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1.
Samples of Atlantic salmon (Salmo salar), saithe (Pollacius virens), blue mussel (Mytilus edulis), brown seaweed (Ascophyllum nodosum) and sediment were collected from six different fish farms. Five of the farms used net pens treated with copper-containing coatings, whereas one farm did not use copper-containing coating (this was used as a reference location). Samples of muscle, liver and gills of Atlantic salmon and saithe, blue mussel and brown seaweed were freeze dried, homogenised, wet digested and analysed for copper by flame atomic absorption spectrometry. The results showed no significant differences in copper concentrations among the samples from the different locations. The copper contents of some of the samples appeared to be in the upper part of the normal concentration range. From a nutritional point of view, the use of copper-coatings on net pens did not affect the quality of the seafood products either within, or around the net pen. 相似文献
2.
Sedimentation and sediment metabolism was measured at eight active milkfish fish pens and at one abandoned site in the Bolinao area, Philippines in order to examine the interactions between sediment and water in this shallow coastal zone. The rates of sedimentation were high in the area due to siltation, but the activities in the fish pens also contributed to enhanced sedimentation as indicated by the difference between the abandoned and active sites. The sediment metabolism appeared to decrease with increasing rates of sedimentation indicating that the microbial activity reached a saturation level in the fish pen sediments. Anaerobic processes dominated the organic matter decomposition, and sulfate reduction rates are among the highest measured in fish farm sediments. The rates decreased with increasing organic loading despite high concentrations of sulfate (>10 mM) at all sites. Presence of methane bubbles in the sediments suggests that sulfate reduction and methanogenesis were coexisting. The sediment metabolism was significantly reduced at the abandoned site indicating that the stimulation of microbial activities is due to active fish production. The anaerobic activity remained high at the abandoned site indicating that the sediment biogeochemical conditions remain affected long time after fish production has ceased. 相似文献
3.
Samples of Atlantic salmon (Salmo salar), saithe (Pollacius virens), blue mussel (Mytilus edulis), brown seaweed (Ascophyllum nodosum) and sediment were collected from six different fish farms. Five of the farms used net pens treated with copper-containing coatings, whereas one farm did not use copper-containing coating (this was used as a reference location). Samples of muscle, liver and gills of Atlantic salmon and saithe, blue mussel and brown seaweed were freeze dried, homogenised, wet digested and analysed for copper by flame atomic absorption spectrometry. The results showed no significant differences in copper concentrations among the samples from the different locations. The copper contents of some of the samples appeared to be in the upper part of the normal concentration range. From a nutritional point of view, the use of copper-coatings on net pens did not affect the quality of the seafood products either within, or around the net pen. 相似文献
4.
Environmental management of marine fish culture in Hong Kong 总被引：4，自引：0，他引：4
Marine fish farming is an important commercial practice in Hong Kong. Marine fish farms located in eutrophic coastal waters often face the threat of severe dissolved oxygen depletion associated with algal blooms and red tides. On the other hand, mariculture activities also contribute to pollution. The sustainable management of mariculture requires proper siting of the fish farms and stocking density control. Both of these are related to the carrying capacity of the water body concerned, which is mainly governed by its flushing characteristics. A simple method to determine the carrying capacity of a fish farm has been developed by using three-dimensional (3D) hydrodynamic modelling and its effective coupling with a diagenetic water quality model. A systematic methodology using numerical tracer experiments has been developed to compute the tidal flushing in a fish farm. The flushing time is determined from the results of a numerical tracer experiment using robust 3D hydrodynamic and mass transport models. A unit tracer concentration is initially prescribed inside the region of interest and zero elsewhere; the subsequent mass transport and the mass removal process are then tracked. The fish farms are usually situated in well-sheltered shallow embayments and may not connect directly to the open water. It is found that it is necessary to define both "local" and "system-wide" flushing times to represent the effectiveness of the mass exchange with the surrounding water body and the open sea respectively. A diagenetic water quality model simulating the sediment-water-pollutant interaction is employed to address the response of the water column and the benthic layer to pollution discharges. With the flushing rate reliably computed, the carrying capacity of the fish farm can be determined in terms of key water quality parameters: chlorophyll-a, dissolved oxygen, organic nitrogen and potential lowest dissolved oxygen level on a day of negligible photosynthetic production. The predictions are well-supported by field data. 相似文献
5.
