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1.
采用静水法研究了恒定温度(24±0.5℃)、饵料密度(3.0×104cell/ml)、不同盐度(20、25、30和35)和恒定温度(24℃±0.5℃)、盐度30、不同饵料密度梯度(3.0×104、4.5×104和 6.0×104cell/ml)对栉孔扇贝稚贝(壳长1.177～2.017 mm)滤水率的影响.结果表明,栉孔扇贝稚贝的滤水率(FRS)开始随着盐度的升高而升高,在25～30之间存在最大值,然后随盐度的升高而下降,与盐度(S)间的相关关系为FRS ＝-30.893S2+1 691.5S-19 610 (r =0.847,以整体干重计算)或FRS＝-0.022S2+1.223 6S-14.522 (r = 0.928,以个体数量计), 通过公式推算在盐度27.8时FRS达到最大值,为3.54L/g*dw*h(2.49×10-3 L/ h*ind);投饵密度(Q)对栉孔扇贝稚贝的滤水率(FRQ)有显著影响(P< 0.05),二者之间的相关关系为FRQ=-0.069 3Q2+0.648 4Q-1.083 5(r = 0.722),其变化趋势亦呈现先升高后下降的抛物线趋势,推算金藻密度为4.7×104cell/ml时滤水率最大,为0.43×10-3 L/ h*ind. 相似文献
2.
采用静态法,以文蛤(Meretrix meretrix)为受试生物,研究了不同盐度(16、18、20、22和24)和pH(6.7、7.7、8.7、9.7和10.7)对文蛤滤水率和摄食率的影响.结果显示,在16-24盐度范围内,文蛤滤水率和摄食率随盐度增加均呈先升后降的变化趋势,盐度为20组(对照组)文蛤的滤水率和摄食率均为最大值,分别为1.51 L/g·h、6.65 mgPOM/g·h,显著高于盐度为16、18、22、24实验组(P＜0.05),推测文蛤最适生长盐度范围为20左右.pH在6.7-10.7范围内,文蛤滤水率和摄食率均随pH增加呈先升后降的变化趋势,pH=8.7(对照组)文蛤的滤水率和摄食率均为最大值,分别为1.04 L/g·h、11.91 mgPOM/g.h,显著高于6.7、9.7、10.7实验组(P＜0.05),而与pH=7.7实验组差异并不显著(P＞0.05),推测文蛤最适生长pH范围为7.7-8.7.研究结果可为文蛤池塘健康养殖提供参考. 相似文献
3.
《渔业科学进展》2016,(6)
采用静态法,以文蛤(Meretrix meretrix)为受试生物,研究了不同盐度(16、18、20、22和24)和pH(6.7、7.7、8.7、9.7和10.7)对文蛤滤水率和摄食率的影响。结果显示,在16–24盐度范围内,文蛤滤水率和摄食率随盐度增加均呈先升后降的变化趋势,盐度为20组(对照组)文蛤的滤水率和摄食率均为最大值,分别为1.51 L/g·h、6.65 mgPOM/g·h,显著高于盐度为16、18、22、24实验组(P0.05),推测文蛤最适生长盐度范围为20左右。pH在6.7–10.7范围内,文蛤滤水率和摄食率均随pH增加呈先升后降的变化趋势,pH=8.7(对照组)文蛤的滤水率和摄食率均为最大值,分别为1.04 L/g·h、11.91 mg POM/g·h,显著高于6.7、9.7、10.7实验组(P0.05),而与pH=7.7实验组差异并不显著(P0.05),推测文蛤最适生长pH范围为7.7–8.7。研究结果可为文蛤池塘健康养殖提供参考。 相似文献
4.
2011年11～12月,以扁藻(Platymonas subcordiformis)为饵料,在实验室条件下采用静水法测定了不同饵料密度、体重和盐度下黄边糙鸟蛤(Trachycardium flavum)的滤水率。结果表明:饵料密度、体重以及盐度对黄边糙鸟蛤滤水率均存在显著性影响。在实验饵料密度范围内,当饵料密度小于10×104cell·mL-1时,黄边糙鸟蛤的滤水率随着饵料浓度的增加而增大,饵料浓度与滤水率之间呈现正相关的幂函数关系;体重对滤水率的影响呈幂函数关系,个体滤水率随着体重的增加而增大;在一定盐度范围内,滤水率随着盐度的升高而增大,在盐度为32.7时滤水率达到最大值0.249 L·(g·h)-1,随后随着盐度的升高滤水率呈下降趋势。 相似文献
5.
