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Coastal aquaculture development and the environment. The role of coastal area management
Abstract
The rapid expansion of coastal aquaculture has serious environmental and socioeconomic consequences, which include large-scale removal of valuable coastal wetlands, land subsidence, acidification, salinization of groundwater and agricultural land, and subsequent loss of goods and services generated by natural resource systems. Practices that are environmentally non-degrading, technically appropriate, economically viable and socially acceptable should therefore be promoted through integrated planning and management within the framework of coastal area management (CAM).
... The development of aquaculture along Taiwan's coastlines has left a profound impact both environmentally and socio-economically. With its farreaching and growing influences, aquaculture is threatening the balance of the local eco-system and the usability of land (Chua, 1992), and worse of all the existential safety of communities over a large area (Ericson et al., 2006;Saito et al., 2007;Syvitski et al., 2009, Higgins et al., 2013. Facing these potential risks, it is necessary for the coastal area management (CAM) (Chua, 1992) to initiate alternative ways of land use based on comprehensive analyses covering the aspects of natural conditions, socio-economical concerns and policies. ...
... With its farreaching and growing influences, aquaculture is threatening the balance of the local eco-system and the usability of land (Chua, 1992), and worse of all the existential safety of communities over a large area (Ericson et al., 2006;Saito et al., 2007;Syvitski et al., 2009, Higgins et al., 2013. Facing these potential risks, it is necessary for the coastal area management (CAM) (Chua, 1992) to initiate alternative ways of land use based on comprehensive analyses covering the aspects of natural conditions, socio-economical concerns and policies. ...
... Fieldwork and qualitative interview (focus interview) were combined as two research methods to explore the effects of government policies on local industry's land use (Chua, 1992). Interview content was first established by gathering data of the government's industry and disaster prevention policies. ...
The Ocean Dumping Act of 1988 phased out dumping of sewage sludge into the ocean. To use sewage sludge beneficially, facilities treat and process it using such techniques as digestion, dewatering, composting, thermal drying and chemical stabilization. All of these processes create waste discharges containing high concentrations of nitrogen, mainly in the form of ammonia. When nitrification occurs in receiving waters, ammonia is oxidized to nitrate and can lower dissolved oxygen levels in the water. Excess ammonia also is toxic to fish and other aquatic life. Nitrogen reduction alternatives for sludge dewatering and processing waste discharges include the following: air stripping; steam stripping; breakpoint chlorination; selective ion exchange; reverse osmosis; and chemical precipitation. To remove wastewater nitrogen using biological processes, ammonia and organic nitrogen first are oxidized aerobically (nitrification) to nitrate nitrogen, which then is converted biologically to nitrogen gas (denitrification) under zero or low dissolved oxygen (anoxic) conditions. Because sludge treatment discharges contain valuable quantities of ammonia, they may be considered for reuse as supplemental fertilizer for land application or for reclamation through spraying or injection into soil. Such discharges also may be used in combustion processes.
... Of the total food fish production from the aquaculture sector (80 million tonnes in 2016, equivalent to USD 231.6 billion), 35.8% were derived from marine and coastal aquaculture (FAO, 2018). Coastal aquaculture, which refers to a range of aquaculture activities in coastal floodplains, estuaries and marine waters (Chua, 1992) rapidly increased across the world throughout the 1980s and 1990s (Ahmed and Glaser, 2016), particularly in Southeast Asia (Primavera, 2000;Richards and Friess, 2016). ...
... Traditional coastal aquaculture of the region is characterized by extensive small-scale subsistence farming and is regarded as one of the major livelihood activities of the coastal communities (Hishamunda et al., 2009;Primavera, 2006). Rapid expansion and intensification of coastal aquaculture were triggered by the advent of export-oriented commercial coastal aquaculture (Chua, 1992;Eng et al., 1989;Hishamunda et al., 2009). Factors that have been suggested as important in the expansion of coastal aquaculture in the region include the economic development strategies implemented by governments, access to mangrove areas, industrial transformation, and financial investment (Huitric et al., 2002;Lebel et al., 2002;Primavera, 2000;Truong and Do, 2018). ...
Coastal aquaculture is socially, culturally and economically important in Southeast Asia, but its expansion in the last fifty years has had negative environmental and social consequences. Through analyses of detailed accounts of the expansion of coastal aquaculture, we aimed to increase knowledge of the factors underlying this expansion to guide future policies for sustainable management of the coastal zone. Using a systematic review of ninety studies, we found that increased aquaculture development and economic opportunities were the most frequently identified proximate drivers of coastal aquaculture expansion, while factors associated with location (e.g. availability of mangrove land), institutional policies and economy (e.g. capital investment and market demand) had lesser influence. However, complex combinations of the underlying factors were also important. For example, the influence of policies that stimulated aquaculture development was often associated with combinations of locational, institutional, economic, technological and social factors. Strategies aimed at enhancing expansion of sustainable coastal aquaculture and mangrove conservation should focus on government policy interventions, including those that support mangrove silvo-aquaculture.
... A decline in forest area due to a sudden coastal erosion event such as a storm, for example, instantly renders the region less morphologically resilient to further erosive forces, thus amplifying the rate at which erosion occurs. As a result the immediate habitable land area is reduced and the area behind the remaining forest is subject to increasing erosive forces (Chua, 1992). A 'long' mechanism refers to a more complex network of interactions between the ecological and morphological systems: Although the initial trigger of the change may be the same as in the 'short' feedback loop, the consequences of the change propagate further into the system, and thus operate over longer timescales (figure 2.4b). ...
... Furthermore, the presence of trees provides friction to slow the movement of water and sediment, allowing the waterway to silt and elevation to increase (Alongi, 2009). A decline in mangrove forest has left an increasing proportion of agricultural land exposed to coastal erosion, inundation and increasing salinisation, with detrimental effects to rice yield (Chua, 1992;Mahata et al. 2012). ...
Utilising the cellular automata model CAESAR-Lisflood, a novel set of metrics is developed to explore the nature of multidecadal morphological change in delta catchment systems under a range of climatic and environmental change scenarios. Whilst this study has a specific focus on the Mahanadi Delta in India,these scenarios are designed in such a way so as to encapsulate stressors that are common to a broad range of deltaic environments; including increased exposure to meteorological extremes, sediment starvation and eustatic sea-level rise.
Compared to terrestrial systems, there have been relatively few studies that focus on the successful simulation of long-term emergent phenomena in coastal catchments, especially in the specific context of deltas. To address this gap, this research aims to enhance our understanding of how emergent processes influence the multidecadal evolution of deltaic environments, and how we can use this information to understand how the system may respond to increasing conditions of climatic stress.
This study also seeks to explore how changes in the emergent morphological system may impact certain factors that influence the habitability of the Mahanadi Delta. Through the development of a novel vulnerability index, this study explores: (1) the impacts of an extreme flood event; (2) potential changes in habitat cover; (3) the effectiveness of the model to explore engineering strategies, with a focus on re-naturalising the delta.
... En una serie de experimentos realizados con bacterias aeróbicas, se comprobó que éstas desarrollaron resistencia a oxitetraciclina y ácido oxolínico después de ser expuestas sólo por 2 días (Midlen y Redding, 1998). Al igual que otros autores, Chua (1993) señala que la creación de resistencia en las bacterias tiene dos efectos: ...
... El uso continuo de antibióticos crea resistencia y afecta la composición de flora bacteriana. Un cambio en la estructura de la comunidad bacteriana de los sedimentos afecta el proceso de descomposición de la materia orgánica y por lo tanto interfiere en el ciclo de algunos nutrientes (Chua, 1993). En un estudio donde se realizaron mediciones de abundancia bacteriana y presencia de antibióticos, se observó que a 2 días de aplicar alimento medicado, la abundancia de bacterias disminuyó a una tercera parte de la inicial; la tasa de reducción de sulfato (como indicador de mineralización de sedimento orgánico) fue afectada significativamente y tardó 2 meses en recuperar los niveles previos al tratamiento (Midlen y Redding, 1998). ...
Presentación
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La acuacultura, sin proponérselo, ha motivado discusiones fructíferas sobre el complejo tema que involucra a todas y cada una de las diferentes actividades económicas que se desarrollan en la zona costera, con objeto de efectuar un balance entre las medidas de protección de los ecosistemas valiosos y el desarrollo de las actividades productivas. El conocimiento científico debe jugar un papel fundamental para definir aquellos hábitat costeros que deben ser protegidos y poder establecer un balance óptimo en el aprovechamiento de los recursos naturales entre las distintas actividades económicas que frecuentemente entran en conflicto al utilizar tales recursos. ..
Dr. Federico Páez Osuna
... Among possible environmental impacts of aquaculture activities in the coastal environment, the major impacts are biodiversity decrease and changes in benthic microfauna, most other changes are rather localised (Chua, 1992) (Table 1). The aquaculture inputs that cause the most serious harms to the environment are feeds and faecal wastes. ...
... Possible environmental impacts † of aquaculture activities in the coastal environment (fromChua, 1992) Site selection will depend on the farming practices and on the characteristics of the different sites: different areas may respond differently to the same pollutant dose. ...
