P. chinensis from the Institute of Oceanology and from the Prawn Farm of Shangma County, Qingdao, were used in 1994 - 1995 experiments using excessive artifical diets as organic pollutants' Twelve about 5 cm body length or 5 about 12 cm body length P chinensis were put into the test pond and control pond' Diet amount supplied to the test pond was twice that of the control pond whose bottom was cleaned everyday' other culture conditions of the two ponds were the same' Various physicochemical and microbiological factors were examined regularly' The lysozyme,SOD, PO activities and histopathological changes of the two shrimp groups were compared. The results were as follows.1. In 10 days, the test pond's Do content decreased strikingly; its COD, NH,-N,No,-N contents increased rapidly and were 2.5, 2.1, 11.3 time that of the control pond respectively. (Tab.1) After 28 days, the test pond H=S content was 2.1 time that of the control pond; the microbiological contents increased greatly and were more than that of the control pond by 2- 3 orders of magnitude. (Tab.2) 2. The lysozyme, SOD and PO activities of the test pond decreased in varying degrees compared with those of the control pond.(Tab.3) 3. Light microscope examination showed the test pond shrimp had much more Hepatopancreatic Parvo-like Virus (HPV) occludsion bodies, and serious pathological changes in the hepatopancreas, gill and midguts, while the microphotos of the body parts of the control pond shrimp before and sometime after experiments were almost the same. (Plate I) The following conclusion could be drawn: organic pollution affects aquatic Environment. The NH-N NO-N and H contents especially increased markedly,changes the shrimp's intraenvironment, decreases its immune level, and may induce disease.
Oceanologia Et Limnologia Sinica