1.5. Water Sources and Water Quality Parameters Used in Aquaculture Production

In aquaculture production systems, it is necessary to use waters with appropriate characteristics to provide the environmental conditions required for the survival of the species to be cultured. In this context, spring waters, rivers, lakes, groundwater and seawater are used as water sources in aquaculture production systems.

1.5.1. Water Sources Used in Aquaculture

1.5.1.1. Spring Waters

According to the definition stated in the Regulation on Water Intended for Human Consumption, spring waters are “underground waters that naturally form within geological units under suitable geological conditions, emerge spontaneously to the earth’s surface from one or more points or are extracted using technical methods, possess the qualities specified in Annex-1 without any treatment other than those permitted in Article 36 of this Regulation, meet labeling requirements and are packaged and placed on the market for sale” (ITASHY, 2005). According to the Regulation on Water Allocations, spring waters are defined as “water that naturally forms within geological units and emerges spontaneously to the earth’s surface” (STHY, 2019). Because spring waters are characterized by minimal temperature variation, it is possible to farm cold-climate fish species in them (Turkish Ministry of National Education, 2015).

1.5.1.2. River

Rivers are another water source that can be preferred for aquaculture. A river can be defined as a mass of water that originates from a specific source and flows along a bed determined by slope (Turkish Language Association – TDK, 2025). Rivers are classified by size as streams, brooks or rivers. The main reason rivers are preferred in aquaculture is that the sections near their sources are cold and generally clean (Turkish Ministry of National Education, 2015). In this respect, rivers can be preferred for the farming of cold-climate fish. When using a river as a source of water for aquaculture, it is very important to ensure that the water does not contain domestic or industrial pollution.

 

1.5.1.3. Lake

Lakes are also used as a water source in aquaculture. Lakes are formed when depressions on the earth’s surface or underground created under various conditions are filled with water (Biricik, 2009). Lakes are divided into two categories: tectonic lakes and barrier (or dammed) lakes (Ondokuz Mayıs University, 2025). Barrier lakes are formed when the front of collapsed areas in landforms or valleys is closed off by a barrier, causing the area to fill with water (Duman & Çiçek, 2012). Because the waters of high-altitude lakes are cold and clean, they are preferred as a water source for aquaculture (Turkish Ministry of National Education, 2015).

1.5.1.4. Groundwater

Groundwater forms as water accumulates in voids within structures such as rock and sediment in regions below the earth’s surface called aquifers (IAEA, 2025). Groundwater is rich in methane, nitrogen and carbon dioxide because it is stored in a closed environment and exhibits minimal temperature variation (Turkish Ministry of National Education, 2015). While minimal temperature variation is an advantage for using groundwater in aquaculture, the presence of gases such as nitrogen and carbon dioxide in the water is a disadvantage (Turkish Ministry of National Education, 2015). Before being used in aquaculture, groundwater should be aerated with oxygen to meet the water quality parameters suitable for the fish species.

1.5.1.5. Seawater

Seawater is a suitable water source for raising species that are tolerant of saltwater. For example, due to its tolerance to salinity levels of 18–20‰, rainbow trout can be cultured both in seawater and in freshwater sources such as spring waters (Turkish Ministry of National Education, 2015). Marine culture is a type of aquaculture in which various fish species, aquatic plants and shellfish are raised in natural marine environments or in systems such as nets, cages, tanks and canals, including seaweeds, mollusks and many fish species (Laird, 2001). In marine environments, aquaculture production systems such as net cages and raft systems are preferred (Ahmad et al., 2021). Table 1 summarizes the aquatic organisms cultivated in saltwater.

 

Table 1. Aquatic species farmed in saltwater (Laird, 2001).