– Site selection for fish farms (located both inland and offshore) is crucial for the sustainable development of the industry. Degradation of the environment where the farms are installed, as well as interference with other activities, has to be foreseen and avoided as much as possible. Likewise, harm to the cultured crop due to a contaminated or inappropriate environment also has to be avoided. A careful study undertaken prior to any installation should be compulsory, in terms of mitigating any possible effects. Some aspects to be taken into account, before the siting of a fish farm are: permit system regulations, conflicts with other water/land uses, hydrographic conditions of the area (temperature, current speed, etc.), water quality, terrestrial inputs, wave climate, wind patterns, seabed characteristics and dynamics, and accessibility and available facilities. The importance of each of these factors, in the selection of a site capable of sustaining a fish farm without harm to the environment, will be considered. Moreover, the use of hydrodynamic and dispersion models will be presented, demonstrating their use as a powerful tool for coastal managers. Such managers have to decide on licences for fish farms, taking into consideration environmental affection and/or multiple pollutant effects (caused by the non-rational grouping of farms). RESUME – "Considérations environnementales sur la sélection du site pour les exploitations marines de pisciculture". La sélection du site pour les exploitations de pisciculture (à l'intérieur et en mer) est essentielle pour le développement durable de l'industrie. Il est nécessaire de prévoir et d'éviter – autant que possible – la dégradation de l'environnement où on va installer les exploitations ainsi que l'interférence avec d'autres activités. De même, il faut éviter de causer des dégâts aux cultures du fait d'un environnement pollué ou inapproprié. Une étude minutieuse doit être réalisée avant toute installation, en ce qui concerne l'atténuation des effets possibles. Avant l'installation d'une exploitation piscicole il faut tenir compte des aspects suivants : réglementation et systèmes de permis, conflits avec d'autres utilisations de l'eau et de la terre, conditions hydrographiques de la zone (température, vitesse des courants, etc.), qualité de l'eau, contributions terrestres, régime des vagues, situation des vents, caractéristiques et dynamique des fonds marins, et accessibilité et disponibilité des installations. L'importance de chacun de ces facteurs sera considérée dans la sélection d'un site capable d'accueillir une exploitation sans causer de dommages à l'environnement. De plus, on va présenter l'utilisation des modèles hydrodynamiques et de dispersion, en démontrant leur utilité comme un outil puissant pour les responsables de zones côtières. Ces responsables doivent décider en matière d'autorisation d'exploitations piscicoles en tenant compte de l'effet sur l'environnement et les multiples effets polluants (provoqués par le groupement non rationnel des exploitations). Mots-clés : Exploitation de pisciculture, sélection du site, études de l'impact sur l'environnement, surveillance.
... The possible environmental impacts of aquaculture activities in the coastal environment are shown in Table 8. (Chua, T.E., 1992) (Chua, 1992). ...
... The possible environmental impacts of aquaculture activities in the coastal environment are shown in Table 8. (Chua, T.E., 1992) (Chua, 1992). ...
... Coastal aquaculture destroys valuable wetlands, causing land subsidence, acidification, and salinization. It also leads to the loss of crucial ecosystem services and disrupts mangrove habitats vital for marine organisms [58,59]. ...
According to the Thailand’s National Strategy (2017-2036) and National Reform Plans, various tools, techniques, or methods are necessary to collect and investigate data for the effective preservation and protection of the country’s natural resources. We aimed to apply various tools and methods for integrated coastal management in Thailand. This study used the InVEST models, including the habitat quality (HQ) and habitat risk assessment (HRA) models, to evaluate the natural habitat quality and cumulative human activity risk in the Sriracha district and Sichang Islands, Thailand. The HQ model revealed the presence of abundant ecological services and high quality natural habitats. We observed habitat degradation in the mooring zone, city area, forests, and coral reefs, with moderate risk to distinct habitats. Our findings identified two potential scenarios. Conservation scenarios exhibited a lower HRA ratio compared to current and development scenarios. Overall, the results showed the effectiveness of the InVEST model in evaluating habitat risk under both present and simulated conditions. Our study highlights the importance of informed management plans and policy-making processes to achieve planned coastal management goals.
... It is one of the most important bodies of water in the country because it contains an international port, a large fishing district, and an oyster and mussel aquaculture site [14]. However, the fishponds place a significant strain on their surroundings [15]. Slope failure begins in Manila Bay with the diking and drying of ponds. ...
The coastal zone around the urban coastline of Metro Manila is said to be suffering major environmental difficulties due to fast population growth and urbanization. This study uses remote sensing and GIS techniques to (i) examine changes in land use/land cover and (ii) detect coastal changes. Between 1992 and 2020, four Landsat map images were obtained to create land-use/land-cover (LULC) maps to detect shoreline changes. Each dataset is subjected to an accuracy assessment, with an average LULC mapping accuracy of roughly 90%. The northern part of the study area, which is in Navotas City was composed of trees and grasslands but as the years went by it was converted into fishponds while the critically important Ramsar site, LPPCHEA, have maintained the preservation of its natural mangrove forest. In a 30-year period, the urban coastline of Metro Manila decreased by around 1.5 kilometers. This study can be used to design a long-term plan and environmental management strategy of Metro Manila.
... Sediments in deltaic areas such as Bulacan naturally subside by "autocompaction"; as older deposits are loaded by successively newer deposits, they are compressed as their water contents are squeezed out. Subsidence from autocompaction, however, is greatly accelerated by massive groundwater extraction for agricultural, domestic, and industrial use (Chua, 1992;Rodolfo and Siringan, 2006;Jago-on et al., 2009;Syvitski et al., 2009). ...
How to cite:
Lagos, D. T., Eco, R. C., Rebadolla, L. J., Farin, F. A. B. (2022) Flooding and Subsidence Research: Bulacan Province, Northern Manila Bay Area, Philippines. Diamonds in the Delta, Technical Report.
Flooding is one of the most common natural hazards that communities in Bulacan face. This is commonly linked to heavy rains, typhoons, storm surges, overflowing of water bodies and subsidence. Floods have resulted in disastrous outcomes. One of the recent catastrophic flooding in Bulacan happened in July 2021, when southwest monsoon rains exacerbated by Typhoon Fabian (International Name: In-fa) submerged more than 50 villages in the province (Silverio 2021). This resulted in deaths, PhP 155 million (≈2.7 million euros) worth of destroyed agricultural products and infrastructures, and the evacuation of more than 500 families (Balbin 2021).
Besides flooding and subsidence, local communities face other risks driven by climate change, which includes other activities contributing to ecosystem degradation (e.g. waste management), and earthquakes. Urbanization and deforestation are also significant reasons for the worsening floods (Rodolfo et al 2003). Coastal and fisherfolk communities also confront the impacts of irresponsible reclamation projects in northern Manila Bay. The community perceives that their vulnerability is heightened by the reclamation projects’ cutting of mangroves, displacement, and their relocation to hazard-prone areas.
This study collaborates with the communities in Barangays (villages) San Jose and San Isidro II in Paombong, Barangay Caliligawan in Malolos, and Barangay Sta. Elena in Hagonoy. It explores, “What are the flooding and subsidence experiences of Bulacan coastal communities? How do local people perceive causes and possible responses to their flooding concerns?”
In particular, this study aimed to:
1. Explain communities’ experience of flooding and their impacts;
2. Identify the changes that people observed over the years, in connection to flooding;
3. Summarize local responses to flooding;
4. Describe people’s perception of the reasons behind the flooding;
5. Examine flooding and land subsidence within broader context of vulnerabilities;
6. Integrate people’s analysis of vulnerabilities with their desired social changes.
... If the current velocity decreases, this efficiency also decreases and the concentration of nutrients increases, affecting the welfare of fish (Poizot et al., 2016). An increase in nutrient concentrations may cause eutrophication (Chua, 1992;Tremont and Mills, 1986), which can lead to algal blooms (San Diego-McGlone et al., 2008), hypoxic or anoxic water (Karim et al., 2002), and fish disease (Snieszko, 1974). These undesirable phenomena can result in mass mortality of farmed fish, which can be a source of water pollution in a coastal environment and lead to heavy economic losses for aquaculture farmers. ...
The management of marine aquaculture requires an accurate assessment of environmental impacts to achieve an environmentally sustainable system. To study the influence of farmed fish schools on the flow field around a fish cage, a pseudo-fish-school structure model was developed to simulate the circular swimming patterns of farmed fish in laboratory experiments. The drag force acting on the fish cage and current velocities inside and around a modeled square fish cage were investigated. A field survey was also conducted. As a result, the non-uniformity and complexity of the flow field of a stocked cage were observed in laboratory experiments. Circular swimming patterns were found to have obvious influences on the flow field distribution. The drag force of the square fish cage decreased by 11.8% because of the presence of the fish-school structure. Based on the field measurements, the averaged velocity inside and downstream of the full-scale fish cage was reduced by 46.2% and 57.8%, respectively. An acceleration was also observed in the current velocity below the fish cage. The vertical mixing of seawater may be because of the water blockage resulting from the cage and the circular swimming pattern of farmed fish schools. The findings presented in this study can be used as benchmarks for numerical models in assessing the potential environmental impact of fish farm sites.
... coefficient of variation, growth, Pacific white shrimp, stocking density, survival is thought to be due to increase in competition for the space and food sources (Maguire & Leedow, 1983), stress induced by crowding (Sumano-Lopez et al., 2006), poor water quality (Thta-Eng, 1993;Wajsbrot et al., 1989), increased susceptibility for pathogen outbreaks (Lin et al., 2015), etc. In a research setting, it is common to use 10-15 animals (initial weight 0.1-1.5 g) in 60-to 70-L aquaria in most of the laboratory-based nutritional experiments in clear water to facilitate easy management or since it is the common density being used in shrimp nutrition research. ...
