首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 390 毫秒
1.
Coastal water bodies are a particularly heterogeneous resource, typified by high spatial and temporal variability that could influence the aquaculture in coastal zones. However, the development of coastal aquaculture may produce negative impacts on the coastal area by the potential release of nutrients and organic matter that can be a source of pollution in receiving waters. The aim of this paper was to evaluate the performance of constructed wetland in controlling the dynamics of deoxygenating matter (organic matter and ammonia) and eutrophicating matter [organic matter and soluble reactive phosphorus (SRP)] in the waters entering (inflow) and flowing out (outflow) from a coastal aquaculture fish farm. We observed that constructed wetland systems are effective in removing fractions of total suspended solids, COD, total ammonia nitrogen and SRP contained in the inflow water with higher efficiency in the spring period (60.37%, 14.89%, 65.38% and 17.6% respectively) than in the summer period (45.10%, 8.06%, 32.43% and 8.00% respectively). Similar pattern was recorded for the treatment of the outflow waters, showing that the wetland system reduced most of the deoxygenating and eutrophicating matter produced as a consequence of feeding and fish metabolic activity. During the summer season, high algae mortality can reduce the performance of the wetland system in the outflow water control; this lower efficiency could be improved by controlling the biomass of algae by vegetation harvesting.  相似文献   

2.
  • 1. The existence of perceived ecological impacts and development of adaptive management solutions to mitigate these problems are important issues in sustainable aquaculture. This paper examines the general impacts of two newly established trial longline installations on the infauna in Twofold Bay, a large, coastal embayment in south‐east Australia.
  • 2. We hypothesized that the physical presence of these longline installations and the biological activities of the mussels they supported would result in temporal changes in densities of infaunal taxa below installations differing from those at undisturbed control sites. We also predicted different patterns of variability in infauna between longline and control sites from before to after the longlines were stocked. These hypotheses were tested by using a beyond‐BACI sampling design and asymmetrical analyses of variance to compare changes in densities of taxa at several different spatial scales below the proposed longline sites with those at two adjacent control sites, before and after the longlines were stocked.
  • 3. After 18 months of longline operations, there was no evidence of any impact on total number of taxa, nor densities of individual taxa. Short‐term temporal trends in densities in plots at control sites from April to May 2001 were often as different from each other as from those at the longline site. This indicates that densities of taxa at the farm site were within the range typically found at undisturbed sites, so there were no ecological impacts from the farm.
  • 4. These results do not concur with previous studies on impact of mussel farming in semi‐enclosed coastal waters. Differences in location, scale of production, duration of operation and assimilative capacity of the environment probably contributed to this discrepancy. The infauna in Twofold Bay either do not respond to this form of disturbance or have not yet been exposed to disturbance of a sufficient magnitude, or for a sufficient period of time, to elicit a detectable response. Better definition of the potential ecological impacts associated with aquaculture, plus their scale and magnitude in different environments is needed to design experiments and monitoring programmes to detect specific impacts. This activity can only be considered sustainable once we know that these impacts are localized, reversible and short‐term.
Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

3.
The overall objective of this research project was to determine if land-based culture of eastern oysters (Crassostrea virginica) is a feasible option using recirculating aquaculture systems with synthetically derived seawater. A twelve week growout study was conducted in a closed-loop recirculating system with zero discharge using synthetically derived seawater. Two species of marine microalgae (Chaetoceros spp. and Isochrysis spp.) were cultured as oyster feed. Oysters were batch fed daily and amounts of algae cells offered to oysters were monitored. Overall, oyster survival remained greater than 99% and growth was steady and averaged 1.3, 1.1, and 0.33 mm per week for length, width, and thickness, respectively. Mean weight increased an average of 0.39 g per week. The means to maintaining suitable water quality was nitrification and supplementation of calcium to maintain ambient levels representative of their natural environments. Data collected is also useful for those who wish to study oysters in controlled environments or for genetic and/or breeding programs.  相似文献   

