Identification of Aquaculture-Derived Organic Matter in the Sediment Associated with Coastal Fish Farming by Stable Carbon and Nitrogen Isotopes

Abstract： Stable carbon and nitrogen isotope analysis was used to identify the aquaculture-derived organic matter in the sediment in and around a coastal fish farm in China. Results showed that mean δ13C value in fish farm area （within 1 O0 m from the edge of cages） and control area （500 m from the edge of cages） was -17.72±1.29/oo and -12.73± 0.380/00, respectively. Mean δ15N value of fish farm area and control area was 6.44 4±0.2%0 and 5.61 4±0.2%0, respectively. The sediment in the fish farm area was characterized by high waste food （47.70%） and faeces （27.71%） ratio, as the distance from the fish cages increased, aquaculture-derived organic matter decreased expontially （y = 97.167e-0.0074x, R2= 0.8481）. The spatial extent of waste dispersal extended to an area up to 400 m.

Logistic Regression Analysis on Factors Affecting Adoption of Rice-Fish Farming in North Iran

We evaluated the factors influencing the adoption of rice-fish farming in the Tavalesh region near the Caspian Sea in northern Iran. We conducted a survey with open-ended questions. Data were collected from 184 respondents （61 adopters and 123 non-adopters） randomly sampled from selected villages and analyzed using logistic regression and multi- response analysis. Family size, number of contacts with an extension agent, participation in extension-education activities, membership in social institutions and the presence of farm workers were the most important socio-economic factors for the adoption of rice-fish farming system. In addition, economic problems were the most common issue reported by adopters. Other issues such as lack of access to appropriate fish food, losses of fish, lack of access to high quality fish fingerlings and dehydration and poor water quality were also important to a number of farmers.

Enhanced Water Quality Control Based on Predictive Optimization for Smart Fish Farming

The requirement for high-quality seafood is a global challenge in today’s world due to climate change and natural resource limitations.Internet of Things(IoT)based Modern fish farming systems can significantly optimize seafood production by minimizing resource utilization and improving healthy fish production.This objective requires intensive monitoring,prediction,and control by optimizing leading factors that impact fish growth,including temperature,the potential of hydrogen(pH),water level,and feeding rate.This paper proposes the IoT based predictive optimization approach for efficient control and energy utilization in smart fish farming.The proposed fish farm control mechanism has a predictive optimization to deal with water quality control and efficient energy consumption problems.Fish farm indoor and outdoor values are applied to predict the water quality parameters,whereas a novel objective function is proposed to achieve an optimal fish growth environment based on predicted parameters.Fuzzy logic control is utilized to calculate control parameters for IoT actuators based on predictive optimal water quality parameters by minimizing energy consumption.To evaluate the efficiency of the proposed system,the overall approach has been deployed to the fish tank as a case study,and a number of experiments have been carried out.The results show that the predictive optimization module allowed the water quality parameters to be maintained at the optimal level with nearly 30%of energy efficiency at the maximum actuator control rate compared with other control levels.

Characteristics, Constraints and Perspectives of the Fish Farming in Burundi

The fish farming was introduced in Burundi in about 1950s. Actually, several fish ponds were abandoned and many others were still unproductive. This study aims to present current state and perspectives of the fish farming for its real contribution to the socio-economic development. The results presented are compilation of physical and chemical parameters series measured in fish ponds and inquiries led in 2010-2014 to the fish farmers in seven provinces （40% of the total area of the country）. Weak values of some physical and chemical parameters showed that the majority of ponds are badly maintained. Thus, the dissolved oxygen values varied between 0.2 mg/L and 3.5 mg/L. The high relinquishment rate of the fish fanning （between 40% and 67% according to the provinces） could be explained by many constraints： no centers of fish farming breeding for various fish species and no production center of complete foods with local sub-products. About 75% of fish famers confirmed that they have never benefited framing in fish fanning. In spite of the diverse constraints, Burundi has a dense rivers system with favorable physical and chemical parameters and many appropriate sites for the fish farming. Thus, the main suggestions concern the sector reorganization.

