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1.
对三门湾和吕四近岸小黄鱼(Larimichthys polyactis)仔稚鱼的矢耳石微结构特征进行了比较研究。结果表明:小黄鱼矢耳石上的轮纹是每日形成的,第一日轮在孵化后第2天形成,由仔鱼期向稚鱼期过渡时形成的次生核;三门湾和吕四近岸海域在个体的生长、发育和次生核之间均表现出明显的一致性:生长较快的个体,第一次生核形成的时间也较早,次生核数量亦多;两个海域小黄鱼的耳石微结构存在明显的差异,吕四近岸的个体在仔鱼期耳石生长率更快(均值为0.039),第一次生核形成时间较短(均值为37日龄),次生核数量较多(78个),表明吕四近岸个体具有较快的生长率和发育速度,这种差异可能是因为吕四近岸的个体在仔鱼期所经历的水温较高。以上研究结果表明,矢耳石的微结构特征可以反映野生小黄鱼的早期生长发育状况,不同海区小黄鱼仔稚鱼的矢耳石微结构特征存在显著差异,可以用于区分小黄鱼不同海域栖息的个体,将为小黄鱼早期资源补充过程和早期选择性死亡等研究提供理论基础。  相似文献   

2.
以中华倒刺鲃(Spinibarbus sinensis)亲鱼为材料,在实验室养殖条件下以人工孵化的丰年虫(Eubranchipus vernalis)为仔、稚鱼饵料,通过已知日龄法观察其耳石的微结构,分析其日轮形成特征。结果表明,仔、稚鱼的微耳石和矢耳石一般由1个中心核和1个耳石原基组成,少数存在多个中心核或原基现象,星耳石中心核和原基区分不明显。微耳石和矢耳石中心核直径分别为(37.73±5.34)μm和(39.78±7.11)μm,耳石原基直径分别为(16.29±3.46)μm和(17.09±3.88)μm。矢耳石和星耳石轮纹清晰度、规律性、周期性和完整性不及微耳石;微耳石第1条日轮在仔鱼出膜后第2天形成,以后每天沉积1轮。30日龄稚鱼微耳石轮纹数(N)与日龄(T)的关系符合直线模型,相关关系式为:N=1.0016T-0.8753(R2=0.9961,P<0.01,n=197),线性方程斜率与1无显著性差异(P>0.05)。在微耳石和矢耳石样本中共观察到孵化标记轮和转移标记轮2种,其中孵化标记轮的出现率分别为78.68%和83.33%,转移标记轮的出现率分别为29.95%和48.98%。60尾33日龄稚鱼微耳石的生长轮宽度变化范围0.522~2.244μm,平均为(1.087±0.231)μm。  相似文献   

3.
对实验室人工繁殖的叉尾斗鱼(Macropodus opercularis)仔鱼耳石形态发育与日轮进行了观察研究.结果显示,叉尾斗鱼微耳石和矢耳石在胚胎时已出现.微耳石在仔鱼刚孵化时为圆盘状,随仔鱼发育转变为近椭圆形,孵出后19 d转变为中部圆凸两端较尖的菱形;矢耳石在仔鱼刚孵出时为圆盘状,随仔鱼发育转变为椭圆形,孵出后19 d转变为一端略尖的桃形;星耳石在仔鱼孵出后第19天才出现,呈中部略凹的椭圆形.叉尾斗鱼仔鱼耳石长径(包括微耳石和矢耳石)与鱼体全长(TL,mm)呈线性相关.仔鱼耳石上第一个轮纹在孵出后第2天形成,其后每日形成1个新轮纹,生长轮数目与仔鱼日龄(D)呈线性相关,且线性方程斜率接近于1.结论认为,叉尾斗鱼仔鱼星耳石出现时间晚,矢耳石形态在后期出现较大变化,而微耳石在胚胎时即形成,形态稳定;日轮可读性较好,故更适合做日轮研究的材料.本研究旨在为叉尾斗鱼自然种群年龄结构调查及其资源保护提供基础数据.  相似文献   