4.
Bivalve cultivation, in single cultivation or in polyculture (including integrated multitrophic aquaculture; IMTA), is generally limited to eutrophic waters. We carried out a modeling study to test if, under meso- and oligotrophic conditions, depth could be a key factor for bivalve productivity associated to IMTA and other polyculture strategies. We applied the model Farm Aquaculture Resource Management (FARM) at three strata of the water column in two coastal fish farm areas in the Mediterranean Sea, using water column variables sampled seasonally to estimate the potential mussel production. According to FARM, mussel production was high in both areas and, in some cases, almost doubled when mussels were cultured below 25-m depth compared to shallower levels. Phytoplankton abundance is expected to notably influence mussel production compared to particulate organic matter. Thus, in meso- and oligotrophic stratified waters, where chlorophyll maximum is relatively deep, depth can be a key factor for the productivity of mussel cultivation. The obtained results could help to maximize the production of suspension-feeding bivalve cultivation and, therefore, the expansion and development of sustainable aquaculture in non-eutrophic marine waters.  相似文献   

5.
In order to estimate the nitrogen loading from fish aquaculture facilities, we studied the nitrogen and carbon stable isotope ratios (δ15N and δ13C, respectively) in the brown macroalga Sargassum piluliferum and small amphipod crustaceans Caprella spp., both of which are lower trophic level biota found at fish and pearl oyster aquaculture facilities situated along the eastern coast of the Uwa Sea, Japan. This coastal region is one of the least populated areas along the Japanese coast. The mean concentrations of chlorophyll a, dissolved inorganic nitrogen, dissolved inorganic phosphate, and dissolved silicate-Si were 1.5- to 2-fold higher in samples from the fish aquaculture facilities than in those from the pearl oyster aquaculture facilities, indicating that the fish aquaculture facilities were associated with nitrogen loading. The δ15N abundance level in S. piluliferum collected from the fish aquaculture facilities was significantly higher (1.3‰) than that in macroalga collected at the pearl oyster aquaculture facilities, whereas that in Caprella spp., primary consumers, was only slightly higher (0.3‰). The feeding style of Caprella spp., which depends on suspended particulate organic matter and attached microalgae, is considered to the primary causal factor for the lack of a significant difference in δ15N abundance level between the two types of aquaculture facilities. Based on these results, we conclude that S. piluliferum found in close proximity of aquaculture facilities is a suitable organism for monitoring nitrogen loading from fish aquaculture facilities, through the analysis of δ15N.  相似文献   

6.
Enteromorpha linza and E. intestinalis thrive in aquatic systems rich in inorganic fixed nitrogen. At 15°C and ca. 1800 μW cm?2 these algae showed a Vmax for nitrate uptake of 129 μmol h? g?1 dry weight ( = ca. 22 μmol h?1 g?1 wet weight) and a Ks of 17 μM. At 20 μM rates averaged 70 ± 21 μmol h?1 g?1. They dropped to 19% of this value at 5°C, and at 0°C nitrate uptake ceased. In the first hour of darkness, nitrate uptake decreased to 35% and in the second hour to 10% of the rate in light. Enteromorpha spp. scavenged nitrate from the medium at concentrations < 0.5 μM, and no nitrate leaked out of the tissue into nitrate-free water. Information from this study may be useful in designing nutrient feeding strategies in aquaculture systems.  相似文献   

7.
通过监测池塘水体藻类群落组成、多项水质指标、底泥总有机碳(TOC)和底泥异养细菌数等指标值,研究了固定化微生物对凡纳滨对虾生产性养殖池塘水质调控和污染底泥的修复能力,微生物固定所用载体为改良沸石和生物活性炭(相应的固定化微生物分别记为ZE-M组和BE-M组)。试验结果显示,处理组(ZE-M组和BE-M组)池塘水体中藻类组成呈多元化,隐藻、蓝藻和绿藻数量比较接近,而对照组则是蓝藻占绝对优势。试验过程中,对照池的氨氮浓度和COD呈直线上升,而处理组氨氮浓度和COD的增长幅度缓慢,ZE-M、BC-M载体微生物的使用是产生差异的直接原因。对照组和处理组的其它水质指标变化规律及差异性不明显,可能是由于池塘水体由诸多不确定因素影响所致。固定化微生物对池塘底泥TOC含量和异养细菌数的影响显著(P<0.05),试验过程中,试验组和对照组池塘底泥TOC含量随着养殖时间均有增加的趋势,但对照组这一趋势更加明显;试验初期,各组表层底泥中的异养细菌数量在3.367×105~8.60×105CFU/g范围内,试验结束时增长到85×105~393.7×105CFU/g。处理组和对照组的异养细菌差异显著(P<0.05),其中ZE-M处理组...  相似文献   

