Fishery water quality testing

NegotiableUpdate on 03/14

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Nature of the Manufacturer: Producers

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Overview

The quality testing of fishery water is the core foundation work to ensure the survival and growth of fishery organisms, improve the quality and safety of aquatic products, and protect the ecological environment of the fishery industry. The scope of application covers natural fishery waters (rivers, lakes, reservoirs, oceans, etc.) and artificial aquaculture waters (ponds, paddy fields, cages, industrial aquaculture ponds, recirculating aquaculture systems, etc.).

Product Details

1Fishery water quality testingPurpose and Scope of Application

core purpose

Determine whether the water area meets the survival, reproduction, and growth needs of fishery organisms (fish, shrimp, shellfish, etc.);

Identify toxic and harmful substances in water quality, prevent fishery biological diseases, deaths, and aquatic product pollution;

Monitor changes in the ecological environment of fishery waters to provide scientific basis for water conservation and aquaculture management.

The scope of application covers natural fishery waters (rivers, lakes, reservoirs, oceans, etc.) and artificial aquaculture waters (ponds, paddy fields, cages, industrial aquaculture ponds, recirculating aquaculture systems, etc.).

2、 Key detection indicators (classified by category)

The indicator requirements for fishery water use need to be combined with the physiological characteristics of aquaculture species (such as cold water fish, warm water fish, and shrimp with significant differences in water quality tolerance). The core indicators are divided into the following three categories:

physical indicators

Water temperature: It directly affects the metabolism, growth, and reproduction of fishery organisms, and different species have specific suitable ranges (such as 10-18 ℃ for cold water fish and 20-30 ℃ for warm water fish).

Transparency: It reflects the content of suspended matter in the water body and is related to the amount of plankton and the density of feed organisms. The transparency of aquaculture ponds should generally be maintained at 20-50cm.

Dissolved oxygen (DO): One of the most critical indicators of fishery water use. Fishery organisms rely on dissolved oxygen respiration. When the DO in water is below 3mg/L, most fish will float or even die; The water for aquaculture should maintain a dissolved oxygen (DO) level of ≥ 5mg/L, and during the seedling stage, it should be ≥ 7mg/L.

chemical index

PH value: It affects the form of nutrients in water, the toxicity of toxic substances, and the acid-base balance of fishery organisms. The suitable pH for freshwater fisheries is 6.5-8.5, and for seawater fisheries it is 7.5-8.5.

Nitrogen compounds: including ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen. Among them, ammonia nitrogen (non ionized ammonia) is a highly toxic substance that can damage fish gill tissue, with a freshwater limit of ≤ 0.02mg/L; Nitrite nitrogen can cause methemoglobinemia in fish, and the aquaculture water should be controlled at ≤ 0.1mg/L.

Phosphorus compounds: total phosphorus, phosphate, excessive can cause eutrophication of water bodies, leading to the outbreak of blue-green algae and damaging aquaculture ecology.

Heavy metals: mercury, cadmium, lead, chromium, copper, etc., have bioaccumulation and can damage the nervous and reproductive systems of fishery organisms. They also pose a threat to human health through the food chain and must strictly comply with limits (such as mercury ≤ 0.0005mg/L).

Toxic organic and inorganic substances: Chemical Oxygen Demand (COD) and Biochemical Oxygen Demand (BOD ₅) reflect the degree of organic pollution in water bodies; Hydrogen sulfide, phenols, and other substances have strong toxicity and can directly cause the death of fishery organisms.

Biological indicators

Plankton: including phytoplankton and zooplankton, whose types and quantities reflect the nutritional level and ecological stability of water bodies. Overbreeding can easily lead to algal blooms or red tides.

Microbial indicators: total bacterial count, coliform group, indirectly reflecting the degree of water pollution from domestic sewage or feces; In addition, it is necessary to monitor specific pathogens (such as viruses, parasite eggs) to prevent the spread of fishery biological diseases.

3、 Testing methods and sampling standards

Classification of detection methods

On site rapid detection: using portable instruments such as dissolved oxygen meters, pH meters, thermometers, and transparency disks, water temperature can be quickly obtained DO、pH、 Transparency and other indicators are suitable for real-time monitoring of breeding sites.

Laboratory precision testing: Bring the collected water samples back to the laboratory and use spectrophotometry (for measuring ammonia nitrogen, nitrite, etc.), atomic absorption spectrophotometry (for measuring heavy metals), gas chromatography (for measuring organic matter), etc., with high detection accuracy and suitable for comprehensive water quality analysis.

Sampling standards have a direct impact on the quality of sampling, and the following requirements must be followed:

Sampling points: natural water bodies are set up according to grid method or functional zones; Aquaculture ponds require sampling at multiple points including the inlet, outlet, center, and edges of the pond.

Sampling depth: Surface water (0.5m below the water surface), middle water (at a depth of 1/2), and bottom water (0.5m from the bottom), sampled in combination according to the depth of the water area.

Water sample preservation: Water samples with different indicators need to be added with fixatives (such as adding sulfuric acid for measuring ammonia nitrogen and nitric acid for measuring heavy metals), and sent for testing within the specified time (such as fixing dissolved oxygen water samples on site and testing within 24 hours).

4、 Quality control requirements

to ensureFishery water quality testingThe accuracy and reliability of the results require the implementation of full process quality control:

Sampling stage: Set blank samples and parallel samples to avoid contamination of the sampling container.

Testing phase: Regularly calibrate instruments, use standard substances to verify reagent purity, and conduct experiments strictly in accordance with operating procedures.

Result stage: Review the detection data, and retest and verify any abnormal results to ensure the authenticity and validity of the data.