4.
东海条石鲷仔鱼耳石日轮与生长的关系   总被引:2,自引:1,他引:1  
2009年4月15日-5月5日在浙江省舟山水产研究所条石鲷(Oplegnathus fasciatus)人工繁殖期间,逐日选择胚胎和仔鱼样本,连续解剖观察发育后期胚胎和前期仔鱼,光镜观察仔鱼矢耳石和微耳石的形态、日轮数,测定其直径,研究条石鲷的耳石日轮和生长。结果表明,受精后约26h,条石鲷胚胎听囊内出现1对矢耳石和1对微耳石;仔鱼孵出第2天形成第1个轮纹,之后每天形成1轮,孵化后天数(N)和矢耳石日轮数(D)的关系为N=D+1;在第8天左右,矢耳石上出现第2条明显的标记轮,为初次摄食轮。仔鱼耳石长径(rs,μm)与鱼体体长(L,mm)呈线性相关,其关系式为rs=18.146L-44.436;矢耳石长径rs与微耳石长径rl之间存在线性相关,其关系式为rs=0.6125rl+1.9882。根据结果确认,矢耳石轮纹可作为条石鲷仔鱼日龄的判别依据。  相似文献   

5.
研究中华倒刺鲃(Spinibarbus sinensis)耳石的发育和生长特征,补充早期生物学资料,为进一步研究该鱼野生资源的早期生活史特征提供基础数据。在实验室养殖条件下观察了乌江中华倒刺鲃仔、稚鱼及3种耳石的形态发育过程和生长特点。结果表明,在水温(26.0±2.1)℃下,初孵仔鱼微耳石和矢耳石已经形成,星耳石在仔鱼出膜后第6天出现。在形态发育过程中,微耳石由出膜时的近圆形经卵圆形发育成贻贝形,且中心核位置偏移到前端靠近背侧;矢耳石由近圆形经卵圆形发育成箭矢状;星耳石由逗号形发育成不规则四边形。3种耳石形态发育的各阶段与鱼体发育阶段存在一定的对应关系。在生长上,仔稚鱼鱼体、3种耳石的长径和短径与日龄均呈显著的线性关系(P0.001),鱼体全长与3种耳石长径呈现出显著的线性关系(P0.001),仔稚鱼鱼体、3种耳石的特定生长率随日龄增加均呈下降趋势。  相似文献   

6.
对江鳕(Lotalota)出膜后仔鱼各个器官的发育进行了系统观察。结果表明,从形态发育来看,江鳕发育分为仔鱼期和稚鱼期。仔鱼期又分为卵黄囊期仔鱼和后期仔鱼,根据外部形态和发育特点分为11个发育期;卵黄囊期(0~31日龄)仔鱼生长发育缓慢;后期仔鱼期(32~62日龄)生长发育较快。稚鱼期主要是鳞片形成(63~67日龄),所有器官形成历时67d。  相似文献   

7.
对江鳕(Lotalota)出膜后仔鱼各个器官的发育进行了系统观察。结果表明,从形态发育来看,江鳕发育分为仔鱼期和稚鱼期。仔鱼期又分为卵黄囊期仔鱼和后期仔鱼,根据外部形态和发育特点分为11个发育期;卵黄囊期(0~31日龄)仔鱼生长发育缓慢;后期仔鱼期(32~62日龄)生长发育较快。稚鱼期主要是鳞片形成(63~67日龄),所有器官形成历时67d。  相似文献   

8.
为研究大黄鱼(Larimichthys crocea)养殖群体与野生群体的鉴别特征,比较分析了大黄鱼养殖群体和野生群体的形态性状、鳞片与矢耳石轮纹特征差异。形态性状比较结果表明,养殖群体的肥满度(Fatness)、体高(BH)/体长(BL)、体厚(BT)/体长(BL)和尾柄高(CPH)/尾长(TL)比值显著大于野生群体(P0.01),野生群体躯干长(TL)/体长(BL)比值大于养殖群体(P0.05),养殖群体在体型上出现偏短、粗现象。养殖群体与野生群体在鳞片轮纹特征上无显著差异,部分个体鳞片上观察到有年轮和副轮分布。野生群体耳石轮纹较为致密,明暗带间隔不均,耳石中心核及周围区域为深黄色,年龄组成复杂,有0~2个年轮;养殖群体耳石轮纹较稀疏,明暗带间隔均匀,耳石中心核及周围区域较透明,观察到有1个年轮。这些差异间接反映了两个群体在生活环境条件、食物饵料供给方面的差异,可作为大黄鱼群体鉴定与资源管理的重要依据。  相似文献   

