日本鳗鲡产卵后生存及其繁育

为证明日本鳗鲡(Anguilla japonica)生活史最后一步一产后鳗的命运,本研究模拟产后的日本鳗鲡继续在海水中养殖,观察其存活率及繁育情况.结果表明,产后鳗在海水中停食约18 d后,体能得到恢复,部分亲鱼开始出现摄食,1个月左右全部恢复摄食,经244 d养殖,雌、雄鳗体质量增加,存活率达94.6%.随后,给产后鳗注射外源性促性腺激素(鲤鱼脑垂体匀浆CPE和人绒毛膜促性腺激素HCG)后激发其退化的性腺(卵巢和精巢)重新发育(与当年银鳗作对照).通过性腺组织切片观察产后鳗和对照鳗性腺发育成熟的全过程及其差异,发现产后鳗起初性腺发育比当年银鳗差,但经多次注射激素后,产后鳗性腺成熟与当年银鳗同步,证明产后鳗生殖细胞对激素的敏感件高.应用17α,20β-双羟孕酮和促性腺激素释放激素类似物(GnRH-A3)使催熟的产后鳗和对照鳗均产卵和排精,并孵化出仔鱼,从而有力地证明,鳗鲡产后虽体质弱,但待体能恢复后能够继续生存和繁殖.本研究旨在探讨利用产后鳗作为今后鳗鲡人工繁殖亲鳗的可行性.     

野生圆斑星鲽的驯养试验

野生的圆斑星鲽必须经过驯养后才能做为人工养殖亲鱼使用。野生亲鱼开口摄食是驯养成功的关键因素之一,活虾和冰鲜虾是野生圆斑星鲽很好的开口饵料。营造好的驯养环境,与人工繁殖的鲆鲽类混养和及时药物处理可缩短驯养时间和提高成活率。试验共驯养野生的圆斑星鲽27尾,最终成活20尾,成活率为74.1%。     

鳗苗驯养技术总结

<正> 鳗苗培育是鳗鱼生产的重要一环,要发展鳗鱼生产,首先必须抓好鳗苗种的驯养培育。鳗苗在自然环境中,它是昼伏夜出,分散觅食,以浮游动物、水蚯蚓等天然饵料为食。鳗苗驯养就是改变它的生活习性、食性,以符合大规模人工养殖的需要。即改变夜间摄食为白天摄食,改变分散觅食为集群摄食,改变食鲜活饵料为摄取配合饵料。驯养的成败是培育好鳗种的关健。根据我场十多年的鳗苗驯养培育经验,现归纳如下。一、放养前的准备工作 1.池子消毒。鳗鱼驯养与培育一般采用水泥的一、二级池。一级池面积30～50m~2。二级池面积100～300m~2。初用时,要在放养前     

海水培育亲鳗摄饵取得成功

中国水产科学研究院珠江水产研究所联合广东省大亚湾水产试验中心开展鳗鲡繁育技术攻关。2008年下半年，科技人员通过采用生态模拟、人工强化营养等技术措施，促使高盐度海水（盐度30‰）中亲鳗摄食人工饵料，首次取得亲鳗驯化摄饵成功。在自然界中，鳗鲡产卵洄游从淡水进入海水后即停止摄食；长期以来国内外科学家从事鳗鲡人工繁育时的亲鳗一旦进入海水后也即停止摄食。     

