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采用电生理学方法对半滑舌鳎头部无眼侧皮肤表面特殊感受器的感觉生理功能进行研究。结果表明,机械刺激时,无眼侧特殊感受器神经产生诱导放电信号,表明无眼侧特殊结构能对机械刺激产生反应;化学物质刺激时,随着反应浓度的增加,无眼侧特殊感受器神经的诱导信号的反应幅度和频率明显增加,表明无眼侧特殊结构对化学刺激产生反应;不同化学物质刺激强弱顺序:沙蚕提取液>L-精氨酸>L-甲硫氨酸>L-赖氨酸>L-组氨酸>二甲亚砜>L-甘氨酸>L-丙氨酸。实验表明,无眼侧特殊结构具有对机械刺激和化学刺激产生反应的双重感觉功能。据推测,这种皮肤感觉器官可能是一种与摄食有关的,在摄食中发挥积极作用的体表感觉器官。 相似文献
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水产战线上的同志知道,尼罗罗非鱼是池塘增产的一个优良品种。然而,根据我们近三年来搞这条鱼的试验和观察,发现它还具有四项特殊的功能。 相似文献
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水产战线上的同志知道，尼罗罗非鱼是池塘增产的一个优良品种。然而，根据我们近三年来搞这条鱼的试验和观察，发现它还具有四项特殊的功能。 相似文献
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头足类动物繁殖生物学研究进展 总被引：1，自引：0，他引：1
对国内外头足类繁殖生物学的研究进展进行了综述.头足类软体动物都具有生殖洄游的现象,繁殖季节雌雄交配后,成熟精子暂时储存在雌体输卵管腺的纳精囊中,成熟卵子产出经过输卵管腺时完成受精作用,雌体在排卵后具有特殊的护卵行为.精子具有特殊的顶体和精核,分别呈螺旋锥体和细长圆筒状,阐述了它们的生物进化和系统分类中的作用;根据卵巢的形态变化,将其发育周期划分为4个时相.性腺既是生殖器官,又具有内分泌的功能,分泌的各种甾类激素具有明显的组织特异性,例如:孕酮、睾酮和17β-雌二醇.精巢中存在大分子精蛋白,并且不同种类的组蛋白氨基酸序列之间存在较大的差异. 相似文献
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全国水产技术推广总站 《中国水产》2009,(10)
(十九)泥鳅【品种来源】自然野生苗种或亲本繁育。【特征特性】泥鳅抗病力强,生长速度快。泥鳅喜欢栖息于静水的底层,常出没于湖泊、池塘、沟渠和水田底部富有植物碎屑的淤泥表层,对环境适应力强。泥鳅不仅能用鳃和皮肤呼吸,还具有特殊的肠呼吸功能,耐低溶氧的能力远远 相似文献
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研制了一种具有增氧、净化、灭菌等功能的SY-Ⅲ水质处理装置,并采用特殊的水循环方式来进行温室养鳖的水质处理,以控制养殖水体的水质和底质。对比试验的结果表明,采用这种水质处理装置和水循环方式,净化效果较好。 相似文献
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微量元素硒的研究进展及其对动物健康的影响 总被引：2，自引：0，他引：2
微量元素对动物具有特殊的功能,是动物体内进行正常生理生化过程所不可缺少的。动物缺乏这些元素将会引起生理功能和组织结构的异常,进而导致各种疾病的发生。硒是动物体内必需的微量元素。近年来大量资料证明,许多疾病与硒缺乏有关。本文综述了硒的生物学作用以及动物因日粮和饮水中缺硒导致的微量元素硒缺乏症。 相似文献
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微量元素硒的研究进展及其对动物健康的影响 总被引：2，自引：0，他引：2
微量元素对动物具有特殊的功能，是动物体内进行正常生理生化过程所不可缺少的。动物缺乏这些元素将会引起生理功能和组织结构的异常，进而导致各种疾病的发生。硒是动物体内必需的微量元素。近年来大量资料证明，许多疾病与硒缺乏有关。本文综述了硒的生物学作用以及动物因日粮和饮水中缺硒导致的微量元素硒缺乏症。 相似文献
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1997－1999年在荷兰Wageningen农业大学攻读水产养殖专业学位期间，有机会系统了解西欧的水产养殖业，受自然资源，传统的饮食习惯，环境，科技水平以及经济和社会环境等诸多因素的影响，西欧的水产养殖业有其独特之处。 相似文献
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Mary E Hunsicker Timothy E Essington Reg Watson Ussif R Sumaila 《Fish and Fisheries》2010,11(4):421-438
Cephalopods are a key component of marine food webs, providing sustenance for myriad marine species. Cephalopods are also of increasing economic importance as evidenced by the rapid rise in their global landings over recent decades. If fisheries continue on this trajectory, conflicts may transpire among cephalopod and finfish fisheries, particularly in ecosystems where cephalopods are highly valuable both directly as a landed commodity and indirectly as prey for other harvested species. We provide the first measure of the ecosystem services that cephalopods contribute to fisheries in 28 marine ecosystems, both as a commodity and an ecological support service. We also evaluate how current demands on cephalopods compare to mid‐20th century conditions. We find that cephalopod contributions to fisheries vary widely, but are substantial in many ecosystems. Commodity and supportive services provided by cephalopods contributed as much as 55% of fishery landings (tonnes) and 70% of landed values ($USD). The contribution of cephalopods as a commodity was generally greatest in the coastal ecosystems, whereas their contribution as a supportive service was highest in open ocean systems. Further, the commodity and supportive services provided by cephalopods to fisheries landings increased in most of the coastal ecosystems between the mid‐20th century (years 1960–70) and contemporary periods (years 1990–2004), indicating the rising demand for cephalopods. Current demands have no historical precedent and ecosystems in which cephalopods are highly exploited as a targeted resource and as an ecological support service should be further evaluated to prevent the unsustainable development of marine fisheries within them. 相似文献
