排序方式: 共有33条查询结果,搜索用时 31 毫秒
1.
通过混养生态系统模拟试验研究了紫贻贝(Grateloupia lanceolata)和披针形蜈蚣藻(Mytilus edulis)不同养殖密度组合下的生态混养状况。选取壳长(45.14±3.85)mm的紫贻贝和长度(62.48±7.38)mm的披针形蜈蚣藻,采用5种湿重配比进行混养实验,分别为G1(1∶0)、G2(1∶0.25)、G3(1∶0.5)、G4(1∶1)和G5(1∶2)。每种组合中紫贻贝密度均为0.63 ind·L~(-1),而披针形蜈蚣藻密度分别为0 g·L~(-1)、1.25 g·L~(-1)、2.5 g·L~(-1)、5 g·L~(-1)、10 g·L~(-1)。36 d后,G3组中紫贻贝特定生长率为(0.21±0.03)%·d-1,极显著高于其它混养组[(0.11±0.028)~(0.21±0.03)%·d-1,P0.01],而单养组的紫贻贝特定生长率仅为(0.063±0.022)%·d-1;G3组中披针形蜈蚣藻特定生长率为(0.96±0.20)%·d-1,极显著高于其它混养组[(0.62±0.16)~(0.96±0.20)%·d-1,P0.01]。G3组生态系统对营养盐(NO_3~--N、NO_2~--N、NH_4~+-N、PO3-4-P)的去除率分别达到(91.38±1.40)%、(96.79±1.97)%、(98.38±2.06)%、(96.86±3.16)%,显著高于G2组(P0.05),而与G4和G5组没有显著性差异(P0.05)。本研究结果表明,当紫贻贝与披针形蜈蚣藻湿重比为1∶0.5时,可以取得较好的生态效应。 相似文献
2.
This paper investigates the potential flexibility within the current legal frameworks governing marine aquaculture across Europe to cater for the installation and management of marine biofilters alongside fish farms. The basis for debate is that deployment of these biofilters could be used to facilitate environmental impact mitigation. Furthermore, they have the potential to facilitate the development of bi-culture or polyculture through the harvesting of species from the biofilters themselves, for example, mussels (Mytilus edulis). This study explores the flexibility within and suitability of the current legal systems within Europe to cater for the specific technology’s adoption and management. The challenges identified from the legislative and policy frameworks are discussed along with the applicability of these to the use of biofilters for the development of bi-culture. Penultimately, recommendations are made as to where additional measures are needed and the challenges and difficulties that such measures will need to overcome before biofilters can be applied for environmental impact mitigation. Finally, the paper illustrates an application of ‘Comparative Legal Analysis’, demonstrating links to the question in hand and through so doing to wider coastal issues. 相似文献
3.
Leonardo Mata João Silva Andreas Schuenhoff Rui Santos 《Aquaculture (Amsterdam, Netherlands)》2006,252(1):12-19
The integrated aquaculture of the tetrasporophyte of Asparagopsis armata Harvey (Falkenbergia rufolanosa) using fish farm effluents may be viable due to the species high capacity of removing nutrients and its content of halogenated organic compounds with applications on the pharmaceutical and chemical industries. In order to optimize the integrated aquaculture of F. rufolanosa, we followed the daily variation of the potential quantum yield (Fv/Fm) of PSII on plants cultivated at different biomass densities and different total ammonia nitrogen (TAN) fluxes to check if they are photoinhibited at any time of the day. Moreover, the photoinhibition under continuous exposure to highly saturating irradiance and its potential for subsequent recovery in the shade was assessed. The potential for year round cultivation was evaluated by measuring rates of O2 evolution of plants acclimated at temperatures ranging from 15 to 29 °C, the temperature range of a fish farm effluent in southern Portugal where an integrated aquaculture system of F. rufolanosa was constructed.Photoinhibition does not seem to be a major constrain for the integrated aquaculture of F. rufolanosa. Only when cultivated at a very low density of 1.5 g fresh weight (FW) l− 1 that there was a midday decrease in maximal quantum yield (Fv/Fm). At densities higher than 4 g FW l− 1, no photoinhibition was observed. When exposed to full solar irradiance for 1 h, F. rufolanosa showed a 33% decrease in Fv/Fm, recovering to 86% of the initial value after 2 h in the shade. A midday decline of the F. rufolanosa Fv/Fm was also observed under the lowest TAN flux tested (∼6 μM h− 1), suggesting that this fast and easy measurement of fluorescence may be used as a convenient diagnostic tool to detect nutrient-starved unbalance conditions of the cultures. Maximum net photosynthesis peaked at 15 °C with 9.7 mg O2 g dry weight (DW)− 1 h− 1 and remained high until 24 °C. At 29 °C, the net oxygen production was significantly reduced due to a dramatic increase of respiration, suggesting this to be the species' lethal temperature threshold.Results indicate that F. rufolanosa has a considerable photosynthetic plasticity and confirm it as a good candidate for integrated aquaculture at temperatures up to 24° C and cultivation densities of at least 5 g FW l− 1. When cultivated at these densities, light does not penetrate below the first few centimetres of the surface zone. Plants circulate within the tanks, spending around 10% of the time in the first few centimetres where they are able to use efficiently the saturating light levels without damaging their photosynthetic apparatus. 相似文献
4.
