夏季高温期美洲鲥1+龄亚成鱼遮荫池塘养殖试验OA

In order to improve the pond culture technology of 1+year-old subadult Alosa sapidissima in high temperature summer,the open-air pond culture mode of A.sapidissima was improved by building and covering film.A three-year farming experiment(from 2022 to 2024)was carried out to analyze the effects of shaded ponds on the growth of A.sa-pidissima during high temperature period.The results indicated that the daily average water temperature in shaded ponds could be maintained below 31.8℃,while the maximum daily average water temperature in unshaded ponds reached 36.8℃.In 2022,with a stocking density of 10 463.33 fish per hectare after 173 days of farming,the body length and mass of 1+year-old subadult A.sapidissima reached(33.64±1.78)cm and(587.61±48.24)g,respective-ly.The specific growth rates for body length and body mass were(0.24±0.03)%/d and(0.79±0.05)%/d,respec-tively,with a survival rate of 58.43%.In 2023,when the stocking density was reduced to 6 586.67 fish per hectare af-ter 174 days of farming,the body length and mass were(36.20±1.92)cm and(672.58±85.67)g,respectively.The specific growth rates for body length and body mass were(0.31±0.04)%/d and(0.89±0.09)%/d,respectively,with a survival rate of 80.41%.In 2024,with similar stocking densities(10 680.00 fish per hectare and 6 636.66 fish per hectare)and after 179 days of farming,the body length were(30.75±1.84)cm and(30.46±1.63)cm,respectively,and the body mass were(493.40±72.69)g and(464.27±75.37)g,respectively.The specific growth rates of body length were(0.14±0.03)%/d and(0.13±0.03)%/d,respectively,and the specific growth rates of body mass were(0.51±0.13)%/d and(0.47±0.11)%/d,respectively,while the survival rates reached 89.32%and 89.80%,respec-tively.Therefore,it is suggested that the stocking density of 1+year-old subadult A.sapidissima should be 10 680.00 fish per hectare in the high temperature season in the Yangtze River Delta region,and the shade film(shading rate of 75%to 85%)should be built and covered in advance the end of May or the beginning of June to ensure the safe passage of 1+year-old subadult A.sapidissima through the high temperature period.