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Changes in the distribution of seafood prices can provide useful insights into the availability of different species to fishermen and to fish markets. We propose a log‐relative‐price‐index (LRPI) and demonstrate how such a concept might be useful for exploring long‐term changes in wild fish communities as a result of intensive exploitation. We estimate the LRPI for 26 fish species in the Celtic Sea (UK) and for 33 species on Italian fish markets. In both systems the LRPI changed significantly during recent decades, and in the Celtic Sea this probably resulted from a decline in the availability of high trophic level target species such as cod and hake as well as an increase in the availability of low trophic level pelagic species. By contrast, the LRPI of Italian fishes remained relatively constant from 1972 to 1980, but declined thereafter as a result of widespread expansion in fin‐fish aquaculture, and a consequential increase in the supply, and hence decrease in the price of high trophic level fish such as seabass and seabream. 相似文献
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D. T. Crisp 《Ecology of Freshwater Fish》1996,5(2):68-75
Abstract– Experimental comparisons were made between release as unfed fry and release as six weeks fed parr, upon the growth and final population density of young salmon and trout over a ten week period. Salmon and trout released into experimental channels as unfed fry at densities of about 19 fish. m-2 showed rapid reduction in numbers, chiefly by downstream dispersal, accompanied by negligible growth. After substantial reduction in numbers, there was a reduced rate of dispersal and rapid growth. Salmon and trout retained in a hatchery at high density (80 to 200 fish. m-2 ) and fed for six weeks on proprietary food showed slow, but measurable, growth. After release into the channels these fish adjusted their numbers, mainly by downstream dispersal, and showed an increased growth rate. At the end of a ten week period, salmon introduced as fed parr had approximately twice the population density of salmon introduced as unfed fry. No similar difference in population density could be shown for trout. For both species, the fish introduced as fed parr had a lower mean weight after ten weeks than had the fish introduced as unfed fry. 相似文献
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The economic benefits of an aquaculture-hydroponic integrated system are evaluated using a hydroponic-lettuce and barramundi fish production system as a case study. Technical data were obtained for a case study farm located at Port Stephens, New South Wales, Australia. The net present values of annual cash flows over a 10-year planning horizon were determined for barramundi and lettuce production as stand-alone units, and alternatively as integrated units, using a capital budgeting framework. Integrated production enables barramundi effluent to be used as a source of nutrients for the lettuce production. This results in an increase in net benefits equal to the reduction in barramundi effluent disposal costs, and the saving of some water and nutrient costs of the lettuce system. 相似文献
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Risk screening of non‐native freshwater fishes in Croatia and Slovenia using the Fish Invasiveness Screening Kit 
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下载免费PDF全文 M. Piria M. Povž L. Vilizzi D. Zanella P. Simonović G. H. Copp 《Fisheries Management and Ecology》2016,23(1):21-31
The Fish Invasiveness Screening Kit (FISK) version 2 was used to assess the invasiveness potential of 40 introduced and translocated freshwater fish species to Croatia and Slovenia. Based on a priori classification of invasiveness, receiver operating characteristic analysis of FISK scores from two independent assessors resulted in a statistically significant calibration threshold of 11.75. This indicated that FISK was able to discriminate reliably between non‐native species likely to pose a high risk of being invasive and those likely to pose a medium or low risk of invasiveness. Seven species were categorised as ‘medium risk’ and the other 33 as ‘high risk’, whereas no species was categorised as ‘low risk’. The two highest scoring species were European catfish Silurus glanis and North African catfish Clarias gariepinus. Mean scores for all species classified a priori as invasive were ranked as ‘high risk’ sensu lato and fell into the ‘moderately high risk’ subcategory. FISK proved to be a valid tool for assessing the risks posed by non‐native fishes in Croatia and Slovenia. For this reason, it can be adopted as a reliable tool for the prevention of new translocations or introductions of potentially invasive species in the risk assessment area, as well as to assist in decisions regarding future management (i.e. monitoring, control and eradication) and conservation strategies. 相似文献
