The amount of dissolved oxygen in the aquaculture water has an impact on the survival and growth, plumpness, and feed coefficient of A. japonicus. The dissolved oxygen in A. japonicus must be kept above 4 mg/L. But at present, many farmers don't pay enough attention to the dissolved oxygen in water, and the breeding efficiency is not high.
1. Consumption factors of dissolved oxygen in sea cucumber culture
1. Effect of sea cucumber consumption on dissolved oxygen
According to relevant data, at different temperatures, the oxygen consumption per unit time of Apostichopus japonicus is proportional to the size of the individual, the oxygen consumption per body wall weight is inversely proportional to the individual size, and the oxygen consumption is proportional to the logarithm of the body wall. There is a linear relationship between them, which is similar to the experimental results in fish and other invertebrates. In the normal range, the oxygen consumption of adult sea cucumber is about 0.4-0.8 mg/hour. Apostichopus japonicus relies on the breathing tree and the body surface to breathe at the same time. The respiration process is only one exhalation after inhaling water for countless times. When the water temperature is 11-14 ℃, it will exhale water once every 9 or 10 times of inhaling water. At 19-22°C, water was exhaled every 9-15 times after water intake. When the water temperature was about 8°C, the anus of A. japonicus only showed slight opening and closing, and it was difficult to distinguish whether it was water inhalation or exhalation. In order to determine the proportion of skin respiration, the respiratory tree was removed. When the water temperature was 8.5 to 13.5 ℃, the proportion of skin respiration was 39% to 52%, and when the water temperature rose to 18.5 ℃, the proportion increased sharply to 60% to 90%. , when the water temperature rises again, the proportion does not change much.
2. The effect of plankton on dissolved oxygen
Part of the dissolved oxygen in water comes from the air, and most of it is produced by plankton photosynthesis. Plankton produces oxygen during the day, but consumes it at night, so there will be a difference in the amount of dissolved oxygen in the water body during the day and night. In cloudy and rainy weather, plankton photosynthesis is weak, producing less oxygen, and Apostichopus japonicus is prone to hypoxia or death at night.