ind/mL,这是苗种培育中不可忽视的重要环节.稚鱼期间在主食枝角类、桡足类的同时进行驯食.本实验采用特制缓沉饲料及时驯化转食再过渡到伞部摄食人工浮性膨化颗粒饲料,驯食时间为21 d,驯食是成功进行人工池塘养殖的关键所在.本研究旨在探讨提高美洲鲥早期培育过程中的成活率及成功进行池塘养殖的可行性. 相似文献
4.
I-Chiu Liao J.V. Juario S. Kumagai H. Nakajima Marietta Natividad P. Buri 《Aquaculture (Amsterdam, Netherlands)》1979,18(2):75-93
A female milkfish, captured at sea, was injected with two hormonal injections of acetone-dried salmon pituitary powder and human chorionic gonadotropin, plus Vitamin B complex. It was stripped, and produced 128,000 ripe eggs with an average diameter of 1.15 mm. Fertilization rate was 38% following artificial fertilization with milt from an uninjected male. A total of 36,000 larvae hatched (74% of fertile eggs) after 26–32 h at 34 ‰ salinity and 27–32°C. The newly hatched larvae measured 3.4 mm in mean total length and possessed a large yolk sac. The mouth of the larvae opened about 54 h after hatching. The larvae were fed with fertilized oyster eggs, rotifers, copepods, brine shrimp, flour and prepared feed, together with Chlorella. A critical period was between the 4th and 6th days with mortality over 80%. The larvae started increasing in length by Day 8, and had the appearance of the wild fry by Day 11. On Day 13 a pigmentation pattern developed and the biggest larva measured 10.0 mm. By Day 18 the larvae measured 12.5 mm, and 14.5 mm by Day 21. A total of 2,859 fry was obtained; the highest larval survival rate obtained from different experimental groups was 46.8%. 相似文献
5.
The use of broodstock of different origin as a method to improve fry production performance and consequently to minimize deformities was examined at industrial scale in a commercial gilthead sea bream hatchery. The outcome of fry production from three different broodstock groups (BA: broodfish (Mediterranean) with multiannual hatchery presence, BB: selected offspring originating from the BA group, and BC: broodfish of Atlantic origin) was investigated in the same rearing conditions and feeding protocol. Performance factors assessed were the survival and weaning of the larvae; the mortality rates from the “weaning until the end of the hatchery stage” of the larvae/fry; the percentage of fry without swim bladder; the percentage of fry with skeletal deformities and the feed conversion ratio. In all factors, no statistical differences among the experimental groups were detected. However, due to early rejection of the deformed individuals, benefits are expected from the decrease of the supplied amount of food and the reduced labor cost. 相似文献
6.
Abstract. Various possibilities of transmitting fish pathogenic VHS, SVC and IPN viruses by the heron, Ardea cinerea , were investigated. Shedding of IPN virus in the faeces could be demonstrated for a period of 7 days when about 1 g of IPN virus-infected trout fry was fed to the birds once only, whereas feeding larger quantities of infected fish on 5 consecutive days resulted in virus excretion for a further 5 days only. Infectious IPN virus could not be isolated from samples of blood and virus specific neutralizing antibodies could not be demonstrated in serum samples. A waterborne infection of trout fry was established by adding very small (0·2 g) quantities of faeces from herons fed IPN virus-contaminated fish to 20 1 water. Infectious SVC and VHS virus was also re-isolated from samples of food which were regurgitated by the herons at different times up to 120 min after feeding of contaminated fish. It was concluded that herons are able to act as mechanical vectors for IPN, VHS and SVC viruses and therefore, may be a potential source of infection and spread of the diseases. 相似文献
7.