Species (Group)	Type	Production Region
Seaweeds	Red Algae	Indonesia, China, Japan, Korea and the Philippines
	Brown Algae	China, Korea and Japan
	Green Algae	Japan, Korea and the Philippines
Mollusks	Oyster	China and France
	Mussel	Europe, Far East, India and the coasts of North and South America
Shrimp	Penaeid Shrimps	Coastal regions of South and Southeast Asia and South America
Fish	Salmon	Chile, Canada, Australia, Norway, Scotland, New Zealand
	Rainbow Trout	Chile
	Milkfish	Indonesia, the Philippines, Taiwan
	Flatfish	Japan, France, Spain, Portugal
	Sea Bass	Greece, Türkiye, Spain
	Coral Fish	Japan

 

1.5.2. Water Quality Parameters

In aquaculture production systems, optimum living conditions and water quality criteria differ for different fish species. For example, trout can survive in cold waters of 4–18 ºC, while carp can live in warm waters of 16–28 ºC. This situation requires different environmental conditions for the two fish species. Dissolved oxygen levels above 5 mg/L are critically important for species such as trout, carp, tuna and shrimp. Another water quality parameter, pH, is expected to be within the optimum range of 6.5–8.5 for most fish species. According to the implementation principles of Article 6(b) of the Republic of Türkiye Aquaculture Regulation, the tables of water criteria to be considered in aquaculture applications in inland and marine waters are presented respectively in Table 2, Table 3 and Table 4.

 

Table 2. Water Quality Parameters for Trout Farming (Annex 1-a of the Implementation Principles of the Aquaculture Regulation) (T.C. Tarım ve Orman Bakanlığı, 2025a)

Water Quality Criteria for Trout Farming
Parameters	Grow-out Farming	Hatchery	Hard Water	Soft Water
Water Flow Rate** (L/s)
Temperature (°C)	4-18ºC	6-13ºC
Dissolved Oxygen (mg/L)	>5
pH	6.5 – 8.5
Ammonia (non-ionized) (mg/L)	0.1	0.02
Nitrate (mg/L)		0 – 40
Nitrite (mg/L)			<0.2	0.06 – 0.1
Alkalinity (as CaCO₃) (mg/L)		10 – 400
Carbonate* (mg/L)		0 – 25
Bicarbonate* (mg/L)		>100
Total Hardness* (as CaCO₃) (mg/L)		10 – 400
Calcium* (mg/L)		4 – 160
Magnesium*(mg/L)	“It is necessary for the buffer system.”
Manganese* mg/lt		0 – 0.01
Iron (total)* mg/lt		<0.5
Ferrous Ion* mg/lt		0
Ferric Ion* mg/lt		0.5
Phosphorus* mg/lt		0.1 – 3
CO₂* mg/lt		<60
Aluminium* mg/lt	<0.1
Cadmium* mg/lt		<0.003		<0.0004
Chromium* mg/lt	<0.05
Copper* mg/lt			<0.01	<0.006
Lead* mg/lt	<0.001
Zinc* mg/lt	0 – 0.1
Mercury * mg/lt	<0.00005
Nickel* mg/lt			<0.05	<0.1
H2S* mg/lt		<0
Suspended Solids mg/lt	<25	<5
Note: For trout, chloride should not exceed 50 mg/L for egg hatching and 200 mg/L for adults; turbidity should not exceed 10 JTU. * Parameters to be monitored when needed. ** A report on the minimum and maximum water flow rates and a document indicating the minimum water allocation available for the facility must be obtained from the General Directorate of State Hydraulic Works (DSİ).

 

Table 3. Water Quality Parameters for Carp Farming (Annex 1-b of the Implementation Principles of the Aquaculture Regulation) (T.C. Tarım ve Orman Bakanlığı, 2025b)