8.
Commercial intensive aquaculture systems werebuilt and are managed in a somewhat differentway in each farm. To evaluate the effects ofseveral management procedures on water qualityin intensive fish ponds, data from severallocations, times and culture conditions indifferent farms were collected and are hereinanalyzed through multivariate statistics. Water quality in the intensive ponds depends onthe water entering, the biological processeswithin, and the water leaving the ponds. Areservoir used as source and sink water supplied theintensive ponds with higher organic loadingthan clear source waters, and its phytoplanktoncontent affected nitrogen cycling within theintensive ponds. The systems with a reservoirhad better water quality in the intensive pondsthan those with only clean source water. Within the ponds (1) compared to paddle-wheelaeration, aeration by pure oxygen increasedoxygen concentration, improved nitrificationand promoted decomposition that reduced organicloading. (2) In concrete ponds accumulation oforganic matter and development of anerobicconditions on the pond bottom was higher thanin the slippery plastic-covered ponds. (3) Allintensive ponds provided good growthconditions, tilapia biomass having relativelysmall influence on water quality. Only inpaddle-wheel aerated ponds did increased tilapiabiomass increased inorganic nitrogen compoundsand soluble phosphorus through excretion, andreduce organic nitrogen through a moreefficient removal of food particles. Water leaving the ponds removes matteraffecting water quality within the pond. (1)Draining sediments accumulated on the bottomavoided development of anaerobic conditionswhere denitrification and phosphorus liberationcan occur. (2) Water exchange removed particleswith nitrifying bacteria and algae that absorbnutrients. A high water exchange rate may havea negative effect from the water quality pointof view and from the extra costs incurred inenergy and feeds washed out. The processes described occur simultaneouslythroughout the culture period and shape waterquality dynamics in the ponds. This researchcontributed to the understanding of howmanagement procedures affect the differentphases of water quality dynamics in real-scaletilapia commercial intensive systems.  相似文献   

9.
Commercial intensive aquaculture systems werebuilt and are managed in a somewhat differentway in each farm. To evaluate the effects ofseveral management procedures on water qualityin intensive fish ponds, data from severallocations, times and culture conditions indifferent farms were collected and are hereinanalyzed through multivariate statistics.Water quality in the intensive ponds depends onthe water entering, the biological processeswithin, and the water leaving the ponds. Areservoir used as source and sink water supplied theintensive ponds with higher organic loadingthan clear source waters, and its phytoplanktoncontent affected nitrogen cycling within theintensive ponds. The systems with a reservoirhad better water quality in the intensive pondsthan those with only clean source water.Within the ponds (1) compared to paddle-wheelaeration, aeration by pure oxygen increasedoxygen concentration, improved nitrificationand promoted decomposition that reduced organicloading. (2) In concrete ponds accumulation oforganic matter and development of anerobicconditions on the pond bottom was higher thanin the slippery plastic-covered ponds. (3) Allintensive ponds provided good growthconditions, tilapia biomass having relativelysmall influence on water quality. Only inpaddle-wheel aerated ponds did increased tilapiabiomass increased inorganic nitrogen compoundsand soluble phosphorus through excretion, andreduce organic nitrogen through a moreefficient removal of food particles.Water leaving the ponds removes matteraffecting water quality within the pond. (1)Draining sediments accumulated on the bottomavoided development of anaerobic conditionswhere denitrification and phosphorus liberationcan occur. (2) Water exchange removed particleswith nitrifying bacteria and algae that absorbnutrients. A high water exchange rate may havea negative effect from the water quality pointof view and from the extra costs incurred inenergy and feeds washed out.The processes described occur simultaneouslythroughout the culture period and shape waterquality dynamics in the ponds. This researchcontributed to the understanding of howmanagement procedures affect the differentphases of water quality dynamics in real-scaletilapia commercial intensive systems.  相似文献   