为了解决冬季培育鲤鱼苗的饲料问题，从1981年冬开始，对鲤鱼苗的人工饲料进行了一系列的研究。1983年初研制成功“5号”人工开口饲料。用这种饲料直接喂养鲤鱼苗，可使其成活及正常生长。在鱼苗放养密度分别为20万尾／米。和10万尾，米^2，水中不合饵料生物的条件下，经过15天饲养，鱼苗体长分别可达到11—13毫米，体重可达15—22毫克，成活率为77—97％．5号饲料的成份为：粗蛋白36．7％，粗脂肪5．5％，粗纤维1．8％，水分8％，灰分19．0％，碳水化合物29％。 相似文献
8.
从山东引进全长3-5cm的美国大西洋牙鲆和漠斑牙鲆幼鱼到宁德市飞鸾镇海鑫育苗场,经2年6个月养殖后,从养殖群体中挑选出大西洋牙鲆雄鱼为父本,漠斑牙鲆雌鱼2为母本,在生殖季节通过埋植激素和人工调控环境条件催熟亲鱼,采用人工受精方法,获得杂交受精卵478．6g,受精率为62．9％,孵化率为75．3％,获得初孵仔鱼36万尾。经过65d的培育,育出平均全长4．20cm的杂交鱼苗22万尾,育苗成活率61．1％。鱼苗生长迅速,初步表现出杂交子代的优势性状。 相似文献
9.
Abstract This study examined juvenile salmonid use of a freshwater tidal creek system draining a wetland on the floodplain of the lower Fraser River, British Columbia, Canada. Chum, Oncorhynchus keta (Walbaum), chinook, O. tshawytscha (Walbaum), and sockeye, O. nerka (Walbaum), salmon fry were abundant in the tidal creeks in spring. The fry were found in non-natal habitat up to 1.5 km from the main channel of the river. The salmon fry ate dipteran adults, larvae and pupae, cyclopoid and harpacticoid copepods, and Collembola. Mysids Neomysis mercedis Holmes (Walbaum), and amphipods, Crangonyx richmondensis occidentalis (Hubricht and Harrison), were also consumed. The upper reaches of an undisturbed creek were the winter rearing habitat for presmolt coho salmon, O. kisutch (Walbaum), where this species ate dipteran pupae and larvae as well as a freshwater isopod, Asellus communis Say (Walbaum). 相似文献
10.
Hossein Ouraji Khosro Jani Khalili Ghaffar Ebrahimi Seyed Ali Jafarpour 《Aquaculture International》2011,19(4):683-691
Kutum Rutilus frisii kutum is known as a valuable commercial species in the southern part of Caspian Sea. Artificial rearing of fry has been introduced
as an alternative to supply kutum fry in order to restock the kutum population in the Caspian Sea. The aim of this study was
to find the suitable time to transfer kutum larvae from live food to artificial feed. The experiment began on day 3 post-
hatching and lasted for 21 days. Mean initial weight of larvae was 4.5 mg. Five experimental groups including Group A (zooplankton
alone for 21 days), Group B (12 days zooplankton + 9 days artificial feed), Group C (8 days zooplankton + 13 days artificial
feed), Group D (4 days zooplankton + 17 days artificial feed) and Group E (artificial feed alone for 21 days) were considered
for this experiment. According to the obtained results, the specific growth rate of kutum larvae varied from 8.01 to 13.58%
day−1, and the highest and lowest specific growth rate were found in A and E treatments, respectively. The lowest mean body weight
(24.6 mg) was found in larvae fed on artificial feed for 21 days. However, survival rates of kutum larvae fed mixed zooplankton
for 8 and 12 days (85.83 and 89.33%, respectively) were comparable with those of larvae fed live food during the entire experiment
(91.6%). The lowest survival rate (69.16%) was found in larvae fed artificial feed during the entire experiment. 相似文献
11.