国家渔业科研动态

海水培育亲鳗摄饵驯化取得成功自然界中鳗鲡产卵洄游从淡水进入海水后即停止摄食,长期以来国内外科学家从事鳗鲡人工繁育使用的亲鳗     

日本鳗鲡仔鱼的开口饵料和行为特征

在连续多年日本鳗鲡人工繁殖实验的基础上,研究了不同饵料对日本鳗鲡仔鱼存活率的影响,并记录了仔鱼的运动特征和摄食行为。结果显示,与对照组(不投饵)相比,投喂以鲨鱼卵、磷虾提取液为基础的饵料和以鲨鱼卵、海蜇匀浆液为基础的饵料以及微绿球藻液均提高了日本鳗鲡仔鱼的存活率,仔鱼发育至柳叶鳗前期阶段;而投喂以鲨鱼卵、卤虫匀浆液为基础的饵料和以卤虫匀浆液、磷虾提取液为基础的饵料,以及轮虫、海带+龙须菜匀浆液或海蜇以及发酵鲨鱼肉,均降低日本鳗鲡仔鱼的存活率。实验同时还研究了日本鳗鲡仔鱼的主动摄食行为,摄食时仔鱼先用吻端反复多次触碰食物,然后张开下颌咬食,证实了日本鳗鲡早期仔鱼的摄食方式是触碰后咬食。     

圆口铜鱼仔幼鱼驯养初试

2010年6月24日至10月8日,以采自金沙江的34尾圆口铜鱼(Coreius guichenoti)仔鱼(出膜3～4d)为驯养试验对象,仔鱼阶段分别以蛋黄和水蚯蚓碎浆作开口饵料,稚鱼、幼鱼阶段投喂人工配合饲料,圆口铜鱼仔鱼、稚鱼、幼鱼均能主动摄食。经107d驯化培育,总体成活率64.71%,幼鱼平均体长(70.5±4.6)mm,平均体重(5.9±1.3)g,表明圆口铜鱼仔幼鱼易于驯养。     

日本鳗鲡人工繁育研究的进展

从日本鳗鲡亲本的选择、人工催熟催产技术、仔鳗的饵料开发、仔鳗的培育装置及培育方法等方面综述了目前在日本鳗鲡繁育方面的最新研究成果,以期为国内日本鳗鲡的人工繁殖研究提供参考资料.     

驼背鲈人工育苗技术初探

选取网箱驯养的野生驼背鲈亲鱼,经过强化培育,采用HCG催熟,网箱中自然产卵受精,采用池塘蓄水和室内玻璃钢水槽培育相结合的方法,成功繁育出驼背鲈3 cm左右鱼苗3万尾,繁育成功的关键技术是亲鱼的驯养和强化,控制好水质,提供适口、营养丰富的开口饵料生物.     

鳗鱼爱德华氏赤鳍病的防治

鳗鱼爱德华氏赤鳍病的防治鳗鱼爱德华氏赤鳍病，又称肝肾病、溃疡病或臌胀病，是危害较大的常见细菌性鳗病。尤其在温室里培育鳗苗时，因绝大部分养鳗场以丝蚯蚓为开口驯养饵料，发病比较普遍，危害十分严重．鳗鱼养殖的关键在于提高鳗苗培育成活率，即在温室里对爱德华氏...     

激素缓释制剂诱导海水养殖鱼类性腺发育成熟与生殖行为的研究进展

综述促性腺素释放激素类似物（GnRH-a)缓释制剂（SRDS），人绒毛膜促性腺激素（HCG）SRDS，类固醇激素SRDS；雄烯二酮（ADSD）和17a-甲基睾丸酮（MT），以及鲤垂体匀浆（CPE）混合SRDS诱导海水养殖鱼类性腺发育成熟和生殖行为的效果，认为采用GnRH-a SRDS处理性腺发育良好的鲈形目鱼类和鲆鲽鱼类，可以显著提高血液促性腺激素（GtH)水平，且持续时间长，诱导排卵成功，HCG乳胶SRDS可诱导日本鳗鲡（Anguila japonicus)血液GtH持续 升高，性成熟系数明显升高并且性腺发育成熟；HCG和CPE水／油／水（W／O／W）复乳SRDS对日本鳗鲡的催熟效果显著，采用ADSD和MT SRDS SRDS可成功诱导日本鳗鲡性腺成熟与排卵。     

Spawning of the Temperate Sea Cucumber,Australostichopus mollis (Levin)