6.
盐度与温度对大珠母贝和合浦珠母贝滤水率及摄食率的影响 总被引：1，自引：0，他引：1
《水生态学杂志》2014,(3)
利用静水清滤法研究了盐度与温度对大珠母贝(Pinctada maxima)和合浦珠母贝(Pinctada fucata)稚贝滤水率及摄食率的影响。试验分为4组,大1组:大珠母贝壳长(1.02±0.07)cm,大2组:大珠母贝壳长(2.94±0.17)cm;合1组:合浦珠母贝壳长(1.15±0.21)cm、合2组:合浦珠母贝壳长(3.08±0.36)cm。结果表明,随着盐度或温度的增加,4个组的滤水率和摄食率均先升高,到达最大值后又降低;其中,大1组在盐度27有最大滤水率(0.274±0.079)L/h,合1组在盐度30有最大滤水率(0.325±0.011)L/h,二者无显著性差异(P0.05),大2组与合2组均在盐度33时有最大滤水率,分别为(0.660±0.027)L/h和(0.329±0.021)L/h,二者有显著性差异(P0.05)。大珠母贝稚贝在盐度30时摄食率最大,合浦珠母贝在盐度33时摄食率最大,二者有显著性差异(P0.05)。2种稚贝在26℃时,滤水率和摄食率达到最大值,二者的最大滤水率和最大摄食率之间均有显著性差异(P0.05);随着贝体生长,大珠母贝的滤水率和摄食率显著高于合浦珠母贝,因此饵料需求量也更大;饵料不足可能是大珠母贝稚贝死亡的重要因素。 相似文献
7.
采用静水法研究了在水温18±0.5℃、饵料密度1.0×104 cell/ml下栉孔扇贝面盘幼虫滤水率的昼夜节律;在水温24℃±0.5℃、饵料密度3.0×104 cell/ml下栉孔扇贝稚贝(壳长1.177～2.017 mm)滤水率的昼夜节律.栉孔扇贝面盘幼虫和稚贝的滤水率分别于17:00、21:00、01:00、05:00、09:00和13:00测定.栉孔扇贝面盘幼虫和稚贝的滤水率均具有明显的昼夜节律,且二者相似.在白天滤水率较低,最低值出现在09:00～13:00,幼虫为0.002 6 ml/h · ind,稚贝为0.1231 ml/h·ind;在夜间有较高的滤水率,最大值出现在凌晨21:00～01:00,幼虫达0.025 8 ml/h·ind,稚贝达0.509 6 ml/h·ind.统计分析表明,栉孔扇贝稚贝和面盘幼虫的滤水率昼夜差异显著(P＜0.01). 相似文献
8.
盐度和温度对大珠母贝与合浦珠母贝滤水率和摄食率的影响 总被引：2，自引：0，他引：2
利用静水清滤法研究了盐度和温度对大珠母贝（Pinctada maxima）与合浦珠母贝（Pinctada fucata）稚贝滤水率和摄食率的影响。试验分为4组,大1组：大珠母贝壳长（1.02±0.07）cm,大2组：大珠母贝壳长（2.94±0.17）cm;合1组：合浦珠母贝壳长（1.15±0.21）cm、合2组：合浦珠母贝壳长（3.08±0.36）cm。结果表明,随着盐度或温度的增加,4个组的滤水率和摄食率均先升高,到达最大值后又降低;其中,大1组在盐度27有最大滤水率(0.274±0.079) L/h,合1组在盐度30有最大滤水率(0.325±0.011) L/h,二者无显著性差异（P>0.05）,大2组与合2组均在盐度33时有最大滤水率,分别为（0.660±0.027）L/h,（0.329±0.021）L/h,二者有显著性差异（P<0.05）。大珠母贝稚贝在盐度30时摄食率最大,合浦珠母贝在盐度33时摄食率最大,二者有显著性差异（P<0.05）。两种稚贝在26℃时,滤水率和摄食率达到最大值,二者的最大滤水率之间或最大摄食率之间均有显著性差异（P<0.05）;随着贝体生长,大珠母贝的滤水率和摄食率显著高于合浦珠母贝,因此饵料需求量也更大;饵料不足可能是大珠母贝稚贝死亡的重要因素。 相似文献
9.