A series of laboratory‐based growth trials were carried out in semi‐closed recirculation system with juvenile Pacific white shrimp Litopenaeus vannamei. The effect of stocking density, initial size variation and replication was evaluated. Trial 1 was conducted for 42 days with different stocking densities (28, 56, 83, 111, 139, 194 and 250 shrimp/m2) to determine the effect of stocking density on performances of shrimp. Trial 2 was conducted for 56 days (2 × 3 factorial design) to test the effect of stocking density (30 and 60 shrimp/m2) and coefficient of variation (CV) at stocking (8%, 15% and 32%) on performances of shrimp. In third trial, data from 15 replicates were randomly sampled to create data sets with varying levels of replications. Significantly reduced growth and survival were noted when increasing the stocking density of shrimp, while the opposite was noted in FCR of shrimp. No significant effect of initial size variation of shrimp was noted on size variation of shrimp at harvest in both stocking densities tested. No interaction was noted between stocking densities and initial CV of shrimp on determining the size variability of shrimp at harvest. In terms of replicate size, a clear improvement in power and reduction in between sample variation was noted as the replication increased, hence suggested that up to 6 replicates are appropriate for a clear water shrimp nutritional study.
... Oceans are the final reservoir of natural and anthropogenic contaminants which affect seawater, coastlines and beaches, and pose a severe threat to coastal/marine ecosystems and human health (e.g., Islam and Tanaka, 2004;Akcil et al., 2015;Ruiz-Fernández et al., 2018;Nalley et al., 2021). The presence of contaminants in the water can also have serious socioeconomic consequences since coastal/marine resources represent a major source of food and direct/indirect jobs for many people, particularly tourist sites in developing countries (e.g., Chua, 1992;Freire and García-Allut, 2000;Façanha-Câmara et al., 2021). Among the contaminants of greatest concern for the environment and health, toxic elements (TEs) like Ba, Hg, Cd, Co, Cr, Cu, Mn, Ni, Pb, V, Zn, and As, and fecal-derived microorganisms stand out due to their persistence in the environment and by the negative effects they cause to ecosystems and humans (e.g., Sankhla et al., 2016;Jaiswal et al., 2018;Joksimovic et al., 2020;Amqam et al., 2020;Al-Mutairi and Yap, 2021). ...
Total concentrations of Ba, Cd, Co, Cr, Cu, Mn, Ni, Pb, V, Zn, and As together with Sr and Pb isotopic compositions of seabed sediments from the worldwide famous tourist destination of Acapulco Bay, Guerrero (southern Mexico) were determined to reveal the origin of detritus and toxic elements (TEs), their potential natural and anthropogenic sources, elemental distribution and their ecological risk. Sediments derive entirely from the nearby Acapulco Granite and their concentrations of TEs are variable and rather low, although, several are above the Local Geochemical Baseline in some sites of the bay. The enrichment factor (EF) and Pb isotopes indicate that TEs derive from the Acapulco Granite with contributions of an anthropogenic source represented, very likely, by ship-bottom paints. Wastewaters are a significant source of Pb and Cu. The ecological risk of TEs is low and only Cu represents a moderate ecological risk in a few sites.
... Lakes, ponds, and rivers are major water sources for freshwater aquaculture whiles the sea serves as water source for mariculture (Ni et al., 2018). Aquaculture uses diverse systems such as cages, pens, ponds, long-lines, rafts, and stakes (Chua, 1992). The activities of any culture system result in the release of waste into the natural water bodies and groundwater which serves a vast community of organisms including humans regardless of the source of water and the type of system. ...
Aquaculture effluent is often associated with increased organic carbon, suspended solids, phosphates, nitrogenous species (nitrates, nitrites, and ammonia), chemical oxygen demand and biological oxygen demand. This is regarded as a global threat to aquatic ecosystems due to its influence on surrounding waters as well as groundwater. The threat of aquaculture effluent is not confined to the aquatic ecosystems as high levels of phosphorus and nitrogen may become poisonous to plants and change their protein synthesis, enzyme activities, photosynthesis, oxidative stress response, membrane permeability, and respiratory processes. Other forms of water pollution such as the presence of heavy metals as well as pathogenic microbes are issues of concern since they can be transferred through the food chain. Bacillus species have demonstrated great ability in the maintenance of water quality in aquaculture which is simple and cost-effective. This review highlights that Bacillus modulates a wide range of water quality parameters including physical (transparency and total dissolved solids) and chemical (pH, conductivity, chemical oxygen demand, dissolved oxygen, biological oxygen demand, alka-linity, phosphates, nitrogenous species, hardness) water quality parameters, heavy metals, oil spillage as well as maintenance of microbial balance; hence reduction in pathogenic microbes. The efficiency of Bacillus in modulating water quality is greatly dependent on factors such as mode of application, dissolved oxygen, pH, temperature, source of nutrients, strain type, and metal ions. This review further highlights aquaculture activities that lead to pollution and the possible mechanisms used by Bacillus for improving water quality. It is recommended that a range of optimum conditions be established to increase the efficiency of Bacillus in modulating water quality. A better understanding of Bacillus to the genetic level and the development of new genetic tools is also recommended since the ability of microorganisms to modulate water quality is related to their genetic make-up.
... Kejadian kematian masal pada benih ikan dan rendahnya tingkat kelulus hidupan pada larva ikan seringkali berhubungan dengan masalah gangguan pada kualitas air. Untuk mengatasi kondisi yang demikian, perlu dilakukan kegiatan monitoring lingkungan perairan secara teratur agar perubahan kualitas perairan dapat diketahui sedini mungkin dan segera agar dapat dilakukan tindakan pengendalian (Chua, 1993;Duff, 1987;Hammo, 1987;Waldichuk, 1987;Wu, 1988;Pillay, 2004). ...
An evaluation of the water quality at the hatchery of Tanjung Riau was conducted to understand the water quality status at the several place of the hatchery unit such as brood stock tanks, larva rearing tank, water storage tank, fi ngerling tank as well as the source of the water supply. The water quality status of Tanjung Riau generally is in a good condition to support the hatchery activities, but for turbidity and salinity were in the exceed and below the normal status and its infl uence on the spawning activity. To overcome the problem on the spawning of the brood stock, the improving of water supply with higher salinity and low turbidity should be set up to ensure the succeeded of the spawning.Key words : Water quality, grouper brood stock, hatchery,Tanjung Riau Batam
... Improvements in morphological vision, freshness of color, lavor, texture, fatty acid composition and the production of pharmaceutical compounds have also been addressed in the process of genetic modi ication [24]. Sustainable aquaculture development requires due consideration of the interactions between environmental, social and economic factors that accompany any development [18,25,26]. Describing processing and marketing strategies with a particular emphasis on niche marketing, selecting a species, a production system and a market, and writing an aquaculture business plan are also important factors for sustainability [27]. ...
... On the other hand, the large-scale reproduction of enteromorpha will cover the aquaculture boxes and suspended nets, thereby hiding the mariculture zone, which may affect marine traffic and port transportation. Therefore, monitoring the growth status and coverage of laver and other marine products in a timely manner is highly important [2]. ...
Timely monitoring of marine aquaculture has considerable significance for marine ecological protection and maritime safety and security. Considering that supervised learning needs to rely on a large number of training samples and the characteristics of intensive and regular distribution of the laver aquaculture zone, in this paper, an inaccurate supervised classification model based on fully convolutional neural network and conditional random filed (FCN-CRF) is designed for the study of a laver aquaculture zone in Lianyungang, Jiangsu Province. The proposed model can extract the aquaculture zone and calculate the area and quantity of laver aquaculture net simultaneously. The FCN is used to extract the laver aquaculture zone by roughly making the training label. Then, the CRF is used to extract the isolated laver aquaculture net with high precision. The results show that the k a p p a coefficient of the proposed model is 0.984, the F 1 is 0.99, and the recognition effect is outstanding. For label production, the fault tolerance rate is high and does not affect the final classification accuracy, thereby saving more label production time. The findings provide a data basis for future aquaculture yield estimation and offshore resource planning as well as technical support for marine ecological supervision and marine traffic management.
... The best management practices (BMPs) for coastal aquaculture presented by Boyd (2003) should be considered as a practical mean for preventing negative impacts of the natural environment and ensuring economic efficiency in this area. Effluent disposal also can be mitigated through adoption of (1) polyculture or diversification of cultured species including fish, mollusks, mangrove, halophytes, and artemia; (2) reduction of water or zero exchange rate; (3) use of oxidationsedimentation ponds; (4) improving the delivering and composition of the feed (Primavera, 1991;Chua, 1992;Hopkins et al., 1995). Disease outbreak can be addressed by ensuring good water quality and lower stocking densities; environment control; high health seed and disease control (good feed with uses of probiotics) (Primavera et al., 1993;Hopkins et al., 1995;Primavera, 1998). ...
