大菱鲆早期变态发育和体表黑色素细胞形态学观察

对大菱鲆早期变态发育及体表黑色素细胞的形成过程进行了研究。绘制了1－60日龄大菱鲆鱼苗形态发育图，同时观察拍摄不同发育时期体表黑色素细胞的形态变化。14－17℃水温时，大菱鲆早期变态发育约需60d。1－14日龄主要为器官发育；14－40日龄主要为形态变化，25日龄左右开始变态；40－60日龄变态基本完成。变态前，鱼苗体表的幼体黑色素细胞对称分布，以素细胞密度先增加后减少。变态开始后，鱼体两侧体色出现不对称。有眼侧体表幼体黑色素细胞减少，逐渐由成体黑色素细胞替代，体色变深；无眼侧幼体黑色素细胞逐渐消褪，未出现成体黑色素细胞，体色逐渐变为白色。若有眼侧体表成体黑色素细胞的出现受阻，则形成白化。     

漠斑牙鲆胚胎及仔稚鱼发育的形态学观察

对漠斑牙鲆(Paralichthys lethostigma)胚胎及胚后发育进行观察,描述各发育时期的发育时序和形态特征.在水温18.5±0.5℃,盐度32～33的条件下,受精卵历时49 h脱膜而出,孵化后仔鱼在水温20.5±0.5℃时,4日龄开口摄食,26日龄进入变态期,45日龄左右完成变态成为幼鱼.漠斑牙鲆的卵子为浮性卵,油球一个.刚孵化仔鱼的消化道细直,3日龄肛门开通,4日龄卵黄囊消耗殆尽,开口摄食.在原肠期胚体下包约1/2时,在视囊和胚盘上出现点状星状的黑色素细胞.孵化后体两侧菊花状黑色素均匀分布;进入变态期后,体两侧的幼体色素逐渐收缩消失,同时在有眼侧出现个体较小的圆形成体色素细胞.在早期发育过程中,伴随着冠状鳍条的发生、伸长和缩短吸收.无鳔器官的发生.     

半滑舌鳎早期发育过程中体表色素变化的研究

对半滑舌鳎(Cynoglossussemilaevis Günther)早期发育过程中体表色素的分布及形态变化进行了连续观察,测量其生物学特征,同时拍摄不同发育时期体表黑色素的形态变化。在水温22～23℃,盐度31～33的条件下,半滑舌鳎完成早期变态发育约需要30d,1～15日龄主要是器官发育,16日龄进入变态期,30日龄左右变态完成。半滑舌鳎在原肠期开始出现幼体色素,以后逐渐密集,色素颗粒变大,幼体色素逐渐变成以树枝状和菊花状为主;仔鱼期体表的幼体色素对称分布,在躯干部形成相互间隔的5个色素带;在变态前期幼体色素发生至最发达时期。进入变态期后,幼体色素逐渐减少,同时有眼侧出现颗粒较小的成体色素,形状为点状为主,在身体有眼侧均匀分布。无眼侧色素完全消失,成为无色。个别个体有眼侧的成体色素形成受阻,幼体色素消失后,形成白化。     

圆斑星鲽网箱养殖研究

在水温15～25℃下，将平均体质量分别为792?27±48?89 g（大）、513?49±39?19 g（中）和185?59±25?51 g （小）的圆斑星鲽（Verasper variegatus），按5?5 kg／m2和7?5 kg／m2的密度，饲养在5 m×5 m×3 m网箱中，投喂冰冻玉筋鱼60 d，以研究不同规格和密度的圆斑星鲽在网箱中的生长、饲料系数和体色变化情况。整个饲养期间，圆斑星鲽日增重变化在1?77～4?24 g／d，其中大规格鱼的日增重最高（3?49 g／d），当水温为15～20℃时，日增重可达4?24 g／d；饲料系数平均为4?87，其中大规格鱼的最低（4?16），当水温为15～20℃时，饲料系数为3?55；密度对圆斑星鲽网箱养殖的生长情况和饲料系数无显著影响；15～20℃时圆斑星鲽生长快于20～25℃时；网箱养殖圆斑星鲽体色逐渐接近野生鱼体色，无眼侧异常黑化的体色逐渐褪黑变白。研究认为，圆斑星鲽是一种适合网箱养殖的新品种。     