为比较文蛤红壳色选育系与江苏野生群体在不同条件下滤水率的差异并找出文蛤最佳滤水率条件,采用了试验生态学方法和响应面法对文蛤红壳色选育系幼贝进行滤水率的研究。试验结果显示,在一定范围内,文蛤幼贝滤水率随盐度、温度和藻类密度的增加而增大,超过一定范围,幼贝滤水率随盐度、温度和藻类密度的增加而减小;在同等条件下,文蛤红壳色选育系幼贝与野生群体滤水率无显著差异,但文蛤红壳色选育系生长速率显著高于野生群体;通过响应面法优化,文蛤红壳色选育系幼贝的最佳滤水率条件为:盐度21.82、温度27.40℃、藻类密度9.96×10^4个/mL,此条件下滤水率的预测值为1.62 mL/(个·min)。 相似文献
10.
温度和盐度对企鹅珍珠贝清滤率、滤食率、吸收率的影响 总被引：3，自引：1，他引：2
采用实验生态学方法研究了温度和盐度对企鹅珍珠贝清滤率、滤食率、吸收率的影响,结果表明,(1) 在盐度28.3～29.1条件下,温度对企鹅珍珠贝的清滤率、滤食率和吸收率产生极显著的影响(P＜0.01);在实验温度(14～32 ℃)范围内,随温度的升高,企鹅珍珠贝的清滤率、滤食率和吸收率增大,29 ℃时均达峰值,分别为0.87 L/h、4.17 mg POM/h和84.01%;温度为32 ℃时,企鹅珍珠贝的清滤率、滤食率和吸收率较29 ℃时均下降,但3个生理指标仍处于较高水平,表明企鹅珍珠贝属典型热带和亚热带品种,表现出对高温的较强适应性;23～32 ℃为企鹅珍珠贝较适宜摄食温度,29 ℃左右为该贝的最佳摄食温度。(2) 在温度27.4～27.8 ℃条件下,盐度对企鹅珍珠贝的清滤率、滤食率和吸收率影响极显著(P＜0.01);在实验盐度(19～37)范围内,随盐度的升高,企鹅珍珠贝的清滤率、滤食率和吸收率增大,盐度为31时均达最大值,分别为0.36 L/h、1.87 mg POM/h和76.95%;盐度为34和37时均下降;盐度为34时,3个摄食生理指标仍呈现较高水平,表明企鹅珍珠贝属典型的狭盐性贝类,表现出对高盐的较强适应性;企鹅珍珠贝较适宜的摄食盐度范围为25～34,最佳摄食盐度为31左右。 相似文献
11.
Freshwater prawn farming in Bangladesh: history, present status and future prospects 总被引：1，自引：0，他引：1
Within the overall agro-based economy in Bangladesh, freshwater prawn ( Macrobrachium rosenbergii ) farming is currently one of the most important sectors of the national economy. During the last two decades, its development has attracted considerable attention for its export potential. Freshwater prawn farming offers diverse livelihood opportunities for a large number of rural poor. Although the prospects for prawn farming are positive, it requires some research and development activities for long-term sustainability. This paper provides an overview of freshwater prawn farming in Bangladesh. 相似文献
12.
Kitojo Wetengere 《Aquaculture International》2011,19(1):33-49
Intensification of farm technologies has shown high potential in improving farm production and enhancing rural food and income
security. Intensification, however, is commodity-specific with high-value crops intensively produced. Farmed fish is one of
the high-value crops introduced in the study area to meet the above ends. The problem, however, is that the level of intensifying
fish farming technology has been very low leading to discouraging results. A study was conducted in Morogoro and Dar es Salaam
Regions, Tanzania, to identify socio-economic factors that influence the intensification of fish farming technology. Data
were collected from 234 respondents randomly sampled from 25 selected villages and were analyzed using multinomial logistic
regression model. Results indicated that age, extension education, profitability, marketability, risk, palatability and easiness
to obtain farmed fish were significant in explaining the intensification of fish farming technology. Three recommendations
emerge from this finding. First, there is need to provide extension education to the practicing farmers on various aspects
of fish farming. The probability of intensifying fish farming is higher for knowledgeable farmers. Second, technology developers
should strive to reduce the risk of farming fish and improve the profitability and marketability of farmed fish. Finally,
any analysis focusing on intensification of a fish farming technology should not confine itself to agronomic and socio-economic
characteristics but should also encompass food characteristics of the technology. Food variables such as palatability and
easiness to obtain farmed fish have been shown to influence the intensification of fish farming technology. 相似文献
13.