The paper aims to achieve two goals. First, it highlights the differences of aquaculture systems in the buffer zones of Xuan Thuy national park, Vietnam. Second, it serves as an assessment of the economic performance and factors that influence net farm income of the systems. A formal survey was used to collect relevant data from 138 farmers in intensive shrimp (ISH) and integrated aquaculture-mangrove (IAM) farming systems. Results demonstrated that ISH produced a total 1,017 million Vietnam Dong (mil.VND) value of output per hectare annually which was more than 32.99 mil. VND from IAM. ISH carried a much higher cost of production (695.39 million VND/ha/year) than IAM (13.29 million VND), and ISH obtained relative higher net farm income (321.17 million VND) than IAM (19.70 million VND). Ordinal least square (OLS) regression was used to assess relationships between social-economic-environmental factors on the net farm income. Maintaining more forestry coverage and reduce the negative effects of polluted water from surrounding rivers are important to achieve greater income of IAM production. Meanwhile, stimulating formal and informal knowledge together with increasing farmers' power in bargaining prices simultaneously reducing negative effects of polluted water, disease occurrence and production costs can help to improve the net farm income of ISH production. The expanded analysis is necessary to render value contributions to ensure farmers receive a higher level of economic returns while conserving the natural ecosystem for the protected areas.
... Aquaculture has great potential to expand and intensify sustainably in order to meet the demand for fish in 2050, as the human population is predicted to continue to grow for the next 40 years before stabilizing at a minimum of 9 billion people (Godfray et al. 2010). The sustainable development of aquaculture requires adequate consideration of interactions among environmental, social and economic factors that accompany any development (Chua 1992;Word Bank, 1998;NACA/FAO, 2000). ...
... In many tropical and subtropical countries, shrimp farming has grown rapidly in recent years but there have been setbacks resulting from diseases and the growing awareness of the environmental and social impacts of shrimp farming (Dwivedi and Kandrika, 2005). Rapid expansion of coastal aquaculture has resulted in large-scale removal of valuable coastal wetlands, salinisation of groundwater and agricultural lands and subsequent loss of goods and services generated by natural resource systems (Chua, 1992). ...
... Aquaculture has great potential to expand and intensify sustainably in order to meet the demand for fish in 2050, as the human population is predicted to continue to grow for the next 40 years before stabilizing at a minimum of 9 billion people (Godfray et al. 2010). The sustainable development of aquaculture requires adequate consideration of interactions among environmental, social and economic factors that accompany any development (Chua 1992;Word Bank, 1998;NACA/FAO, 2000). ...
Freshwater fish ponds, besides producing fish, function as valuable aquatic habitats, contribute to the maintenance and enrichment of the quality of the ecosystem, play an important role in water and landscape management, provide services for various recreational activities and contribute to the preservation of the cultural heritage. The multifunctional character of pond fish farming has been recognized for long time; however, recently it has also been realized that the deliberate multidirectional use of fish ponds (production, angling, recreation, education, etc.) offers additional economic benefits. Experience with the operation of multifunctional fish farms in Hungary has clearly shown that the diversification of activities is a promising alternative during the development of sustainable pond fish farming. However, further efforts are required to investigate the specificities and applicability of the various factors and also the optimal ratio between them to utilize the opportunities offered by multifunctional use of freshwater fish ponds. Research on multifunctional pond fish farming has mainly been limited to descriptions of the various functions of fish ponds, for example environmental services. However, the attitude of farm managers towards the possible multifunctional use of their farming system has never been investigated. In this study, the importance of the various existing or potential functions of a pond fish farm and their role in the future development of multifunctional pond fish farms have been investigated through the analysis of the appraisal of experienced farm managers by analytic hierarchy process. The results of the research provide empirical evidence that can be used for the elaboration of policies, development strategies, R&D and the legal frameworks needed for the sustainable development of multifunctional pond fish farming.
... Water in coastal and estuarine areas is often contaminated by various pollutants, including trace metals, as a consequence of human activities (Chua, 1992;Wang and Wang, 2007). Trace metal pollution in aquatic environments has become a global phenomenon because of its toxicity and persistence for several decades in the aquatic environment (Cheung and Wang, 2008). ...
Ridgetail white prawn (Exopalaemon carinicauda) is widely distributed in Chinese coastal zones, especially in the Yellow Sea and Bohai Sea. It is not only considered as an important economic species in China, but also taken as a potential indicator species for the environmental pollution in the estuaries. At present, the responses of this species to environmental toxicants, including trace metal are not well understood. In this study, the acute toxic effects of zinc (Zn) and mercury (Hg) on the survival, oxygen consumption, ammonia-N excretion, and metal accumulation were investigated in the juveniles of E. carinicauda. The median lethal concentrations (LC50) of Zn were 76.4, 44.0, 30.2, and 17.2 mg/L, respectively, after the juveniles were exposed in for 24, 48, 72, and 96 h, and the LC50 of Hg was 0.212, 0.096, 0.084, and 0.065 mg/L under the same exposure duration. The juveniles decreased the oxygen consumption by 51.4%, and increased ammonia-N excretion by 129% when they were exposed in Zn at the concentration of 76.4 mg/L compared with their controls without Zn exposure, therefore the O:N ratio decreased by 82.9% compared with the control. Hg exposure with the concentration of 0.212 mg/L caused the inhibition of oxygen consumption by 48.1% and increasement of ammonia-N excretion by 161%, and the atomic ratio of consumed oxygen to excreted ammonia-nitrogen (O:N ratio) decreased by 80.6% in the juveniles in comparison with the control. A concentration-dependent accumulation of heavy metals was observed in the gills, hepatopancreas and muscles of the experimental animals, with a maximum accumulation of 16.3 folds for Zn and 72.8 fold for Hg in the gills of the juveniles after 24 h exposure. The data obtained from the present study would provide useful information for help further understanding on the toxicological responses of this species to trace metals.
... The cultured shrimp contributed 29.93 % in quantity out of 461,239 tonnes and 63.47 % out of $ 1,478 million to the total seafood exports in 2004 (MPEDA 2005). Rapid development of aquaculture has led to large scale removal of valuable coastal wetlands and subsequent loss of goods and services generated by natural resources systems (Chua 1992), threatening the long term sustainability of the shrimp aquaculture itself. ...
Rapid development of aquaculture in coastal areas has raised worldwide concern on its potential role in mangrove habitat loss. This study is an attempt to assess the impact of shrimp aquaculture on the mangroves eco systems. The land resources used for aquaculture development were mapped from satellite data and analysed using Geographical Information System (GIS) to assess the extent of conversion from different land types to aquaculture. The digital data from Landsat-TM of 1987, IRS 1B-LISS II of 1994, IRS 1C-LISS III of 1998 and IRS-1D LISS III of 2004 were used for the study. Aquaculture area has increased from 6.91 ha in 1987 to 386.33 ha in 2004. Change detection analysis using GIS indicated that mangroves of 4.84 ha and degraded mangroves of 6.16 ha were converted for aquaculture. Major development of aquaculture has occurred from agricultural lands (176.99 ha) and fallow lands (234.25 ha). Forest plantation of 21.68 ha, mud-flats of 23.63 ha, water bodies of 18.13 ha and sandy areas of 60.87 ha were converted for aquaculture between 1987 and 2004. The aquaculture farms of 15.03 ha, converted from Asian Fisheries Science 20(2007):325-338 326 agricultural lands were reconverted back to agriculture due to disease problems. The shrimp culture practiced in 109.47 ha was abandoned and lying as fallow lands. Mangroves at Pichavaram were not affected due to the development of shrimp culture. The study indicated that remote sensing and GIS techniques are ideally suited to the task of assessing changes in the mangrove environments due to aquaculture and have the potential to contribute for sustainable aquaculture.
... Ayrıca yetiştiricilik yapılan işletmelerden doğal ekosisteme salınan besin elementlerinin fitoplanktonlarca kullanılarak ötrofikasyona sebep olabileceği de yine yapılan çalışmalarca ortaya konmuştur (Phillips ve ark. 1985;Weglenska ve ark., 1987;Wisniewski ve Planter 1987;Rast ve Holland 1988;Aura ve Stigebrandt 1990;Chua 1993;Okumuş 1997;Çelikkale ve ark., 1999;Pulatsü ve Karaca, 2001). ...