9.
大黄鱼人工育苗技术总结   总被引:5,自引:0,他引:5  
介绍了大黄鱼受精卵的孵化和生物饵料的营养强化技术,以及仔,稚鱼的形态特征和生态习性,提出了仔鱼期,稚鱼期,幼鱼期的鱼苗培育技术,并对人工育苗的关键技术进行了探讨。  相似文献   

10.
本文介绍了大黄鱼受精卵的孵化和生物饵料的营养强化技术,以及仔、稚鱼的形态特征和生态习性;提出了仔鱼期、稚鱼期、幼鱼期的鱼苗培育技术,并对人工育苗的关键技术进行了探讨。  相似文献   

11.
To determine the optimal condition of photoperiod for embryo development and larval culture of tawny puffer, Takifugu flavidus, the effects of photoperiod on egg hatching and the growth and survival of larvae from 3 to 23 d after hatching (dah) were assessed. The results show that photoperiodic responses varied with the developmental stage during the early development of tawny puffer. Photoperiod did not significantly affect the hatch rate, viability of 24 h post‐hatch larvae, and total mortality rate of tawny puffer embryos; however, it affected the incubation period, which significantly increased with increasing photoperiod from 6 to 24 h. The shortest incubation period was predicted to occur at 3.56 h day length from the quadratic relationship. However, photoperiod strongly affected the growth and survival of the tawny puffer larvae from 3 to 23 dah. Increasing the day length resulted in improvement of the larval growth and survival within the 0–12 h day length range; however, beyond the 12 h day length, a longer day length was not beneficial, and a 24 h continuous light had a negative effect on growth. From the quadratic relationships, the highest growth and survival rates were predicted to occur at 14.16 h and 17.74 h day length, respectively. Therefore, the optimal photoperiods for tawny puffer embryos and larvae were 3–6 and 12–18 h day length, respectively. The results of this study are useful in increasing the production of the species during incubation and larval culture.  相似文献   

12.
A histological method was used to describe the ontogenetic development of the digestive tract of laboratory-reared miiuy croaker (Miichthys miiuy) and to evaluate the effects of short-term food deprivation on the morphology and histology of the digestive tract. Larvae and juveniles were maintained at 24 °C in a thermostatically controlled system. Three starvation experiments were conducted during different developmental stages: 1–7 days after hatching (dah; prior to benthic swimming); 26–35 dah (during settling); and 42–53 dah (after benthic swimming). According to the structural changes in the ontogenetic development of the digestive tract, three stages were observed. The first stage was from hatching to 3 dah; the digestive tract was undifferentiated in newly hatched larvae and then showed remarkable morphological changes and differentiation. During this period, larvae depended on endogenous nutrition. The second stage (4–20 dah) was a critical period in which larvae transitioned from endogenous feeding to exogenous feeding and the digestive tract fully differentiated into the buccopharynx, oesophagus, stomach, anterior intestine and posterior intestine. Goblet cells and vacuoles appeared in the digestive tract, and pharyngeal teeth and taste buds developed. During the third stage (20–36 dah), the gastric glands developed and the stomach differentiated into the fundic, cardiac and pyloric regions. At 25 dah, pyloric caeca developed and mucosal folds and spiral valves were clearly distinguishable. After 30 dah, the digestive tract did not undergo any noticeable differentiation, indicating the complete development of the digestive system. The wet weight and SGR (specific growth rate) of miiuy croaker larvae and juveniles greatly decreased when they were deprived of food, and compensatory growth was observed in re-feeding juveniles. The livers of starved larvae and juveniles were atrophied and dark coloured, the intestines were transparent and thin, and the stomach cubages were reduced. The histological effects of starvation were mainly evident in the degeneration of cells in digestive organs, as seen in the shrinkage and separation of cells and the loss of intercellular substances in the liver, pancreas, intestine and stomach. These changes became more severe with increased duration of starvation. In addition, the histological structure of the digestive tracts of starved larvae and juveniles partly recovered after re-feeding, and the effects of starvation on miiuy croaker were age dependent.  相似文献   