Bernt Aarset 《Aquaculture Economics & Management (Blackwell Science)》2013,17(2):177-191
Abstract During the past 20 years, Norwegian salmon fanning has grown to achieve export sales of 7 billion Norwegian kroner (NOK). In the same period, Arctic char has been promoted as a lucrative farmed species. Paradoxically, despite the well‐documented advantages of Arctic char farming, this commercial activity has not prospered. Here I study the interaction between research and development and fish farming, and how this interaction affects industrial development within salmon farming and Arctic char farming, respectively. Effective communication between these systems presumes organization by some superior structure that controls the flow of industrial information to the research system, and prepares research results for industrial utility. The focus here is on: the perceptions of industrial actors of tasks for the research community; how researchers interpret and respond to these tasks; how the results are imparted to the fish‐farmers; and how the research results function in practice. I contend that adequate conditions for interaction between research and industrial activity exists for salmon farming, but not for Arctic char farming. 相似文献
14.
The technology diffusion process of green mussel, Perna viridis, farming in Kerala, India, was studied by analyzing the adoption pattern, socioeconomic profile of mussel farmers, differences in farming methods, profit variations, development of trade and downstream industries, and the social factors responsible for the growth of this new industry. The farming practice has been adopted by villagers from 1996, and because of its rapid growth, India has risen to one among the top 10 farmed mussel producing nations in Asia, with an annual production of 10,060 tonnes, worth $US1.79 million at farm‐gate level. Three types of farm ownerships were observed: individual ownership (IND), family ownership (FAM), and ownerships by self‐help groups (SHG). The adoption curves are such that there were only a few adopters initially followed by an increasing rate of adoption in the subsequent years because of the demonstration effect. The study indicated the deep‐rooted “risk aversion” attitude widely prevalent among technology adopters. Age could not be significantly related to technology adoption, while education and occupation of the respondents significantly (P < 0.05) influenced the technology adoption process. The biggest outcome of mussel farming in Kerala was the empowerment of women with 87% of the SHG farms owned by women. The successful diffusion of mussel farming is the result of a combination of factors, chiefly, the availability of suitable water bodies; high rate of education; proximity of mussel markets and high degree of mussel consumption in the area; and a unique synergy between technology developers, promoters, and credit advancers. This development scenario can work as a role model for developing nations. 相似文献
15.
Nesar Ahmed Faisal Ahammed Martin Van Brakel 《Journal of the World Aquaculture Society》2008,39(1):37-50
This paper deals with production systems, cost structure, and profitability of freshwater prawn, Macrobrachium rosenbergii, farming in a new area of Mymensingh district in the north‐central part of Bangladesh. In the study area, prawn farming practice is still extensive, and only a few farmers (20%) cultivate semiintensively. The costs and returns of extensive and semiintensive farming systems are compared. All farmers in different farming systems made a profit, with seed and feed dominating variable costs. Considerable variation in production costs and profitability was observed. Based on the Cobb–Douglas production function model, return to scale indicates that there is scope to increase production and income from prawn farms in extensive and semiintensive systems by applying more inputs (i.e., seed, feed, and fertilizer). 相似文献
16.
The Yunlin coastal area is the largest oyster culture in Taiwan; however, the oyster farmers reported the negative impact of a prolonged oyster culture period and an increased operating cost in 2010. This study uses the translog cost function to consider the possibility of an oyster culture period extension to estimate oyster cost elasticity, own‐price elasticities, and cross‐price (substitution) elasticities, to evaluate whether the oyster farming industry in Yunlin County has economies of scale, and to assess the relationship with a substitution of inputs. We found that the Yunlin oyster culture has economies of scale, and that the oyster farmers can expand production scale to reduce costs. The own‐price elasticities of demand for inputs are less than 1, indicating fairly inelastic factor demands in oyster production. The oyster farming industry displays strong substitutability between the prolonged culture period and capital input, suggesting that the oyster farming industry is more responsive to a higher prolonged culture period cost, in terms of capital input. 相似文献
17.