Water Quality Criteria for Carp Farming
Parameters	Grow-out Farming	Hatchery	Hard Water	Soft Water
Water Flow Rate (L/s)**
Temperature (°C)	16-28	18-20
Dissolved Oxygen (mg/L)		5
pH		6.5 – 8.5
Ammonia (non-ionized) (mg/L)	0.02
Nitrate (mg/L)		0.3
Nitrite (mg/L)	0.06 – 0.1
Alkalinity (as CaCO₃) (mg/L)*		50 – 400
Carbonate (mg/L)*		0 – 40
Bicarbonate (mg/L)*		75 – 100
Total Hardness (as CaCO₃) (mg/L)*		50 – 400
Calcium (mg/L)*		10 – 160
Magnesium (mg/L)*	It is necessary for the buffer system.
Manganese (mg/L)*		0 – 0.1
Phosphorus (mg/L)*		0.01 – 3
CO₂ (mg/L)*		0 – 15
Cadmium (mg/L)*			0.012
Copper (mg/L)*			0.112	0.005
Lead (mg/L)*	0.1
Zinc (mg/L)*		0 – 0.05	2.0	0.3
Nickel (mg/L)*	0.5
H2S* mg/lt		<0
Note: For carp and warm-water fish, turbidity should not exceed 25 JTU, electrical conductivity should not exceed 2000 µmho × 10⁶, BOD or organic matter should not exceed 4 mg/L, and chloride should not exceed 2000 mg/L, while SO₄ should not be less than 0.5 mg/L.   * Parameters to be monitored when needed.   ** A report on the minimum and maximum water flow rates and a document indicating the minimum water allocation available for the facility must be obtained from the General Directorate of State Hydraulic Works (DSİ).

 

 

 

Table 4. Water Quality Criteria for Marine Aquaculture (Annex 1-c of the Implementation Principles of the Aquaculture Regulation) (T.C. Tarım ve Orman Bakanlığı, 2025c)

Water Quality Criteria for Marine Aquaculture
Parameters	Gilthead Seabream	European Seabass	Tuna	Red Seabream	Turbot	Sturgeon	Shrimp	Bivalves
Oxygen (mg/L)	≥4	≥4	≥5	≥4	≥3	≥4	≥5	≥5 (%70)
Salinity (%)	5–40	5–40	12-40	15–40	10-40	0-20	15-35	10-37
Temperature (°C)	15-25	10-25	12-30	14-25	10-25	7-25	20-35	12-30
pH	6.5-8.5
Free CO₂ (mg/L)	0.1-10
Ammonia (NH₃) (mg/L)	0.02-2.5	0.02-2.5	0.02-2.5	0.02-2.5	0.01-0.06	0.01-0.02	0.01-0.02	0.01-0.02
Ammonium (mg/L)	0.05-1.5							**
Nitrite (NO₂) (mg/L)	<0.5							**
Nitrate (NO₃) (mg/L)	<40							**
Phosphate (mg/L)*	<1							**
Silicate (mg/L)*	2-5							**
Iron (mg/L)*	0.5-1							**
Sulphur (mg/L)*	<1							**
Suspended Solids (mg/L)*	5-80							**
Hydrocarbons (µg/L)*	<0.031							**
Turbidity (NTU)*	<29							**
* Parameters to be monitored when needed. ** Must comply with the criteria specified in the “Communiqué on Water Quality Standards for Shellfish Growing Waters” published in the Official Gazette dated June 2, 2008 and numbered 26894. (Türkiye)

 

References

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Duman , N., & Çiçek, İ. (2012). Erçek Gölü Havzasının Jeomorfolojisi ve Gölün Oluşumu. Uluslararası Sosyal Araştırmalar Dergisi, 246-260.

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Laird, L. (2001). Mariculture Overview. Encyclopedia of Ocean Sciences (Second Edition) (s. 1572-1577). Academic Press.

Ondokuz Mayıs University. (2025, March 29). Hydrography-II Lecture Notes [PowerPoint slides]. Retrieved from https://avys.omu.edu.tr/storage/app/public/tamero/64066/H%C4%B0DRO%202.pdf

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T.C. Tarım ve Orman Bakanlığı. (2025b). Su ürünleri yetiştiriciliği yönetmeliğine ilişkin uygulama esasları [Annex 1-b of the Implementation Principles Related to the Aquaculture Regulation].

T.C. Tarım ve Orman Bakanlığı. (2025c). Su ürünleri yetiştiriciliği yönetmeliğine ilişkin uygulama esasları [Annex 1-c of the Implementation Principles Related to the Aquaculture Regulation].

Turkish Language Association (TDK). (2025, March 22). Meaning of the word “Akarsu”. TDK Website: https://sozluk.gov.tr/

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