圆斑星鲽胚胎及仔鱼发育的观察

对圆斑星鲽(VeraspervariegatusTemmincketSchlegel)胚胎及胚后发育进行观察,描述了各发育时期的形态特征和发育速度。在水温为(11±0.5)℃时,受精卵历时153h脱膜孵出,孵化后仔鱼在水温为(15±0.5)℃时经过6d开口摄食,50d完成变态而成幼鱼。圆斑星鲽的卵子为半浮性卵,其卵黄量很多。卵裂后期,卵裂球的大小和卵裂速度均出现差异。眼泡在体节形成之前出现。刚孵化仔鱼消化道细而直,孵化5d肛门打通,6d开口。随着卵黄囊的消失,消化道开始弯曲。色素细胞首先出现在86h的胚体中,至140h在卵黄囊上零星分布,且随着胚体发育,色素细胞增多,至变态完成后全身密布黑色色斑。胚体色素细胞的形状由孵化前的雪花状逐渐变为圆形,但卵黄囊上的色素细胞始终为雪花状。     

圆斑星鲽的生殖调控和人工繁殖技术

题组自1999开始从事圆斑星鲽人工繁殖技术的研究，历经7年的试验探索，掌握了圆斑星鲽野生亲鱼驯化、生殖调控技术，系统地研究了人工催产、人工授精技术。2001年至今每年在星鲽繁殖期内都可以稳定获得优质受精卵。目前项目组共驯化培育圆斑星鲽亲鱼106尾，亲鱼年龄3龄以上，全长32-65cm，体重600-4500g。鱼体体质健壮，表现性状正常。     

维生素C对圆斑星鲽早期发育的影响

本研究旨在探究维生素C(V_C)对圆斑星鲽(Verasper variegatus)早期发育中孵化率、出膜率和成活率的影响,对其消化酶和脂蛋白脂酶(Lipoprotein lipase,LPL)及肝脂酶(Hepatic Lipase,HL)的影响。实验用圆斑星鲽为人工受精卵,分为5组,孵化水体V_C浓度分别为0、20、25、30和35 mg/L,分别在成熟卵、受精卵、原肠中期、晶体出现期、内源营养期(2日龄)、混合营养期(6日龄)及外源营养期(9日龄)取样。记录圆斑星鲽的出膜时间、出膜率和成活率,测定对照组和生长指标优越组的消化酶活性和2种酯酶的活性。结果显示,25 mg/L的V_C能显著提高圆斑星鲽的出膜率和成活率,并缩短出膜时间(P0.05)。V_C能促进圆斑星鲽早期发育过程中蛋白质的沉积。外源营养期后,胃蛋白酶活性显著提高(P0.05),淀粉酶活性在混合营养期显著提高(P0.05),脂肪酶和胰蛋白酶活性在内源营养期就显著提高(P0.05)。25 mg/L V_C溶液浸泡使圆斑星鲽胚胎发育过程中的LPL和HL比活力显著升高(P0.05)。合子中的LPL和HL基因可能在原肠期开始表达,合成脂质水解酶分解脂质,为胚胎发育供能。研究表明,圆斑星鲽成熟卵受精后脂肪酶和胰蛋白酶酶优先发挥作用,分解卵黄中的碳水化合物为胚胎发育迅速提供能量。25 mg/L的V_C能显著提高消化酶活性,并促进蛋白质的沉积,有利于孵化成活的V_C浓度可以显著促进圆斑星鲽早期发育的脂质代谢。     