10.
  • 1. Macroalgae are one of the biological parameters considered in the European Water Framework Directive (WFD) for establishing the ecological status of coastal water bodies. In order to test the metric used to assess this element in the Cantabrian coast, the quality of rocky bottoms (CFR) index was applied to 164 transects at 28 sites on the coast of Asturias (northern Spain) in the summers of 2007 and 2008.
  • 2. At each sampling point, three variables were measured: species richness, cover of characteristic and opportunistic macroalgae, and in 2008 the percentage of the area occupied by each characteristic species was also estimated.
  • 3. Application of the Shapiro–Wilk test to the variables ‘cover of characteristic macroalgae’ and ‘cover of opportunistic algae’ revealed that the data were not normally distributed (P<0.001). A Kolmogorov–Smirnov test revealed: (a) significant differences (P<0.01) between the exposed and semi‐exposed sites, for the three variables studied; (b) significant differences in cover, for six species depending on the type of exposure; and (c) significant differences (P<0.01) in opportunistic macroalgal cover in relation to the two subtypes of water bodies in the study area. However, no significant differences were observed for overall macroalgal cover or species richness.
  • 4. According to the results obtained, new reference conditions and class boundaries are proposed for the implementation of the CFR index in Asturian coastal waters. The ranges proposed for the CFR index in the present study provide better discrimination for evaluating the ecological status of the studied area.
  • 5. The results of SIMPER and MDS analyses reinforced the conclusion that the type of exposure and the degree of human impact are the factors that best explain the degree of similarity between the sites sampled. Copyright © 2010 John Wiley & Sons, Ltd.
  相似文献   

11.
Blooms of toxic dinoflagellates of the genus Ostreopsis, which is known as a producer of palytoxin (PTX) analogs, may pose a threat to human health in tropical, subtropical, and temperate regions around the world. In the present study, we established a suitable culture method for Ostreopsis spp. isolated from Japanese coastal waters and characterized their growth potential using the method to discuss their bloom dynamics. Each clonal strain of Ostreopsis cf. ovata, Ostreopsis sp.?1, Ostreopsis sp.?5, and Ostreopsis sp.?6 was incubated in 25?×?150?mm test tubes with a flat bottom containing various kinds of medium. Since Ostreopsis spp. strains grew well in IMK and/or f/2 media, we selected these media for cultivation of all the Ostreopsis spp. isolates. Growth rates of O. cf. ovata (0.834?divisions/day), Ostreopsis sp.?1 (0.619?divisions/day), and Ostreopsis sp.?6 (1.04?divisions/day) that produce PTX analogs significantly differed (p?<?0.05) respectively and are clearly higher than those of other reported epiphytic dinoflagellate Gambierdiscus toxicus, Prorocentrum lima, and Coolia monotis cultures, which suggest that these species have ecological advantages to predominate through the algal succession in Japanese coastal waters, resulting in a potential risk to human health in this region.  相似文献   

12.
Biofouling is a significant operational problem for the aquaculture industry globally; however, options for on‐farm management are limited. In New Zealand, the green‐lipped mussel, Perna canaliculus, has historically been cultivated at inshore locations, but increased competition for space has led the industry to develop offshore farming sites several kilometers from the coast. We hypothesize that the distance to these farm sites from coastal locations, and their placement over extensive soft‐sediment habitats, may provide a barrier to colonization by biofouling species with limited natural dispersal abilities. A study of two offshore mussel farms revealed that they supported relatively impoverished biofouling communities by comparison with inshore mussel farms and other artificial structures. Offshore sites had a relatively low number of taxa and a low prevalence of short‐dispersing organisms such as ascidians, which are a problematic group of fouling organisms in aquaculture. We suggest that newly established offshore marine farms have the potential to be kept free of a range of problematic fouling organisms, provided the introduction of such species via human transport pathways can be mitigated.  相似文献   