在水温8．9～14．2℃下,在平列糟（长3m,宽0．4m,高0．2m）中采用A、B和C组三种投喂方式驯养刚开口摄食、体质量0．129±0．07g的哲罗鱼（Huchotaimen）苗60d,以探讨驯化方式对哲罗鱼仔、稚鱼生长、存活和种群变异系数的影响：A组以浮游动物开口,投喂浮游动物3d,投喂水蚯蚓15d后,改投人工饲料;B组以水蚯蚓开121,投喂水蚯蚓15d后,改投人工饲料;C组直接以人工饲料开口。结果表明：C组体质量特定生长率（3．577±0．78％／d）,明显大于A组（3．132±0．87％／d）和B组（3．024±0．91）;A、B、C组的成活率分别为75．67％、74．87％和84．36％,C组明显大于A、B组;A、B和c组鱼体质量变异系数依次为21．47％、22．59％和11．32％,实验表明,直接以人工饲料开口是哲罗鱼规模化养殖中合理的驯化投喂模式。 相似文献
12.
Jürgen Flüchter 《Aquaculture (Amsterdam, Netherlands)》1980,19(2):191-208
Intensive fishing of whitefish (Coregonus lavaretus) and a survival rate of the early stages of the fry that is generally too low lead, at present, to the whitefish stocks not being able to utilize fully the natural food resources now produced many times in excess of the requirements by the eutrophication of lakes.Feeding experiments in aquaria have, for several years, shown very impressively, that there are two main reasons for the high mortality of the larvae in the natural environment: high sensitivity to even a short-term lack of food and specific food requirements — the necessity for the larvae to feed on the juvenile stages of certain zooplanktonic crustaceans.Artificial breeding of whitefish eggs in cold water at 1°C caused a delay in hatching of about 8 weeks compared with natural hatching, thus allowing the release of the larvae at a time when the density of zooplankton is about ten times higher and mainly juvenile stages of crustaceans needed by the whitefish larvae are present. Hence, this is one proven way of improving the survival rate of whitefish larvae in the natural environment.Young fish, after metamorphosis, have less specialized food requirements than the larval stage and can even be fed adequately with dry food. In rearing the larvae, natural zooplankton can be replaced by the nauplii of the brine shrimp, Artemia salina. Larvae have not yet been reared on dry food or even on slowly frozen zooplankton or Artemia, but Artemia nauplii shock-frozen in liquid nitrogen (at ?196°C) were found to be as acceptable as living ones and allowed metamorphosis of the larvae to take place. The substance, assumed to be present in the living Artemia, which was lost on slow-freezing but retained after shock-freezing and was shown to be essential to the whitefish larvae, was insoluble in water. Biochemical investigation and identification of this substance are urgently required in order to synthesize an artificial complete food for whitefish larvae.As long as this artificial food is not available, attention will have to be focussed on rearing the larvae in natural ponds where the specific and essential zooplankton can be encouraged. 相似文献
13.
This study examined the effects of water hardness and salinity on yolk sac larvae and swim‐up fry survival of Nile tilapia, Oreochromis niloticus (Chitralada strain), eggs during artificial incubation. Four experiments were conducted to evaluate the effects of hardness, salinity and the sources of saline incubation water. High water hardness treatments (500–4200 mg L?1 as CaCO3) resulted in higher yolk sac larvae and swim‐up fry survival than low water hardness treatments (50.0 and 132 mg L?1 as CaCO3); although yolk sac larvae and swim‐up fry survival did not differ among the high or low hardness treatments. Salinity of 4.0 g L?1 using seawater, and 4.0 and 8.0 g L?1 using unprocessed common salt resulted in the higher survival rate of yolk sac larvae and swim‐up fry than other salinity treatments. Yolk sac larvae and swim‐up fry survival was found to decrease with the increase in salinity and increase with the increase in water hardness. The present study demonstrated the positive effects of increased water hardness level (>132 mg L?1) on yolk sac larvae and swim‐up fry survival. The study also showed that seawater salinity of 4 g L?1 was the most appropriate salinity level for incubating Nile tilapia eggs. 相似文献
14.
Masatsugu Yamazaki Taisuke Ohtsuka Yasushi Kusuoka Masayoshi Maehata Hiroyuki Obayashi Kiyoyuki Imai Fujiyoshi Shibahara Makoto Kimura 《Fisheries Science》2010,76(2):207-217
We examined the effects of predation by Nigorobuna Carassius auratus grandoculis larvae and fry, a crucian carp endemic to Lake Biwa, Japan, on the community structure of aquatic organisms in rice fields.