Integration of Fish and Poultry Farming into Cropping Systems to Improve Production Yields

This study aims to evaluate and compare the fertilizing effects of fish-breeding water and river water combined or not with composted poultry manure on the growth and production of okra and lettuce crops. Thus, a sample of 2000 Nile tilapia Oreochromis niloticus fry and a sample of 100 Cobb 500 strain chicks were reared and monitored for six months and fifteen days. Poultry manure and fish-breeding water were then collected and used to fertilize and water okra and lettuce crops. Two systems were used for the crops (okra and lettuce) tested in an elementary plot design with replicates for each treatment (T1: fish-breeding water alone;T2: river water alone;T3: fish-breeding water combined with manure;T4: river water combined with manure). Morphometric parameters and phenological traits of okra and lettuce crops as well as the total harvest weight and production yield were evaluated and compared between treatments. The results reveal better growth and higher yields (0.67 kg/m2 vs. 0.45 kg/m2) of okra crops that received treatment T1 compared to T2. The best growth and yields of lettuce were obtained with treatments T3 (3.34 kg/m2) and T1 (1.89 kg/m2) compared to T4 (1.23 kg/m2) and T2 (1.20 kg/m2). These results show that fish-breeding water combined with poultry manure can boost okra and lettuce production and would be a real asset to stimulate local agricultural development. Thus, the adoption of such an agro-ecological approach integrating fish farming and animal husbandry could increase local production and provide food of good nutritional quality.

The Influence of Land Use and Fish Farming on the Contents of Ca²⁺, Mg²⁺, K⁺and Na⁺in Pond and Reservoir Ecosystems in an Agricultural Small Watershed, China

It is not understood well that how the effects of land use and fish farming on the contents of alkali metals (Ca2+, Mg2+, K+ and Na+) in small water bodies of pond and reservoir ecosystems at the watershed scale. In this study, the concentrations of Ca2+, Mg2+, K+ and Na+ in water bodies were measured for 103 ponds and reservoirs used as fish farming or surrounded by different agricultural land use types in the subtropical hilly watershed of Jinjing (105 km2), China. The two important environmental factors of fishing farming and agricultural land use influenced the spatial variation the contents of alkali metals. The ponds and reservoirs in residential area had significantly higher concentrations of Ca2+ and Na+ than those with other land use types, reflecting the influence of domestic wastewater. Compared with those of natural ponds with non-fish farming, no significant increase of alkali metal contents occurred in fish farming ponds, due to the regular cleaning of ponds by farmers. However, the effect of fish culture on alkali metal contents was still supported indirectly by the fact that the alkali metal contents significantly correlated with nitrate contents in fish farming ponds and but high related with that of DIP in natural ponds. The suitability assessment for irrigation on the pond water indicated that almost all of ponds were suitable for irrigation except some ponds surrounded by residential area and tea plantation. Generally, our results demonstrated that fish farming and agricultural land use affected the contents of alkali metals in ponds and reservoirs. The agricultural water irrigation would be with caution from the ponds with tea plantation and residential area in the subtropical hilly watershed.

Fish Farming Boost

AFRICAN fish farmers are benefiting from improved livelihoods and a better food security status, thanks to the introduction of two strains of improved Nile tilapia in Egypt and Ghana. This follows 10 years of breeding research, culminating in the introduction of the Abbasa strain of the Nile tilapia （Oreochroml：s nlToticus） in Egypt. The species is indigenous to much of Africa. It grows 28 percent faster than most of the common varieties in Egypt, such as the Kafr El Shaikh strain. The second new tilapia Akosombo strain,

Wave and Current Effects on Floating Fish Farms

The paper is partly a review on hydrodynamic and structural aspects of fish farms. In addition, new numerical results are presented on the stochastic behavior of bending stresses in the floater of a realistic net cage in extreme wave conditions. The behavior of traditional-type fish farms with net cages and closed fish farms in waves and currents is discussed. Hydroelasticity can play a significant role for net cages and closed membrane-type fish farms. The many meshes in a net cage make CFD and complete structural modeling impracticable. As an example, a hydrodynamic screen model and structural truss elements are instead used to represent the hydrodynamic loading and the structural deformation of the net. In addition, the wake inside the net due to current plays an important role. The described simplified numerical method has been validated by comparing with model tests of mooring loads on a single net cage with two circular elastic floaters and bottom weight ring in waves and currents. It is discussed which parts of the complete system play the most important roles in accurately determining the mooring loads. Many realizations of a sea state are needed to obtain reliable estimates of extreme values in a stochastic sea. In reality, many net cages operate in close vicinity, which raises questions about spatial variations of the current and wave environment as well as hydrodynamic interaction between the net cages. Live fish touching the netting can have a non-negligible influence on the mooring loads. It is demonstrated by numerical calculations in waves and currents that a well boat at a net cage can have a significant influence on the mooring loads and the bending stresses in the floater. The latter results provide a rational way to obtain operational limits for a well boat at a fish farm. Sloshing has to be accounted for in describing the behavior of a closed fish farm when important wave frequencies are in the vicinity of natural sloshing frequencies. The structural flexibility has to be considered in determining the natural sloshing frequencies for a membrane-type closed fish farm. Free-surface non-linearities can matter for sloshing and can, for instance,result in swirling in a certain frequency domain for a closed cage with a vertical symmetry axis.