13.
Intensive and semi-intensive sea cucumber aquaculture produces effluents that impact the quality of the local aquatic environment and sea cucumber growth; such effluents are an important cause of coastal water eutrophication. Integrated aquaculture has been shown to efficiently reduce the release of nutrients during aquaculture and to provide economic benefits. In this study, we report our investigation of a polyculture system utilizing Styela clava (stalked sea squirt) and Stichopus japonicus (Japanese sea cucumber) under two feeding modes. To examine purification of the water in the system, nutrients in the water and the sediment, attached heterotrophic bacteria, and the survival rates and growth rates of S. clava and S. japonicus were determined. Tank cultivation trials showed that, under the same feeding modes, the concentration of nutrients in the polyculture system was approximately 50–60 % of the sum of the nutrients in the S. japonicus mixture and S. clava monoculture systems. The abundance of attached heterotrophic bacteria in the polyculture system was remarkably lower than that of the mixed culture system under the same feeding mode. S. japonicus in the polyculture system grew better than those in the mixed culture system under the same feeding mode. These results demonstrate that the S. clavaS. japonicus integrated culture system offers a means of constraining or reversing the pollutive impacts of coastal sea cucumber aquaculture.  相似文献   

14.
The impact of shellfish farming on the water column nutrient concentration and the benthic community structure was investigated seasonally at a mussel farm (Mytilus galloprovincialis L.) of Maliakos Gulf (Eastern Mediterranean). In most cases concentration of nutrients and chl a at the farm site was lower than those observed at the control sites. Statistical analysis in concentration of all nutrients and chl a indicated significant interactions between sites and seasons, which in all cases were temporal. Furthermore, no significant interactions were found between sites and seasons for all sediment and benthic community parameters, except for Shannon–Wiener diversity index and species richness. The significant interactions detected in the biotic data were temporal. Analysis of similarity and similarity percentages analysis revealed a certain fluctuation of benthic macrofaunal community during the overall sampling year mainly due to temporal rather than spatial effects. Cluster analysis and multidimensional scaling ordination plot indicated the clearly separation of the farm site and the control sites in most of the seasons. K-dominance curves showed small difference in elevation and overlap indicating minimal difference in biological stress between the farm site and the control sites. All the above indicates that probably the farming of mussels was beneficial for the trophic status of Maliakos Gulf and that there was a minimal environmental stress caused by the shellfish farming for the surrounding benthic environment.  相似文献   

15.
ABSTRACT

Most marine aquaculture activities remain strongly dependent on coastal ecosystems. In the case of shellfish farming, this dependency is related mainly to water quality and to the various ecological interactions resulting from the dynamics of coastal food webs. Such ecological constraints have influenced the overall evolution of blue mussel farming in the Mont-Saint-Michel Bay, leading producers to negotiate collective arrangements regarding production capacity and techniques and to develop production strategies at the farm level. This article presents an analysis of the location choices of mussel farmers in the Mont-Saint-Michel Bay based on an empirical investigation conducted in 2002. A typology of farms with respect to their land structure is developed in which some farms choose to concentrate their activity in a single part of the bay while others distribute their activity more widely. Determinants of the location choices of each farm category, including distance to port, natural productivity differentials, and predation of mussel stocks, are analyzed. The role of the institutional arrangements allowing mussel farmers to develop these location strategies is also discussed.  相似文献   

16.
This study analyzed water and soil quality and environmental impacts of shrimp farming in the southwestern coastal region of Bangladesh. Shrimp farming in the region is very traditional in nature where two culture systems viz. shrimp–rice and shrimp-only are being practiced, which are characterized by lower production, repeated stocking, irregular feeding, and fertilizing. Water quality in both farming systems was found suitable for optimum growth and survival of shrimp (Penaeus spp.). The level of 5-day biological oxygen demand (BOD5) in both systems even in canal water was within the recommended level provided by the Government of Bangladesh which is less than 5 mg/l. Therefore, effluents of shrimp farms in the study area did not show any nutrient pollution on the surrounding environment. However, saltwater intrusion has caused many problems like loss of agricultural production, reduced availability of fodder for livestock, and fresh water for domestic uses in the coastal region. The findings of this study confirmed that shrimp farming using saline water have long-term effect of soil salinization. As a result, it poses a real threat toward sustainability of coastal shrimp farming as well as coastal development in Bangladesh.  相似文献   

