How to Keep Seafood Alive? A Detailed Guide to Rearing Methods and Key Technical Points
Seafood is a very delicious food. As the name suggests, it lives in the sea, but artificial holding and rearing is also very common nowadays. So, how do you keep seafood alive?
1. Prepare artificial seawater
After live seafood arrives at its destination, it must first be sorted, removing any seafood that is dead, seriously injured or diseased, and then rinsed. If tap water from the city is used as the water source for holding seafood, the chlorine must be removed before use. The simplest way to remove chlorine is by sun-drying: leave the water standing for 3-4 days in advance before using it. If sun-drying is not possible, a chemical method can be used to remove chlorine; the commonly used dechlorinating agent is sodium thiosulfate, typically added at 1 gram of sodium thiosulfate per 10 kg of tap water. The dechlorinated water is then adjusted with concentrated seawater or solid sea salt to the required salinity, producing artificial seawater, which can then be used to hold live seafood.
2. Suitable water temperature
Water temperature is an important factor in keeping seafood alive. The suitable water temperature for seafood is generally maintained at 18°C-21°C, but abalone and geoduck clam belong to low-temperature, high-salinity varieties, with an adaptive temperature of 12°C-15°C. When the temperature is too high, it is unfavorable to the held organisms, easily causing disease and losses.
3. Sufficient dissolved oxygen
Fish, shrimp, shellfish and others all use gills to breathe the dissolved oxygen in the water. Generally, the dissolved oxygen content in water for holding seafood should be maintained above 5 mg/L; below 3 mg/L, it is not suitable for fish to survive. Improving water quality, installing aeration equipment, increasing the frequency of water changes, reducing the number held, increasing light exposure time, and using a water circulation system to filter the water in the holding tank can all increase the dissolved oxygen content in the water.
4. Adjusting the pH of the water
The pH of the water is closely related to the survival of various types of seafood. The substances commonly used to adjust the pH of water quality are sodium dihydrogen phosphate and sodium bicarbonate. Before use, these two chemicals should be dissolved separately in pure water to make a 1:100 solution. Sodium dihydrogen phosphate can increase the acidity of the water; sodium bicarbonate can increase the alkalinity of the water. When using, the prepared solution can be added drop by drop to the water as needed, stirred thoroughly, and continuously tested with pH paper until the pH of the water reaches the requirement; the change in pH of the water should be controlled within a range of ±0.1.
5. Holding management
To manage a closed recirculating system well, you need to practice the “three diligences”: diligent inspection. Check whether the system equipment is operating normally, whether aeration is sufficient, and whether water flow is smooth. Diligent cleaning. Promptly remove dead seafood from the holding tank to avoid water quality deterioration caused by decomposing dead seafood. Diligent observation. Frequently observe whether the held seafood shows any abnormal reactions and whether the water quality remains good; if problems arise, find out the cause promptly and deal with them immediately.
Seafood rearing involves a certain degree of difficulty, but as long as water source, water temperature and other factors are mastered scientifically and reasonably, seafood can also grow healthily.