zet: Su ürünleri yetiştiriciliği Türkiye'de nispeten yeni ve gelişmekte olan bir endüstridir. Su ürünleri yetiştirme teknolojisinin gelişimi ile beraber çiftliklerde gökkuşağı alabalığı (Oncorhynchus mykiss, Walbaum, 1792), levrek (Dicentrarchus labrax, L., 1758) ve çipura (Sparus aurata, L., 1758) yetiştiriciliği artarak devam etmektedir. Bu çalışmada; su ürünleri yetiştiriciliğinin doğal ekosistem üzerindeki etkileri konusunda yapılan çalışmaları sınıflandırmak ve bütünsel bir yaklaşımla bu konudaki literatür boşluklarını ortaya koymak amaçlanmıştır. Su ürünleri yetiştiriciliğinin doğal ekosistem üzerindeki etkilerine dair ulusal ve uluslararası indeksli yayınlar taranmış, yapılan yüksek lisans ve doktora tezleri ve projeler incelenmiştir. Taranan çalışmalara göre su ürünleri yetiştiriciliğinin ekosisteme etkileri su kalitesi, bentik kompozisyon ve biyolojik çeşitlilik ve kommünite ilişkileri olmak üzere üç başlık altında ele alınmıştır. Bu çalışmalarda genel olarak; su ürünleri faaliyetlerinin su kalitesi üzerinde anlamlı farklılıklara neden olduğu tespit edilmiştir. Derlenen çalışmalarda yetiştiricilik aktivitelerinin su kolonu (fiziko-kimyasal parametreler ve besinsel element) ve sedimentte yaratabileceği olası değişimler ön planda gözükmektedir. Su ürünleri yetiştiriciliğinin bentik kommunite yapısı (tür kompozisyonu, bolluğu ve çeşitliliği) üzerine etkilerine dair çalışmalar da bulunmaktadır. Derlenen bazı çalışmalarda kafeslerin belli bir uzaklığa kadar bentik ortamı etkileyebileceği, bu bölgedeki balık kommünitelerinin yapısında değişim olabileceğine dair kaygılara yer verilmiştir. Bununla birlikte su ürünleri yetiştiriciliğinin türler arası etkileşimlere olan etkisini içeren detaylı çalışmalara rastlanmamıştır. Ekosistem hizmetlerinden sürdürülebilir bir şekilde maksimum yarar elde edebilmek için ekosisteme bütüncül yaklaşım önemlidir. Su ürünleri yetiştiriciliğinin ekosistem üzerindeki olası etkilerini daha iyi analiz etmek için abiyotik etkenlerle birlikte türler arası ilişkilerin ve besin ağlarına ait dinamik yapıların da değerlendirilmesi önerilir. Abstract: Aquaculture is a relatively new and developing industry in Turkey. The rainbow trout (Oncorhynchus mykiss, Walbaum, 1792), sea bass (Dicentrarchus labrax, L., 1758) and sea bream (Sparus aurata, L., 1758) farming increasingly continue with the development of aquaculture technology. In this study; it is aimed to classify the investigations done on the impact of aquaculture on natural ecosystems and to reveal gaps on the literature in this regard with a holistic approach. The national and international indexed publications on the effects of aquaculture on natural ecosystems were scanned and masters and doctoral theses and projects were searched. According to the compiled references, the effects of aquaculture on ecosystems were assessed under three topics; water quality, the biodiversity of benthic composition and community relations. In these studies generally, water quality was the main issue on the effects of aquaculture on aquatic ecosystems. The changes in physicochemical parameters and nutrient constituent of water column and possible changes in the sediment structure were the foreground subjects according to compiled studies. The effects of aquaculture on benthic community structure (species composition, abundance and diversity) were also well documented. There were some concerns about the cage fisheries may affect the benthic environment up to a certain distance to cages in terms of causing changes in the structure of the fish community. On the other hand, there was a few detailed work including aquaculture effects on interactions between species. The holistic approach about ecosystem is an important theme in order to obtain maximum benefit from ecosystem services in a sustainable manner. The relationships between species with abiotic factors and the dynamic nature of the food web should be evaluated for a better analyze of the potential impacts of aquaculture on ecosystems.
... Logam berat mungkin diakumulasioleh bivalvae dan ikan yang tumbuh di perairan pantai yang terkontaminasi dengan limbah industri dan pertanian (Chua, 1992 Pada umumnya nilai MPC disajikan dalam basis material basah (wet basis), sedangkan konsentrasi Hg sampeldalam studi inidisajikan d alam dry basis. Jika diasumsikan konsumsi ikan penduduk wilayah studi adalah 25 kg/kapita/tahun atau 68,5 g/kapita/ hari, maka asupan Hg harian penduduk Ratatotok sebanyak 0,0685 kg/hari x (1-0,7 x 0,075 mg/kg, dengan asumsi kadar air ikan 70%) = 0,0015 mg Hg/ hariatau sekitar 4,5% (0,0015/0,0329) dariTDl/70 kg. ...
Studi ini telah dilakukan di kawasan pesisir Teluk Ratatotok, Kabupaten Minahasa Selatan, Sulawesi Utara dari tanggal 26 Juli - 1 Agustus 2004, bertujuan untuk mengetahui distribusi kandungan merkuri (Hg) dalam komponen ekosistem di kawasan pesisir T. Ratatotok. Metode survai dipadukan dengan Sistem Informasi Geografi digunakan dalam studi ini.
... The cultured shrimp contributed 29.93 % in quantity out of 461,239 tonnes and 63.47 % out of $ 1,478 million to the total seafood exports in 2004 (MPEDA 2005). Rapid development of aquaculture has led to large scale removal of valuable coastal wetlands and subsequent loss of goods and services generated by natural resources systems (Chua 1992), threatening the long term sustainability of the shrimp aquaculture itself. ...
... The causes of the mortality were variously attributed to industrial pollution, bacterial diseases, and viral diseases. repeated efforts to revive the industry resulted in additional collapses in 1992 and 1993, despite attempts to switch from P. monodon to alternate species such as P. japonicus and P. penicillatus (Chua 1993). in 1994, shrimp production in Taiwan had dropped to 25,000 mt, and most Taiwanese shrimp farmers had switched to marine fish culture. ...
... Shrimp farms are often located near the coast and draw seawater directly from coastal areas to use for rearing the shrimp. However, coastal water is often contaminated by many kinds of heavy metals because of human activities (Chua, 1992). Hence, the impacts of heavy metals on shrimp culture should be observed. ...
The objectives of this study were to evaluate the acute toxicity of copper in different life stages of shrimp Litopenaeus vannamei, and to determine the effect of sub-lethal copper concentrations on osmoregulatory capacity. In L. vannamei, the increase of the tolerance to copper is apt with the developmental stage. The 24 h LC50 values were low in nauplii and zoeae (between 11.98 and 25.25 νg Cu 1-1), and slightly increased in mysis (178.90 to 895.84 μg Cu 1-1). In mysis, the 48 h LC50 values were comprised between 84.89 and 368.90 μg Cu 1-1. After metamorphosis, the 48 h LC50 increased sharply. Post-larvae 10 (PL10) were less tolerant than PL5 after the exposure to copper for 24 and 48 h. However, after being exposed 96 h, the LC50 of PL10 (1577.37 μg Cu 1-1) was higher than that of PL5 (989.9 μg Cu 1-1). The most tolerant stage was juvenile. The 24 h, 48 h and 96 h LC50S of juvenile were 8576.58, 6387.65 and 2094.09 μg Cu 1-1, respectively. The juvenile of L. vannamei has low ability to maintain hemolymph osmoregulation under copper exposure. After the exposure to 675, 1325 and 2010 μg Cu 1-1 at salinity 15, the osmoregulatory capacity of exposed individuals significantly reduced by 70.3, 77.2, and 77.8% respectively compared to control animals.
... It is believed that the rapid development of aquaculture and its social-economic environment necessitates a periodical re-assessment of the guidelines as well as their implementation. The sustainable development of aquaculture requires adequate consideration of interactions among environmental, social, and economic factors that accompany any development (Chua 1992;WB 1998;NACA/FAO 2000). In assessing the sustainability of any enterprise or technology, consideration should be given to at least the following (Frankic and Hershner, 2003): ...
Aquaculture is one of the fastest growing segments of the Turkey agriculture. Its popularity and success as an investment opportunity and a means of diversifying farming operations have resulted in a growing interest among traditional agriculture producers and others. As Turkish people have become more health conscious, the demand for fisheries production has increased. Per capita consumption of seafood has grown from about 1kg in mid 1980's to around 7 kg in 2008. To be successful, producers must have the ability to make a reasonable assessment of sustainable aquaculture enterprise opportunities and limitations including current breeding, feeding, water quality, production technologies and management practices. Therefore, in the present paper some aspects of sustainable aquaculture on the rural development will be discussed.
... Its biological cycle consists of three larval stages (five nauplii, three protozoea, three mysis), followed by the postlarva, juvenile, and adult phases (Rosenberry 2002). Most shrimp farms are located near the coast but coastal waters may be contaminated with heavy metals, including Pb, because of human activities (Chua 1992). Hence, the impacts of lead on shrimp culture should be considered. ...
The purpose of this study was to evaluate the acute toxicity of lead for different life stages of shrimp, Litopenaeus vannamei, and to determine the effect of its sublethal concentrations on osmoregulatory capacity (OC) as well as the possible histological alteration in the gills of juvenile shrimp. The 24-, 48-, and 96-h LC50 values for lead to L. vannamei increased progressively with increasing life stage, from nauplii < zoeae < mysis < postlarvae < juvenile. After 15-d exposure to 3.25, 6.50, and 9.75mg Pb/ L, the OC values of exposed shrimp were reduced by 39, 73, and 157%, respectively compared to control animals. Compared to controls, the lead concentrations in gill tissues increased significantly by 127,500, 137,500, and 141,000% in shrimps exposed to 3.25, 6.50, and 9.75mg Pb/ L, respectively. After lead exposure, hemocytic congestion in efferent vessels and multiple hyperplasia were observed in gill filaments, resulting in narrowed hemolymphatic lacuna. The histopathological effects increased with increasing Pb concentration.
... This prawn is widely distributed in the coastal zone in China, especially in the Yellow and Bohai Seas as well as in estuaries. Because of human activities, water in coastal and estuarine areas is often contaminated by kinds of pollutants, including heavy metals (Chua, 1992;Wang and Wang, 2007). Heavy metal contamination in aquatic systems is reportedly one of the most critical environmental issues (Páez-Osuna, 2000). ...
... A large number of shrimp farms have been sited in areas where production failed after a relatively short period of time (Chua, 1993). Factors contributing to farm failures include inappropriate soil conditions, poor husbandry practices, disease outbreaks stemming from infected water supplies and seedstock, and pollution from urban and industrial sources (Miller, 1996). ...
... Worldwide, the rapid expansion and intensification of cultured shrimp production has degraded coastal ecosystems at high social and economic cost [11][12][13][14][15]. Nevertheless, this has not prevented the further intensification of the industry in existing areas or the damaging exploitation of new stretches of coastline [16]. ...