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Quality improvement by vacuum treatment of boiled skipjack loins for the production of dried skipjack 总被引：1，自引：0，他引：1
ABSTRACT: This study attempted to reduce the lipid and water contents in boiled skipjack loins by vacuum treatment and the quality of vacuumed boiled meat was then evaluated during the chilled and frozen storage. The boiled meats were vacuumed at a pressure of 400 Pa for 30 min using a vacuum freeze dryer as an experimental convenience in order to degrease, cool and dehydrate rapidly. The vacuumed boiled meats were stored at 0.0 ± 0.2°C for 10 days and at −20 ± 0.5°C for 90 days. The unvacuumed boiled meats were cooled by air-cooling and stored as the control. Lipid content on a wet basis (w.b.) was reduced as much as 0.5% in the ventral part and 0.4% in the dorsal part of the boiled meats after vacuum treatment. Water content (w.b.) was reduced as much as 2.5% in the ventral part and 3.0% in the dorsal part. The thiobarbituric acid and volatile basic nitrogen values in vacuumed boiled meats were significantly lower ( P < 0.05) than that in unvacuumed boiled meats during storage. Inosine monophosphate (IMP) was only detected as a major nucleotide (about 70%) in boiled meats, and the decomposition of IMP in vacuumed boiled meats was smaller than that in unvacuumed boiled meats during storage. It was concluded that the quality of boiled skipjack loins could be improved by vacuum treatment as a preprocessing procedure in the production of dried skipjack such as katsuobushi . 相似文献
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- 1. Invasive species may have direct effects on native species, such as predation or competition, as well as indirect effects such as altering habitat or the behaviour of a native species. Indirect effects can be difficult to detect, but whole‐system removal of invasive species presents an excellent opportunity for revealing these more subtle effects.
- 2. American bullfrogs were introduced to California in the late 1800s and have been implicated in the declines of native ranid species. Invasive American bullfrogs were removed from a series of 12 ponds to test for changes in microhabitat use of federally threatened California red‐legged frogs, using a neighbouring field site with six ponds as a control.
- 3. There was a marked increase in the total number of adult California red‐legged frogs seen in all of the ponds after the first year of bullfrog removal, suggesting that these adults were in the ponds, but hiding when invaders were present. Ontogenetic partitioning of habitat in this species was documented, as well as a shift in that partitioning and increased hiding behaviour with adult bullfrog presence. California red‐legged frogs used willows significantly more as cover, and were found on bare shores half as often when adult bullfrogs were present.
- 4. These results support recent suggestions that behavioural responses of prey to predators can play a substantial role in total predator effects and suggest that careful management of invasive species may be necessary to accurately evaluate population sizes of this threatened amphibian species.
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Consumption of feeds containing the antibiotic sulfadiazine by gilthead sea bream (Sparus aurata,L.) and rainbow trout (Onchorynchus mykiss,Walbaum) 下载免费PDF全文
下载免费PDF全文 Alicia Estévez Mónica Ríus‐Francino Jordi López Joan Freixes 《Aquaculture Research》2017,48(5):2291-2302
A method for studying the efficacy of sulfadiazine as a marker to estimate feed intake is presented. Feeding studies were carried out with two species, rainbow trout as a freshwater fish model and gilthead sea bream as a marine fish model, using two temperatures and two sizes of juveniles. The study showed the different feeding behaviour observed in both species, depending on the temperature and the number of days feeding the particles with sulfadiazine, and confirmed a dominant‐subordinate behaviour especially in the case of gilthead sea bream juveniles. 相似文献