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1.
为了研究不同光照强度、温度对黑鲷(Acantho pagrusschlegelii)(♀)×真鲷(Pagrosomus major)(♂)杂交F1代受精卵孵化效果及仔鱼存活的影响,作者采用试验生态学的方法比较不同温度(16、18、20、22、24、26℃)下杂交鲷受精卵的孵化率、畸形率、孵化时间、7日龄仔鱼的存活率;比较不同光照强度下(10、100、300、800、1500、4 000、10 000 lx)受精卵孵化率、畸形率、孵化时间;比较不同光照强度下(200、1 000、2 000、5 000、10 000、15 000、20 000 lx)7日龄仔鱼的存活率。结果表明:在盐度为22条件下,受精卵最高孵化率(34.00%)和最低畸形率(16.65%)的孵化温度为20℃;在16～26℃范围内,温度与孵化时间呈负相关,与7日龄仔鱼存活率也呈负相关。不同的光照强度对受精卵孵化率和孵化时间的影响不显著,孵化率为65.88%～71.88%;但大于800lx的光照会令畸形率上升(大于15.21%);另外,5000～10000lx的光照强度更适宜仔鱼生存,7日龄仔鱼存活率达到38%～40.75%。黑鲷(♀)×真鲷(♂)杂交子代最佳孵化温度为20℃,最适光照强度为5 000～10 000 lx。 相似文献
2.
黑鲷(Acanthopagrus schlegeli)肿瘤坏死因子α cDNA的克隆及特征分析 总被引：1，自引：0，他引：1
采用同源克隆的方法，从黑鲷中获得肿瘤坏死因子(TNFα)全长cDNA序列。该序列含1288个核苷酸，可编码253个氨基酸的TNF前体蛋白。它是一种跨膜蛋白，无糖基化位点和信号肽结构。黑鲷TNFα与其它鱼类的TNFα的相似性很高，占据进化上独立的分支；与哺乳类TNFα和TNFG源于共同的祖先。基因结构分析显示，该基因含有TNF家族pmfile和TNF家族的标签序列；在参与TNFα基因二硫键形成的两个半胱氨酸和TNFα三聚体形成的位点高度保守；空间结构模拟显示，它与哺乳类TNFα的空间结构相似，都是由两个β折叠片组成，每个折叠片包含5个反向平行的β链。表达研究结果表明，黑鲷TNFα在检测的各个组织中均为组成型表达，表现为在刺激与非刺激鱼体中，都可以检测到黑鲷TNFα的表达，但是其表达水平在不同组织中有很大差异。黑鲷TNFα在头肾、脾脏和鳃的表达量较高，而在心脏、肝脏、血液、肾脏和大脑中表达量较低。 相似文献
3.
研究了盐度对黄鳍鲷SparuslatusHouttuyn、平鲷Rhabdosargussarba（Forskal）、黑鲷Sparusmacrocephalus（Basilewsky）和真鲷Pagrsomusmajor（TemmincketSchlegel）4种鲷鱼精子活力的影响。对南海区4种鲷鱼精子的适盐性及其活力进行了比较,黄鳍鲷、平鲷、黑鲷和真鲷精子激活所需的最低盐度分别为8、10、＞8、＞10;激活的最适盐度则分别为21、22、25、25,与之相应的精子活动（涡动）时间分别为14．7、17．7、17．2、18．0min;在高盐条件（盐度40左右）下,黄鳍鲷精子的适应性最强,精子活力最好,其次是黑鲷、真鲷的精子,平鲷精子对高盐条件的适应性最差。 相似文献
4.
