负压状态下压力变化导致鲫鱼身体组织的损伤

Crucian (Carassius auratus auratus) damage caused by pressure changes under subatmospheric conditions*

通过试验研究负压状态下压力变化过程对鲫 (Carassiusauratusauratus)的损伤 ,试验采用真空泵和空气压缩机在试验容器内形成不同的压力变化过程 ,统计不同体长的鲫经历压力变化过程后的损伤情况 ,并对部分受损伤的鲫进行解剖和组织观察。研究发现负压状态下压力时变导数较大的变化过程会对鲫的生存构成直接威胁 ,主要损伤是鱼鳔部分或全部受损 ,在肝胰脏、肾脏等处有明显出血点。综合分析不同试验条件对鲫损伤的情况 ,得到了对鲫尽可能安全的压力时变导数极限值 ,从而为新型环保水力设施的设计提供参考依据 ,起到保护渔业资源的作用 [动物学报 49(1) :6 7～ 72 ,2 0 0 3]。

With increasing awareness of environment protection, the damage to fish caused by hydraulic machinery is attracting more and more scientific interest. We conducted experiments to study damage to the crucian (Carassius auratus auratus) caused by pressure changes under subatmospheric conditions. In the experiments, we used a gas access system composed of a pressure vessel, a vacuum pump and an air compressor to simulate the pressure changes in hydraulic structures, and a digital signal system composed of a pressure sensor, amplifier, A/D card and a computer to obtain pressure-time data. Crucians grouped according to body length were placed under these various conditions. After the exposure of each group to different pressure conditions, damage to fish and the corresponding pressure changes were recorded. Some injured fish were anatomized and histological observation was also conducted to determine the main damage. The results demonstrate that crucians can be seriously injured or even killed by pressure changes with high pressure derivative relative to time, resulting in partial or completely injured swim bladders and obvious bleeding under the kidney capsule and liver-pancreas, especially in the marginal region. We conclude that controlling the pressure derivative with respect to time in hydraulic passages can effectively prevent such injuries. An estimate of the maximum derivative of pressure with respect to time that allows crucians to pass through hydraulic passages safely is provided, this could be a criterion for the design of new environmental-friendly hydraulic structures protecting fish culture operations. The mechanism whereby fish are damaged by pressure changes is also discussed [Acta Zoologica Sinica 49(1):67-72, 2003].