This paper investigates the link between shrimp farming development and salination processes in the coastal Cai Nuoc district of Ca Mau province, Mekong delta, Vietnam. Surface water, groundwater, and soils were sampled for four consecutive seasons (2002–2004). Salinity in the surface water (40.04–44.78 ‰) was, during the dry season, higher than that of the oceans and remained high during the wet season (more than 8‰). Soils were highly affected by salinity (EC(1/5) 4.57 dS/m), even during the wet season (EC(1/5) 3.78–3.90 dS/m). Salinity levels in both surface water and soils were regulated by seasonal rainfall patterns. The groundwater seemed to be unaffected by shrimp farming development though its salinity level (1.04‰) was higher than the normal values acceptable for human consumption. As a result of shrimp farming development, soil and water salination is currently a serious environmental issue in the Cái Nước district.
... (EIA) protocols of many countries worldwide [9, 10], but analysis of the literature from the last decades has highlighted a large number of unclear aspects. Many seminal reviews [11, 12], reports, and books [13, 14] have attempted to delineate the trend of aquaculture effects on the environment, but most of the information, since it is spatially and temporally fragmented, is still insufficient to define the precise dynamics and magnitude of the impacts. In this regard, even peer-reviewed papers very often lack an experimental approach, data collected too often remain linked to local dynamics, or there is a general inhomogeneity in the use of environmental descriptors. ...
More than 30 peer-reviewed articles (1980–2005) were analysed using meta-analytical reviewing techniques, and about 340 study cases were used to test whether aquaculture facilities had any effects on physical and chemical variables. The analysis tested differences between experimental conditions vs. chosen-by-author controls. Across all study cases, cultivated organisms (fish, shrimps and bivalves) did not have any clear effects on the water temperature and salinity. Dissolved oxygen also was found to be unaffected by aquaculture practices. On the other hand, crowding led to significant pH variations, which was more accentuated in shrimp (d+=0.66; P0.05). Water transparency and turbidity were significantly affected by shrimps and fish farming.
... Sustainable development includes careful consideration of multiplicity of parameters and their interactions. Therefore, sustainable development of shrimp culture requires adequate consideration of interactions among environmental, social, and economic factors that accompany any development (NACA/FAO, 2000;WB, 1998;Chua, 1992). Management choices will be required when certain activities can appear in the same locations based on suitability analysis of the area. ...
This paper briefly describes the status of shrimp culture development in India, discusses its ecological and socio-economic impacts and recommends measures to achieve long term sustainability using advanced tools like remote sensing and Geographic Information System (GIS). It highlights a selected number of remote sensing case studies on applications of remote sensing and GIS for sustainable management of shrimp culture. This paper addresses the potential capabilities of evolving satellite remote sensing technology and GIS for the sustainable management of shrimp culture through the analysis of various dataset depicting the criteria of sustainability. The need for accurate prediction of water quality parameters within the context of sustainable shrimp culture demands the application of advanced methods like Artificial Neural Network (ANN) combined with remote sensing and GIS. These are essential in the spirit of sustainable development and management, particularly in developing countries, which are often more vulnerable to environmental degradation.
... Along the west coast, Kerala has dominant traditional system of paddy-cum-shrimp culture, followed by traditional systems in Karnataka and Goa. Rapid expansion of coastal aquaculture has serious environmental and socioeconomic consequences, namely large-scale removal of valuable coastal wetlands, salinization of groundwater and agricultural lands, and subsequent loss of goods and services generated by natural resource systems 1 . In addition, concentrations of copper and barium were higher in freshwater than in brackish waters. ...
Realizing the impact of aquaculture on environment, a study was taken up to assess the feasibility of generating information on aquaculture in a part of coastal Andhra Pradesh, southern India, using Landsat-TM, SPOT-MLA, IRS-1C/-1D-LISS-III and PAN data. By virtue of higher spatial resolution, the LISS-III and PAN-merged data permitted the detection of individual aquaculture ponds. In addition, shape factor derived from the ratio of area and perimeter of aquaculture ponds has shown promising result in segregation of aquaculture into prawn culture ponds and fish ponds, which is important from environmental health point of view. The area under aquaculture has grown tremendously during the period 1986 to 2001.
... The quality of organic matter is also important as a determinant of consequences of carbon transport for fauna. For example, excessive labile organic matter (e.g., from shrimp farming) can lead to extensive hypoxia zones (Chua 1992), whereas more refractory organic matter can accumulate in marine sediments (POC) or can be transported in dissolved form (DOC) offshore (Alongi and Christoffersen 1992). ...
The role of mangrove primary production in the carbon cycle of mangrove ecosystems and in the coastal zone continues to be an issue of debate. Although it was long hypothesized that a direct trophic link exists between mangroves and faunal communities in adjacent aquatic habitats, all recent studies find little or no evidence for the existence of such a link, and many of the earlier work which fed the persistence of the "outwelling hypothesis" may need to be re-interpreted. Mangrove ecosystems are highly variable, however, and a data compilation from widely differing mangrove ecosystems shows that although organic carbon stocks in intertidal mangrove forests can be very high and almost entirely of mangrove origin, there are also systems in which deposited estuarine or marine suspended matter is the dominant source of organic carbon and nitrogen in these sediments. Such variations are expected to have a major impact on the carbon dynamics in mangrove ecosystems. In particular, we find that the carbon substrate for microbial populations varies strongly between mangrove ecosystems with different sedimentary carbon inputs, and that for "flow-through" systems with important external carbon inputs to the intertidal zone, surprisingly few species of macro-invertebrates make significant use of mangrove carbon as a food source. Preliminary results suggest that as more mangrove litter is retained within the system, its trophic importance also becomes higher. Large uncertainties remain concerning the ecological fate of exported mangrove carbon. As little evidence can be found for its assimilation by subtidal faunal communities, and as the sedimentary organic carbon pool in some systems suggest that its contribution is minor, mineralization might represent a quantitatively important fate of mangrove production, although very few direct measurements exist. For an extensive mangrove ecosystem in the Gautami Godavari delta (east-India), we demonstrate that very abrupt local changes can occur in the aquatic biogeochemistry, whereby mangrove creeks act as localized sites of mineralization of organic matter, and for subsequent efflux of CO_2 towards the atmosphere.
... A large number of shrimp farms have been sited in areas where production failed after a relatively short period of time (Chua, 1993). Factors contributing to farm failures include inappropriate soil conditions, poor husbandry practices, disease outbreaks stemming from infected water supplies and seedstock, and pollution from urban and industrial sources (Miller, 1996). ...
... Shrimp farms are frequently located near the coast where they draw seawater directly from adjacent coastal waters. Coastal water is, however, often contaminated by many kinds of metals resulting from polluting human activities (Chua 1992). The impact of metals on shrimp culture should, therefore, be considered. ...
This study compared the acute toxicity of Cd and Zn on juvenile Litopenaeus vannamei when administered at different salinities. It also evaluated the effect of sublethal Cd and Zn concentrations on the osmoregulatory capacity (OC) of the juvenile shrimp. Tolerance to Cd and Zn increased progressively with increasing salinity. Cadmium was more toxic than zinc. The 96 h LC50's of cadmium to juvenile L. vannamei were 450, 690, and 1020 µg Cd L−1 at 5, 15, and 27 ppt salinity, respectively. The 96 h LC50's of zinc were 3780, 5520, and 8910 µg Zn L−1 at 5, 15, and 27 ppt, respectively. Exposure to sublethal concentration of Cd and Zn reduced the hyper-OC of exposed shrimp at 5 and 15 ppt salinity, and increased the hypo-OC of exposed animals at 27 ppt salinity.
Coastal resources like the mangroves of the Southeast Asian and the Pacific regions are under pressure from economic development. Mangroves are important coastal ecosystems and provide direct and indirect benefits as well as essential ecological services. It is argued that since many of these benefits are not marketed, there is a general lack of appreciation of them, hence mangroves are regarded as ‘wastelands’. An overview of major threats to mangroves in these two regions is presented. Unsustainable use of mangrove resources is discussed in terms of market and policy failures. These failures result in non-recognition of mangrove values in development decisions often resulting in irreversible conversions to alternate land uses. Total Economic Valuation Methodologies to capture all economic values (which are both marketed and non-marketed) are discussed. The application of these methodologies is illustrated by two case studies drawn from the Southeast Asia and the Pacific regions. These case studies of economic valuation demonstrate that mangroves are not ‘wastelands’ but have highly comparable values to several alternate use values. Development options which result in unsustainable use or irreversible conversions provides greater justification to undertake total economic valuation.
Many analyses suggest that after significant growth in the last three decades, production from capture fisheries is unlikely to grow much further, and will be increasingly limited by physical and biological capacity, by the costs of exploitation, and by deteriorating environments. Aquaculture production has been widely expected to compensate for shortfalls from traditional fisheries (see for example Pillay, 1990). Here, inputs, production processes and quality of output can be at least partially controlled, and ownership, care and environmental responsibility might be more easily established. By removing natural constraints to survival and productivity, and by husbandry and management, production need be limited only by availability of simple inputs such as land, water, seed, fertilizer and feeds. According to FAO statistics, aquaculture has grown steadily in recent decades (Table 1). On present trends, by the year 2000, farmed production might account for some 20 million t y-1, some 16–18% by weight, perhaps as much as 45% by value of total output.