真鲷仔稚鱼微粒饲料中DHA与EPA最佳比例的研究 总被引：10，自引：2，他引：8
制备4种n-3HUFA含量相同,DHA和EPA含量比[m(DHA)：m(EPA)]分别为1．70：1,2．00：1,2．30：1和2．60：1的微粒饲料,探讨DHA与EPA的配比对真鲷(Pagrus major)仔稚鱼生长、存活和体内相关成分的影响。30d的养殖试验结果表明．m(DHA)：m(EPA)≥2．30：1的2种微粒饲料与m(DHA)：m(EPA)≤2．00：1的2种微粒饲料相比,真鲷仔稚鱼的生长速度和成活率,前者明显优于后者。该比例即m(DHA)：m(EPA)≥2.30：1应是真鲷微粒饲料中DHA与EPA的最佳配比。养殖试验结束后,对仔稚鱼体内相关成分的分析结果表明,仔稚鱼体内DHA的含量随微粒饲料中DHA含量的增加而增大。 相似文献
5.
RH Bennett PD Cowley A-R Childs CG Attwood L Swart TF Næsje 《African Journal of Marine Science》2017,39(4):475-489
Understanding movement behaviour is essential for effective management of fishery species. Dart tags were used to study coastal movement patterns of white steenbras Lithognathus lithognathus, an overexploited seabream (Sparidae) in South Africa. In total, 6 962 fish (190–1 080 mm fork length) were tagged throughout the species’ distributional range, in four long-term fish-tagging programmes. The predominant behaviour recorded was residency, with relatively short-ranging movements. More than 60% of the 351 recaptured fish were recaptured within 1 km of their tagging site, some of which were at liberty in excess of three years. Most of the juveniles (93.9%), subadults (71.7%) and adults (64.0%) were recaptured within 10 km. Occasional long-distance movements of up to 800 km were recorded. Recapture distances were positively, but weakly, correlated with fish fork length (n = 257 fish measured at recapture; r2 = 0.166, p < 0.001). Low levels of connectivity among coastal areas suggest that large-scale annual spawning migrations, as previously hypothesised for this species, are unlikely, which raises the possibility of multiple spawning sites. Seventy-seven percent of L. lithognathus tagged within three marine protected areas (MPAs) were recaptured within the same MPA, suggesting that area closures provide protection for L. lithognathus through the post-estuarine juvenile, subadult and adult life stages. We confirm that the country’s current network of coastal MPAs plays a vital role in sustaining this species, and suggest that additional closures, or otherwise substantial reductions in catch rates, are necessary for the species’ recovery. 相似文献
6.
The presence of organochlorine pesticides and polychlorinated biphenyls in wild and farmed gilthead sea bream (Sparus aurata) from the Western Mediterranean, Spain, is investigated. These pollutants were determined in white and red muscle and liver by gas chromatography coupled to tandem mass spectrometry. Contaminant profiles present in both wild and farmed fish tissues include DDTs, PCBs and HCB. The highest concentrations of contaminants were found in liver, and an increase in pollutant levels was observed in autumn, before spawning. This fact is explained in light of increased food intake when sea water temperatures increase. Gilthead sea bream from Western Mediterranean populations showed significantly higher concentrations of DDTs and PCBs than farmed fish from the same area. This fact is attributed to the low level of organochlorine contaminants present in fish feed supplied to the cultured fish. The diet is highlighted as an important factor in understanding differences observed in organochlorine pollutants levels of fish tissues. 相似文献
7.
将海水鱼类黑鲷Sparusmacrocephalus从盐度为26.6的海水直接转入淡水,考察渗透压的急剧降低对黑鲷的生长激素(growthhormone,GH)及其受体(growthhormonereceptor,GHR)等生理指标的影响。研究发现:(1)黑鲷从海水直接转入淡水后48h有33%的鱼死亡,对照组无死亡现象;(2)黑鲷在转入淡水48h内其血清生长激素(GH)含量、肝脏及鳃中GHR及GHRmRNA含量与对照组均无显著差异;(3)黑鲷在转入淡水48h后其肾脏中GHR含量较对照组显著升高(p<0.05),肾脏中GHRmRNA含量在24h及48h显著高于对照组(p<0.05)。结果表明,从GH含量看,黑鲷从海水环境到淡水低渗环境与鲑鳟鱼类从淡水到海水环境的适应性调节机制有差异,而黑鲷肾脏中GHR的含量变化可能参与黑鲷对外界环境渗透压的这种急剧降低的适应性调节。 相似文献
8.
