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1.
Planktonic eggs of the white mullet, Mugil curema, were collected in Biscayne Bay, Florida, and the larvae were reared in four laboratory experiments. Static rearing systems were used and copepod nauplii and copepodites were fed to larvae. Larvae grew from 2.1 mm standard length (SL) at hatching to 28.5 mm SL (35.9 mm total length) at 36 days after hatching. No significant mortalities occurred beyond 12 days after hatching. At 20 days, survival ranged from 1.2 to 23.0%. Most larval mortality occurred when larvae sank to the bottom of the rearing tanks, a phenomenon previously reported for striped mullet, Mugil cephalus. Successful culture of white mullet could have potential for meeting the demands of the live bait market for recreational fishing in south Florida.  相似文献   

2.
The gut microbiota plays key roles in the health and general welfare of fish larvae, the present study characterized the bacterial communities associated with grouper Epinephelus coioides larvae during a period of 22 days post hatch (DPH) in an intensive hatchery using both cultivation‐based and cultivation‐independent approaches. Both approaches confirmed that bacteria were present in the gut of larvae before and after the onset of exogenous feeding, and the number of cultiviable bacteria increased gradually from 2 DPH to 22 DPH. A more complex bacterial profile was present in larvae fed fertilizer oyster eggs for 4 days (8 DPH), probably as a result of the onset of exogenous feeding. Interestingly, similar internal microbiota were observed in larvae fed fertilized oyster eggs for 4 days (8 DPH) and rotifers for 2 weeks (22 DPH), although different microbial communities were present in the two feeds. This might suggest that the gut environment of E. coioides larvae selects for a common microbiota, which is more closely related with the rearing water than the two feeds. Therefore, bacterial community of the rearing water may play a critical role in the establishment of gut microbiota of fish larvae and more attention should be paid to its practical modulation by using probiotics. In addition, some potentially beneficial bacteria, such as Lactococcus spp., were the major components of the microbiota associated with fertilized oyster eggs, while these bacteria were not detected in larvae samples.  相似文献   

3.
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   

4.
5.
Hydrated eggs obtained from a female milkfish, Chanos chanos, were artificially fertilized with the milt collected from a male injected with acetone-dried pituitaries of salmon. The fertilized eggs (1.1–1.25 mm in diameter) developed normally in seawater in basins and petri dishes at a salinity of 30–34‰, and successfully hatched in 25–28.5 hours at a temperature of 26.4–29.9°C. The yolk was completely absorbed in about 2.5 days and during this period many postlarvae died. A few larvae were reared up to 5 days but all died on the 6th day. Attempts were made to feed the postlarvae with freshly hatched trochophore larvae of oysters obtained from eggs artificially fertilized in the laboratory.  相似文献   

6.
Larvae of the grey mullet Mugil cephalus L. can be reared successfully using careful procedures following induced spawning of the adults with purified salmon gonadotropin or human chorionic gonadotropin.Preliminary incubation of the eggs to the gastrula stage at high density for 12 h at 22°C is preferred, using stirred irradiated seawater (32‰ salinity) and the antibiotics penicillin (80 IU/ml) and streptomycin (0.05 mg/ml). The eggs are transferred before hatching to circular rearing tanks at a density of 250 eggs/l.The mouths of the larvae are open and ossified and the eyes are sufficiently pigmented for the larvae to begin feeding on the third day. The larvae are fed cultured phytoplankton and rotifers supplemented with available natural plankton. Nauplii of Artemia are provided on the seventh day.The migratory behavior of the larvae during early development and their physiology are discussed, being relevant to the procedures and the techniques applied.Mass propagation in large (over 12-ft diameter) circular tanks with total light control is recommended.  相似文献   