17.
多维视角下的新时代水产养殖业发展   总被引:1,自引:1,他引:0  
董双林 《水产学报》2019,43(1):105-115
由于经济因素的驱动,我国水产养殖规模和集约化水平在快速扩大和提高,同时,土地、淡水和鱼粉等资源制约日趋明显,氮磷排放、碳足迹、生态足迹在迅速增大,因此,我国水产养殖业需要生态集约化发展。从多维和可持续发展的视角可以推知,内陆大水域未来仅适于发展不投饲的养殖种类或称净水渔业,近岸(10 m以浅、距岸2 km以内或有遮蔽的海域)可发展不投饵的贝、藻养殖和增殖,离岸(距岸2 km以外、水深10~50 m)应增殖、养殖并举,深远海养殖(50 m以深、高海况开放海域和12 n mile以外的专属经济区海域)大有可为,陆基池塘生态集约化改造和陆基循环水养殖的阳光工厂化改造任重道远。  相似文献   

18.
  1. During this study, the effects of epiphytic filamentous algae on the survival of demersal spawned fish eggs were investigated in one of the most important spawning grounds of herring in the western Baltic Sea, which is subject to intense and ongoing eutrophication.
  2. In coastal marine ecosystems all over the world, eutrophication is a primary water quality issue, often resulting in mass developments of bloom‐forming algae. Macro‐algal blooms have immense ecological effects, as they alter the structure and the function of an ecosystem. Numerous fish species are affected, as they depend on those coastal areas for spawning and as juvenile habitats.
  3. A comparison of the survival of herring eggs on two natural spawning beds re‐vealed an immense impact of a filamentous algal bloom. The mortality rate reached nearly 100% in the area with massive occurrence of filamentous brown algae.
  4. Hypothesizing that the presence of filamentous algae facilitates herring egg mortality, field and laboratory experiments were conducted and revealed particular effects of distinct algal species. The survival rate of artificially spawned eggs on algal substrates and control substrates was compared. Whereas filamentous forms of the green alga Ulva intestinalis induced no immediate effect, significantly higher egg mortality was documented in experiments with the filamentous brown alga Pylaiella littoralis.
  5. Considering the ecological and economical importance of herring and other coastal spawners on the one hand and the persisting and increasing effects of eutrophication and climate change on the other hand, the results of our study clearly underpin the necessity to increase global efforts to reduce nutrient loads in coastal waters.
  相似文献   

19.
Large‐scale artificial upwelling was tested as a method to enhance the environmental conditions for the growth of non‐toxic algae in a Norwegian fjord (61°0′N, 6°22′E). The experiment was designed to evaluate if nutrient‐rich seawater, brought up from below the mixed zone of a stratified fjord to the euphotic zone by air bubbling, would stimulate the growth of non‐toxic relative to toxic algae. Pumping 44 m3 min?1 of air at 1 atm through a pipe diffuser submerged at 40 m depth formed a buoyancy flux that lifted 60 m3 s?1 of deep water to the upper 17 m over a period of 21 days. The supply of silicate, inorganic nitrogen and phosphate to the upper 10 m in the fjord increased, and a significant increase in the biomass of non‐toxic algae was observed. The upwelling gave an increased growth of the non‐toxic dinoflagell ates Ceratium furca and C. tripos. After termination of the experiment, the phytoplankton biomass decreased significantly, whereas a distinct increase occurred in the relative biomass of the potentially toxic Dinophysis spp. The result is considered promising when it comes to creating controlled geographical areas with non‐toxic food for mussel production.  相似文献   

20.
印度尼西亚渔业发展概况   总被引:1,自引:0,他引:1  
印度尼西亚海域辽阔,渔业资源丰富,具有极大的发展潜力。本文在查阅近年来国内外相关文献基础上,着重介绍了印尼的渔业资源状况、管理方式、产品加工和国际合作等。印度尼西亚主要渔业类型为海洋捕捞和水产养殖业,其中金枪鱼渔业是最主要的捕捞业。近年来,水产养殖(如虾类、海藻等)逐渐成为印尼渔业的主要支柱;印尼渔业管理的主要部门为海洋事务与渔业部,地方各级渔业行政机构和渔业协会组织共同参与管理;印尼政府鼓励国外投资渔业,并大力促进海外渔业合作。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号