不同体色血鹦鹉鱼的色素细胞种类、数量及色素含量

用显微镜观察了体长7.0~10.0cm的黑、黑黄、黄、红4种体色血鹦鹉鱼色素细胞的形态结构,用紫外分光光度计法测定了其总类胡萝卜素含量。结果显示,(1)黑色血鹦鹉鱼通体分布树突状和圆点状两种形态的黑色素细胞,内含大量黑色素颗粒,黄色素细胞较少,颜色较浅;(2)黑黄色血鹦鹉鱼体上的树突状黑色素细胞的中心胞体扩散,分枝细长,黑色素颗粒为棕色,聚集能力弱,黄色素细胞大颜色深且数量较多;(3)黄色血鹦鹉鱼体上的黑色素细胞数量很少,黄色素细胞遍体分布,颜色深,有少量圆点状的红色素细胞,形状小,颜色浅;(4)红色血鹦鹉鱼体的黑色素细胞稀少,有少量的黄色素细胞,红色素细胞遍体分布。(5)红色血鹦鹉鱼的肉、鳞片、鳍条和皮肤的类胡萝卜素含量与其他3种体色的鱼相比差异均极显著(P0.01);黑、黑黄、黄3种体色的血鹦鹉鱼的上述4个部位的类胡萝卜素含量差异均不显著(P0.05)。本试验结果为深入探究色素细胞的发育机制提供了参考。     

星斑川鲽与其他鲆鲽类杂交研究简报

以星斑川鲽为母本,分别以条斑星鲽、圆斑星鲽为父本进行了属间杂交,成功获得了星斑川鲽(♀)×条斑旱鲽(♂)、星斑川鲽(♀)×圆斑星鲽(♂)的杂交后代,并且性状优良,生长良好.以大菱鲆为母本、星斑川鲽为父本进行了属问杂交,获得的大菱鲆(♀)×星斑川鲽(♂)杂交胚胎发育顺利,但仔鱼1日龄全部死亡,不能进一步发育.同时对杂交胚胎的发育情况进行了详细观察和记录,并确定了胚胎发育的时序.     

圆斑星鲽的早期生长发育特征

圆斑星鲽成熟卵子透明、光滑、无油球,卵径1.75±0.08 mm(n=30).在水温11土0.5℃、盐度31～32、DO≥5 mg/L条件下,受精卵经159 h脱膜孵出,胚胎发育下限温度为5.14℃,发育时间与温度呈负相关关系.初孵仔鱼体色透明,全长4.95±0.15 mm(n=30),7日龄,仔鱼体覆黑色素,口和肛门贯通,口裂0.32 mm时开始摄食轮虫;11日龄,卵黄囊耗尽,仔鱼由内源性营养转化为外源性营养方式,开始摄食卤虫无节幼体;17日龄,进入尾椎弯曲期,尾扇和下尾骨形成;28日龄,尾鳍色素沉积;33日龄,尾椎弯曲完成,仔鱼左眼开始向右侧翻转,进入变态期,尾鳍条增至18根;45日龄稚鱼体表色素带形成,背、腹鳍各覆4～5个棕黑色斑点;50日龄,变态完成,左眼完全翻转至右侧,开始营底栖生活;70日龄,幼鱼体被鳞片逐渐形成,各鳍条均发育至定数,体态和生活习性与成鱼无异.     

