Final Report Summary - AQUAS (WATER QUALITY AND SUSTAINABLE AQUACULTURE: LINKS AND IMPLICATIONS)
The general aim of the 'Water quality and sustainable aquaculture: links and implications' (AQUAS) project is divided into specific objectives:
- to establish a conceptual framework for the studied areas;
- to structure the existing knowledge and advance the state-of-the-art concerning the relationship between aquaculture activities and water quality;
- to collect, structure and further exploit existing water quality and nutrient flux data from previous projects in two selected core study sites;
- to perform an initial analysis of the effects of aquaculture on local water quality and the effects of water quality on aquaculture, for the selected study sites;
- to assess the carrying capacity of the studied systems in terms of concentration levels (patterns) and gradients under average and selected critical conditions;
- to start considering alternative aquaculture management practices within the context of sustainable and integrated coastal zone management;
- to start developing a list of possible predictors and data necessary to conduct an adequate assessment of water quality conditions;
- to begin creating the base from which to derive a set of guidelines for sustainable aquaculture in partially limited waterbodies;% -to define a conceptual framework for the nutrient, pollutant and farm wastes, identifying source - sink - resuspension processes in coastal / estuarine systems, leading to quantitative estimations of the nutrient input from aquaculture into the environment;
- to develop alternative management criteria to better structure aquaculture development;
- to identify and assess alternative management practices oriented to the improvement of coastal water management, in order to allow a more efficient development in socially, economically and ecologically admissible terms.
The expected end results are those described in the objectives of the project. In particular, the estimation of the carrying capacity of the studied systems and the identification of alternative management criteria and practices are the main contributions from the project. The plan for using and disseminating the knowledge includes a project webpage: http://lim-ciirc.upc.es/aquas/(s’ouvre dans une nouvelle fenêtre) a project brochure, papers in scientific journals and press releases, as well as different forums to transfer project results to responsible administrations, private companies and general public.
Work performed and main achievements
The work performed started with the compilation of information from previous projects related to both case studies: Valencia Coast in Spain and Patos Lagoon in Brazil. On the other hand, data were also collected on one complementary site: San Quintin Bay (Mexico), which is dedicated to oyster culture.
A description of aquaculture facilities in the three sites was also carried out. In Valencia Coast they consist in farms with cages dedicated to intensive culture of gilthead seabream and sea-bass. Although there are 15 farms in this area, only 4 (Crimar, Cultipeix, Acuimed and Gramasa) were analysed.The data collected in this area include:
- water samples: salinity, temperature, pH, turbidity, suspended solids, nutrients, chlorophyll a, bacteria and phytoplankton;
- sediment samples: organic matter, dissolved oxygen, total nitrogen and total phosphorus;
- meteo / oceanographic data: waves, winds and currents;
- socio-economic data.
Moreover, hydrodynamic and water quality numerical simulations were carried out in both main areas (Valencia Coast and Patos lagoon). From the combined analysis of data and simulations, circulation patterns in both areas were determined.
Selected findings: Patos lagoon estuary
A preliminary set of sustainable management criteria were defined for the three sites. For Patos lagoon estuary, in order to develop a sustainable shrimp aquaculture (SSA), the following measures were proposed:
- To use only shrimp indigenous specie (Farfantepenaeus paulensis) to avoid risks of impacts related to displacement of ecological niches.
- The SSA should be implemented on a familiar basis, as complementary activity to the fishery and agriculture for the rural community, and should involve the community in a participatory management.
- The SSA should avoid the use of antibiotic substances and high density storage systems.
- The SSA must protect key functional processes, as the quality and the circulation of the water, the primary productivity and the maintenance of biodiversity.
- Shallow waters of estuarine embayments are nursery areas. Their biodiversity is key for the trophic ecology of the estuary and the development of the aquaculture must be done carefully in order to maintain it in good environmental quality.
- The installation of the structures inside the estuarine embayment should avoid the submerged prairies of Ruppia maritima.
- An environmental monitoring program should be implemented to control the dissolved nitrogen, organic matter and turbidity in the water column.
- In order to avoid use conflicts, and promote social and gender equity SSA should privilege the development of artisanal fishermen community and encourage the women involvement.
