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1.
渤海生产力研究：叶绿素a,初级生产力与渔业资源开发潜力 总被引：9，自引：0，他引：9
根据1982～1983年渤海生产力调查资料,主要探讨了渤海浮游植物现存量(叶绿素a)及其初级生产力的‘分布特征和季节变化规律。并对渤海水域的有机生产能力和渔业资源开发潜力作了估算,渤海的初级生产力为112gC/m~2·a,每年的初级生产量为1000万t有机碳,每年的水产品(鱼、虾、贝类)产量约为100万t,其可捕量在50万t以上。 相似文献
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2010年6-10月对江西省南昌市蒋巷镇太子河养殖水域浮游植物进行调查.结果表明,太子河有浮游植物5门、74种;其中,绿藻门种类数最多(占藻类总种数的48.64％),其次是蓝藻门(29.72％)和硅藻门(14.86％).10月的浮游植物种类最多,其次为9月和8月,7月最少.浮游植物密度7月最高,为313×105个/L,其余月份浮游植物密度相差不大,变化范围为(79 ～ 101)×105个/L,蓝藻门微囊藻属是绝对优势种.浮游植物Shannon-Wiener多样性指数及均匀度指数7月最低,分别为0.10、0.03,其余月份Shannon-Wiener指数范围为0.37 ～0.69,均匀度指数范围为0.10 ～0.18.综合分析浮游植物密度、多样性指数和均匀度指数,太子河水体存在富营养化.浮游植物对鲢鳙的鱼产力估算为12.675 kg/hm2. 相似文献
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青山水库浮游生物群落及鲢,鳙鱼产力的估算 总被引：1，自引：0，他引：1
青山水库属平原型水库，有养殖水面１１２０公顷。调查结果共有浮游植物８２属，年平均生物量７５．３ｍｇ／Ｌ；浮游动物３５属，年平均生物量１３．８８ｍｇ／Ｌ。估算鲢鳙年鱼产力为１０９１．６ｋｇ／ｈａ。而青山水库１９８３－１９９１年年均鲢鳙产量仅５６．９２ｋｇ／ｈａ，生产潜力很大。 相似文献
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近年来，朱隈水库的鲢鳙渔业有了较大的发展，1975-1976年，以鲢鳙为主(90％以上)，平均单产达33．2斤／亩。1977年，产量跌落，亩产16．2斤／亩。查明鱼产量变动的原因，提出渔业利用措施，这是发展朱隈水库鲢鳙渔业急待解决的问题。 相似文献
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浮游植物的初级生产力与黑白瓶测氧法 总被引：5，自引：0，他引：5
<正> 我国淡水渔业的主要养殖对象——鲢、鳙均能直接以浮游植物为食,浮游植物的生产量与鱼产量密切相关。众所周知,用个数或生物量所表示的浮游植物现存量(Standing crop或Standingstock)仅代表着某一采水时刻单位水体中存在的浮游植物总量,因而在评价水质“肥瘦”或生产性能时,只能作为一种指标加以应用。如欲用能量估算的方法探讨浮游植物与鱼产量之间的内在联系,仅有现存量的资料是不够的,还必须测定浮游植物的生产 相似文献
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研究了莱州湾浮游动物及其潜在能量来源颗粒有机碳与溶解有机碳的稳定同位素特征,发现颗粒有机碳、溶解有机碳以及浮游动物碳稳定同位素分别为(-23.24±0.52)‰、(-22.93±0.59)‰、(-21.63±0.76)‰。陆源有机碳在颗粒有机碳库、溶解有机碳碳库中的相对含量分别为(58.2±5.7)%、(54.8±6.6)%,均超过海源有机碳相对含量。陆源有机碳对浮游动物能量贡献为(45.2±8.5)%,略低于海源有机碳贡献。海源有机碳在浮游动物体内更为"富集",浮游动物更倾向于利用海源有机碳。陆源有机碳作为补充碳源,为浮游动物提供了额外能量。 相似文献
11.