13.
Based on the analysis of 11 morphometric variables of body (total length, body area and perimeter, myotome height and eye diameter) and yolk sac (length, height, area, perimeter and volume) of pike larvae, the aim of this study was to evaluate how larval size at hatching and growth of larvae hatched from single egg batches vary according to three hatching times: early, mid and late. Hatching time structures strongly pike larval morphometrics. Early hatched larvae have smaller body sizes at hatch, faster growth and higher yolk use efficiency than late hatched ones. Early hatched larvae seem to be premature and hatch at precocious developmental stage whereas late hatched individuals continue their growth within the egg shell and hatch at larger size but with lower reserves (yolk). A compensatory growth phase was observed for the early hatching pike larvae particularly during the first 5 days post hatch. Consequently, no significant difference in body parameters was recorded from day 10 post hatching whatever the hatching time. The higher growth accomplished by early hatched larvae may be related to a particular metabolic activity that converts more efficiently yolk into body tissues.  相似文献   

14.
The influence of the absence of Artemia nauplii from larval diet protocols on growth and digestive system ontogeny was studied using histological techniques in the shi drum (Umbrina cirrosa). One group of larvae was reared using the standard intensive rearing protocol, which offers a combination of enriched rotifers (Brachionus plicatilis), Artemia spp. nauplii and artificial diet (Std-group). Another group was reared using the same protocol, but without the offering of Artemia nauplii (group No-Artemia). The ontogenesis of the digestive system from hatching to metamorphosis was a very rapid process, and there were no differences between the two feeding regimes in the temporal appearance of the various components of the digestive system. The first organised presence of the hepatic and pancreatic tissue appeared at 2–3 d after hatching (dah), suggesting that these organs function from a very early developmental stage. In the No-Artemia larvae between 13 and 29 dah there was a reduction in the height of enterocytes in the intestinal mucosa, a progressive flattening of the primary intestinal folds in the anterior and posterior intestine and a decrease in lipid stores in the liver, suggesting a period of relative starvation. However, by the end of the study at 41 dah, there were no significant differences in body length, intestinal morphology or liver lipid stores between larvae reared under the two feeding regimes. The study suggests that the diet may influence the maturation and/or function, but not the ontogeny of the digestive system. Furthermore, the rapid differentiation of the digestive system in shi drum and the prompt recovery of the No-Artemia larvae from the symptoms of starvation by 29 dah, indicate a plasticity during ontogenesis and the ability of larvae to adapt to artificial diets at very early developmental stages.  相似文献   

15.
对驼背鲈(Chromileptes altivelis)的胚胎发育及仔、稚、幼鱼的形态特征进行了详细的观察与研究,描述了从受精卵到仔、稚、幼鱼各发育期的时间和形态特征变化。结果表明,在水温25-26℃、盐度30的海水中,受精卵历时27 h 25 min完成整个胚胎发育过程,经历从卵裂、囊胚、原肠、神经胚到肌节形成、各器官的逐渐形成、变化、完善等一系列的胚胎发育和变化过程;根据其卵黄囊消长情况、鳞片的覆盖状态、体色发生的不同变化以及第二背鳍和腹鳍的消长,将胚后发育分为仔、稚、幼鱼3个阶段。在水温22-26℃、盐度29-31、DO≥5 mg/L的条件下,2-3 d仔鱼卵黄囊消失,开口摄食;生长发育至31 d,仔鱼已变态进入稚鱼期;培育至57 d,稚鱼完成变态,成为幼鱼。第二背鳍棘和腹鳍棘的生长与收缩等石斑鱼类早期发育的共性生长特征及其体表特性体色变化特征为驼背鲈胚后发育过程中最明显的特征。  相似文献   