Experiments were conducted to evaluate the feasibility of using juvenile giant clams (Tridacna) to remove dissolved inorganic nutrients (nitrate and phosphate) from aquaculture effluent. Three (T. derasa Roding, T. maxima Roding, and T. squamosa Lamarck) of the four species tested during a two-month experiment all had very high survivorship in both effluent and control seawater, but T. gigas (Linne) experienced 50% mortality. T. maxima and T. squamosa showed virtually no growth in both effluent and control waters. T. gigas had the fastest growth rate among the four species. T. derasa grew significantly faster in effluent than in seawater. In a 24-h experiment (12 h dark followed by 12 h light), all the four species absorbed similar and significant amounts of nitrate and phosphate from effluent during the light period. Our study demonstrates that although it may not be possible to rely on giant clams alone to remove all excess dissolved nutrients from intensive food fish aquaculture effluent, it is entirely feasible to use giant clams to remove all excess nutrients in effluent of marine ornamental species. Giant clams can be either incorporated into a polyculture system with other marine aquarium trade species, or they can be grown in effluent in separate tanks.
Aquaculture, Resource Use, and the Environment places aquaculture within the larger context of global population growth, increased demand for sustainable, reliable sources of food, and the responsible use of natural resources. Aquaculture production has grown rapidly in recent decades as over-exploitation and environmental degradation have drastically reduced wild fish stocks. As fish production has increased, questions have persisted about the environmental sustainability of current aquaculture practices. Aquaculture, Resource Use, and the Environment is a timely synthesis and analysis of critical issues facing the continued growth and acceptance of aquaculture practices and products. Chapters look at the past, present, and future demands for food, aquaculture production, and tackle key issues ranging from environmental impacts of aquaculture to practical best management practices in aquaculture production. Providing broad coverage of issues that are essential to the continued development of aquaculture production, Aquaculture, Resource Use, and the Environment will be vital resource for anyone involved in the field of aquaculture.
Aquaculture can affect the environment in a number of ways, including organic enrichment around the farm, increased dissolved nutrients or chemicals in the growing area, escapees affecting native species, loss of habitat and loss of amenity. Likewise, the environment can affect aquaculture, through poor water quality (e.g. pollutants, high particulate matter), predators and nuisances species such as jellyfish or seals, or changing climate regimes. These impacts can be reduced by careful site selection, to provide the appropriate conditions for the species being cultured, and good farm management. New technologies are assisting in minimising these environmental impacts. Recent developments in remote sensing and seabed mapping have improved site selection. Monitoring and assessment of the environment around aquaculture farms is becoming more common, and this is also being supported by new technology. A range of probes is now available that can be used in the field to provide an immediate measure or placed in situ to continuously monitor environmental conditions. Other advances include the use of visual techniques with digital cameras and remotely operated or autonomous underwater vehicles. Computing capability and mathematical models are also becoming increasingly important to management, both for determining carrying capacity of growing areas and for prediction of impacts. These models are becoming increasingly sophisticated and are capable of linking across different temporal and spatial scales and across trophic levels and incorporating social and economic parameters.
Aquaculture is one of the fastest growing food industries. However, the rapid growth of aquaculture worldwide has resulted in growing concerns about its impact on important ecosystems. The expansion of aquaculture farms in the coastal areas has led to conversion of mangroves, more rapidly. To assess the impact of aquaculture on mangroves, the present study has been undertaken in Mahanadi delta of Orissa, East coast of India which is famous for its distinctive mangrove ecosystem. It has undergone tremendous changes due to the development of aquaculture and agriculture activities during last two decades. For this, satellite data of different time periods (Landsat MSS of 1973, Landsat TM of 1990 and IRS P6 LISS III of 2006) were used. It was found that the delta was occupied by dense mangrove (12.6%), open mangrove (3.3%), aquaculture (12.9%) and agriculture (30.9%) in 2006. A loss of 2606 ha mangrove area and an increase of 3657 ha aquaculture area was observed from 1973 to 2006 clearly depicts the augment of aquaculture industry. It is suggested that, regular monitoring of the mangroves and effective implementation of coastal management laws be strictly undertaken to prevent the further loss mangroves in Mahanadi delta.
The concentration and distribution of Fe, Mn, Ni, Cu, Cd, and Zn among the tissues of wild and farmed pre-adult shrimp Penaeus vannamei collected from the northwest coast of México was determined. Distinct inter-tissue and inter-site differences in metal concentrations were observed. In general, highest concentrations of Zn, Ni, and Cd were found in hepatopancreas while higher levels of Cu and Fe occurred in gills. The highest Mn concentrations were noted in the antennal organs and exoskeleton. Differences between shrimps were evident in the exoskeleton (for both sexes) and hepatic material (females). The farmed shrimp (larger in size) accumulated more Fe than the wild shrimp. Similarly, in the hard tissues (exoskeleton and antennal organs) the farmed shrimp accumulated more Cu than the wild shrimp for both sexes, while the wild shrimp accumulated more Mn than the farmed shrimp in the hard tissues of both sexes.
An overview of national and international factors shaping Indonesia's coastal environmental management is provided. Indonesia is committed to sustainable development of its coastal lands and waters, but the inventory and capacity of coastal resources for supporting Indonesia's rapid economic growth is not well known. There is a need for Indonesia to evolve from unsustainable single‐purpose resource uses toward sustainable multiple resource uses supported by planning and management integrated at the national and provincial levels. Key coastal environmental management challenges are to create a national cross‐sectoral coordinating agency, develop provincial management capabilities, and foster community and private sector participation. As this populous developing country begins its second 25‐year development cycle, increasing the economic contribution of coastal resources in context with sustainable national development goals will be essential.
The marine environmental problems of developing regions are a particular cause for concern because of the great dependence of their human populations on marine resources for survival, and because a significant portion of the world's natural heritage is threatened. Of the problems, the destruction of shallow-water ecosystems and organic (sewage) pollution are the most prominent. The environmental issues typical for Third World countries are clearly related to their socioeconomic conditions, so that attempts at solutions must possess an adequately broad perspective, i.e. they must consider all relevant aspects of a problem. There is also a great need to strengthen the capabilities of developing nations to care for their own environment.
The importance of aquaculture as a means of supplying the predicted shortfall of fish- eries and other aquatic products has been increasingly proposed. It would appear certain that increased demands from growing populations must be met from managed systems in which outputs can be increased from selected productive inputs. While aquaculture largely meets such criteria, this is far less the case for marine fisheries, whose ecological and institutional complexity constrains most options for growth. However, aquaculture itself is by no means free of constraints, and is unlikely to have unlimited potential for expan- sion and the sustainable delivery of benefits. This paper explores comparative features of aquaculture and marine fisheries, internationally and at the regional North Atlantic level, and considers the extent and circumstances in which marine fisheries will retain their significance, and in which, if at all, aquaculture might be expected, to supplant their former role. The conclusion drawn is that while aquaculture can offer important advantages of controllability, ownership rights and responsibilities, and market adaptation, the future may see greater integration of the aquaculture and marine fisheries sector, and greater appreciation of their comparative roles.
A threatened green sea turtle (Chelonia mydas) rookery (nesting beach) in Java, Indonesia, requires protection within a complex regulatory regime. The unsustainable exploitation of turtle eggs and potentially damaging land use threaten Java's prime C. mydas rookery at Pangumbahan. The regional imperative for economic development must be reconciled with national protection and sustainable use policy declared in the National Marine Turtle Conservation and Management Strategy of 1991. A discussion is presented of the complexities of protecting this rookery and how implementing recent legislation and improving cross‐sectoral cooperation could achieve a better long‐term prospect for the resource.
Nitrogen pools and transformations and benthic communities at a Perna canaliculus farm and a nearby reference site without direct influence of marine farming in Kenepuru Sound, New Zealand, were compared on four dates between September 1982 and May 1983. The organic nitrogen pool in the top 12 cm sediment was 7.4 to 10.8 mol m-2 at the mussel farm and 6.1 to 8.9 mol m-2 at the reference site. The nitrate and nitrite pools were similar in both sediments, but the ammonium pool in the mussel farm sediment was about twice as high as in the reference sediment. In January, the sediment ammonium concentrations ranged from 418 nmol cm-3 (surface) to 149 nmol cm-3 (12 cm depth) at the mussel farm and from 86 to 112 nmol cm-3 at the reference site. The molar C:N ratio of the sediment organic matter was 6.2 to 7.2 at the mussel farm and 7.9 to 10.0 at the reference site. The molar N:P ratio of the sediment organic matter was 4.3 to 7.2 and 3.3 to 6.1 at mussel farm and reference site, respectively. The total nitrogen mineralisation rate in the top 12 cm sediment ranged from 21.7 to 37.1 mmol m-2 d-1 at the mussel farm and from 8.5 to 25.0 mmol m-2 d-1 at the reference site. Ammonium excretion by mussels was about 4.7% (January) and 7.4% (May) of the combined nitrogen mineralisation by mussels and sediment. The sediment-denitrification rate was 0.7 to 6.1 mmol m-2 d-1 at the mussel farm and 0.1 to 0.9 mmol m-2 d-1 at the reference site. In January, 76 and 93% of the nitrate reduced in the sediments were denitrified at the mussel farm and reference site, respectively. The denitrification rate on the mussel lines (determined on detritus-covered mussels) was twice the mussel farm sediment-denitrification rate and 10 times the reference sediment-denitrification rate. Total denitrification at the mussel farm was 21% higher than at the reference site. The loss of nitrogen through mussel harvest and denitrification was 68% higher at the mussel farm. The surface layers of both sediments contained about 75 mg m-2 chlorophyll a. Sediment phaeophytin levels were 52 mg m-2 at the reference site and 137 mg m-2 at the mussel farm. While the benthic infauna of the mussel-farm sediment consisted only of polychaete worms, the reference sediment contained also bivalve molluscs, brittle stars and crustaceans.
