How to overwinter tilapia? Try keeping warm with a hot water boiler
Guangdong entered autumn overnight, and temperatures over the past 10 days have stayed around 21-28°C, with a comfortable and pleasant climate. As temperatures drop, the tilapia streptococcosis that was raging wildly just two months ago has begun to subside, giving farmers great relief. However, as the saying goes, "with each autumn wind comes a chill," and as temperatures continue to fall, the work of keeping tilapia warm in autumn and winter must not be neglected.
Hot water boiler warming makes water quality easier to control
The survival temperature range for tilapia is 15-35°C. When the water temperature is below 15°C, tilapia enter a dormant state. It is understood that current methods for overwintering farmed tilapia include natural overwintering, insulated shed overwintering and groundwater-insulated overwintering. Groundwater insulation can keep water temperature above the critical value year-round, but it only applies to places with groundwater resources and has limitations; where there are no severe cold waves and winter water temperatures do not fall below 10°C, the natural overwintering method is widely used, but after the massive fish deaths during the 2008 freeze disaster, most farmers no longer dare to take it lightly; of course, to be absolutely safe, overwintering under an insulated shed is the safest method, but the cost is relatively high, so at present insulated sheds are mostly limited to fry ponds and broodfish ponds.
"Using a hot water boiler for heating and insulation can be considered," Liang Cong, general manager of Guangzhou Wulonggang Aquatic Development Co., Ltd., told reporters. In the Nanhai area of Foshan, quite a few largemouth bass culture ponds and fry ponds use hot water boilers with circulating water to keep warm through the winter, and some fry farms that start producing fry early in spring also use hot water boilers to heat and speed up maturation for spawning. He had conducted on-site inspections of this and felt that this overwintering method is clearly effective and economical, and he also plans to install a hot water boiler for heating at his own fry farm.
"I think the hot water boiler warming method is very suitable for the Maoming area, and it is also suitable for all of Guangdong," Liang Cong said. Maoming is located in the southern part of Guangdong, where water temperatures are relatively high (mostly above 11-12°C), and there are not many extremely low-temperature periods in a year. "Only about 20 days to a month each year require heating, and it is enough to keep the water temperature above the critical value for tilapia," so fuel costs are not high.
"Because the greenhouse is a closed environment, it is difficult to control water quality, while heating and insulating with a hot water boiler does not have this problem." Liang Cong said that a hot water boiler can be fired whenever needed, with smooth air exchange with the outside; once a greenhouse is covered, however, one must wait until April or May of the following year to remove it. In this way, over several months, there is basically no airflow exchange between the greenhouse and the outside, humidity inside the shed is high, there is a lot of mist, and dissolved oxygen is also a serious problem. Add to that feed pollution, and relatively high nitrite and ammonia nitrogen, and water quality is very difficult to regulate, making disease outbreaks easy to trigger.