POPULATION DYNAMICS AND FREQUENCY DISTRIBUTION OF THE NEMATODE PRO CAMALLANUS FULVIDRACONIS AND TREMATODE GENARCHOPSIS GOPPO IN YELLOW HEAD CATFISH PELTEOBAGRUS FULVIDRACO IN LIANGZI LAKE OF HUBEI PRO VINCE, CHINA

elminths in the stomach of the yellowhead catfish Pelteobagrusfulvidraco (Richardson) in the Liangzi lake of HubeiProvince were investigated from February 2001 to July 2002?Three nematode species Procamallanusfulvidraconis, Camallanuscotti, Spinitectus gigi and a trematode Genarchopsis goppo were found.The latter two nematode species, with very low infectionlevel, were not included in the further analysis as follows.Frequency distribution of P.fulvidraconis and the seasonal changes andfrequency distribution of G.goppo were analyzed.Prevalence, mean abundance (±SD) and variance to mean ratio of P.fulvidraconis were 96.70%, 21.59±23.37 and 25.29, respectively.Its frequency distribution could not be described by the negative binomial model.There were positive correlations between abundance of P.fulvidraconis and the fish age and length (Rx, y=0.3038, px, y=0.3938, px, y=0.1694, p±20.0517=27.58; F=16.7, p <0?001).The pattern of life history may be the cause of the seasonal changes of the parasite.Relationship between the yellowheadcatfish and the two parasites was also discussed in the study.