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作者对加州鲈鱼繁殖习性及早期胚胎发育进行了阐述,对受精卵孵化与水温的关系进行了研究。结果表明:加州鲈鱼2龄即达性成熟,3—6月繁殖产卵,水温20℃—24℃时达产卵盛期;雄鱼具有筑巢护卵及护苗等生殖习性;水温17.4℃—19.5℃,平均18.3℃时,受精卵孵化时数为74小时25分钟;在实验温度范围内,孵化时数与水温负相关,而与有效积温正相关。有效积温与平均水温负相关。  相似文献   
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Portugal has the third highest seafood consumption per capita in the world and current patterns of seafood consumption are linked to how seafood products were embodied in the Portuguese society. The objective of this research is to understand Portuguese seafood consumption's main drivers and its consequences. For that official statistics were analyzed and a literature review on seafood consumption was undertaken. Portuguese seafood consumption is characterized by a wide diversity of species and preparing modes, when compared to other countries in Europe. Cod (salted and dried), does not exist in Portuguese waters but due to several factors, such as politics, religion and tradition, became the main species in Portuguese seafood consumption, representing around 38% of the national seafood demand. Five drivers are suggested to explain why Portuguese eat so much seafood: geography, marine resources, fisheries, social forces and politics; and consequences for the environment, economy and health are discussed. Hence while most dietary recommendations advise an increase in fish consumption is not applicable to Portugal and a more sustainable seafood consumption for the future is advocated.  相似文献   
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Reducing emissions of greenhouse gases is facilitated by changes in several consumption activities, such as food choices. This paper examines factors explaining red meat consumption in Norway, especially the role of climate concerns. The paper adds to our knowledge as most existing analyses of (red) meat consumption focus on health and animal welfare issues. Moreover, it expands our understanding by drawing on perspectives from both institutional and social psychological theory, including variables emphasizing the social dynamics behind consumption decisions. The study is based on data from a survey of 2000 people aged 18 years or older conducted in 2018. The data are analyzed using structural equation modelling. We find that there is a strong pro-meat culture in Norway, currently rather weakly influenced by climate concerns – specifically, personal norms and social pressures focused on reducing climate impacts. Instead, habits, beliefs about the qualities of red meat (being tasteful, nutritious, healthy) and social norms supporting red meat consumption are the three most important factors explaining the variation observed. Gender and income also influence red meat consumption, but less than found in other studies. The paper discusses policy implications of these findings, including for taxation, point-of-sale information and communicative processes to support changes in the perceptions of what could be a new “normal” diet.  相似文献   
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我们连续观测了虎皮鹦鹉、小白鼠和鲫鱼等动物的习性及季节、气象和饲养环境等的影响.结果表明,不同种类的动物具有各自的昼夜活动节律,并与季节、气象等变化密切有关.这为进一步分析动物的习性异常与地震的关系提供了依据.  相似文献   
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The senegale sole, Solea senegalensis Kaup, 1858, is a commercially valuable fish and it is beginning to be cultured in a semi-intensive way in fish farms in southern European countries. The present study was initiated to investigate the diet of S. senegalensis under semi-extensive conditions. The feeding habits of sole were studied in two earthen ponds of a fish farm in the Sado estuary. In one earthen pond, artificial fish ration was given. S. senegalensis feeds on few prey items, its diet is mainly composed of insect larvae (Chironomus salinarus) and polychaeta (Hediste diversicolor). The diet composition of this species suggests feeding specialization, by consuming mainly annelids and insect larvae and by avoiding other items, extremely abundant in the environment, such as gastropods. In the water reservoir where ration was given, some fish consumed simultaneously benthic organism together with ration. However, benthic organisms seem to be the most important component of S. senegalensis diet.  相似文献   
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