G. Jay Parsons Sandra E. Shumway Sue Kuenstner Alexander Gryska 《Aquaculture International》2002,10(1):65-77
Commercial and developmental operations for the culture of the seascallop, Placopecten magellanicus, are present in AtlanticCanada and New England. In an experiment designed to examine the commercialfeasibility of polyculture of scallops with Atlantic salmon(Salmo
salar), we measured growth andsurvival of sea scallops grown in suspension at two salmon aquaculture sites innortheastern Maine (Johnson Cove (JC) and Treats Island (TI)). Sea scallop spatwere grown in pearl nets and deployed on drop lines containing ten nets inAugust 1994. One drop line of ten nets was sampled about every four months andscallops were counted, measured and weighed. Scallop tissues were also analysedfor paralytic shellfish toxins (PSP). The maximum level of PSP recorded duringthe study was 1174 g STX equiv.·100 gtissue–1 (excluding adductor muscle weight). After one year,shell heights were 53.6 and 56.4 mm, growth rates were 0.11 and0.12 mm per day and wet adductor muscle weights were 3.3 and 4.1g (TI and JC, respectively). These growth rates were comparable tosea scallops grown in suspension culture to a nearby scallop aquaculture siteand other areas in Atlantic Canada. Reduced rates of survival were found duringthe latter part of the experiment and were attributable, in part, to heavyfouling, predators and high stocking density. The potential for supplementalincome, diversification of the salmon aquaculture industry, and feasibility ofculturing scallops at adjacent sites to salmon operations does exist. 相似文献
5.
对虾池不同综合养殖系统效率和效益的比较研究 总被引:7,自引:0,他引:7
利用50个5.0×5.0×1.8m陆基围隔研究了中国对虾与台湾红罗非鱼、海湾扇贝和缢蛏投饵或施肥混养及鲈鱼与中国对虾和台湾红罗非鱼混养最佳结构的生态效率、生产效果和经济效益。结果表明,几种综合养殖系统最佳结构下各种养殖对象对N的绝对利用率由高至低依次为:鲈鱼-对虾-罗非鱼(30.91%)>对虾-海湾扇贝(21.09%)>对虾-罗非鱼施肥混养(20.12%)>对虾-罗非鱼投饵混养(17.81%)>对虾-缢蛏(16.93%)>单养对虾(11.52%);对P的绝对利用率由高至低依次为:对虾-缢蛏(16.08%)>鲈鱼-对虾-罗非鱼(12.83%)>对虾-罗非鱼投饵混养(12.63%)>单养对虾(10.88%)>对虾-海湾扇贝(6.01%)>对虾-罗非鱼施肥混养(4.04%);其产出投入比由高至低依次为:对虾-罗非鱼投饵混养(1.99)>对虾-罗非鱼施肥混养(1.98)>对虾-海湾扇贝(1.53)>单养对虾(1.38)>鲈鱼-对虾-罗非鱼(1.30)>对虾-缢蛏(1.23)。 相似文献
6.
[目的]研究稻田鳖、鱼、虾混养技术模式,克服高密度单养造成生态环境恶化、疾病频发、风味下降等问题。[方法]选择3块水源、排灌设施等条件良好的稻田作为试验田,进行鳖、鱼、虾混养试验,分析其经济效益与生态效益。[结果]经过10个月饲养,共收获商品鳖6 904.3 kg、商品虾1 428 kg、商品鱼3 744 kg、收割稻谷24 625 kg,其中日本鳖、青虾饵料系数分别为1.8、1.6,实现总产值81.3万元,纯利润43.2万元,平均利润127 065元/hm2,投入产出比1∶2.13。[结论]该混养模式经济、生态效益显著,值得在安徽省大面积推广应用。 相似文献
7.