16.
斜带石斑鱼消化系统胚后发育的组织学研究   总被引:25,自引:0,他引:25       下载免费PDF全文
吴金英 《水产学报》2003,27(1):7-12
利用形态学和连续组织切片技术,对出膜后1-60d的斜带石斑鱼各期仔鱼、稚鱼和幼鱼的消化系统进行了光镜观察,描述了其消化器官发育过程和组织学特性。研究表明,实验水温为22.0-27.8℃时,孵化后第4天,上下颌形成,卵黄囊被吸收,消化系统明显分化成食道、胃、肠、直肠以及肝脏、胆囊和胰脏等,鱼体由内源性营养转向外源性摄食营养,表明其消化系统的形态变化与食性的变化相适应。此后随着鱼体的生长,其消化系统从功能和结构上逐步完善成熟。胰脏在出膜后第4天出现,是和肝脏相互分开的一个独立的器官,但是发育到第35-60天,位于肠道后部的胰脏组织内出现许多大空泡。  相似文献   

17.
Morphological development and allometric growth patterns of Seriola lalandi larvae were assessed to characterize normal growth patterns under culture conditions. Early ontogenetic stages of yellowtail kingfish exhibited an exponential growth in terms of standard length as a function of age. Five development stages were characterized from hatching to the juvenile stage: larval stage I (0–2 days post hatch, dph) with endogenous feeding, characterized by a small yolk sac, unpigmented eyes, primordial finfold surrounding the body and a closed mouth; larval stage II (2–15 dph) characterized by mouth opening, complete pigmentation of eyes and the beginning of the exogenous feeding; subsequently, in the larval stage III (15–25 dph) the posterior tip of notochord of the larvae bended upward and the first rays appeared in fins, concomitant with a change in swimming behaviour; thereafter, larval stage IV (post‐flexion stage; 25–30 dph) began when larvae resembled in morphology to a juvenile organism; however, caudal and dorsal fins were not completely development. Lastly, the juvenile stage was reached 30 dph characterized by a morphology and fin structures similar to those of the adults. Growth and development of structures and organs associated with vital functions such as feeding, sensorial and breathing systems seemed to be more critical previous to 23 dph, which was reflected with a positive allometric growth of head and eyes during this period. The results from this study can be used as a tool‐guide to assess normal development in larval research with S. lalandi to improve existing rearing protocols in hatchery production.  相似文献   

18.
The development of thyroid follicles and the change of thyroid hormone concentrations in whole body were examined, and the relationship between thyroid follicle differentiation and growth were also studied during early development of Korean rockfish Sebastes schlegeli . Total length (TL) and body weight (BW) of larva at parturition were 6.3 ± 0.1 mm and 3.6 ± 0.1 mg respectively. The larvae transformed to juveniles from 20 to 30 d after parturition with continuous growth. The thyroid primordium of the rockfish was observed histologically in newly born larvae, suggesting that the thyroid primordium may have been formed during yolk-sac larval stage after hatching as with other marine telosts. In addition, although the Korean rockfish is a viviparous fish, the developmental features of the thyroid gland in number, size and shape are very similar to the general development features of marine oviparous fish. As the larvae grew, the thyroid follicles of Korean rockfish increased in number, became variable in size, and changed from the normal spheroid/ovoid shape to more irregular forms in shape after parturition, and then concentrated mostly along the areas immediately adjacent to the ventral aorta. In addition, thyroid cell height and thyroid hormone concentrations were related with physiological activity at a specific developmental stage.  相似文献   

19.
20.
In order to understand better the recruitment variability in European anchovy in the Bay of Biscay, it is important to investigate the processes that affect survival during the early life stages. Anchovy juvenile growth trajectories and hatch‐date distributions were inferred over a 3‐year period based on otolith microstructure analysis. Otolith growth trajectories showed a characteristic shape depending on their hatch‐date timing. Earlier‐born juveniles had notably broader maximum increments than later born conspecifics, resulting in higher growth rates. This observation suggests that early hatching would be beneficial for larval and juvenile growth, and, therefore, survival. The estimated juvenile hatch‐date distributions were relatively narrow compared with the extended anchovy spawning season (March–August) in the Bay of Biscay and indicated that only individuals originated mainly from the summer months (June–August) survived until autumn. Hatch‐date distributions were markedly different among years and seemed to influence the interannual recruitment strength of anchovy. We conclude that years characterized by juvenile survivors originating from the peak spawning period (May and June) would lead to considerable recruitment success. Downwelling events during the peak spawning period seem to affect larval survival. Furthermore, size‐dependent overwinter mortality would be an additional process that regulates recruitment strength in the anchovy population in the Bay of Biscay.  相似文献   

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