大菱鲆仔鱼皮肤发育及超微结构

The histological development and ultrastructure of larval turbot skin were studied by both light and transmission electron microscopes.The early larvae showed a complete bisymmetry of skin.The skin of 1-25days old larvae developed slowly and was composed of the thin epidermis of 1-2layers epidermal cells and undeveloped dermis before the metamorphosis.But the skin developed significantly when the.metamorphosis began.Till the completion of metamorphosis(about 60days old),the skin contained 3-4layers epidermal cells and very developed collagenous strata.Wisth the process of metamorphosis,the ocular side skin and blind side skin became different in ultrastructure.Ultrastructural observation showed the epidermis of turbot contained three types of epidermal cells;filament-containing cells,mucus cells and chloride cells.The ocular side epidermis with looser structure consisted one type of filament-containing cells,but the blind side epidermis was structured densely and two types of filament-containing cells were observed in it.Melanophores,iridophores,fibroblasts and other cell types and tisssues were found in the spongiosum of dermis.The distribution of melanophores depended on the larval developing stage and the pigmentation of skin.The differentiation of skin seems to be an adaptation for the change of life style of turbot larvae from pelagic living to benthonic living after the metamorphosis.     

Dual appearance of xanthophores,and ontogenetic changes in other pigment cells during early development of Japanese flounder <Emphasis Type="Italic">Paralichthys olivaceus</Emphasis>

Flatfishes display a left–right asymmetry that is unique in the animal kingdom. In order to clarify the mechanisms of the asymmetrical development of pigment cells, changes in pigment cell densities were examined in Japanese flounder Paralichthys olivaceus. During development from symmetrical larvae to asymmetrical juveniles, pigment cell densities were monitored on the skin on both the left side (ocular side in juvenile; eventually has two eyes) and the right side (blind side in juvenile; eventually has no eyes). A symmetrical and constant decrease was observed in leucophores and larval type melanophores. A mostly symmetrical (slightly delayed on the blind side) and constant increase in iridophores from metamorphosis was observed. Adult-type melanophores appeared and then increased only after metamorphosis on the ocular side. However, the pattern of xanthophores was complicated: they first existed symmetrically and decreased symmetrically until metamorphosis, and they later increased only on the ocular side. The dual appearance of the xanthophores, as well as the differences between their depths and sizes on the ocular and blind sides, may suggest the presence of two types of xanthophores—just as melanophores are well known to exhibit two types. The ontogenetic study of pigment cells described here is likely to help to elucidate the process of abnormal pigmentation in flatfishes.     

半滑舌鳎酪氨酸酶基因(TYR)和多巴色素异构酶基因(DCT)的克隆表达与分析

作为我国鲆鳎鱼类中的一种主要养殖品种,半滑舌鳎(Cynoglossus semilaevis)有时会发生无眼侧黑化(Melanism)、有眼侧白化(Albinism)的体色异常现象。本研究克隆了半滑舌鳎体色相关的酪氨酸酶基因(TYR)和多巴色素异构酶基因(DCT)的cDNA序列,并对这2个基因进行系统发育分析和时空表达分析。实验获得了TYR基因编码区cDNA序列长度为1620 bp,编码539个氨基酸;DCT基因编码区cDNA序列长度为1551 bp,编码516个氨基酸。结果显示,TYR和DCT在20日龄前的鱼苗体内表达量较高,尤其是在变态关键时期(15~20日龄)表达量最高,30日龄时的表达量锐减到很低水平;在其他时期的皮肤组织中,这2个基因在有眼侧正常皮肤和无眼侧黑化皮肤的表达量最高,在有眼侧白化皮肤和无眼侧正常皮肤中表达量极低;在其他时期的其他组织中,在眼睛中的表达量最高,其次是肝脏,在脾脏和肌肉中表达量极低。研究表明,TYR和DCT基因是半滑舌鳎无眼侧黑化发生和有眼侧体色维持的关键基因。本研究为查明半滑舌鳎体色异常机制提供了重要依据和参考。     

Early weaning of winter flounder (Pseudopleuronectes americanus Walbaum) larvae on a commercial microencapsulated diet