- The spatial planning of SSA development must consider all regulations at federal, state and local levels as the water use code and the municipal environmental plan.
- The SSA should take in consideration the code of conduct for responsible fisheries.
Selected findings: Valencia coast
Along the Valencia coast, one of the main sources of nutrients and pollutants are the rivers (e.g. Jucar) discharging in the area and the coastal lagoons (e.g. la Albufera) with open mouths to the sea. These waters have high nutrient concentrations due to the intensive agricultural exploitation of the river drainage basin, with the subsequent return of waters 'enriched' with pesticides and fertilisers and to the discharge of partially treated domestic and industrial wastewater from upstream towns. Another major source of nutrients and especially pollutants in this area are the marine outfalls of coastal towns, which discharge, in general, relatively close to the shoreline both treated and untreated waters.
Besides other secondary sources (illegal spills of wastewater or irrigation flows from ditches) that can introduce little amounts of nutrients and pollutants to the coastal systems, another source of these substances in Valencia coastal area are the wastes from aquaculture. The two main sources of wastes generated by fish farms are the excess of food supplied that is not consumed and fish excretions. The main near-field impacts are on the benthos below the cages.
Collected data allowed analysing the environmental impact of fish cages. Almost all the cages are dedicated to the culture of the gilthead seabream (Sparus Aurata) and sea-bass (Dicentrarchus labrax).
The analysis of data collected close to four fish farms in the Valencia Coast showed that chlorophyll a concentrations were between 40 % and 140 % higher than at a zone taken as reference. There, the coincidence of several peaks can be observed, suggesting that these concentrations follow temporary patterns related with aquaculture productive processes. Nevertheless, the dispersion of nutrient results suggests that the distribution of nutrient clouds arising from the farms is strongly influenced by local hydrodynamics.
On the other hand, significant changes in the phytoplanktonic biomass and in the population composition in the near field of marine fish farms off the coast of Valencia were detected. The effects observed are larger percentages of chlorophyceae and chryptophyceae, and lower values for the picocianobacteria / euchariot ratio and percentage of prymnesiales.
A preliminary set of sustainable management criteria were defined for Valencia coast in order to develop a sustainable aquaculture of fish cages:
- Aquaculture is an increasing activity in Valencia coast, with a number of facilities, which are being monitorised in the frame of Environmental Surveillance Programs (ESPs). These ESPs must continue to guarantee the assessment of farm environmental impacts.
- There is a lack of harmonisation among ESPs, since the measured parameters are not the same in different farms. A process of harmonisation must be implemented.
- Most of the indicators controlled and measured in the ESPs are useless. There is a lack of definition of the most suitable indicators in order to establish potential environmental impacts at medium and long term. An effort must be made to define more representative and suitable parameters.
- Most of the aquaculture farms in Valencia coast are well located, in zones with high dilution. As a consequence, no great impacts are foreseen, except in the areas located below the cages, which must be monitorised to control potential impacts.
- The production in Valencia coast is intensive with high fish densities (up to 90 fishes/m3). This facilitates the transmission of diseases and the use of substances (e.g. antibiotics) which can harm other species of the ecosystems where facilities are located. Moreover, some organisms (e.g. bacteria) can develop resistance to antibiotics, being a potential source of diseases. The use of these substances must be limited to the amount strictly necessary.
- Some pollutants are not measured in the ESPs (e.g. antibiotics, substances antifouling, etc.). They must be controlled, in particular how much time they persist in the environment.
- About 20 % of the supplied food is lost, settling directly on the bottom. Aquaculture producers must optimise nourishment minimising losses of food.
- There is not homogeneous legislation at a regional level. This also should be harmonised.
- The determination of long term effects on the environment requires constant monitoring and additional research. This is a job to be performed altogether by authorities, companies and scientists.
Selected findings: San Quentín bay
Although surrounding San Quintín bay there is a valley with significant agricultural activities (and the associate use of nematocides, herbicides, pesticides and fungicides), sedimentary concentrations of organic pollutants in San Quintín bay are low and likely they do not affect the oyster cultures. The estimated water residence time for Falsa bay, based on salt budgets, is 4-6 days in the spring and summer months, and 12 days during winter. In order to develop a sustainable oyster aquaculture in San Quintín bay some problems were detected and several indicators were proposed to detect bivalve aquaculture impacts and their impacts on the environment.