《African Journal of Marine Science》2013,35(2):191-201
Blacktail seabream Diplodus capensis were sampled from proximate (10 km apart) exploited and unexploited areas in southern Angola to compare their population structures and life-history parameters. Females dominated the larger size and older age classes in the unexploited area. In the exploited area the length and age frequency distributions were more equitable, but there was a lack of large and old individuals in this area due to the selective nature of fishing gear. Growth zone deposition rate was validated as being annual using mark-recapture of chemically injected (oxytetracycline) fish. In the unexploited area, females attained larger sizes and greater ages than males; however, growth and longevity were more equitable between the sexes in the exploited area. Length- and age-at-50% maturity were similar between the sexes in both areas. The sex ratio was heavily female-skewed (1:4.7) in the unexploited area but less so in the exploited area (1:2.2). Although the growth curves were significantly different for fish between areas, this was likely due to a reduction in longevity rather than a physiological change in growth. The length- and age-at-50% maturity was also similar between areas, indicating that this species either does not have the ability to respond to exploitation through physiological change in these life-history characteristics, or that the current level of exploitation is not high enough to elicit such a response. However, the female dominance in the smallest size class in the exploited area (compared to the unexploited area) indicated that a threshold may have been reached, and that this species responds to exploitation by increasing the relative number of fish that mature as females. 相似文献
9.
Lny Mercier Jacques Panfili Christelle Paillon Awa N'diaye David Mouillot Audrey M. Darnaude 《Estuarine, Coastal and Shelf Science》2011,92(4):534-545
Accurate knowledge of fish age and growth is crucial for species conservation and management of exploited marine stocks. In exploited species, age estimation based on otolith reading is routinely used for building growth curves that are used to implement fishery management models. However, the universal fit of the von Bertalanffy growth function (VBGF) on data from commercial landings can lead to uncertainty in growth parameter inference, preventing accurate comparison of growth-based history traits between fish populations. In the present paper, we used a comprehensive annual sample of wild gilthead seabream (Sparus aurata L.) in the Gulf of Lions (France, NW Mediterranean) to test a methodology improving growth modelling for exploited fish populations. After validating the timing for otolith annual increment formation for all life stages, a comprehensive set of growth models (including VBGF) were fitted to the obtained age–length data, used as a whole or sub-divided between group 0 individuals and those coming from commercial landings (ages 1–6). Comparisons in growth model accuracy based on Akaike Information Criterion allowed assessment of the best model for each dataset and, when no model correctly fitted the data, a multi-model inference (MMI) based on model averaging was carried out. The results provided evidence that growth parameters inferred with VBGF must be used with high caution. Hence, VBGF turned to be among the less accurate for growth prediction irrespective of the dataset and its fit to the whole population, the juvenile or the adult datasets provided different growth parameters. The best models for growth prediction were the Tanaka model, for group 0 juveniles, and the MMI, for the older fish, confirming that growth differs substantially between juveniles and adults. All asymptotic models failed to correctly describe the growth of adult S. aurata, probably because of the poor representation of old individuals in the dataset. Multi-model inference associated with separate analysis of juveniles and adult fish is then advised to obtain objective estimations of growth parameters when sampling cannot be corrected towards older fish. 相似文献
10.
《African Journal of Marine Science》2013,35(2):321-326
The reproductive style of Diplodus capensis was examined in an unexploited coastal area in southern Angola. The mean length of females was significantly greater than that of males and, although not significant, females dominated the older age classes. The overall sex ratio was 1 male:4.7 females and female dominance increased with size. Histological analysis of gonads revealed that this species is a rudimentary hermaphrodite, with individuals possessing a non-functional bipotential ovotes-tis in the juvenile phase. Histological examination of the gonads of four macroscopically staged ‘intersex’ individuals suggested that they were functional males with a persistent ovarian portion in their gonads from the juvenile ovotestis. The heavily female-biased sex ratio and female dominance in the larger length classes are thought to be an alternative to sex change that is more resilient to exploitation when compared with the protandrous strategy displayed by the South African population of D. capensis. 相似文献