Like most small marine fish larvae, the stomachs of winter flounder Pseudopleuronectes americanus are undeveloped at first feeding and have relatively reduced digestive capacity. This work was undertaken to test whether larvae at the onset of stomach differentiation (larval size about 5.5 mm) could be early weaned onto a commercial microencapsulated diet. We assessed the effect of early weaning by first comparing growth performance (standard length, total protein content and age at metamorphosis) of larvae fed enriched live prey from first feeding to a size of 5.5 mm and then reared on three different feeding regimes until metamorphosis: (1) live prey (LP) as a control group; (2) mixed feeding of live prey and microencapsulated diet (LP‐ME); (3) exclusively microencapsulated diet (ME) after fast weaning over 4 days (to a larval size of 6.2 mm). No differences were observed between larval development in the two first groups, which began metamorphosis at 40 days old. The larvae of the third group showed significantly slower growth that resulted in a delay of 4 days in the onset of metamorphosis. Differences in live prey availability between the treatments and the short transition period to allow the larvae to adapt to the new diet were identified as possible contributing factors to the slower growth and to the delay in metamorphosis of early weaned larvae. In a second experiment, the transitional weaning period was increased until the larvae were 6.6 mm in length. Weaning at that size resulted in no slowing of growth or delay in metamorphosis, suggesting that the feeding schedule was adequate.     

云纹石斑鱼胚胎发育及仔、稚、幼鱼形态观察

对云纹石斑鱼Epinephelus moara胚胎发育及仔、稚、幼鱼形态进行了观察与研究,详细描述了各发育期的形态特征和发育时间。结果表明:1)在水温22±0.2℃、盐度30、溶氧7.8mg/L、pH8.25的条件下,云纹石斑鱼的受精卵历时38h 17min开始孵化出膜。胚胎发育可分为受精卵、卵裂、原肠、神经胚和器官形成及出膜6个阶段,受精、胚盘形成、2细胞等28个时期。2)在水温23±1℃,盐度30±3,DO≥5mg/L,pH8.0±0.5的海水中,培育至5d,卵黄囊完全消失,成为后期仔鱼;培育至27d,发育最快的云纹石斑鱼结束仔鱼期,进入稚鱼期;培育至65d,发育最快的稚鱼完成变态,成为幼鱼。胚后发育过程主要是根据卵黄囊、鳍膜、鳞片、体色及第1腹鳍棘与第2背鳍棘相对长度的变化分为仔鱼、稚鱼和幼鱼3个时期。其中仔鱼期又根据其卵黄囊的有无划分为前期仔鱼和后期仔鱼。     

Morphological development of larval and juvenile blacktip grouper, <Emphasis Type="Italic">Epinephelus fasciatus</Emphasis>

The morphological development of larval and juvenile blacktip grouper, Epinephelus fasciatus, was examined using a hatchery-reared series. By about 5 mm body length (BL), the larvae developed characteristic pigmentation patterns of groupers, such as melanophores on the dorsal part of the gut, on the tips of the second-dorsal and pelvic fin spines, and on the midpoint of the tail to form a cluster. In addition, characteristic spines of groupers, such as spinelets on the second-dorsal and pelvic fin spines, and the preopercular angle spine developed by about 6 mm BL. The notochord end was in the process of flexion in larvae of 6–7 mm BL, by when major melanophores, spines, and jaw teeth started to appear. After the fin ray counts attained the adult complement at about 14 mm BL, somewhat densely pigmented bands started to appear on the body. The fish had the five distinct transverse bands and attained adult-like attire at about 40 mm BL when the major head spines disappeared and body parts in relation to BL became stable.     

Formation process of staining-type hypermelanosis in Japanese flounder juveniles revealed by examination of chromatophores and scales