Sustainable Mangement of Drainage Water of Fish Farms in Agriculture as a New Source for Irrigation and Bio-Source for Fertilizing

Two field experiments were carried out during growing seasons 2011 and 2012. It was executed in research farm of National Research Center in Nubaryia region, Egypt to study the effect of irrigation systems, fertigation rates by using the wastewater of fish farms “WWFF” in irrigation of potato. Study factors were irrigation systems (sprinkler irrigation system “SIS” and trickle irrigation system “TIS”), water quality (traditional irrigation water “TIW” and WWFF) and fertigation rates “FR” (20%, 40%, 60%, 80% and 100% NPK). The following parameters were studied to evaluate the effect of study factors: 1) Calculating the total amount of WWFF per season;2) Chemical and biological description of WWFF;3) Clogging ratio of emitters;4) Yield of potato;5) Irrigation water use efficiency of potato “IWUEpotato”. Statistical analysis indicated that, maximum values were obtained of yield under SIS × FR100% NPK × WWFF, also, there were no significant differences for yield values under the following conditions: SIS × FR100% NPK × WWFF > SIS × FR80% NPK × WWFF > SIS × FR60% NPK × WWFF > TIS × FR100% NPK × TIW. This means that, using WWFF in the irrigation can save at least 40% from mineral fertilizers and 100% from irrigation water under sprinkler irrigation system.

Effect of Socio-Economic Variables on Fish Production of Small Farmers in Tocantins State, Brazil

Fish farming is a strategic activity for both the economy and food security of the Tocantins state. Nowadays, there are about eighty small fish farmers in the region of Divin6polis in Tocantins state. The technological level of fish farmers is low and it was found that only 30% of farmers could ever get to the point of selling fish. Therefore, the objective of this paper is to investigate which socioeconomic factors have influence on the fact of fish farmers in the region of Divin6polis and in Tocantins state reach a level of efficiency in production enough that the fish can be good for sale in the local market. To estimate this relation the logit model was chosen, with methodology based on the empirical model used in Musaba and Namukwambi. Following the production of fish farms in the Western of Tocantins state, the collect of the data, during 2012, were conduct with interviews of 30 fish farms, visiting them in their homes and applying a questionnaire. Through the use of econometric models of probability for limited dependent variables, it was found that factors such as participation in federal programs to transfer income, total area of water and production in ponds are key factors in determining the likelihood of producer to sell fish.

AQUAM——A Decision Support Software for Fish Farm Management

farm is presented.The software called AQUAM is dedicated to fresh water fish farms.Its aim is to make an efficient management of resources through planning,monitoring,analysis and decision support.Successful planning and management requires the integration of data related to ponds,fish species,fish growth,water and energy and economic analysis.AQUAM computes farm budgets relating various costs and returns in order to determine short and long term profitability.A simulation of the profit,as a function of the fish holding density,is performed with AQUAM.The data used in the simulation are from a fish farm of semi-intensive type,located in the region Danube Delta,at village Jurilovca,Tulcea county,Romania.The fish species that were taken into account were carp and sanger.

Problems and prospects of fish farming in the Chattogram Hill Tracts of Bangladesh:Community-based aquaculture might be a right choice

The study was carried out in Matiranga Upazila,Bandarban district,which is considered one of Bangladesh’s major hill tract regions.The study aimed to identify present farming conditions,prospects,and problems and suitable solutions to the problems of fish farming.Different participatory rapid appraisal tools such as focus group discussion,field visits,and farmers’interviews were used to collect relevant fish farming information in the study area.The polyculture method was the most practised aquaculture method.Among the selected farms,eleven fish species were identified as culture species.The transportation cost for seeds purchased from remote areas was high(11%of total seed cost).The average transportation-related mortality of fish fry and fingerlings was 7.2%and 2.8%.Feed cost was found as the major cost(58.4%)in aquaculture.Costs and revenue for fish production per decimal varied from BDT 311 to 3528 and BDT 23 to 1268.Utilization of vacant lake,youth and women engagement,integrated aquaculture,the desire of people to engage in aquaculture,and available human resources were found as significant prospects.The major problems identified were lack of hatchery,high feed cost,lack of stakeholder linkage,lack of capital for fish farming,and lack of proper knowledge,guidelines,and consultancy for fish culture.A community-based aquaculture model was proposed to overcome the present challenges and problems in the study area.The model may help to expand aquaculture and thus improve the livelihood and socio-economic status of the people of the hilly areas of Bangladesh.