7.
Profiles of oocyte growth were obtained from female striped mullet Mugil cephalus L. held in salinities ranging from fresh water to seawater during two consecutive spawning seasons (1988–1990) in Hawaii. Females underwent vitellogenesis at all salinities (i.e., 32–35, 13–20, and 0%‰) tested. Females maturing in fresh water exhibited a slower rate of oocyte growth, and a significantly lower number completed vitellogenesis. All females were induced to spawn in full seawater. The number of fertilized eggs per spawning was highest from females maturing in brackish water. More females were able to be induced to spawn twice in brackish water during the 1989–1990 season than in fresh or seawater. The results from the current investigation suggest that salinities ranging from 13–35 ppt are adequate for ovarian maturation in captive striped mullet females.  相似文献   

8.
The collection of fertilized eggs for mass culture of Pacific bluefin tuna (PBT) relies on the spontaneous spawning of broodstock in captivity, and the spawning season of the broodstock is generally from mid‐May to September. The diameter of fertilized eggs from the broodstock decreases during the spawning season. To investigate the influence of three potential factors, the egg diameter (larger or smaller), the rearing water temperature (25 or 28 C), and the aeration rate during the night (strong or weak), on early survival and on growth of PBT larvae, replicate trials were conducted to assess these three factors until 7 d after hatching (d.a.h.). At 7 d.a.h., survival rates of larvae reared with strong nighttime aeration were found by a three‐way ANOVA to be significantly higher than for larvae reared with weak aeration. Furthermore, growth rates of PBT larvae hatched from larger eggs were significantly faster than those from smaller eggs. However, a significant difference in the survival rate was not detected for the factors, egg diameter and rearing water temperature. The results indicate that rearing with strong nighttime aeration significantly improved the early survival of PBT larvae and the egg diameter (a proxy for egg quality) and influenced growth.  相似文献   

9.
对室内培育的多棘海盘车Asterias amurensis胚胎和幼虫的发育以及外部形态进行了显微观察。多棘海盘车为雌雄异体,体外受精,成熟卵卵径为(130~150)μm,卵裂属完全均等型。水温为(10.5~11.5)℃时,受精卵经20min左右释放第1极体,约50min进行第1次卵裂,约7h时进入桑葚期,19h40min发育成为膜内旋转囊胚,23h40min发育成为脱膜旋转囊胚,26h30min发育成为早期原肠胚,纤毛幼虫(初孵幼虫)出现在46h,从受精到短腕幼虫历时25d。由纤毛幼虫到短腕幼虫的过程中幼虫体长经历了先增大后减小的过程。进一步发现,投喂混合饵料(小新月菱形藻Nitzschia closteriumf.minutissima和海洋红酵母Rhodomonas sp.1∶1)的幼虫发育速度比单独投喂小新月菱形藻的快,但差异不显著(P0.05)。  相似文献   

10.
本研究采用不同盐度的海水对(鱼免)状黄姑鱼受精卵的沉浮性、胚胎发育的孵化时间、孵化率、仔鱼的分布状态和成活率的影响进行研究。结果表明:(鱼免)状黄姑鱼受精卵在盐度26.9‰以下的海水呈沉性,在盐度40.7‰以上的海水呈浮性,盐度26.9‰~40.7‰则由沉性向浮性过渡。(鱼免)状黄姑鱼受精卵在盐度13.7‰~53.0‰均可孵化,但孵化适合盐度为26.9‰~40.7‰。从仔鱼的分布状态、活动情况、成活率等几方面综合分析、(鱼免)状黄姑鱼仔鱼的合适盐度为26.9—33.4‰。  相似文献   

11.
安氏高原鳅胚胎和仔鱼发育的观察   总被引:5,自引:1,他引:4  
通过人工授精获得受精卵,利用显微镜进行连续观察,并用数码相机拍照记录,对安氏高原鳅胚胎及仔鱼的发育特征进行了详细描述,并确定了到达各发育期所需的时间.成熟卵直径为0.87~1.05 mm,受精卵卵膜径为1.24~1.41 mm,微粘性.水温16.3~18.1 ℃,受精卵历时119 h 44 min孵出,所需积温为2083.4 ℃·h.受精卵发育的理论起始温度为4 ℃,发育所需的理论有效积温为1610.4 ℃·h.胚胎发育过程可划分为6个阶段,35个发育期.初孵仔鱼平均全长约为4.58 mm,仔鱼期历时28 d.  相似文献   