The spawning of sea cucumbers is related to the interaction of environmental cues and reproductive maturity. Groups of Australostichopus mollis were collected every 2 wk during the summer reproductive season from mid‐October to early February. They were observed for spawning in the hatchery during heat‐shock trials conducted 3–5 C above ambient seawater temperature. Lunar periodicity existed with spawning being most prominent in the week following a full moon. In the week prior to a spawning event, there was also a decrease in ambient incoming seawater temperature. More than 75% individuals spawned during most trials in which spawning occurred. In total, 40% of the 270 individuals spawned during the reproductive season. Reliable spawners were females with a yellow gonad color and large numbers of vitellogenic oocytes, and males with large numbers of spermatocytes and an absence of motile spermatozoa. Furthermore, the percentage germinal vesicle breakdown of oocytes exposed to starfish radial nerve extract compared to seawater was greater for the more orange‐colored gonad of nonspawners. Gonad color is useful in determining the likelihood of spawning over a 2‐wk period in the presence of a cue. Sea cucumbers held for short periods in the hatchery during the reproductive season maintain a natural rhythm of spawning that can be monitored using visual indices and augmented using heat shock.     

Effects of silvering state on induced maturation and spawning in wild female Japanese eel <Emphasis Type="Italic">Anguilla japonica</Emphasis>

ABSTRACT:   The effects of silvering state of wild female Japanese eels Anguilla japonica on the success of induced maturation and the following spawning were examined. Thirty-eight females, collected in Mikawa Bay, were divided into four stages based on their silvering state: yellow (Y1), late-yellow (Y2), silver (S1) and late silver eels (S2). Despite injections of salmon pituitary extract (SPE) through the standard technique, Y1 and Y2 eels did not respond to the treatment with undeveloped gonad (gonad-somatic index [GSI]: 0.3–0.9), and all these females died by 5 weeks, probably due to an abnormal physiological condition. Most S1 (81%) and S2 eels (100%) matured completely (GSI: 17.8–51.4), and finally spawned successfully (69% for S1, 89% for S2). S2 eels fully matured with oocytes of over 750 μm in diameter by significantly smaller number of injections of SPE (5–6 times) than the case of S1 eels (6–8 times). The amount of eggs released by S2 eels (0.65 ± 0.11 g/fish per body weight [BW]) was significantly larger than those by S1 eels (0.54 ± 0.09 g/fish per BW). There was no difference in fertilization and hatching rates between eggs released by S1 eels and those of S2 eels. These results indicate that the success of induced maturation and spawning in wild female Japanese eels depends on their silvering state, and matured eggs can be obtained efficiently through the use of S2 eels rather than other stages.     

Several possible spawning sites of the Japanese eel determined from collections of their eggs and preleptocephali

The spawning area of the Japanese eel is located at the southern part of the West Mariana Ridge in the western North Pacific, but their spawning events have not been observed. To further understand Japanese eel spawning ecology, an interdisciplinary research survey by the R/V NATSUSHIMA (NT14-09, 14 May–4 June 2014) was conducted to detect spawning sites based on the seamount, salinity front, new moon and third quadrant (spawning south of front, west of ridge) hypotheses. Attempts were made to film spawning events with underwater camera systems and to consider if eels might be detected in hydroacoustic observations. Although no Japanese eels or spawning events were video-recorded and no eel aggregations could be clearly identified acoustically, three eggs were collected at two stations in the third quadrant region at or just south of 13° N on 26 and 27 May. Three or four days later, newly hatched preleptocephali were collected at two stations far to the south, including 224 at a station > 160 km southwest of the egg catches, and a few preleptocephali were caught at two stations closer to the egg stations. The eggs and southern preleptocephali were from discrete spawning events, which indicated that at least two spawning sites occurred in May 2014.