Applicability of Perinereis aibuhitensis Grube for Fish Waste Removal from Fish Cages in Sanggou Bay,P.R.China

The present study investigated the applicability of integrated polychaete-fish culture for fish waste removal to offset negative impact induced by organic benthic enrichment.A field study demonstrated that deposition rate was significantly higher underneath the fish farm than that in control area.The material settling under the farm was characterized by a high amount of fish feces(45%) and uneaten feed(27%).Both feeding rate(FR) and apparent digestibility rate(ADR) increased with decreasing body weight,as was indicated by significantly a higher rate observed for the groups containing smaller individuals in a lab study.The nutrient in fresh deposited material(De) was higher than that in sediments collected under the farm(Se),resulting in lower feces production but higher apparent digestibility rate for the De group as feeding rate was similar.Consequently,higher nutrient removal efficiency was observed in the De group.A mass balance approach indicated that approximately 400–500 individuals m^(-2) is required for removing all waste materials deposited underneath the fish farm,whereas abundance can be lower(about 300–350 individuals m^(-2)) when only the fish waste needs to be removed.The results showed that a significant amount of waste had been accumulated in the fish cages in Sanggou Bay.The integration of fish with P.aibuhitensis seems promising for preventing organic pollution in the sediment and therefore is an effective strategy for mitigating negative effect of fish farms.Thus such integration can become a new IMTA(integrated multi-trophic aquaculture) model in Sanggou Bay.

Conservation of Traditional Rice Varieties in a Globally Important Agricultural Heritage System (GIAHS):Rice-Fish Co-Culture

The traditional rice-fish farming system is selected as a ＂globally important agricultural heritage system＂ （GIAHS） by the Food and Agriculture Organization （FAO）,United Nations Development Programme （UNDP）,and Global Environment Facility （GEF）,etc.In Zhejiang Province of China,where the pilot site for this GIAHS farming system is located,we compared the use of traditional rice varieties in rice-fish co-culture and rice monoculture.Further,we determined how traditional rice varieties were performed in this rice-fish system.Only 19% of the farmers who practiced rice monoculture planted traditional varieties while 52% of farmers who practiced rice-fish co-culture planted traditional varieties.Traditional varieties represented 13% of the total land cultivated under rice in the rice-fish system but only 2% in the rice monoculture system.In the rice-fish system,yield was lower for traditional rice varieties than hybrid varieties but application of fertilizers and pesticides was also lower.In a field experiment in the rice-fish system without pesticides,rice planthopper numbers and sheath blight incidence were lower from three traditional varieties than one hybrid variety;yields were 8 to 32% lower from the traditional varieties than the hybrid.Our results showed that traditional rice varieties can be preserved through conserving GIAHS rice-fish co-culture.Our study also indicated that traditional rice varieties can survive in the rice-fish system because these varieties are helpful to the whole system and beneficial to the farmers.

The Occurrence of Bacteria of the Genus Aeromonas spp.in Oreochromis niloticus(Tilapia)and in the Water of Amateur Sport Fish Ponds and Sensitiveness to Antimicrobials

Since amateur fishing in fishponds has been on the increase in Brazil, there is a great concern on the microbiological quality of fish. One hundred and thirty-eight samples were collected during the dry and rainy periods in ten fish farms. Aeromonas spp. counts and tests for sensitiveness to antimicrobials were performed, coupled to the physical and chemical analyses of water. Tests revealed that 70% of samples were contaminated by Aeromonas spp., with water averaging 2.92 Log CFU/100 mL during the rainy period and 3.16 Log CFU/100 mL during the dry one. Fish contaminated by Aeromonas spp. averaged 2.58 Log CFU/100 mL during the rainy period and 3.53 Log CFU/100 mL during the dry one. Aeromonas spp. samples were multi-resistant to 2 or 8 antimicrobials in 62.5% of the samples. Ampicillin was the antimicrobial with the highest resistance percentage rate. Results showed that fish bred in amateur fish farms constituted a health risk for the population.