Relative growth,survival and harvestability of bighead carp,silver carp,and their reciprocal hybrids
Growth and survival in the primary rearing phase (42 days) for bighead carp, silver carp, bighead × silver carp (BHC × SC), and silver × bighead carp (SC × BHC) in ponds and concrete tanks stocked at 370 500 fry/ha were studied. Mean survival for fishes in ponds was 93%, that in tanks was 73%. Yields among all fishes averaged 338 kg/ha. The growth rates of fishes in ponds were similar; in tanks, silver carp grew faster than the bighead carp.Growth, survival, and harvestability by seine during the secondary rearing phase (60-day duration) for the same groups of fish were studied. Fingerlings (0.9 g mean weight) were stocked in earthen ponds at 49 400 fish/ha and 98 800 fish/ha. Mean survival of fishes at low stocking rate was 77%, similar to that (71%) for the high stocking rate. Fish yields were similar at the low stocking rate. At the high rate, the BHC × SC yield (846 kg/ha) was greater than the SC × BHC yield (582 kg/ha). The BHC × SC and SC × BHC had greater mean weights at low stocking rate than at high stocking rate. The mean weights for bighead carp were similar at both rates. Bighead carp and the reciprocal hybrids were more easily harvested by seine than silver carp. 相似文献
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The effect of fish density and species combination on growth and utilization of natural food in ponds 总被引：2，自引：0，他引：2
Abstract. Interactions between bottom-feeding fish (common carp, Cyprinus carpio L., and hybrid tilapia) and a filter feeder (silver carp, Hypophthalmichthys molitrix (Valenciennes)) in polyculture were studied in fertilized ponds with no supplementary feeding. The silver carp were stocked at two densities: 1300 and 2600/ha. Growth rate and yield of each of the species were also compared with those in polyculture of bottom feeders alone, and in a monoculture of silver carp alone, at the same densities. The consumption of natural feed as melabolizable energy (ME) was calculated by the energy balance (requirement for maintenance and growth divided by the utilization efficiency).
Increasing the density of silver carp reduced proportionally their own growth rate, due to the limited amount of food. Above a density of about 1000/ha, silver carp inhibit the growth rate of common carp and tilapia. This inhibition was small at 1300 silver carp/ha, but considerable at 2600/ha. However, the presence of bottom feeders increased the growth rate of silver carp at both densities. Calculated natural food consumption showed that growth interactions between species were brought about through the availability of food. The synergistic effect of the bottom-feeding fish on the silver carp is assumed to be due to the upwelling of bottom nutrients to the upper layers of water by the burrowing of the fish in the mud. Combined yield of all species in the polyculture was highest at the density of 1300 silver carp/ha (2116 kg/ha in 156 days). At 2600 silver carp/ha the inhibition of growth rate of silver carp itself, reduced total yield as compared with the lower density. 相似文献
Increasing the density of silver carp reduced proportionally their own growth rate, due to the limited amount of food. Above a density of about 1000/ha, silver carp inhibit the growth rate of common carp and tilapia. This inhibition was small at 1300 silver carp/ha, but considerable at 2600/ha. However, the presence of bottom feeders increased the growth rate of silver carp at both densities. Calculated natural food consumption showed that growth interactions between species were brought about through the availability of food. The synergistic effect of the bottom-feeding fish on the silver carp is assumed to be due to the upwelling of bottom nutrients to the upper layers of water by the burrowing of the fish in the mud. Combined yield of all species in the polyculture was highest at the density of 1300 silver carp/ha (2116 kg/ha in 156 days). At 2600 silver carp/ha the inhibition of growth rate of silver carp itself, reduced total yield as compared with the lower density. 相似文献
13.
不同养殖结构鱼塘能量生态学研究 总被引：9，自引：0，他引：9
本文从养针池生态系统利用能量利用各环节,分析了两种不同养殖结构鱼生态学能量利用效率。主养草食性鱼类,其输入的总补助能,光合能、生物能的转换效率分别为９．８６％、６．９２％、１０．１０％;其生产吨鱼总补且能、光合能、生物能分别为４６．６４ＧＪ、６６．４６ＧＪ、４５．５４ＧＪ。而对于主养滤食性鲢、鳙的池塘,其对应的指标 ８．３．％、３．７５％、８．６６％、４６．９９ＧＪ、１０５．５２ＧＪ、４５．７３Ｇ 相似文献
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A study was conducted to 1) evaluate the compatibility of prawns (Macrobrachiurn rosenbergii) with carps, especially the effect of the common carp (Cyprinus carpio); and 2) measure the ability of prawns to utilize the foods available in manured systems. Carps used were the silver (Hypophthalmichthys molitrix), bighead (Aristichthys nobilis), grass (Ctenopharyngodon idella) and common carp (Cyprinus carpio). Four ponds (0.09 to 0.17 ha) were stocked with silver, bighead and grass carps while common carp were stocked in only two ponds. Total fish densities were 8,600/ha where four carps were stocked, but only 6,200/ha when common carp were omitted. Post-larval prawns (wt 0.116 g) were stocked at densities of 17/m2. Swine (approximately 60/ha of pond surface area) were housed on pond dikes so that fresh manure continuously entered each pond. Two lots of swine were fattened