S. K. Garg 《Aquaculture International》1996,4(2):143-155
In order to assess the possibilities of utilizing drainage effluents (salinity range 5.0–12.5), fish culture experiments were carried out. Experiments on polyculture using cow dung (24 000 kg ha–1 y–1) as pond fertilizer were conducted at five different salinity levels (0.3–8.5). Studies have revealed that carp perform well in salinities up to 7.5 and reasonably high fish production has been obtained. Even though the ponds had a high trophic status, higher salinities ( > 7.5) appear to repress fish growth probably due to low dissolved oxygen (DO), high BOD and high NH4-N. Experiments on monoculture of common carp (Cyprinus carpio) conducted at two different salinity levels (0.3–0.9 and 6.0–7.0) using four different organic fertilizers (cow dung at 24 000 kg and 20 000 kg, poultry at 1500 kg, duck at 6000 kg and sheep/goat at 1500 kg ha–1 y–1) have revealed the highest fish growth to be in poultry-treated ponds, followed in decreasing order by duck and sheep/goat wastes. Similar trends in fish production were observed both in fresh- and salt-water ponds. However, fish production was lower in ponds having higher salinities ( > 7.5). Nevertheless, these studies indicated that inland saline waters can be utilized for fish culture. With minor modifications in the existing technology of fish culture in stagnant freshwater fish ponds, animal wastes could be used to fertilize brackishwater fish ponds. 相似文献
8.
Ana Milstein 《Aquaculture International》1995,3(4):292-314
To analyse the relationships among fish species performance and management procedures, a database was built up with data from 31 fish farms during the period 1976–1987 (1673 observations) and analysed through multivariate statistics (factor analysis). The data include nurseries, grow-out and operational ponds with mono- and polycultures of common carp, Cyprinus carpio, tilapia hybrid, Oreochromis niloticus × O. aureus, silver carp, Hypophthalmichthys molitrix, and mullet, Mugil cephalus. The main conclusions include the following. (1) The highest total yields and best tilapia performances were obtained in polyculture ponds where tilapia was the main species. (2) The best carp performances occurred in grow-out polyculture ponds where carp was the main species. Carp performance was improved in polycultures with mullet and silver carp, irrespective of whether tilapia were present or not. (3) Carp and tilapia yields increased as the nutritional inputs (feed pellets, sorghum pellets, manure), pond size and culture duration increased. The effect of the nutritional input was not linear, but logarithmic. (4) Growth rate of common carp was more affected by total density and stocking size than that of tilapia. Better carp and tilapia growth occurred in grow-out ponds when stocked at large sizes and cultured during short periods, mainly when both species were present. (5) Carp growth varied with the geographical region and size of fish pond, being better in smaller than in larger ponds due to reduced access to natural benthic food in deep ponds. 相似文献
9.
研究了大黄鱼与三疣梭子蟹的池塘混养技术。2011年4月初向池塘内投放80~100 g/尾的大黄鱼,混养池塘投放4 000~5 000尾/hm~2,共投放4 500尾/hm~2,5月下旬投放规格为150~200只/kg的三疣梭子蟹,混养池塘投放30 000只/hm~2,共投放33 000只/hm~2,梭子蟹单养池塘60 000只/hm~2,共投放66 000只/hm~2。大黄鱼单养池塘投放8 000~10 000尾/hm~2,共投放9 000尾/hm~2;当年11月中下旬收获商品大黄鱼,大黄鱼单养池塘平均单产2 118.7~2 238.7 kg/hm~2,混养池塘1 329.6~1 460.3 kg/hm~2,存活率分别为76.2%和85.3%;9~11月收获商品梭子蟹,梭子蟹单养池塘的平均单产1 701.8~1 747.1 kg/hm~2,混养池塘的平均单产为1 253.5~1 314.3kg/hm~2,存活率分别为17.8%和21.3%。混养、大黄鱼单养、梭子蟹单养投入产出比分别为1∶1.83~1∶1.96、1∶1.69~1∶1.81、1∶1.57~1∶1.76。由此可见,大黄鱼与三疣梭子蟹的混养有助于提高综合效益。 相似文献
10.
Existing and impending constraints to the use of synthetic pesticides, along with changing legislation in favour of an integrated approach to pest management, are driving uptake of ‘alternative’ approaches to pest control. Polyculture is one such approach, often relying upon the presence of non-host plants within the crop to reduce colonisation by pest insects. The diamondback moth, Plutella xylostella (L.), is known to oviposit on non-host plants and the present study showed that neonates were able to move relatively large distances, enabling them to relocate from non-host natal plants to nearby hosts. Although fewer larvae were found on host plants when they hatched on non-hosts, it is concluded that even a low level of re-location of neonates could potentially reduce the potential for polyculture to control this pest. It is proposed that non-host oviposition and neonate movement could explain why polyculture sometimes fails in controlling pest insects. 相似文献