基于氨氮平衡的水产养殖换水率计算方法研究

为进一步掌握海水养殖鱼类氮排泄的规律,准确计算养殖所需换水率(量),为深远海大型养殖平台养殖模式与系统设计提供基础数据和技术支撑。研究了斑石鲷(Oplegnathus punctatus)在不同投饲频率条件下的排氨情况,分析了维持氨氮平衡所需换水率的优化计算方法,并通过流水实验进行验证。结果显示,斑石鲷在空腹、日投喂1、2、3次等4种条件下,水体氨氮质量浓度随时间变化基本呈线性增长趋势,排氨率平均值分别为(6.23±6.71)、(18.16±11.90)、(21.69±17.52)和(17.98±12.93)mg/(kg·h)。根据物质平衡原理,提出基于氨氮平衡的换水量计算方法。以该计算方法获得换水率分别为0.18、0.55、0.66和0.55次/h。验证实验中,设计养殖密度13.4 kg/m~3,计算所需换水率为1.09次/h(换水量0.147 m~3/h)。在该条件下的流水养殖实验结果表明,氨氮能够稳定维持在设计要求范围内。

Studies on water exchange ratio calculation method based on TAN balance

In order to deeply understand the nitrogen excretion rules of marine cultured fish,precisely calculate the water exchange ratio ( amount) needed,and provide basic data and technical support for the design of Deep Sea Aquaculture Farming Platform,TAN excretion rate of Oplegnathus punctatus under different feed frequencies was studied and the calculation method of water exchange ratio was analyzed. Results show that the ammonia excretion rate of Oplegnathus punctatus is (6.23±6.71)mg/(kg·h) under starved condition,(18.16±11.90) mg/(kg·h) when fed one time per day,(21.69±17.52)mg/(kg·h) when fed two times per day,and (17?98±12.93)mg/(kg·h) when fed three times per day.Based on the principle of mass balance,one kind of water exchange ratio calculation method is put forward for keeping TAN stable. By using the method,the water exchange ratio under 4 different conditions are 0.18,0.55,0.66,and 0.55 times/h,respectively.The verification test is under the condition of culture density 13.4 kg/m3,and the water exchange ratio is calculated as 1.09 times/h.Results show that TAN concentration can be maintained within the required level of the test design.