Six experimental plots with three different rice-straw treatments in the presence/absence of stocked larvae were prepared.
In each plot, the number of aquatic organisms ranging in size from 30 μm to 5 mm in the water, as well as those from 63 μm
to 5 mm in size in the surface sediments, was surveyed 6, 13, 20, 26, 34, and 41 days after the onset of irrigation. Three-day-old
fish larvae were released on day 10. Undigested organisms in the gut contents of the larvae or fry were identified on days
20, 26, 34, and 41, respectively. Ten-day-old larvae mainly preyed on Cladocera, but the fry thereafter shifted to Diptera
as their main prey. While Cladocera and Podocopida decreased in fish-stocked plots, Euglenales and Halteriida became more
abundant there. Top-down or bottom-up effects of fish seemed to control these changes in community structure. 相似文献
15.
采用静水压法处理半滑舌鳎(Cynoglossus semiliaevis)受精卵以抑制其卵裂并进行染色体加倍,筛选出有效的静水压处理起始时间、处理强度及其持续时间。结果表明,孵化水温(23±0.2)℃时,授精后21.5 min,采用40 MPa的静水压压力,休克处理4.5 min,四倍体诱导效果最好,鱼苗四倍体率达到68.3%。采用流式细胞仪分析了四倍体鱼苗细胞DNA含量,表明四倍体鱼苗细胞DNA含量为二倍体对照鱼苗的2倍。通过染色体制作分析表明四倍体鱼苗的染色体数为84条,而二倍体对照鱼苗的染色体数为42条。本研究采用静水压方法,在国内外首次建立了半滑舌鳎四倍体诱导方法。本项技术的建立旨在为大量生产半滑舌鳎三倍体不育群体奠定基础。 相似文献
16.
17.
A novel method for increasing fry yield in guppy breeding tanks was tested in the laboratory and commercial farms. It is based on lighting the fry collecting net baskets to attract newborn guppies into these safe refuges, which in turn reduces their exposure to cannibalism. A laboratory experiment revealed a significantly higher fry yield (by 30.2%) using illuminated net baskets than baskets without light. No significant effect of the timing of fry collection (08:00, 12:00 or 16:00) was found. Under commercial culture conditions in two farms, fry yields significantly increased by 13–28% in various guppy strains, using illuminated baskets. Overall, the results of this study demonstrated the efficacy and high economic potential of the proposed method in increasing fry yield in commercial-size breeding tanks. 相似文献
18.
《Journal Of Applied Aquaculture》2013,25(1):77-82
This study deals with the predation potential of aquatic insects from five genera, upon the fry of common carp, Cyprinus carpio. The fry ranged in size from 7-19 mm. Aquatic insects from five genera were divided by size into three classes. Pantala (Libellulidae). Coenaarion (Coenagrionidae) and Notonecta (Notonectidae) increased their predation potential as they increased their length. as opposed to Tropisternus (Hidrophilidae), which ate more fry when smaller. The largest insects ate very few small fry but ate larger fry that were longer than their own body length. Pantala was the most effective fry predator, eating an average of 1.64 fry per day, followed by Notonecta (1.5), Coenagrion (0.43), and Tropisternus larvae (0.35 fry/day). Sigara were not predators and did not eat any fry; The insect size/fry size interaction proved to be directly proportional for all insects; that is, the larger the insect, the larger the fry it could capture. 相似文献
19.
根据对引进的美国杂交条纹鲈的生长发育需求及生理生态要求和食性，应用我国池塘精养技术，肥水培育苗种，进行调控水质，培养天然饵料，精心投喂，科学管理，经1年饲养管理，共出塘鱼种26000余尾，平均全长达14．0cm，平均尾重31．9g，成活率达22．7％。得出初步的苗种培育技术。 相似文献