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改革开放以来,我国加入WTO以后,随着人们生活水平不断提高,饮食结构也跟着改变,从过去的解决温饱问题到今天要求高品质食物。滤食性鱼类肉质细嫩,属高蛋白、低脂肪、低胆固醇的肉食品,是消费者的上佳选择。滤食性鱼类指以过滤水体中浮游生物为饵料的鱼类,如鲢(白鲢)、鳙(花鲢)等。现将我县平班水库网箱养殖滤食性鱼类的经验介绍如下。 相似文献
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一、虹鳟对环境的要求 虹鳟适宜生活的温度为12~18℃,在适温范围内摄食旺盛,生长迅速,机体保持着良好的新陈代谢状态;低于8℃或高于20℃,食欲减退,生长缓慢,抗病力降低;超过24℃停止摄食,温度达到27~30℃时,短时间内死亡;溶氧充足时,短时间可耐受26℃的高温。虹鳟不仅要求低水温,也要求较高的溶解氧。一般情况下,虹鳟的安全临界溶氧是3.15毫克/升,低于4.3毫克/升时鱼就开始浮头,与此同时出现死亡;溶氧低于5毫克/升则虹鳟呼吸频 相似文献
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郑传雅 《养殖与饲料.饲料世界》2009,(12):13-14
赤眼鳟,因其眼睛上缘有一月牙式艳丽的红斑而得名。地方名俗称其红眼睛、野草鱼、红眼捧、马浪鱼、红眼马郎、红眼鲮、参鱼、醉眼角等。赤眼鳟隶属硬骨鱼纲,鲤形目,鲤科,雅罗鱼亚科,赤眼鳟是单型种鱼类。为淡水中上层鱼类,喜成群游动。赤眼鳟在自然水系的环境中是一种偏植物型的杂食性鱼类,在人工养殖条件下也喜食人工配合料。 相似文献
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如何在确保养殖经济效益的同时,最大限度地实现环保效益、社会效益就显得尤为重要.立体生态网箱养殖模式的产生就较好地解决了这一问题,对于淡水鱼养殖会起到较佳的指导意义.本文首先阐述了国内网箱养殖的发展过程,其次,分析了在淡水鱼养殖中推广应用立体生态网箱养殖模式的社会经济效益,再次,探讨了在淡水鱼养殖中推广应用立体生态网箱养殖模式的优点,具有一定的参考价值. 相似文献
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(上接第5期第38页)
2.投饵率.投饵率是指在正常的摄食状态下,投饵量与鱼体重量的百分比.它与水温高低成正比,与鱼体的体重成反比.网箱养殖虹鳟的日投饵率、投饵次数和粒径见表1. 相似文献
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斑点叉尾鲴(Ictalurus Punctus Rafinesque)亦称美洲鲶、沟鲶,属于鲶形目(Siluriformes)、鲴科(Ictaluridae),是我国20世纪末从美国引进的鱼类新品种,其营养丰富,肉质细腻、味鲜美,没有肌间小刺,该鱼具有适应性强、食性杂、适温广、抗病力强、生长快、产量高、易饲养、易捕捞等特点,深受广大群众喜爱。为调整本地区养殖品种,优化养殖结构,提高养殖效益,我们于2007年在双牌水库进行网箱养殖试验,试验结果报告如下。 相似文献
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《Strength and Conditioning Journal》2020,73(6):786-795
Forage and grazing (FG) systems can store a substantial amount of soil organic carbon (SOC) under appropriate land use management and reduce atmospheric CO2 concentrations. Increasing SOC levels along with many interlinked ecosystem services are essential for increased productivity and sustainability of FG lands (FGLs). Although adoption of improved management practices (MPs) that support SOC sequestration (SOCq) is necessary, clear understandings of challenges and opportunities which are sometimes unique to individual FGLs, are also important for implementation of MPs. The objective of this forum paper is to explore the latest scientific knowledge on opportunities to address major challenges for increasing SOCq in FGLs. In intensively managed FGLs where the goal is often to maximize yields, lands are heavily fertilized and thus, usually drive towards SOC loss. Diversifications of both forage and grazing species along with strategic grazing plans have been proven as effective MPs for increasing SOCq. However, challenge of maintaining productivity levels still remains. Implementing improved grazing for nutrient cycling and integrating forage diversification for increased biodiversity are found to improve soil health attributes, which are critical for SOCq. However, to achieve this, we also need to consider site- and soil- specific factors. Extreme climatic events often lead to a decline in soil fertility status, SOCq and overall productivity of FGL systems. To address these challenges, uses of models to simulate the FGL systems and have definite choices of suitable MPs are helpful. However, we must be able to access a wide range of datasets to develop system-level adaption strategies that are effective in mitigating these adverse effects. Ultimately, participatory research with novel views and improved perceptions based on the value of SOCq and long-term benefits of the implementation of the best MPs and developing education and outreach materials to enrich the producers’ knowledge gaps are helpful for climate-resilient FGL systems. 相似文献
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退耕地林草植被碳汇及与农业生态经济系统的关系-以陕西省县南沟流域为例 总被引:2,自引:0,他引:2
《联合国气候变化框架公约》签订后,国内外学者开展了大量碳汇方面的工作,而碳汇与农业生态经济系统关联性的研究较为薄弱。因此,作者通过野外采样和室内试验,结合课题组累积的15年调研资料,利用灰色关联分析方法,分析县南沟流域碳汇与农业生态经济系统的关系,以期为碳汇与农业生态经济系统的研究与实践提供参考。结果表明:退耕还林(草)工程实施以来,林草碳汇显著增加,年碳汇增量从2523.17 Mg增加至4562.06 Mg。在碳汇增加的过程中,农业土地利用结构和产业结构(以收入结构为表征)的演替对其产生了较强的正向效果,土地利用结构调整通过扩大林草面积增加碳汇量;产业结构的变化通过非农收入的增加和高效设施农业的发展减轻对土地的压力,进而促进和稳固土地利用结构。根据研究结果,建议今后应进一步优化农业系统结构,以促使林草碳汇的稳定增加。 相似文献