In the East China region, the extreme high temperatures have persisted since late July. As a result, the mortality rate of pond-raised Chinese mitten crabs has doubled. According to an “crab farmer’s” estimate, he has incurred losses exceeding one million yuan in over a thousand mu of ponds he manages.
Every year, Chinese mitten crabs undergo five molts, with each molt leading to a size increase. Starting last week, the Chinese mitten crabs in the Yangtze River Delta region entered their fourth molt, coinciding with a continuous 40-degree Celsius heatwave. This has resulted in slow growth, delayed molting, and a mortality rate of over 20%.
A crab farmer named Wei from Kunshan told “Red Star News” that recently, he has been losing on average 20 to 30 Chinese mitten crabs per day in his crab ponds. In normal weather conditions last year, the average daily crab mortality did not exceed 10.
This year, a crab farmer named Fu in Gu Chenghu, Northern Jiangsu, who leases over a thousand mu of ponds for Chinese mitten crab breeding, told “Metropolis Express” that “the duration of high temperatures is too long.” He said, “We are losing over three thousand crabs every day, which has a significant impact on us crab farmers.” Fu estimates a loss of one to two million yuan in income this year.
Ms. Xie, a Chinese mitten crab breeder from Yangcheng Lake, mentioned that they are taking remedial measures such as changing water, increasing oxygen, and planting lotus seeds, but with the high temperatures still ongoing, the extent of the losses is hard to estimate.
The sustained high temperatures not only increase the mortality rate of Chinese mitten crabs but also lead to delays or reductions in molting, resulting in smaller crab sizes and delayed market entry.
Wei, the crab farmer, noted that as the Chinese mitten crabs are in the fourth molting stage and are relatively weak, the hot weather has affected their appetite. He predicts that this year, the crabs will have smaller sizes.
With the Mid-Autumn Festival falling on September 17th this year, steamed Chinese mitten crabs are a traditional delicacy during the festival. However, based on the current situation, it is highly likely that this year’s Chinese mitten crabs will not make it to the market before the eve of the Mid-Autumn Festival. Hangzhou businessman Wang Zhiqiang, with over two decades of experience in the Chinese mitten crab business, mentioned, “There might be some smaller crabs available for tasting, but the high-quality large crabs will have to wait for a later date.”
Furthermore, due to the increased mortality rate in Chinese mitten crab breeding, the overall yield is affected, leading to a rise in this year’s purchase prices for Chinese mitten crabs. Fu mentioned that especially for larger crabs, if the purchase price does not increase by around 15% compared to previous years, he definitely will not buy.