12.
Tasmanian species of flounder were cultured successfully following stripping and fertilizing eggs after hormone-induced ovulation. The larvae were fed rotifers followed by Artemia nauplii. Survival rates of larvae from first-feeding to metamorphosis, which were as high as 94–98% for R. tapirina and 65% for A. rostratus, indicate that both species can be readily cultured in captivity.  相似文献   

13.
纹稿虾虎鱼胚胎、早期仔鱼发育与盐度的关系   总被引:1,自引:0,他引:1  
本文对纹缟虾虎鱼受精卵和早期仔鱼发育与盐度的关系进行了初步研究。结果表明:受精卵在盐度0~40时均表现出沉性;受精卵孵化的适盐范围为5~40,最适盐度为20~35;仔鱼在盐度低于30时,主要分布于底层,活力较差,盐度高于30时,主要分布中上层,活力较好;仔鱼在盐度5~45和无投饵状态下,SAI值为2.93~15.66,其中在盐度30~35时,SAI值最大(14.43~15.66)。从不同盐度下仔鱼的分布状态及仔鱼的生存指数综台分析,纹缟虾虎鱼仔鱼培育的最适盐度范围为30~35。  相似文献   

14.
黄颡鱼早期发育阶段受精卵和鱼体脂肪酸组成变化   总被引:11,自引:2,他引:9       下载免费PDF全文
研究了黄颡鱼受精卵孵化期间和仔鱼发育阶段脂肪含量和脂肪酸的组成变化规律.采用常规化学分析方法和气相色谱法对黄颡鱼从鱼卵受精开始至仔鱼孵化后未投饵的7 d内的脂肪含量和脂肪酸组成进行测定.结果表明,受精卵在整个孵化期间脂肪含量有下降趋势.受精卵中不饱和脂肪酸含量大于饱和脂肪酸含量.受精卵在整个孵化期间各种脂肪酸含量无明显变化.仔鱼孵化后,鱼体总脂肪含量急剧下降,总脂含量从0日龄的4.57%降低到7日龄的0.75%.仔鱼在饥饿期间鱼体脂肪酸组成发生明显变化,单不饱和脂肪酸含量下降最为明显,尤其是C18:1.仔鱼在饥饿期间,脂肪酸按n-9>n-6>n-3顺序被先后利用,黄颡鱼仔鱼发育阶段主要以单不饱和脂肪酸作为能量代谢基质,而C20:4n6(AA)和C22:6n3(DHA)优先于C20:5n3(EPA)被保存下来.  相似文献   

15.
Eggs and sperm were obtained from a female (6.3 kg/BW) and a male (8.4 kg/BW) longtooth grouper Epinephelus bruneus following HCG injection in July 2003. The eggs were fertilized artMcially with the sperm and incubated in one of two 50-m3 tanks after washing the fertilized eggs. The fertilized eggs were 830–950 pn (average 900 ± 2 μm) in diameter and the respective fertilization and hatching rates were 97.7 ± 0.6% and 96.8 ± 0.5% at a water temperature of 25.0 ± 0.5 C. With this regime, the survival rate by day 93 was 7.5% in the 50-m3 tank. The elapsed time from hatching to opening the mouth was 3 d at 25 C. The initial mouth size (z) of the larvae was 0.22–0.23 mm. The newly hatched larvae were 2.02 ± 0.02 mm TL; this increased to 4.12 ± 0.09 mm TL by day 11. By day 54, the larvae had metamorphosed into juveniles and reached 41.12 ± 1.20 mm TL, and by day 93 the juveniles reached 93.78 ± 1.98 mm TL. In all, 49.5% of the larvae were malformed and the type of malformation was diverse.  相似文献   

