共查询到18条相似文献，搜索用时 284 毫秒
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真蛸为福建省近年来新兴的海水养殖优良种类,具有较高的营养价值、商品价值和产业化养殖前景。本文报道了福建省水产研究所2008年-2011年真蛸人工繁殖及受精卵孵化结果：127头雌亲蛸经强化培育,共有77头产卵,获卵194×10^4粒,孵出143．4×10^4头浮游幼体。雌亲蛸获产率46．2％～86．7％,卵子受精率75．6％-91．8％,受精卵孵化率77．9％～95．0％。在20．0～22．5℃水温条件下,真蛸受精卵经21～36d开始孵出,孵出后4～6d为孵出高峰,每窝卵开始孵出至孵化结束维持10—16d。 相似文献
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短蛸繁殖行为及胚胎发育过程 总被引：1，自引：0，他引：1
采用光学显微镜观察的方法,对短蛸(Octopusocellatus)的胚胎发育过程进行观察。在人工养殖环境下,选用成体短蛸培养1个月后(五月份)即产卵。观察发现,雌蛸一直对其卵子进行看护,直到幼体孵化出膜,随后两周之内雌蛸相继死亡;受精卵卵裂方式为盘状卵裂。根据Naef的划分标准,短蛸胚胎发育过程划分为20期,期间胚胎经历2次翻转,受精卵的孵化水温为16～21℃时,第1次翻转发生在第15天,胚胎原基由动物极转向植物极;第2次翻转发生在第40天,胚胎由卵柄端转向卵柄相对端;从受精卵到幼体孵化出膜共经历41d;刚孵化出的幼体为浮游型,浮游期12d左右,之后营底栖生活。本文系统地描述了短蛸的繁殖行为和胚胎发育各个阶段的形态变化,旨在丰富短蛸繁殖生物学和胚胎发育生物学的基础理论研究,并为开展大规模开展短蛸人工育苗、养殖以及人工增殖放流提供科学依据。 相似文献
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2005~2007年春、夏期间,在浙江南麂岛开展了真蛸亲体培育、产卵及孵化的试验研究。结果表明:亲蛸培育成活率为77.5%~95.5%,平均产卵率为68.0%~83.3%。不搭配雄体产卵率为65.0%,搭配一定比例的雄体后产卵率达92.5%,最高达100%。不同附卵器附卵效果以方形鲍鱼箱为最好,圆形鲍鱼皮桶次之,扇贝笼最差。在南麂海域暂养在网箱中的真蛸当水温上升到13.5℃以上时就开始有少量产卵,多数开始产卵在16.0℃左右,主要产卵期在4~6月。不同个体真蛸的产卵量变化很大,少者只有22 632粒,多者达170 684粒,平均102 665粒,平均每颗卵粒重量在1.670~2.207 mg之间,大小为长2.8~3.1 mm、宽0.915~0.950 mm。在水温13.5~28.0℃范围内,真蛸卵可以正常孵化,孵化率达60.0%~80.0%,超过28℃时孵化率明显下降。真蛸卵的孵化时间较长,至少需要20 d以上。孵化时间长短与水温关系密切,水温越高,孵化时间越短。孵化期间平均水温16.5℃,整个孵化时间长达47 d。当孵化期间平均水温为21.6℃时,从产卵到稚蛸出膜大致需要25 d左右。此外,还发现亲蛸护卵可以减少疾病,提高孵化率,本文也论述了有关其对疾病防治方面的探索。 相似文献
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水温对石磺胚胎发育的影响 总被引：15，自引：3，他引：12
通过实验室研究,对石磺（Onchidium sp．）胚胎发育过程进行了详细观察,比较了不同水温下石磺胚胎发育的速度,探讨了膜内面盘幼虫孵化出膜的主要条件。结果表明：石磺的胚胎发育过程类似于肺螺亚纲其他贝类,行体内受精,刚产出的卵为受精卵,细胞未进行分裂,卵裂从卵产出体外开始,分别经过卵裂期,囊胚期,原肠期,膜内担轮幼虫期,膜内面盘幼虫期,经过孵化期孵化出膜为自由生活的面盘幼虫期。对各阶段幼体的大小、形状、内部器官等特征以及发育变态过程进行了详细的显微观察和描述。26℃,28℃,30℃3个水温组中,从受精卵到膜内面盘幼虫孵化出膜分别需要300h,290h,288h;发现影响幼虫孵化出膜的主要因素是水温和海水的刺激作用;繁殖盛期卵群工厂化水泥池自然水温孵化时间为10～14d。并报道了水温低于23℃时石磺胚胎停止发育现象。 相似文献
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于1997年12月～1998年12月在辽河水系的舍力虎水库和西湖水库采集1100尾大银鱼(Protosalanxhyalocranius)性成熟样本进行生物学指标测量。结果表明,辽河水系大银鱼绝对怀卵量5112～20628粒;相对怀卵量423～960粒/g。在辽河水系,大银鱼的产卵高峰期只有1次,为每年的12月15日至12月底,高峰期持续3～6d,成熟卵一次产出体外,卵径(842.9±13.5)μm;当孵化水温4～5℃时,受精卵经过1106h可孵化出膜,孵化积温4424～5530℃·h;胚胎发育至高囊胚期是计算受精率的最佳时期。 相似文献
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石磺繁殖生物学的实验研究 总被引：10，自引：1，他引：10
用实验室小型试验、贝类育苗场生产性试验和自然群体实地观察的方法，结合养殖池塘内石磺（Onchidium sp.）繁殖习性跟踪观察，2年内研究了沪浙地区石磺的繁殖季节，繁殖方式，繁殖力，受精卵的发育孵化，水温和盐度对胚胎发育的影响，胚胎停止发育现象，幼虫发育及变态前形态变化，对石磺繁殖生物学作了比较系统的实验研究。结果显示石磺雌雄同体，雄性先熟，异体交配，体长5 cm体重10 g以上的个体为繁殖的主要群体，其生物学最小型为体长3.1 cm和体重3.5 g；交配期多在气温22 ℃以上的5月中下旬至9月下旬，6～8月为繁殖盛期。产卵前经过5～10 h的求爱和1～5 h的交配过程，交配后15 d左右产出受精卵，多在大潮日至小潮日期间3～5 d内的晚间产卵；繁殖期具有6个明显的产卵高峰。卵群表面积15～30 cm2，每平方厘米卵群含卵子2 650±300个，每个卵群含卵子4.4～8.0万粒。水里与潮湿环境中卵群孵化率没有明显差异；26～35 ℃的水温下，卵群孵化时间10～14 d，水温23 ℃以下石磺胚胎出现停止发育的现象。适合卵群孵化的海水盐度为6～20，孵化出膜2～3 d后的面盘幼虫开始摄食单胞藻。自由生活面盘幼虫经23 d培育后出现明显的革质膜；变态后的幼体可能存在不断蜕去革质膜的过程，面盘幼虫的变态过程和变态条件仍有待研究。 相似文献