- to establish a conceptual framework for the studied areas;
- to structure the existing knowledge and advance the state-of-the-art concerning the relationship between aquaculture activities and water quality;
- to collect, structure and further exploit existing water quality and nutrient flux data from previous projects in two selected core study sites;
- to perform an initial analysis of the effects of aquaculture on local water quality and the effects of water quality on aquaculture, for the selected study sites;
- to assess the carrying capacity of the studied systems in terms of concentration levels (patterns) and gradients under average and selected critical conditions;
- to start considering alternative aquaculture management practices within the context of sustainable and integrated coastal zone management;
- to start developing a list of possible predictors and data necessary to conduct an adequate assessment of water quality conditions;
- to begin creating the base from which to derive a set of guidelines for sustainable aquaculture in partially limited waterbodies;% -to define a conceptual framework for the nutrient, pollutant and farm wastes, identifying source - sink - resuspension processes in coastal / estuarine systems, leading to quantitative estimations of the nutrient input from aquaculture into the environment;
- to develop alternative management criteria to better structure aquaculture development;
- to identify and assess alternative management practices oriented to the improvement of coastal water management, in order to allow a more efficient development in socially, economically and ecologically admissible terms.
The expected end results are those described in the objectives of the project. In particular, the estimation of the carrying capacity of the studied systems and the identification of alternative management criteria and practices are the main contributions from the project. The plan for using and disseminating the knowledge includes a project webpage: http://lim-ciirc.upc.es/aquas/(s’ouvre dans une nouvelle fenêtre) a project brochure, papers in scientific journals and press releases, as well as different forums to transfer project results to responsible administrations, private companies and general public.
Work performed and main achievements
The work performed started with the compilation of information from previous projects related to both case studies: Valencia Coast in Spain and Patos Lagoon in Brazil. On the other hand, data were also collected on one complementary site: San Quintin Bay (Mexico), which is dedicated to oyster culture.
A description of aquaculture facilities in the three sites was also carried out. In Valencia Coast they consist in farms with cages dedicated to intensive culture of gilthead seabream and sea-bass. Although there are 15 farms in this area, only 4 (Crimar, Cultipeix, Acuimed and Gramasa) were analysed.The data collected in this area include:
- water samples: salinity, temperature, pH, turbidity, suspended solids, nutrients, chlorophyll a, bacteria and phytoplankton;
- sediment samples: organic matter, dissolved oxygen, total nitrogen and total phosphorus;
- meteo / oceanographic data: waves, winds and currents;
- socio-economic data.
Moreover, hydrodynamic and water quality numerical simulations were carried out in both main areas (Valencia Coast and Patos lagoon). From the combined analysis of data and simulations, circulation patterns in both areas were determined.
Selected findings: Patos lagoon estuary
A preliminary set of sustainable management criteria were defined for the three sites. For Patos lagoon estuary, in order to develop a sustainable shrimp aquaculture (SSA), the following measures were proposed:
- To use only shrimp indigenous specie (Farfantepenaeus paulensis) to avoid risks of impacts related to displacement of ecological niches.
- The SSA should be implemented on a familiar basis, as complementary activity to the fishery and agriculture for the rural community, and should involve the community in a participatory management.
- The SSA should avoid the use of antibiotic substances and high density storage systems.
- The SSA must protect key functional processes, as the quality and the circulation of the water, the primary productivity and the maintenance of biodiversity.
- Shallow waters of estuarine embayments are nursery areas. Their biodiversity is key for the trophic ecology of the estuary and the development of the aquaculture must be done carefully in order to maintain it in good environmental quality.
- The installation of the structures inside the estuarine embayment should avoid the submerged prairies of Ruppia maritima.
- An environmental monitoring program should be implemented to control the dissolved nitrogen, organic matter and turbidity in the water column.
- In order to avoid use conflicts, and promote social and gender equity SSA should privilege the development of artisanal fishermen community and encourage the women involvement.
- The spatial planning of SSA development must consider all regulations at federal, state and local levels as the water use code and the municipal environmental plan.