Seasonal Variations in Serological Profiles and Growth Status of Farmed and Wild Clarias gariepinus （Burchell, 1822） Obtained from Asaba, Nigeria

Seasonal variations in serological profiles and growth status of farmed and wild Clarias gariepinus were investigated. Serological profiles of Clarias gariepinus can be an effective tool for proper monitoring of stress induced by management practices in intensive fish culture, which may elicit devastating effect on fish. Spectrophotometry procedures were used to analyze serum parameters of Clarias gariepinus. No different seasonal patterns were observed for mean values of albumin, total protein, urea, cholesterol, glucose and alanine amino-transferase. However, aspartate amino-transferase showed different seasonal pattern. Levels of cholesterol and alanine amino-transferase were highly significant in farmed and wild fish, separately. Juvenile fish had high level of urea irrespective of season. Seasonal variations in water quality parameters were observed except for pH which had no seasonal pattern. The growth exponential shows b-values between -0.048 and 7.434 for Clarias gariepinus. Adult female and juvenile fish from the wild had the highest b-value and the least b-value, separately. In this study, b-values were higher in the wild fish than the farmed fish. The condition factor for Clarias gariepinus ranged from 0.422 to 0.698, and was observed to be high in juvenile fish. With a condition factor less than 1, fish may not be doing well, probably due to environmental stress. Some serological parameters varied according to season and environment of fish. Thus, serological profile of fish is an effective and sensitive tool to monitor fish response to stress factors in the environment.

Food Restriction Programs and Their Applications in Fish Aquaculture

Food restriction is a strategy to improve the productive efficiency of some aquatic organisms.It is expected with the implementation of food restriction programs to first reduce the feed consumption by the cultivated species and consequently reduce the waste load in the water.In addition,there is a lower employment of labor during periods of food restriction.However,the efficiency of the feed restriction and the compensatory gain of weight by the organisms cultivated will depend on the adaptation and the characteristics of the species in question.Several methodologies have tested forms of food restriction applied to fish farming.Some of them are addressed in this review,as well as results and comparisons made with several authors on the subject in question.The purpose of this paper was to describe the main reasons for using food restriction,its implications on fish organism and to compare results from previous studies.

Bio-Filtration Technologies for Filtering Ammonia in Fish Tank Effluent for Reuse--A Review

Peri-urban fish farms with limited access to open natural water bodies draw fresh water from urban water supply and dug wells,which is unreliable and costly.Reuse of fish pond effluent is also limited by high ammonia concentration(>0.3 mg/L)that renders water toxic and is stressful to fish.Despite the existence of several fish effluent treatment methods,not all may be appropriate for a particular location.This review article therefore examines the various fish effluent treatment methods to aid selection of the most suitable one(s)for peri-urban areas.The key parameters considered in their comparison were:initial,operational and maintenance costs;ammonia removal efficiency;energy consumption and land requirement.The effluent treatment methods are both conventional and non-conventional.Despite a slight higher treatment efficiency and less space requirement by conventional methods,they mainly require reliable power supply for continuous running,highly skilled labor for operation and maintenance leading to high operational costs.In addition,their investment costs are higher than non-conventional methods,hence not widely applied in developing countries and majority have broken down.On the other hand,non-conventional methods such as constructed wetlands are widely in use for treating effluent mainly due to their cost effectiveness and no or little energy requirement.Constructed wetlands were found most suitable bio-filtration system for treating fish effluent because they are cost effective,require less skilled labor and still have better effluent treatment though space required is slightly more.Vegetables(lettuce,collards,etc.)have potential to grow in constructed wetlands thus form vegetable-based bio-filtration units which serve not only as bio-filters but also provide additional sources of nutrition and income.This review indicated limited information on the appropriate size and performance of vegetable-based bio-filtration unit utilizing indigenous vegetables and recommended further research to explore the idea.

Monitoring Trace Metals in Some Cultured Freshwater Fish Species in Saudi Arabia

Three species of freshwater fishes, Oreochromis niloticus, Clarias lazera and Cyprinus carpio, were collected in marketing size from some fish farms in Al-Kharj region, Riyadh area, Saudi Arabia and examined throughout the year 2012 for the following trace metals contents： chromium （Cr）, lead （Pb）, cobalt （Co）, nickel （Ni）, copper （Cu）, zinc （Zn）, iron （Fe） and cadmium （Cd）. The results showed no detection of Cd in all examined species, however, the mean values of other tested metals were within the standard permissible levels except for Pb which showed higher mean levels ranged from 2.05 ± 0.65 mg/kg to 5.30 ± 0.60 mg/kg in O. niloticus, 0.15 ± 0.13 mg/kg to 6.40 ± 0.10 mg/kg in C. lazera and 1.7 ± 0.20 mg/kg in C. carpio compared to the maximum permissible limits recorded by Saudi Arabia Standards Organization （SASO） for fish and shellfish. Consequently, from the public health point of view, efficient routine examination of cultured fishes to control trace metals during culture processes and before marketing is recommended.