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从白洋淀水产种质资源保护区捕获的抱卵虾中挑选出200 kg作为孵化用亲虾,经1020 d培育,受精卵破膜孵化出幼体。自然水温(2020 d培育,受精卵破膜孵化出幼体。自然水温(2030℃)条件下,青虾初孵幼体经2530℃)条件下,青虾初孵幼体经2530 d的培育,生长发育成体长1.030 d的培育,生长发育成体长1.01.5 cm的仔虾。2013年,利用450 m3水体共培育仔虾4 800万尾,培育密度最高达15.6万尾/m3,最低6.8万尾/m3,平均11.1万尾/m3。 相似文献
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南美白对虾的性腺发育、交配、产卵和受精 总被引：2，自引：1，他引：2
对池养南美白对虾 (Penaeusvannamei)亲虾进行人工促熟 ,并使之交尾、产卵、受精。实验在上海金山区杭州湾河口低盐地区一套自行设计的水循环系统中进行 ,育苗用水通过兑配使盐度为 2 7～ 2 8。育苗期间基本不换水和移动亲虾。亲虾 2 0 5尾 ,雌雄比约 1∶1。雌虾切除眼柄后 3～ 4d ,性腺即开始发育 ,6～ 7d产卵 ,但未受精。手术后约 30d ,亲虾出现追尾现象、随之发生交配并出现受精卵。实验进行了约 6 0d ,共收集虾卵 4 5 6 .7万粒 ,其中受精卵出现后所产卵为 137万粒 ,通过设置在水循环系统内的集卵网袋 ,可收集到 95 %以上的卵 ,共获受精卵 6 1万粒 ,平均日受精率为 4 4 .5 % ,无节幼体 2 5 .1万尾 ,受精卵的平均孵化率为 4 1.2 % ,最高达 87.5 %。文中还重点讨论了雌雄亲虾性腺发育的特点 ,产卵交配规律 ,以及亲虾规格大小、饵料种类、水质状况对南美白对虾交配和受精的影响 相似文献
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采用24个已报道的多态微卫星标记对天津市天祥水产有限责任公司养殖的大鳞鲃Barbus capito F_2亲本及F_3成活和病发死亡个体进行基因分型,结果有8个标记无多态,13个标记用以分析本研究群体的遗传多样性、亲缘关系及遗传结构。遗传参数分析显示,13个标记在87个大鳞鲃个体中分别检测到2~7个等位基因,平均等位基因数(4.27~4.53)极显著高于平均有效等位基因数(3.09~3.22)(P0.01);观察杂合度(0.58~0.64)整体低于期望杂合度(0.64~0.65),多态位点比例明显下降(8/24),表明大鳞鲃F2及F_3个体的纯合度增加,遗传多样性下降。聚类分析显示,F2亲本与成活子代亲缘关系更近,聚在一起;而死亡子代单独聚为1支。遗传结构分析显示,亲本与子代清晰地划分成两大类群,多数亲本与多数成活个体归为第一类群(划分概率为51.8%~97.7%),少数亲本与多数死亡个体归为第二类群(划分概率为52.9%~98.4%),这与亲缘关系分析的结果一致,表明少数亲本是F_3死亡个体遗传组成的直接贡献者。本研究初步认定,由于几个亲本的近亲交配,子代基因组纯合度增加,遗传多样性下降,抗逆性下降,这可能是F_3出现不明缘由病发死亡的主要原因之一。 相似文献
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P. Routray A.K. Choudhary D.K. Verma P. Swain S.D. Gupta 《Aquaculture (Amsterdam, Netherlands)》2006,261(4):1204-1211
Cryopreservation of semen collected from dead fishes showed that it is possible to use it for fish production. We humanely killed individuals of the Indian major carp rohu, Labeo rohita and stored at different temperature regimes of 31 °C, 0 °C, − 10 °C and − 30 °C till 8 h. At every one hour interval semen from these fishes were collected by Pasteur pipette and evaluated for sperm yield/kg body weight, motility, pH, spermatocrit (%) and sperm count. The semen having suitable characteristics such as; 70% spermatocrit or above and motility index of 4 or above was cryopreserved by following a specific protocol. The cryopreserved semen of the dead fishes was stored for 7 days and then thawed in a water bath at 37 °C for 50 s. It was found that up to 8 h, spermatozoa of rohu were viable when stored at 0 °C or − 10 °C. Sperm collected after 8 h of fish death and maintained at 0 °C was the best stored condition that showed 30% larval survival. The spermatozoa