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951.
952.
虾蟹类幼体的脂类需求及脂类与发育的关系 总被引:9,自引:0,他引:9
虾蟹类(包括鱼类)幼体发育阶段使用饵料的质量是保证成活率的关键,它直接关系到虾蟹类育苗的成败,是主要生产要素之一。因此研究和掌握虾蟹类幼体发育的营养需求特点,并采用适当措施提高幼体阶段的饵料质量很有必要。本文综述了国内外有关的研究成果和研究动向,为今后进一步研究提供参考。.1 研究动态有关虾蟹类营养需求的研究,国内外多集中于经济价值较高种类对脂类的营养需求,但涉及到幼体发育阶段的研究较少,且主要集中于长链多不饱和脂肪酸的营养需求[1~5]。主要原因是:①脂类对虾蟹类幼体的发育有相当重要的影响,而用于培育幼体的活… 相似文献
953.
通过对含有元素磷的水体中鱼类的血清胆碱酯酶和三磷酸腺苷(ATP)酶活性的测定,发现元素磷对上述两类酶的活性有一定的抑制作用。当抑制率为40%~70%时,即可导致鱼类亚急性中毒死亡。结果表明:元素磷不但是一种剧毒物质,能引起鱼类的急性中毒,而且是一种稳定的可积累的毒物,它能破坏鱼类的肝细胞,抑制正常代谢,造成神经毒性,以致引起鱼类的亚急性和慢性中毒死亡。 相似文献
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褐菖鲉生长缓慢,在浙江南麂海域2001年4月30日放养0.9g的苗种,至2001年6月7日达8.3g,当年底达24.8g,2003年6月26日达112.3g。总养殖成活率20.1%,平均日增重0.14g,平均增重率0.62%。秋末至夏初低水温期是其主要生长期。冬春季养殖成活率高于秋夏季,第一年夏季养殖成活率低,仅28.1%。饵料系数为3.6,食性为杂食性,对网箱具有明显的清洁作用。在9~13%低水温期亦会摄食与生长。适温下限在7.2℃以下,适温上限在25.6℃以下。养殖方式以混养为宜,生产安排以10月份收购502左右的苗种养至翌年6月达100g以上规格出售为好,该养殖模式能避开台风期与高温期。褐鲉鲇肉质细嫩,味道鲜美,近年颇受人们欢迎,其经济价值高,且我国沿海褐菖鲇苗种资源丰富,养殖开发前景良好。 相似文献
956.
Shiang‐Lin Huang Haiping Wu Xianyan Wang Chongwei Peng Chun‐Chieh Wang 《水产资源保护:海洋与淡水生态系统》2020,30(9):1775-1782
- Protecting critical habitats of the Indo‐Pacific humpback dolphin, Sousa chinensis, is a hot topic of discussion for marine biodiversity conservation in China and many Southeast Asian countries. In practice, sound habitat protection action (HPA) planning often suffers from information gaps in macroscopic habitat configurations and changes in the habitat conditions of humpback dolphins.
- Recent publications in the journal Aquatic Conservation: Marine and Freshwater Ecosystems (AQC) have served to advance humpback dolphin conservation in Chinese waters by resolving such habitat configurations and indicating significant changes in distribution patterns and habitat characteristics under intense coastal anthropogenic activity.
- We highlight an integrative research framework to investigate habitat configuration and long‐term habitat changes when planning a holistic HPA programme for humpback dolphins. When constructing habitat configuration baselines, field surveys should be designed and conducted in a systematic manner to ensure survey efforts cover diverse environments equally, in either a spatially stratified or gridded pattern, to minimize potential spatial sampling biases. Long‐term habitat changes can be revealed by comparing satellite images from different decades. Changes in habitat preferences and habitat characteristics can be explored through questionnaire surveys on local ecological knowledge, associating historical occurrences with coastline features and projecting historical habitat configuration by species distribution modelling exercises.
- A lack of good communication and sharing of information between research and management sectors can still be an obstacle to the implementation of sound conservation practices, however, even though there is robust scientific evidence to fill knowledge gaps in distribution and habitat baselines. We have addressed the need to establish a mechanism to improve and streamline information sharing between research teams, management sectors, and stakeholder groups.
957.
Xugan Wu Yongxu Cheng Liying Sui Xiaozhen Yang Tianzuo Nan & Jinqing Wang 《Aquaculture Research》2007,38(14):1459-1467
The morphological characteristics, tissue indices, proximate and fatty acid compositions of hepatopancreas, gonad and muscle of pond‐reared (PR) and lake‐stocked (LS) Eriocheir sinensis broodstock were compared. Lake‐stocked crabs are characterized by a blue carapace, white abdomen, golden legs and yellow setae while PR crabs have a brown carapace, grey abdomen, black legs and similar yellow setae. The carapace length and width of PR crabs were significantly less than those of LS crabs of the same wet weight (WW). The results showed that the hepatosomatic index (HSI) of PR males was significantly higher, but the gonadosomatic index (GSI) was significantly lower for PR females when compared with LS individuals of the same sex. Regardless of their origin, the muscular index (MI) of males was higher than that of females. The hepatopancreas of LS crabs had higher protein levels and lower lipid levels compared with PR crabs. The results of proximate analysis of male gonads from two different sources were similar, while the protein level in the ovary of LS females was higher than that of PR females. The tissues of males had higher water content but lower lipid and protein levels compared with females regardless of their source. The LS crabs had higher highly unsaturated fatty acid (HUFA) levels than PR crabs in their gonad and hepatopancreas. In conclusion, our results suggest that the nutritional quality of LS crabs is better than that of PR crabs, the nutritional quality of males is poorer than that of females. The reproductive performance and larval quality of crabs from these two rearing systems should be further verified. 相似文献
958.
Molecular characterization was carried out on an iridovirus isolated from yellow grouper, Epinephelus awoara . The major capsid protein (MCP) gene was located, sequenced and compared with homologous genes from other iridoviruses. The nucleotide sequence is 1392 bases long and contains a single open reading frame beginning at an ATG codon from the 5' end and terminating at a TAA codon at the 3' end. The open reading frame encodes a protein of 463 amino acids with a predicted molecular weight of 50 272 Da. Pairwise amino acid alignments detected a high degree of sequence identity between grouper iridovirus (GIV) MCP and the homologous genes of other iridoviruses. The MCP gene of GIV was most similar to the MCP gene from frog virus 3 (FV3) with 70% nucleotide and 73% amino acid sequence identity. The predicted molecular weight of the protein of this gene is comparable with the apparent weight obtained by SDS–PAGE. Pathogenicity of the GIV was investigated in yellow grouper by intraperitoneal injection of 107 and 104 TCID50 virus. Cumulative mortalities reached 100% within 11 and 25 days post-infection, respectively, while no grouper died in the control group. The molecular studies demonstrated that GIV is a member of the genus Ranavirus . 相似文献
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960.