The Classification And Population Biology On Monogenean Of Fishes In Ergis River

Monogenean, belonging to Platyhelminthes, Monogenea, are harmful to fishes.The specific composition, community structure and phylogeny of some parasites were investigated through traditionary methods of parasite investigation and molecular biology techniques from the fishes of Ergis River. The main conclusions are as follows:(1) Twenty Monogeneans were collected from the fishes of Ergis River, belonging to four orders, five families and eight genera. Six species were new record of Monogenea, one was new genera record of Diplozoidae. The characteristics of new record species were described.(2) The community structure and seasonal dynamics of the Monogeneans were analysised. The results showed that the community dominance index of Berger-parker (d) was 0.0009-0.2106; species diversity index (H) was 1.8090; dominant concentration index was 0.0016; evenness index (E) was 0.6039, the dominance species were determined according to the dominance index (d). Seasonal dynamics indicated that the Monogeneans of Dactylogyridae and Ancylostomidae were found in spring, summer, autumn;Diplozoidae were found in four seasons; Ancyrocephaildae were primarily found in spring, summer and autumn; Gyrodactylidae were only found in spring, which showed significant seasonal dynamic variation.(3) The population ecology of Tetraonchus monenteron was investigated by means of field sampling research. The results showed that the prevalence and infection intensity had different tendency with the increases of host body length, the mean prevalence was 45.4%, and the mean infection intensity was 11.8±6.05. the prevalence decreased and the infection intensity increased with the increases in host body length; the abundance and S2/X then decreased, the S2/X was large than one in all host body length, the over-dispersion of parasite population in host population was observed, and the degree of the aggregation increases with the increase in mean abundance.(4) The 28S and ITS1 rDNA gene sequences were PCR amplified with specificity primers for the first time, gained 332bp and 513bp gene fragments. The 28S and ITS1 rDNA phylogeny tree were constructed with MEGA4.0 software, which showed that the Tetraonchus borealis and Tetraonchus monenteron belonged to one ramus, support rating were 83% and 87%.(5) One species was identified with the.characteristics and 28S rDNA gene sequencing method. The results showed that the the homology of 28S rDNA sequence between this species and Ancyrocephalus paradoxus was 99.45%, and the species was a new record, the phylogeny were analyzed.