during the experimental period and loadings of swine manure were calculated based on hog size and feed consumption. Growth periods were 163 days for fish and 107 and 121 days for separate stockings of prawns. Gains in biomass by prawns averaged 714 kg/ha in ponds without common carp and 364 kg/ha in ponds containing common carp. Gains in biomass for both fish and prawns were 3,619 kg/ha (19.8 kg/ha/day) in ponds with common carp and 2,924 kg/ha (18.0 kg/ha/day) in those without common carp. Prawn survival was higher (X = 84.5% vs X = 72.5%), but final average weight of prawns was lower (2.64 vs 5.86 g) in the presence of common carp due to competition for food between common carp and prawns. Competition from carp is believed to have exerted less influence on prawn survival than predation on small prawns by larger, faster-growing prawns. 相似文献
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Muhammad A. Latif Mohammad J. Alam Mohammad A. Rahman 《Journal of the World Aquaculture Society》1993,24(3):402-409
An experiment on integrated duck-cum-fish farming was conducted in 11 ponds of 0.1 ha each at the Fisheries Research Institute, Mymensingh, Bangladesh. Khaki Campbell layer ducks Anas platyrhychos were housed directly over the pond water surface at 200, 400 and 500 dncks/ha. Each density had three replicate ponds and two ponds had no ducks. Fish fingerlings were stocked at a total density of 8,850/ha. The species composition was silver carp Hypophthalmicthys molitrix 33.9%; catla Catla catla 12.4%; rohu Labeo rohita 18.1%; mrigal Cirrhina mrigala 28.8%. grass carp Ctenopharyngodon idella 1.4% and sor puti Puntius gonlonotus 5.4%. The fish were not given any supplemental feed, and the ponds were not fertilized except for the split duck feed and duck manure falling directly into the ponds. Ducks were fed with a feed formulated from locally available ingredients.
After one year the fish were harvested. The yield of fish increased with an increase in duck density. Highest net fish production of 4,250 kg/ha/yr was obtained from ponds with 500 ducks/ ha, compared to 490 kg/ha/yr from the control ponds. Manure of each duck contributed a net fish yield of 6.9–7.5/yr. Average egg production was 237 eggs per female duck per year. Economic analysis of the technology showed a net profit of about 100% of the total costs, indicating the economic viability of the technology. 相似文献
After one year the fish were harvested. The yield of fish increased with an increase in duck density. Highest net fish production of 4,250 kg/ha/yr was obtained from ponds with 500 ducks/ ha, compared to 490 kg/ha/yr from the control ponds. Manure of each duck contributed a net fish yield of 6.9–7.5/yr. Average egg production was 237 eggs per female duck per year. Economic analysis of the technology showed a net profit of about 100% of the total costs, indicating the economic viability of the technology. 相似文献
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Rom Moav G. Wohlfarth G.L. Schroeder G. Hulata H. Barash 《Aquaculture (Amsterdam, Netherlands)》1977,10(1):25-43
In 1974 and 1975 nine experimental treatments of fish polyculture in stagnant water ponds without aeration were conducted at Dor. The polyculture was composed of common carp, silver carp, white amur (grass carp) and Tilapia. The treatments differed in stocking densities, feeding and manuring levels. The most productive treatment of the experiment, in which the fish were fed with protein-rich pellets, produced 50 kg/ha per day, probably a record for unaerated ponds of stagnant water. Two treatments (low and high stocking densities) fed exclusively with liquid cow manure produced an average yield of around 32 kg/ha per day. The yields of the treatments receiving high-protein pellets exceeded those of the treatments receiving grain pellets by 20 and 9.6 kg/day per ha, at high and low stocking densities, respectively, and in both cases the yield increments justified the extra cost of high-protein feed. The responses of the four fish species to the different levels of feeding and stocking densities were widely different. The common carp and white amur showed the greatest responses to increased feeding inputs while the silver carp and Tilapia, even at high densities, have done equally well at low feeding levels. Total body fat contents of the common carp were 20%, 15% and 6.2% when fed with high-protein pellets, grains pellets and liquid cow manure, respectively. Intermittent harvesting did not result in increased yields. 相似文献
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Shafiqul Hassan Peter Edwards David C. Little 《Journal of the World Aquaculture Society》1997,28(3):268-274
A comparison of a monoculture of Nile tilapia Oreochromis niloticus and a polyculture of carps (silver carp Hypophthalmichthys molitrix; rohu Labeo rohita; and mrigal Cirrhinus mriga la; ratio 4:3:3) was carried out in 200-m2 earthen ponds fertilized with cattle manure and supplemented with inorganic fertilizer at 3-kg nitrogen and 1.5-kg phosphorus/ha per day. A control treatment of a tilapia monoculture without fertilizer inputs was included to assess the effect of pond basal fertility. Net yields of 23.5 kg/pond per 112 d (3.8 t/ha per 1 yr) in the tilapia monoculture and 19.2 kg/pond per 112 d (3.1 t/ha per yr) in the carp polyculture were not significantly different; net yields from unfertilized tilapia monoculture ponds were negative. In the carp polyculture, silver carp was the dominant species at harvest contributing 73% of the total net fish production compared to 9% and 19% by rohu and mrigal, respectively. Water quality data suggested that tilapia yields could have been further improved by increasing fertilization rate but that critical dissolved oxygen concentration constrained this option for carp polyculture. 相似文献