16.
银鲳人工育苗技术研究   总被引:1,自引:0,他引:1  
2005~2006年,在舟山海域银鲳繁殖季节(4~5月),随流刺网和张网捕鱼船出海,捕捞性腺成熟的银鲳进行人工授精,把胚胎运回岸上在孵化桶中继续孵化,得到初孵仔鱼并移入水泥池中进行培育。在水温19.0~24.0℃、盐度25.0~28.0的人工育苗条件下培育苗种。饵料为轮虫、卤虫无节幼体和配合饲料,孵化后3 d仔鱼开始开口摄食。银鲳初孵仔鱼~12日龄为仔鱼期,13~40日龄为稚鱼期,41日龄起转为幼鱼期。经50 d培育,获得20~27 mm叉长的银鲳幼鱼。育苗成活率为5%~14%。  相似文献   

17.
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   

18.
Female blue crabs were induced to produce eggs out of their normal spawning season. One group of crabs, held in the laboratory at 19° C, was fed every 7 days; another group, held at 15° C, was offered food at the same interval. Photoperiod simulated ambient winter conditions in both groups. Of ten crabs held at 19° C, two produced egg masses and one died when spawning was about to commence. Among those crabs not producing egg masses during the experiment, ovarian development at 19° C proceeded further than among those held at 15° C.Survivorship of larvae from induced eggs raised on a rotifer diet was comparable with that for naturally spawned larvae through the first 28 days of development.Zoeae survived well to metamorphosis when fed a diet of rotifers during the first two stages, followed by Artemia salina nauplii. However, only six zoeal stages were present instead of the usual seven. Possible explanations for this observation include genetically controlled variation, variation due to origin of eggs (induced), or effect of diet.Survivorship and growth were not adversely affected when synthetic sea water was used as the culture medium.  相似文献   

19.
大弹涂鱼仔鱼的摄食、生长和成活的研究   总被引:19,自引:1,他引:19       下载免费PDF全文
张其永  张杰 《水产学报》1988,12(3):203-212
本文主要论述大弹涂鱼仔鱼阶段有关摄食和生长发育,以及不同饵料对仔鱼生长和成活的影响。结果表明,孵化后3—5日龄即仔鱼危险期,正处于内源性(包括混合性)营养转入外源性营养。颗粒有机碎屑是仔鱼的开口饵料,培育期间以底栖硅藻分解后形成的颗粒有机碎屑为饵料,其后期仔鱼成活率高达42.04%。6日龄起逐渐加投桡足类幼体和成体,其16日龄后期仔鱼平均全长可达6.15mm,平均体重1.24mg.  相似文献   

20.
Florida red tilapia (Oreochromis sp.) were reared in 23 m3 seawater (37 ppt) pools. Monosex males (1.3 g mean weight) were stocked at a density of 25 fish/m3 and reared to fingerling size (>10 g) in pools receiving either chicken manure applied at a rate of 105 kg/ha day−1 or pelletized feed (30% protein) administered ad libitum. Following the nursery period, fingerlings in fed pools were reared through adult, marketable sizes.

After 20 days of nursery rearing, mean fish weights (5.7–9.6 g) and survival (77.5–98.6%) in manured pools ranged from less than to greater than values in fed pools (7.9–9.4 g and 95.5–98.2%). By day 33, while mean weights (11.3±0.4 g) and survival (84.5±5.2%) in manured pools were significantly less than those in fed pools (18.0±0.6 g and 95.9±1.4%), fingerling-size fish were obtained from manured pools at an overall productivity of 55 kg/ha day−1.

After 170 days in fed pools, mean fish weight was 467±9 g, survival was 89.7±0.9%, and food conversion was 1.6±0.2. Daily weight gain achieved a maximum of 4.4 g day before a rapid decline in water temperature from 28–29°C to 24–25°C caused a loss of fish appetite and evidence of disease.

The results suggest that while nursery rearing of Florida red tilapia in seawater pools fertilized with chicken manure is feasible, considerable variability in fish performance among pools can be expected, despite identical management methods. In pools receiving prepared feed, high growth rates and survival through adult, marketable sizes suggests a potential for commercial production of Florida red tilapia in seawater.  相似文献   


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