Sediment oxygen consumption, TCO2 production and nutrient fluxes across the sediment-water interface were measured in sediments within and along a transect from four fish pens with production of milkfish (Chanos chanos) in the Bolinao area, The Philippines. The four fish pens were each representing a specific period in the production cycling. There was a positive linear relationship between the rates of sedimentation inside the fish pens and the sediment oxygen consumption indicating that the benthic processes were controlled by the input of organic matter from fish production. The nutrient fluxes were generally higher inside the fish pens, and nitrate was taken up (1.7-5.8 mmol m(-2) d(-1)) whereas ammonium (1-22 mmol m(-2) d(-1)) and phosphate (0.2-4.7 mmol m(-2) d(-1)) were released from the sediments. The sediments were enriched in organic matter with up to a factor 4 compared to outside. A mass balance for one crop of milkfish was constructed based on production data and on measured fluxes of nutrients in the fish pens to assess the loss of carbon and nutrients to the environment. There was a loss to the surroundings of carbon and nitrogen of 51-68% of the total input, whereas phosphorus was buried in the sediments inside the fish pens which acted as net sinks of phosphorus. The results obtained suggest that fish pen culture as practiced in the Bolinao area, leads to even greater impacts on benthic carbon and nutrient cycling than those found in suspended cage cultures. 相似文献
6.
Xiaoyan Li Hongwei Lu Li He Bin Shi 《Stochastic Environmental Research and Risk Assessment (SERRA)》2014,28(2):281-295
In this study, an inexact stochastic optimization model (ITSOM) is developed for agricultural irrigation management with a case study in China. Functional intervals are introduced into the modeling framework to much accurately address the spatial and temporal variation of system components. According to the results of case study, the developed model shows effectiveness in dealing with functional information of system parameters, and brings no difficulty in obtaining optimal water allocation patterns. It is indicated that the surface water resource (i.e. Heshui River) has better be used as the major source, and proper exploration of groundwater can curtail the related expense and further increase the system net benefit. Among eight farms, hybrid rice farm is going to obtain the greatest amount of water than the others, while watermelon farm has the priority to get water due to its highest benefit and penalty rate. In comparison, water allocations to rapeseed and tea farms are to be minimal within the respective fluctuation ranges. Scenario analysis is also conducted to clarify the differences between ITSOM and a conventional interval two-stage stochastic programming (ITSP) model. A total of 60 scenarios are initiated respectively linking to 60 monthly ITSP models for the entire planning horizon. The results show that the optimal objective function values of all ITSP models always fall into the range of that obtained from ITSOM. As each ITSP solution can only correspond to the system condition under a certain time point, it is highly vulnerable to system variation. 相似文献
7.
This field study aims to determine whether increased levels of organically enriched particulate matter released by net pen fish farms (Eilat, Red Sea) would affect the growth of nubbins taken from the branching coral Stylophora pistillata. We followed the survival and growth of 1322 nubbins pruned from five colonies that were transplanted at a depth of 6 m in the vicinity of the fish cages and in a reference site, in front of the Interuniversity Institute (IUI). Nubbins were attached on U-shaped PVC plates in three orientations (up, vertical and down positions). After 50 days, survival was high in both localities and no difference was recorded between the spatial orientations. At the fish farm, however, burial of the nubbin's lateral growths and partial coverage of nubbins by settled particulate matter resulted in significant reduction of the lateral growth rates of nubbins settled in the up position as compared to the reference site. On the other hand, faster growth rates were recorded in the vertical set of nubbins at the fish farm when compared with the IUI site. These results strengthen the conclusion that physical effects, rather than nutrient enrichment, may constitute the main cause of stress for minute coral fragments (resembling coral recruits) growing near the vicinity of a fish farm. 相似文献
8.
W. Steffens Th. Mattheis M. Riedel 《Aquatic Sciences - Research Across Boundaries》1993,55(3):173-178
Effluents from brown coal mines are frequently rich in iron, the water being red-brown in colour and turbid. For several years a fish farm in the Lusatia (Brandenburg, Germany) has used such mine effluents for rearing rainbow trout. The total iron content of this water varies between 5 and 10 mg/l with pH ranging from 6.7 to 7.4. Water turbidity is high with a transparency of 10 to 40 cm at the most due to the substantial ferric hydroxide concentrations. Until 1989 trout have been reared in net cages within concrete settling basins destined for settling the ferric hydroxide mud. The cages were stocked with fingerlings in autumn, reaching portion size in the spring of the following year. Specific growth rate was 0.98% per day, comparable to that of trout in another farm unpolluted by iron but stocked at higher densities. The results show that fingerling rainbow trout may live in water containing more than 5 mg/l total iron but in the absence of Fe2+. These concentrations of water-borne iron seem to have only a limited detrimental effect on fish growth and feed conversion and do not prevent trout culture in principle. 相似文献
9.