Staining-type hypermelanosis, defined as blind-side melanosis occurring after completion of metamorphosis, reduces commercial value in hatchery-produced flatfishes. Detailed characterization was performed on the stained area of juvenile Japanese flounder Paralichthys olivaceus to physiologically understand this phenomenon. From 80 to 120 days after hatching, juveniles were reared in sandy and sandless tanks. By classifying the staining degree into 7 levels, about 2 times higher occurrence of middle-level staining was reconfirmed in sandless tank (about 80 %) than in sandy tank (about 40 %). In the stained area, we found 3 types of chromatophores (melanophore, xanthophore, and iridophore) and ctenoid scales, which would be typically observed on the normal ocular side. Detailed examination on the melanophores revealed further similarity between the stained area and the normal ocular side, in terms of the distribution at 2 layers (shallower and deeper than scale), and the densities in both layers (about 1000 cells/mm² above scale and 200 cells/mm² beneath scale). These results strongly suggest that the staining is a status change in the body surface conditions from the blind side to that on the ocular side, and not a simple darkening caused by disordered proliferation of melanophores on the blind side.     

Transplantation of pigmented and non-pigmented scales into the ocular and blind sides of the Japanese flounder Paralichthys olivaceus,suggesting the presence of ocular-side characteristic inducer in pigmented scales

After metamorphosis, both eyes of the Japanese flounder Paralichthys olivaceus are located on its left side, with only the ocular side becoming pigmented. Staining, or hypermelanosis, occurs on the blind side at 2–3 months after metamorphosis, thereby lowering the market price of the fish. To understand the pigmentation expansion process, we performed scale transplantation between the blind and ocular sides of an individual. About 40 % of transplanted scales were successfully engrafted, regardless of donor or recipient site. When blind-side scales were transplanted to the ocular side, they became pigmented after 2 weeks, while no change was observed when the scales were transplanted to the blind side. Ocular-side scales did not lose pigment, regardless of the recipient site. However, after removal of transplanted ocular-side scales, pigmented scales regenerated after 3 weeks, even at blind-side sites. Identical results were obtained when the stained area on the blind side was used as the recipient location. When an ocular-side scale with skin tissue was inserted under blind-side scales, the scales immediately above the transplanted area became pigmented, whereas ocular-side scales stripped of tissue did not induce pigmentation. These results strongly suggest the presence of an ocular-side characteristic inducer in pigmented scale tissues.     

Morphological and habitat characteristics of settling and newly settled Roughscale Sole Clidoderma asperrimum collected in the coastal waters of northeastern Japan

This report first describes the morphological and habitat characteristics of larval and juvenile Roughscale Sole Clidoderma asperrimum. Five metamorphosing larvae (22.1–31.7 mm standard length, SL) and 12 juveniles (23.7–46.4 mm SL) were collected from two locations in coastal waters of northeastern Japan, Shizugawa Bay (rocky habitats, 6–12 m depth) and Iwaki (sandy habitats, 10–50 m depth), respectively, using a hand net while SCUBA diving and a small trawl net during May–August in 2008 and 2010. Underwater observation in Shizugawa Bay revealed that metamorphosing larvae and juveniles that had settled on rocks or stones showed transparent and variegated body coloration, which is cryptic to a rocky habitat. Juveniles in Iwaki showed monotonic coloration. The settlement would occur during metamorphosis because the same larva observed on a stone subsequently swam with a left-lateralized body posture. The larval morphology was characterized by a dense covering of fine spines on the whole body surface. Spines on the ocular side developed steadily, gradually forming bony tubercles with growth, whereas those on the blind side regressed with development and finally disappeared in metamorphosed juveniles. Our results indicate that Roughscale Sole can settle and adapt to rocky and sandy habitats in coastal waters with wide depth range.     

波纹巴非蛤人工育苗技术初探

2008年～2009年,对波纹巴非蛤人工繁殖、胚胎发育、幼体开口饵料、幼虫变态附着和稚贝培育技术等进行研究,人工育苗获得成功。结果表明,在自然水温29.6℃～23℃,盐度28～34,pH值7.8～8.4,溶解氧4～7mg/L的生境下,受精卵约17h发育成"D"形幼虫,第6～7d,幼虫个体大小180μm×165μm(壳长×壳高),开始变态附着。经约80d人工培育,共获得壳长3.4mm～15mm的波纹巴非蛤稚贝21.6万粒。