Abstract: The eustrongylidiasis caused by Eustrongylides in fish and birds, was a great threat to wildlife conservation and breeding industry. From April 2012 to April 2013, 58839 eel visceras were examined by helminthology post-mortem method. We observed and analyzed Eustrongylides’ mean abundance, the length of the worm and relationship between length and survival time. Meanwhile, we checked eels’ blood pH. The results showed that，Eustrongylides’ mean abundance was 5.45%; the mean abundance in spring and summer (7.85%) was higher than that in autumn and winter (3.73%), and the mean abundance of wild eels (5.77%) was higher than farming eels (1.10%), which indicated Eustrongylides’ mean abundance was affected by the season and farming methods. The averge length of 300 Eustrongylides was 49.69 mm, whose length ranged from 26.80 to 70.50 mm, the length of the worm in spring and summer was 47.10 mm,and in autumn and winter 54.86 mm. It showed that the length of Eustrongylides in autumn and winter was longer than that in spring and summer; the average survival time of Eustrongylides (the length less than 30, 30 to 39.9, 40 to 49.9, 50 to 59.9, more than 60 mm) were 2.5,3.6,4.4,5.4,9.0 d, which indicated that the worm’s survival time was in positive correlation with the length of the worm. Eels blood pH had no apparent seasonal variation. The results of the tests could provide basis for the eustrongylidiasis prevention in Hunan province.

Key words:

eel; Eustrongylides; mean abundance; length; survival time