Rivers, lakes, and coastal waters are chaotic systems — physical, chemical, and biological parameters influence their development. Each parameter itself is influenced by the system. Human interaction has led to fast eutrophication. Oxygen input and artificial mixing have been considered as tools to overcome the biggest problems of fish kills, algal blooms, and bad odour. The favoured technology for destratification and oxygen input so far is the bubble curtain. This technology has been applied successfully in several cases. But often, this technology could not be implemented because of high investment and operating costs.
Alternatively, the free jet is discussed as an efficient and low investment and operating cost technology. The free jet may transport oxygen-rich water from the surface down into the hypolimnion, thereby destratifying a water system. A free jet entrains on its way down even more oxygen rich and warm epilimnic water. This water will finally — if some mixing with the cold hypolimnic water occurs — be transferred to the metalimnion. The density differences will make this water travel long distances.
The energy input may be very low and the objective must not be to totally overturn a system. A jet started in early spring may help a lake to have a deep enough epilimnion, relatively large in volume in respect to the hypolimnion, and the normal wind will recirculate the water transferring enough oxygen to the deeper part, thus expanding the fish habitat and enabling benthic fauna. Literature also shows that the occurrence of massive algal blooms may be reduced.
The oxygen efficiency can be multifold compared to standard technologies. 相似文献
10.
Survivorship of coral juveniles in a fish farm environment 总被引：1，自引：0，他引：1
Intensive fish farming is an emerging coastal activity that can potentially enhance sedimentation and promote eutrophication in fringing coral reefs. Here, we investigate the effect of fish farm effluent on the juvenile survivorship of the reef-building coral Seriatopora caliendrum. One-month old juvenile corals (on terracotta tiles) were deployed in fish farm and reference (reef) sites in Bolinao, the Philippines at a depth of 2m. After forty days, no survivor was recovered in the fish farm, while survivorship was low (11%) in the reference site, with the survivors' growth rate at 3.3polypsmo(-1) or 1.3mm(2)mo(-1). The fish farm deployed tiles were covered with muddy sediment and were colonized by barnacles, whereas those in the reference site were overgrown by a short stand of filamentous macroalgae. Environmental monitoring revealed higher nutrient levels (ammonia and phosphate), sedimentation rate, and organic matter flux, as well as diminished water transparency and dissolved oxygen levels in the fish farm compared to the reference site. Hence, intensive fish farming offers a suite of physical, chemical and biological modifications of the coastal marine environment which have a detrimental effect on the survivorship of coral juveniles. 相似文献
11.
长期以来,我国的氡观测一直以模拟水氡观测为主。模拟水氡观测是地震监测预报中前兆观测的重要测项,一直采用定时取样、鼓泡、测值计算及数据入库等一系列人工观测手段。其观测方法落后,且带有较大程度的人为操作误差,使观测数据的质量受到一定程度的影响。“鼓泡”是模拟水氡观测过程的关键环节,鼓泡操作是否规范直接影响水氡测值的准确性。通过对传统模拟水氡鼓泡装置进行改造,研制出一套适用于所有模拟水氡仪器的自动鼓泡装置,解决传统人工鼓泡过程中鼓泡时间与鼓泡速率不规范对水氡测值产生较大干扰的问题。自动鼓泡装置可降低鼓泡操作难度,减少人为操作误差,提高水氡观测资料质量。 相似文献
12.