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Matei Dimitrov 《Aquaculture (Amsterdam, Netherlands)》1984,38(3):241-253
Intensive polyculture of common carp and herbivorous fish (silver carp and grass carp) at high stocking densities and with intensive feeding with fodder and mineral and organic fertilization was carried out without mechanized aeration and automated feeding.Two stocking patterns were tested. The first, in Pond 1 (with an area of 2.5 ha), had the following stocking rates: one-year carp (C1), 8000 fish/ha; one-year silver carp (S1), 1500 fish/ha; and one-year grass carp (G1), 200 fish/ha. The yield was 6292 kg/ha of standard consumer fish (C1+ 743 g, S1+ 944 g, and G1+ 1000 g) at a relatively low food conversion ratio (2.24) and high survival of all fish. Within the total yield, the two-year carp contributed 76%, the silver carp 21%, and the grass carp 3%. The second stocking pattern, in Pond 2 (0.25 ha), had the following rates: C1, 8500 fish/ha; S1, 2000 fish/ha; and G1, 200 fish/ha, and produced a still higher total yield (6629 kg/ha) at a relatively low food conversion ratio (2.10). The two-year carp in Pond 2 contributed 88% of the total yield, and the herbivorous fish only 12% even though they accounted for 20% of the stock.Our results (Pond 2) are compared with other record yield experiments under similar conditions but including tilapia. At a total stocking rate of 10 700 fish/ha and without participation of tilapia, over a period of 186 days (as against 126 days in the other experiment), our experiments gave a total yield which was 347 kg/ha higher at a food coefficient 15% lower. The growth period was 60 days longer in our experiments but it included April and October when water temperature is much below the optimum and only 4% of the total amount of fodder was assimilated. 相似文献
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Adel K. Soliman Abdou A.A. El-Horbeety Mohamed A.R. Essa Mohamed A. Kosba Ibrahim A. Kariony 《Aquaculture International》2000,8(4):315-326
Raising ducks on fish ponds (fish-duck culture) on a commercial scale is a new practice in Egypt, therefore, a study was undertaken to evaluate this practice from production, carcass composition and economic viewpoints.Five earthern ponds were used in the non-integrated system (no ducks) whereas four earthen ponds, in which each pond was supplied with 125 Pecking ducks per 0.42 ha, were used for the Integrated system. In both systems, each pond was stocked with four species of fish (common carp Cyprinus carpio, silver carp Hypophthalmichthys molitrix, Grey mullet Mugil cephalus and tilapias Oreochromis niloticusand O. aureus) at the same densities.There were no differences in temperature or pH in any of the ponds but dissolved oxygen levels were lower in integrated ponds concomitant with increasing levels of ammonia, phosphate and nitrate. Water in integrated ponds was richer in natural productivity (phytoplankton and zooplankton) either in species or density when compared with those variables in non-integrated ponds.Fish species reared in integrated ponds exhibited better body weight, food conversion and protein efficiency ratios compared with those of fish species in the non-integrated ponds. Fish yield per 0.42 ha produced from the integrated ponds was significantly higher than that obtained from non-integrated ones. Also, body composition of fish species was affected by the type of farming. Carcass crude protein of grey mullet, silver carp and tilapia was improved in the integrated system. The data on return on sales, return on costs, return on equity, pay-back period and break-even point showed that the integrated system was more profitable than the non-integrated system. 相似文献
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H. Chaudhuri R.D. Chakrabarty P.R. Sen N.G.S. Rao S. Jena 《Aquaculture (Amsterdam, Netherlands)》1975,6(4):343-355
Composite fish culture of the Indian major carp, Catla catla, Labeo rohita and Cirrhinus mrigala together with the Chinese silver carp Hypophthalmichthys molitrix and grass carp Ctenopharyngodon idella and the Indonesian strain of common carp (Cyprinus carpio communis) was carried out in experimental ponds in 1971–1972 and 1973–1974. The management techniques adopted aimed at high yields of marketable fish (around 1 kg) in 1 year.In the first year, production varied from 3 889 to 5 600 kg/ha/year and this rose to an average of 8 200 kg/ha/year with a maximum of 9 389 kg/ha/year in the second year. The important changes made to the management schedule in 1973 were increased stocking density, greater use of feed and fertilizers, and provision of more weeds for grass carp.The experimental studies demonstrate the practicability of raising large crops of healthy marketable fish in India. 相似文献