     

Transport and survival of Japanese sardine (Sardinops melanostictus) eggs and larvae via particle‐tracking experiments

Particle‐tracking experiments were performed to infer the distribution of larvae of the Japanese sardine (Sardinops melanostictus) and to detect effects of transport environment on sardine recruitment, using the output of a high‐resolution ocean general circulation model and observed data of sardine spawning grounds during 1978–2004. By the 60th day following spawning, approximately 50% of the larvae had been transported to the Kuroshio Extension (KE). Whereas the spawning period and grounds changed markedly in relation to the stock level, the proportion of larvae transported to the KE remained relatively constant and no significant correlations were found between sardine recruitment and the transport proportion. Instead, the recruitment was found to be correlated with physical parameters including the mixed layer depth and the sea surface temperature along several major transport trajectories of sardine larvae. The correlations were most significant for the trajectories in the region 0.5° south to 1° north of the Kuroshio axis (defined as the location of velocity maxima at each longitude) and for larvae spawned in February and March during the high stock period (1978–94), and for larvae spawned in March and April during the low stock period (1995–2004).     

Gonad development and spawning in Anadara granosa (L.) (Bivalvia: Arcidae)

A study of gonad development and spawning in Anadara granosa (L.) from the west coast of West Malaysia was carried out between September 1977 and November 1978 based on (a) changes in the condition of the whole animal and (b) histological changes in the gonad. Gonads did not develop until a length of 17.5 mm had been attained and the first spawning probably occurred at a length of 24–25 mm. There was evidence of a low level of spawning activity throughout the year but the largest size group spawned in October in 2 consecutive years. There was inconclusive evidence for a second spawning in May/June. A condition index of dry/wet weight of tissue adequately reflected spawning in specimens longer than 30 mm. There was no deviation from a 1 : 1 ratio of males to females in any of the size classes studied.     

Spawning of injured compared to uninjured female Atlantic salmon, Salmo salar L.

Abstract. Observations of spawning by uninjured and injured Atlantic salmon, Salmo salar L., indicated that uninjured fish usually spawned in the outlets, or inlets, to pools and on coarse bottom sediments, whereas injured females spawned in different places. Frequently, the spawning sites lay in very shallow water with a slow current and on a bed of sand or fine gravel. Subsequent excavation of the spawning redds revealed that about 28% of the eggs laid by uninjured females were recovered, compared with only about 8% of those laid by injured females. This difference was significant (P < 0·01).     

Seasonal gonadal changes in the clam, Paphia laterisulca

The seasonal gonadal changes in the edible clam, Paphia laterisulca, from the Kalbadevi Estuary at Ratnagiri were studied for the period from May 1972 to April 1973 with the help of fresh gonad smears and histological study. The observations of gonad smears revealed the probable commencement of spawning between September and April from the occurrence of spent gonads. Male and female clams were present in almost equal numbers throughout the year.Histological details revealed that the clam P. laterisulca has a prolonged spawning period extending from mid-September to the end of March with two peaks, the first in October–November and the second in February–March. Lysis of the ripe gametes in both sexes for 2.5 months preceding spawning was observed. The second spawning peak was followed by regression in the gonads.Active gametogenesis was observed in May and June (33.5°C and 30.0°C), and again in December and January (21.5°C and 26.0°C) in clams that had spawned during the first spawning peak.The spawning stimulus in Paphia laterisulca appeared to be the sudden increase in salinity (from 4.1 to 22.5‰) in September in the Kalbadevi Estuary.     

模仿自然繁殖条件下的黄鳝人工繁殖试验

黄鳝(Monopterus albus)属合鳃目,合鳃科,黄鳝属,是我国重要的经济鱼类之一,受环境污染及滥捕的影响,自然资源量不断下降。而人工养殖因受苗种繁殖的制约,尚难以形成规模。我国鱼类学家伍献文和刘建康等曾对黄鳝的生殖习性和幼体变态作过研究,国内外许多学者对黄鳝性逆转等方面亦作过许多报道,但有关黄鳝人工繁殖的报道却不多。由于黄鳝属吐泡营巢繁殖的鱼类,且怀卵量低,一般黄鳝在繁殖期间,黄鳝先在水表面吐泡沫,做成泡沫巢,然后雌鳝在水中产卵,与此同时,雄鳝即排精,精液将卵子托于泡沫巢中,受精卵在泡沫巢中