collected 8 h after fish death was mostly normal as observed under scanning electron microscope and the total length of rohu spermatozoa was 25-30 μm. The hatchlings produced with this cryopreserved semen grew normally and juvenile fishes of rohu could be produced. This study suggests that germ cells such as spermatozoa of dead fishes can be cryopreserved and utilized for restoration of a species. It has the potential use in cryo-conservation of endangered fishes, restoration of animals through fertilization and genetic manipulation studies. 相似文献
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M. Paula Sotelano Gustavo A. Lovrich Federico Tapella 《Aquaculture International》2016,24(4):1025-1037
Losses of king crabs (deaths) in massive rearing conditions are frequently attributed to cannibalism. As several factors could influence cannibalism intensity during culture, the aim of the present study was to determine the effect of molt condition, stage and density on cannibalism among Lithodes santolla juveniles. Comparisons between intermolt and molt conditions and between C1 and C2 stages during intermolt were performed at three densities (6, 12 and 18 individuals per flask; that is equivalent to 236, 472 and 708 individuals m?2). After 16 days of juvenile coexistence, cannibalism (injured + dead) was higher during molting (33.9 ± 4.5 %) than intermolt (21.7 ± 3.9 %), even though only 36 % of crabs had molted. Although cannibalism was similar in C1 and C2 stages, the proportion of dead animals was higher by a factor of three in C1 stage, probably due to the fact that animals reach the first juvenile stage with low energetic reserves, after the lecithotrophic larval development. Density was the main factor influencing cannibalism in our experiments. Higher densities promoted higher deaths, while agonistic interactions evidenced by injured crabs remained constant. Walking appendages were lost more often than chelipeds during first agonistic encounters. We recommend the use of intermediate densities (450 crabs m?2 at most), the early detection of exuviae and the sorting of crabs after molting, for L. santolla rearing. 相似文献
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Giovanni Bearzi Nino Pierantonio Silvia Bonizzoni Giuseppe Notarbartolo di Sciara Massimo Demma 《水产资源保护:海洋与淡水生态系统》2010,20(6):644-654
- 1 The view that whales are malicious monsters has been pervasive throughout history. Conversely, the idea that these animals experience suffering has emerged only recently. One way of investigating perceptual, as well as behavioural, shifts is assessing general public reactions to mortality events involving wild, rare and charismatic animals.