This paper discusses the basis for cage culturing of salmonids and mussel long-line rearing in Scandinavian marine aquaculture, it also includes a discussion on the support that is required from the marine environment to sustain production; how aquaculture fits into the marine ecosystem; and what side-effects and changes it may cause. Local as well as regional environmental effects are evaluated and related to the growth and economic development of the aquaculture industry. The support from marine and agricultural ecosystems needed to provide the farming of salmonids with food is estimated (in energy terms) to be about 6 times larger than the contributions of all industrial activities directly or indirectly involved with the cage-farming. The development of a sustainable aquaculture industry implies that culturing has to be carefully dimensioned to the capacity of the ecosystems to support aquaculture production, and should not exacerbate environmental degradation. It is proposed that a combined strategy of culturing mussels and salmonids would be one way towards this goal.
The concept of sustainability and its corollary, sustainable development, have become part of the political rhetoric of the 1980s, in part due to the recent publication of the Brundtland Commission report. Our Common Future. Governments, groups, and individuals use these concepts to justify their proposed (and sometimes conflicting) actions; a number of definitions have been offered. This paper examines the concept of sustainability and its application in a variety of contexts including single biological resources (such as a fishery), multiresource ecosystems, and in more complex social‐economic‐physical settings. A series of questions are raised concerning the concept: intergenerational implications of patterns of resource use, equity concerns, time horizons, and non‐negotiable alternatives, among others. Examples from the Philippines, Thailand, and Malaysia are used to illustrate these issues. In spite of divergent views on what sustainability means, the discussion leads to certain findings that have broader policy implications.
Coastal aquaculture is a traditional practice in Southeast Asia. Accelerated development in the last three decades has created negative environmental impacts, such as extensive mangrove conversion to ponds, changes in hydrologic regimes in enclosed waters due to proliferation of aquaculture structures, and discharge of high levels of organic matter into coastal waters. Similarly, the increasing deterioration of coastal water quality resulting from the discharge of domestic, agricultural and industrial wastes into coastal waters has affected aquaculture production and profitability. Furthermore, the increased frequency of red tides in the region has posed serious threats to coastal aquaculture, especially to mollusc cultivation. The introduction of management measures to mitigate deteriorating coastal water quality and the adverse environmental impacts of aquaculture development has now become a matter of urgency to the region.
A rapid procedure for the quantitative determination of the antibiotic oxytetracycline in sediments and in seawater using high performance liquid chromatography is presented. The mean recoveries from the sediment and from seawater were 98.4% and 99.5%, respectively. The limit of detection was 0.1 ppm for sediment and 0.01 ppm for seawater when injecting 150 μgl of sample. The persistence of oxytetracycline in the sediment was highly dependent on the rate of sedimentation. Based on measurements during the first 12 weeks and with a very small sedimentation rate, the half-life () of the antibiotic was 32 days. When the oxytetracycline layer was immediately covered with an additional 4 cm of sediment, the degradation was much slower (). The degradation of oxytetracycline in seawater was rapid. The half-lives were 128 and 168 h at 5 and 15°C, respectively, under illumination for 24 h a day with a 40-W fluorescent tube, and 390 and 234 h, respectively, in aquaria maintained in darkness.
The response of infaunal macrobenthic communities beneath salmonid seacages to solid organic wastes (food pellets and fish excreta) was tested by means of the ABC-method (abundance, biomass comparison method: Warwick 1986) on samples collected from the SAFCOL seafarm at Badger Cove, southeast Tasmania, from February to July 1988. The intermittent nature of the addition of organic waste allowed us to monitor decline and recovery of the macrofauna, i.e., harvesting of a cage permitted a period of recovery whilst restocking precipitated a decline. The ABC-method proved to be a sensitive indicator of community health. Under a normal feeding regime the macrofaunal community structure indicated a moderately disturbed condition. Only 7 wk after the cage was harvested, species richness had increased markedly and the community adopted an undisturbed condition. Further improvement was apparent 14 wk post-harvest. Similarly, a decline to a moderately disturbed condition was apparent 7 wk after restocking and species richness had declined. No such changes occurred under a cage which contained fish continuously over the same period.
The effects of waste from a salmon farm on the benthos of a fjordic sea loch on the western coast of Scotland have been studied. Within 3 m of the floating cages the sediment was highly reducing, and dissolved oxygen content of the water overlying the sediment ranged from 35 to 75% saturation. At ⩾ 15 m from the cages the sediment was oxygenated, and the dissolved oxygen content of the water overlying the sediment was 50–85% saturation. Sedimentary redox potential and dissolved oxygen content of bottom water showed a seasonal variation. The benthic fauna showed marked changes in species number, species diversity, faunal abundance, and biomass in the region of the fish farm, with four zones of effect identified. Directly beneath, and up to the edge of the cages, there was an azoic zone. A highly enriched zone, dominated byCapitella capitata (Fabricius) andScolelepis fuliginosa (Claparède), occurred from the edge of the cages out to as 8 m. A slightly enriched ″transitional ″ zone occurred at ⩽ 25 m, and a “clean” zone at distances > 25 m. This study showed that salmon farming had similar effects on the benthos as other forms of organic enrichment, but the effects were limited to a small area in the immediate vicinity of the cages
A study of 57 salmon farms in Scotland has shown that acute organic enrichment, usually accompanied by sediment outgassing, occurred beneath most cages. Development of these conditions is considered likely to result in ‘self-pollution’ of the fish farm. A relationship between the seabed type, water depth, water movement, and the intensity of organic enrichment was observed. Site selection guidelines are suggested for reducing the risk of ‘self-pollution’ and these are compared with those used by the fish farm industry elsewhere. The long seabed recovery time found at sheltered sites emphasizes the importance of site selection and also indicates that some site management practices may need modifying.
The persistence of oxytetracycline, an antibacterial agent, in bottom deposits from fish farms was investigated. The drug was found in concentrations capable of causing antimicrobial effects up to 12 weeks after administration. A half-life of approximately 10 weeks was estimated through a pilot study. Possible effects on sulphide ion activity are suggested.
Ambio, ISSN 0044-7447, vol. 19, nr. 1, 28-35 This paper deals with phosphorus and nitrogen loads resulting form Swedish fish-farming operations. The nutrient loads from the actual 1986 fish production of 3945 tons, from the licensed production of 17 323 tons, and from a scenario of 40 000 tons are calculated. The phosphorus and nitrogen loads from Swedish farming in 1986 were about 35 tons of phosphorus and 260 tons of nitrogen. These loads correspond to 0.6% and 0.2% of the total Swedish phosphorus and nitrogen load on the surrounding sea areas. Compared to the total load from all surrounding countries, including atomspheric deposition, the share of the Swedish fish-farming activities to the adjacent seas is 0.05% for phosphorus and 0.02% for nitrogen. The contribution of phosphorus and nitrogen via precipitation and dry deposition over the Swedish land area is about 100 times greater for phosphorus and about 1100 times greater for nitrogen, than the load from all Swedish fish-farming operations. The overall nutrient load from aquaculture is obviously negligible in comparison with other nutrient sources. Local effects on coastal areas can, however, be of importance and therefore local authorities have been restrictive with licensing.
Public health aspects of seafood-borne zoonotic diseases Hannover, Federal Republic of Germany The environmental impact of aquaculture. In Fish health management in Asia-Pacific. Report on a regional study and workshop on fish disease and fish health manage-ment
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The effecls of salmon farming on the benthos of a Scottish sea loch Proposed draft code of hygienic practice for the products of aquaculture
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Report on the Working Group on Environmental Impacts of Mariculture Aquaculture in Shallow Seas: Progress in Shallow Sea Culture
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Economic aspects of Pyrodinium red tides in the Western Pacific
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Maclean, J. L. (1989). Economic aspects of Pyrodinium red tides in the Western Pacific. In Biology, epidemiology and management of Pyrodinium red tides (G. M. Hallegraeff & J. L. Maclean, eds). ICLARM Conf. Proc. 21.
Red tides and Asian seafarming In Fish health management in Asia-Pacific. Report on a regional stud)' and work-shop on fish disease and fish health management
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Eutrophication resulting from salmonid fish in fresh and salt water: Scandinavian experience. Paper presented at the International Symposium of Feeding Fish in our Waters: Nutritional Strategies in Management of Aquaculture Waste
- G Persson
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Third World aquaculture and the environment
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Pullin, R. S. V. (1989). Third World aquaculture and the environment. Naga: ICLARM Q. 12: 10-13.
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Codes of practice and manual of procedures for consideration of introductions and transfers of marine and fresh-water organisms
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Ecology of antibiotic-resistant determinants of R plasmids from fish pathogenic bacteria
- Aoki
Marine pollution implications of coastal area development
- GESAMP
Reducing environmental impacts of coastal aquaculture
- GESAMP
Chemical and microbial contamination of fisheries products
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Report on the Working Group on Environmental Impacts of Mariculture, 27–31 March 1990. Aberdeen, Scotland
- ICES
Aquaculture in Taiwan
- Liao
Red tides and Asian seafarming
- Maclean
Chemicals for worldwide aquaculture
- Schnick