- The SSA should take in consideration the code of conduct for responsible fisheries.
Selected findings: Valencia coast
Along the Valencia coast, one of the main sources of nutrients and pollutants are the rivers (e.g. Jucar) discharging in the area and the coastal lagoons (e.g. la Albufera) with open mouths to the sea. These waters have high nutrient concentrations due to the intensive agricultural exploitation of the river drainage basin, with the subsequent return of waters 'enriched' with pesticides and fertilisers and to the discharge of partially treated domestic and industrial wastewater from upstream towns. Another major source of nutrients and especially pollutants in this area are the marine outfalls of coastal towns, which discharge, in general, relatively close to the shoreline both treated and untreated waters.
Besides other secondary sources (illegal spills of wastewater or irrigation flows from ditches) that can introduce little amounts of nutrients and pollutants to the coastal systems, another source of these substances in Valencia coastal area are the wastes from aquaculture. The two main sources of wastes generated by fish farms are the excess of food supplied that is not consumed and fish excretions. The main near-field impacts are on the benthos below the cages.
Collected data allowed analysing the environmental impact of fish cages. Almost all the cages are dedicated to the culture of the gilthead seabream (Sparus Aurata) and sea-bass (Dicentrarchus labrax).
The analysis of data collected close to four fish farms in the Valencia Coast showed that chlorophyll a concentrations were between 40 % and 140 % higher than at a zone taken as reference. There, the coincidence of several peaks can be observed, suggesting that these concentrations follow temporary patterns related with aquaculture productive processes. Nevertheless, the dispersion of nutrient results suggests that the distribution of nutrient clouds arising from the farms is strongly influenced by local hydrodynamics.
On the other hand, significant changes in the phytoplanktonic biomass and in the population composition in the near field of marine fish farms off the coast of Valencia were detected. The effects observed are larger percentages of chlorophyceae and chryptophyceae, and lower values for the picocianobacteria / euchariot ratio and percentage of prymnesiales.
A preliminary set of sustainable management criteria were defined for Valencia coast in order to develop a sustainable aquaculture of fish cages:
- Aquaculture is an increasing activity in Valencia coast, with a number of facilities, which are being monitorised in the frame of Environmental Surveillance Programs (ESPs). These ESPs must continue to guarantee the assessment of farm environmental impacts.
- There is a lack of harmonisation among ESPs, since the measured parameters are not the same in different farms. A process of harmonisation must be implemented.
- Most of the indicators controlled and measured in the ESPs are useless. There is a lack of definition of the most suitable indicators in order to establish potential environmental impacts at medium and long term. An effort must be made to define more representative and suitable parameters.
- Most of the aquaculture farms in Valencia coast are well located, in zones with high dilution. As a consequence, no great impacts are foreseen, except in the areas located below the cages, which must be monitorised to control potential impacts.
- The production in Valencia coast is intensive with high fish densities (up to 90 fishes/m3). This facilitates the transmission of diseases and the use of substances (e.g. antibiotics) which can harm other species of the ecosystems where facilities are located. Moreover, some organisms (e.g. bacteria) can develop resistance to antibiotics, being a potential source of diseases. The use of these substances must be limited to the amount strictly necessary.
- Some pollutants are not measured in the ESPs (e.g. antibiotics, substances antifouling, etc.). They must be controlled, in particular how much time they persist in the environment.
- About 20 % of the supplied food is lost, settling directly on the bottom. Aquaculture producers must optimise nourishment minimising losses of food.
- There is not homogeneous legislation at a regional level. This also should be harmonised.
- The determination of long term effects on the environment requires constant monitoring and additional research. This is a job to be performed altogether by authorities, companies and scientists.
Selected findings: San Quentín bay
Although surrounding San Quintín bay there is a valley with significant agricultural activities (and the associate use of nematocides, herbicides, pesticides and fungicides), sedimentary concentrations of organic pollutants in San Quintín bay are low and likely they do not affect the oyster cultures. The estimated water residence time for Falsa bay, based on salt budgets, is 4-6 days in the spring and summer months, and 12 days during winter. In order to develop a sustainable oyster aquaculture in San Quintín bay some problems were detected and several indicators were proposed to detect bivalve aquaculture impacts and their impacts on the environment.