Abstract. The growth of the Atlantic salmon, Salmo salar L., aquaculture industry has been tremendous; from a modest beginning, today's world production of salmon farming is close to 260 million tonnes in ten different countries. In particular the last 20–30 years have seen a dramatic increase in annual sales and production.
The methods vary. From exploiting the natural migrations of this anadromous fish, sea ranching has produced a viable industry. However, controlling the entire life cycle in closed systems has been more successful.
The growth of the farming industry is seriously hampered by such factors as diseases and parasites, algae blooms, environmental pollution, sabotage and rough seas. Several of these factors will not easily be eliminated, although methodical research and development could make the fish farming industry more efficient. Most of the fish farming is situated in remote regions, and the product has to be transported to heavy populated areas for sale, often across borders. The approximate average production costs per kilo differ according to the organization of the industry, average salary, the feed costs and the industrial hurdles, expressed as loss of fish, due to a variety of factors. Even though the market is growing, we must expect fierce competition. Farms producing fish of high quality at low cost will survive. The industry needs healthy fish in well-run farms, smart farmers and a government which helps the industry with reasonable regulations, guidance, applied and basic research, and insight into the future. 相似文献
The methods vary. From exploiting the natural migrations of this anadromous fish, sea ranching has produced a viable industry. However, controlling the entire life cycle in closed systems has been more successful.
The growth of the farming industry is seriously hampered by such factors as diseases and parasites, algae blooms, environmental pollution, sabotage and rough seas. Several of these factors will not easily be eliminated, although methodical research and development could make the fish farming industry more efficient. Most of the fish farming is situated in remote regions, and the product has to be transported to heavy populated areas for sale, often across borders. The approximate average production costs per kilo differ according to the organization of the industry, average salary, the feed costs and the industrial hurdles, expressed as loss of fish, due to a variety of factors. Even though the market is growing, we must expect fierce competition. Farms producing fish of high quality at low cost will survive. The industry needs healthy fish in well-run farms, smart farmers and a government which helps the industry with reasonable regulations, guidance, applied and basic research, and insight into the future. 相似文献
18.
Michael Bernard New 《Aquaculture Research》2005,36(3):210-230
A review of the current status of freshwater prawn farming globally, with comments on the statistical information available is provided in this symposium keynote paper. A brief overview of the research on freshwater prawn farming that has been published in international journals since 2000 is also provided. Finally, some research needs are listed and some scenarios for future expansion are explored. 相似文献
19.
This paper provides baseline information on the involvement of women in small-scale coastal aquaculture such as the farming of slipper oyster, Crassostrea iredalei (Faustino 1933), and green mussel, Perna viridis (Linnaeus 1758). Data were gathered during a socio-economic survey of oyster and mussel farming in Western Visayas, Philippines conducted from July to December 1991.There were 175 respondents interviewed; 18.5% and 2.4% of oyster and mussel farmers were females. Fishing and related activities were the major source of livelihood for the majority of oyster and mussel farmers. In 1990, 79.4% and 69.8% of oyster and mussel farmers earned an annual income of less than P30 000 (1 USS P23). Based on the 1988 (latest data available) poverty threshold of P2654 (monthly) for Western Visayas, 80.4% and 71.7% of oyster and mussel farmers lived below poverty level in 1990. of 175 respondents. 79.3% and 48.2% of oyster and mussel farmers indicated that their household members participated in farming activities. More female household members were involved in oyster farming compared with mussel farming. Harvesting in mussel farming and both harvesting and marketing in oyster farming generated the widest participation among female household members. 相似文献
20.
Jia Yudong Gao Yuntao Wan Jinming Gao Yunhong Li Juan Guan Changtao 《Fish physiology and biochemistry》2021,47(4):1133-1147
Fish Physiology and Biochemistry - Hypoxia has gradually become common in aquatic ecosystems and imposes a significant challenge for fish farming. The loss of equilibrium (LOE), 50% lethal time... 相似文献