AN ECOLOGICAL STUDY ON ACANTHOCEPHALANS PARASITIC IN THE INTESTINE OF PSEUDOBAGRUS EUPOGON IN HUANGZHOU SECTION OF THE YANGTZE RIVER

The acanthocephalans parasitic in the intestine of Pseudobagrus eupogon in Yangtze River was reported by Yu Y,Wu H S,1989.However ecological study on acanthocephalans parasitic in the intestine of P.eupogon are so far lacking.For this reason the present study provide a reference material for the control of acanthocephalans epizootis.133 P.eupogon in Huangzhou section of the Yangtze River were collected from June to July,2001.The fish sampled were taken to the laboratory,measured,and dissected.The entire alimentary canal was removed and divided into ten segments based on percentages of the total length from the anterior end.Each segment was carefully checked for acanthocephalans.The number of acanthocephalans in each fish was recorded.The numbers was used to statistics and analyses.The results showed that infection rate of Brentisentis yangtzensis in P.eupogon population was 48.1%,the infection intensity was 5.4(worm/fish)and the mean abundance of parasites was 2.5(worm/fish).The infection rate of Heterosentis parasiluri in the P.eupogon population was 21.8%,the infection intensity was 5.5(worm/fish)and the mean abundance of parasites was 1.2(worm/fish).The distribution of the two acanthocephalans species was all clumped in the host population.When two acanthocephalans species were co parasitic in the intestine of hosts,their intensity of infection rate did not alter obviously though the niche width of each species decreased as compared with sigle species infection. The interspecific correlation of the two acanthocephalans species was positive.