A. David McKinnon Rebecca A. O’Leary Daniel M. Alongi 《Marine pollution bulletin》2010,60(9):1489-1501
The fate of aquaculture wastes from a seacage farm within a pristine mangrove environment was studied. Seasonal and tidal differences were most important in determining water quality within receiving waters and obscured any nutrient enrichment effect by the farm. Farm wastes added significantly to the N budget status of the creek system, but overall water quality conformed to Queensland EPA Water Quality standards. Mangrove trees throughout the creek system contained 15N signatures traceable to aquaculture feeds, but the footprint of the farm itself was best indicated by the ratio of Zn:Li in sediments. The creek became hypoxic (<2 mg l−1) during wet season low tides. Consequently, we recommended monitoring of water-column oxygen concentrations to warn of hypoxic conditions threatening to fish health, as well as Zn:Li ratios in sediment accumulation zones to determine the area of influence of the farm. 相似文献
13.
San Diego-McGlone ML Azanza RV Villanoy CL Jacinto GS 《Marine pollution bulletin》2008,57(6-12):295-301
The coastal waters of Bolinao, Pangasinan, Philippines experienced environmental changes over a 10-year period (1995-2005), the most significant effect of which was the major fish kill event in 2002 that coincided with the first reported Philippine bloom of a dinoflagellate Prorocentrum minimum. Days before the bloom, dissolved oxygen was < 2.0 mg/l in the waters that were stratified. These conditions may be linked to the uncontrolled proliferation of fish pens and cages to more than double the allowable limit of 544 units for Bolinao waters. Mariculture activities release organic matter from unconsumed feed and fecal material that accumulate in the water and sediments. In over 10 years, water quality conditions have become eutrophic with ammonia increasing by 56%, nitrite by 35%, nitrate by 90%, and phosphate by 67%. The addition of more fish pens and cages placed additional stress to this poorly flushed, shallow area that affected water quality due to changes in the water residence time. 相似文献
14.
《Marine pollution bulletin》2009,58(6-12):295-301
The coastal waters of Bolinao, Pangasinan, Philippines experienced environmental changes over a 10-year period (1995–2005), the most significant effect of which was the major fish kill event in 2002 that coincided with the first reported Philippine bloom of a dinoflagellate Prorocentrum minimum. Days before the bloom, dissolved oxygen was <2.0 mg/l in the waters that were stratified. These conditions may be linked to the uncontrolled proliferation of fish pens and cages to more than double the allowable limit of 544 units for Bolinao waters. Mariculture activities release organic matter from unconsumed feed and fecal material that accumulate in the water and sediments. In over 10 years, water quality conditions have become eutrophic with ammonia increasing by 56%, nitrite by 35%, nitrate by 90%, and phosphate by 67%. The addition of more fish pens and cages placed additional stress to this poorly flushed, shallow area that affected water quality due to changes in the water residence time. 相似文献
15.
An integrated multi-trophic aquaculture assessment for Pacific oyster (Crassostrea gigas) aquaculture as a bioremediation strategy in areas impacted by fish farm effluents in Rio San Pedro was assessed by combining geographic information system with carrying capacity models. Sites of 0.44 km(2) were evaluated considering constraints; physical factors, growth and survival factors, environmental quality factors, water and sediment quality criteria, factor suitability ranges, and Multi-Criteria Evaluation. Isleta and Flamenco are promising sites for oyster production, and Dorada is of marginal interest. Carbon and nitrogen removal from the water by algae and through detritus filtration was estimated. The biodeposition of organic material from longline leases was found to have little negative impact on sediment. The eutrophication results indicate that phytoplankton removal had a positive impact on water quality at the Dorada. This case study quantified the direct profitability and bioremediative environmental service advantages that fish-shellfish farms can have relative to fish monocultures. 相似文献
16.
The community composition and production of phytoplankton in fish pens of Cape Bolinao, Pangasinan: a field study 总被引：1，自引：0，他引：1
From 1995 up to the present, fish pens proliferated in the municipal waters of Bolinao, northern Philippines. Since then, fish kills and phytoplankton blooms have been recurrent. Have fishpens altered the phytoplankton community composition and production of these waters? The phytoplankton community in Cape Bolinao, Lingayen Gulf is typical of a tropical coastal area where diatoms alternate with dinoflagellates during the dry and wet seasons. In the nutrient-rich fish pens, phytoplankton in this study showed a lower diatom/dinoflagellate ratio and unusually high phytoplankton counts of 10(4) cells/l and even as high as 10(5) cells/l. Correlations between physico-chemical parameters, phytoplankton production and community composition were made in 2001. This paper tried to explain the occurrence of a Cylindrotheca closterium bloom (10(5) cells/l), during the dry season of the same year and a Prorocentrum minimum bloom (4.7 x 10(5) cells/l), which accompanied a massive fish kill during January 2002. 相似文献
17.