- 2 Here, the responses of 118 individuals to questions regarding the mass stranding of seven sperm whales (Physeter macrocephalus) along the Adriatic Sea coast of Italy in December 2009 are reported through interviews taken at the stranding site and in the direct proximity of the dead animals.
- 3 When asked why the whales were stranded, 44.1% of the respondents suggested anthropogenic causes and 21.2% non‐anthropogenic. The remaining 34.7% mentioned a generic ‘disorientation’ or stated they did not know. When asked how they felt about the whales, 68.6% expressed feelings of compassion or care towards the animals. Clearly non‐compassionate attitudes accounted for only 4.1% of the sample. Finally, 21.2% expressed feelings that were ambiguous in terms of being suggestive of compassionate or non‐compassionate attitudes, including 11.9% amazement, 4.2% deprecation and 5.1% powerlessness.
- 4 These results are in stark contrast with information obtained from accounts of similar events that have occurred in historical times, up until the first half of the 20th century. For centuries, responses to cetacean live strandings—typically including killing and harming of the animals—were either utilitarian or characterized by feelings including fear and a desire to ‘subjugate the beast’, with no apparent concern for their suffering and death.
- 5 It is concluded that attitudes towards whales—today strikingly revolving around sadness, compassion and a sense of loss—have changed dramatically over time, with a steep turnaround in the 1970/1980s. Full appreciation of the ongoing evolution in public perception can channel marine conservation efforts and assist in the design of response strategies to marine mammal strandings. Copyright © 2010 John Wiley & Sons, Ltd.
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《Fisheries Research》2007,87(2-3):85-91
In marine invertebrate populations natural mortality events tend to be episodic in nature. The impact of these episodic mortality events can be estimated from the decline in catch rate of live animals over time obtained through successive population sampling. However, the high variability of catch rates makes them relatively insensitive indicators of mortality. For bivalve mollusks another means to estimate mortality is to assess the change in abundance of recently dead animals, called clappers, which are gaping shells still hinged together. We present a change in ratio estimator and its associated variance of the proportion of animals dying due to an episodic mortality event. This estimator is more sensitive to mortality events and may be preferable to a traditional estimator based upon changes in catch rates of live animals. When applied to a scallop population in Narragansett Bay, RI, the change in ratio estimator indicated that a 72% reduction in the population occurred after an intense mortality event associated with an epizootic of a rickettsia-like organism. 相似文献
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美人蕉种植根区水对藻类生长的影响 总被引：4，自引：0，他引：4
通过取用美人蕉(Canna indica)种植根区水置于光照培养箱中对小球藻(Chlorella vulgaris)和卵形衣藻(Chamydom onas ovalis)进行培养和观察,获得两种藻类的生长数据。结果显示:根区水在6 d对小球藻的化感效应为-0.7331,对卵形衣藻则为-0.4408;小球藻试验组与对照组的细胞数量在2~6 d差异显著(P<0.05),而卵形衣藻的细胞数量在5~6 d出现显著差异(P<0.05)。显微镜观察还发现,试验组卵形衣藻部分细胞颜色变白、细胞器溶解,并出现胶群体,对照组没有发现这种现象。实验说明美人蕉根系能分泌一些化感物质影响藻类生长,化感物质对藻类的影响具有选择性。 相似文献
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- The Mediterranean common dolphin (Delphinus delphis), considered to have been very common in the past, had undergone a dramatic decline across most of the basin by the end of 1970s. In the northern Adriatic Sea, one of the regions with most available historical information, the common dolphin is thought to have been the most common and abundant cetacean throughout most of the 20th century. However, by the end of 1970s, it had virtually disappeared from the region and is now considered generally absent from the entire Adriatic Sea.
- This contribution summarizes the occurrence of common dolphins in the Gulf of Trieste and provides a brief review of published records in other parts of the Adriatic Sea.
- Systematic boat surveys in the wider area of the Gulf of Trieste between 2002 and 2019 confirmed that the common bottlenose dolphin (Tursiops truncatus) is the only regularly occurring cetacean species in this area. Despite this, several records of common dolphins were documented in the Gulf of Trieste between 2009 and 2012, through sightings of live animals or recovery of dead stranded animals.
- Dorsal fin markings allowed the photo-identification of some of these, suggesting that at least four different live individuals (three adults and one calf) occurred here in recent times. Most cases involved single adult individuals, but one included a mother-calf pair that was temporarily resident in a port for several months, a behaviour atypical for this species. Photo-identification showed that the presumed mother had previously been sighted in the Ionian Sea in Greece, over 1,000 km from the Gulf of Trieste, making this the longest documented movement for this species worldwide.
- At present, the common dolphin continues to be rare in the region.