Yao Ji Guohe Huang Wei Sun Yanfeng Li 《Stochastic Environmental Research and Risk Assessment (SERRA)》2016,30(2):621-633
Water quality management is a significant item in the sustainable development of wetland system, since the environmental influences from the economic development are becoming more and more obvious. In this study, an inexact left-hand-side chance-constrained fuzzy multi-objective programming (ILCFMOP) approach was proposed and applied to water quality management in a wetland system to analyze the tradeoffs among multiple objectives of total net benefit, water quality, water resource utilization and water treatment cost. The ILCFMOP integrates interval programming, left-hand-side chance-constrained programming, and fuzzy multi-objective programming within an optimization framework. It can both handle multiple objectives and quantify multiple uncertainties, including fuzziness (aspiration level of objectives), randomness (pollutant release limitation), and interval parameters (e.g. water resources, and wastewater treatment costs). A representative water pollution control case study in a wetland system is employed for demonstration. The optimal schemes were analyzed under scenarios at different probabilities (p i , denotes the admissible probability of violating the constraint i). The optimal solutions indicated that, most of the objectives would decrease with increasing probability levels from scenarios 1 to 3, since a higher constraint satisfaction probability would lead to stricter decision scopes. This study is the first application of the ILCFMOP model to water quality management in a wetland system, which indicates that it is applicable to other environmental problems under uncertainties. 相似文献
18.
Environmental fate of fish farm wastes (FFW) released from an open-sea-cage farm at Kat O, Hong Kong was examined by measuring carbon and nitrogen stable isotope (SI) ratios in selected benthic organisms collected along a 2000 m transect from the farm. Our results showed that FFW significantly influenced the energy utilization profile of consumers near the fish farm. Although nitrogen enrichment effect on δ15N was anticipated in biota near the farm, the predicted patterns did not consistently occur in all feeding guilds. Two species of suspension-feeders, which relied on naturally δ15N-depleted sources, were δ15N-enriched near the fish farm. In contrast, both species of benthic grazer and deposit-feeder, which relied on naturally δ15N-enriched algal sources, were δ15N-depleted under the influence of FFW. The SI signatures of biota can, therefore, serve as feasible biomarkers for FFW discharges only when the trophic structure of the receiving environment is fully elucidated. 相似文献
19.
This study presents a factorial two-stage stochastic programming (FTSP) approach for supporting water resource management
under uncertainty. FTSP is developed through the integration of factorial analysis and two-stage stochastic programming (TSP)
methods into a general modeling framework. It can handle uncertainties expressed as probability distributions and interval
numbers. This approach has two advantages in comparison to conventional inexact TSP methods. Firstly, FTSP inherits merits
of conventional inexact two-stage optimization approaches. Secondly, it can provide detailed effects of uncertain parameters
and their interactions on the system performance. The developed FTSP method is applied to a hypothetical case study of water
resources systems analysis. The results indicate that significant factors and their interactions can be identified. They can
be further analyzed for generating water allocation decision alternatives in municipal, industrial and agricultural sectors.
Reasonable water allocation schemes can thus be formulated based on the resulting information of detailed effects from various
impact factors and their interactions. Consequently, maximized net system benefit can be achieved. 相似文献
20.
In agriculture, water is a fundamental but increasingly scarce resource that requires careful use. The goal of fostering water-savings could be achieved with a regulation that imposes more efficient irrigation systems. This might represent the only policy option when water withdrawals cannot be controlled and when the operational context does not allow filling the information asymmetry between policy makers and farmers with metering systems, quotas, or market rights. The regulation could involve higher costs for farmers. However, it could represent an opportunity to increase farm revenues if consumers are willing to pay a higher price for goods produced according to an ecological standard. Knowledge of the costs and possible benefits is relevant because it would enable us to understand the potential cost allocation among stakeholders according to how the policy is designed. The results of this study indicate that the management cost of a sustainable irrigation system could be at most 48% greater than that of a wasteful, traditional system. However, the higher costs of the regulation could be compensated for because consumers are willing to pay 6.8% more for less intensive water-use agricultural products. Therefore, a regulation associated with the promotion of hypothetical water-saving label can be the best strategy to irrigation efficiency in agriculture. 相似文献