Studies On The Parasitic Capability Of Glochidia Of Lamprotula Fibrosa To Five Species Of Host-fishes

By cultivating the host-fishes in aquariums, we studied the parasitic capability of glochidia of Lamprotula fibrosa from the survival time, capability of activity, parasitic number in the host-fishes' gills, abortion rate, dropping number of the larva mussels and the dropping rate. The results showed: At the temperature of 10 1 , the glochidiim which existed naturally in the aquariums could survive for 31 days by far. And with agitation, the time was 29 days. The survival rates of glochidium descended with the enhancement of dropping days. 1-2 days after dropping, the survival rate was 100%. From the beginning of the third day, the survival rate of natural existence was higher than that of agitation. The survival rate descended to 48.9% at the ninth day under agitation, while that of natural existence was 53% at the twentieth days. The dropped glochidium' shells opened and closed freely. The average opened and closed number and the highest opened and closed number decreased with the increment of dropped days: The average opened and closed number was 12.75 at the first day, and the highest opened and closed number was 25. While at the seventh day , the numbers were 1.80 and 4. At the eighth day, the opened and closed number of the living glochidium was 0. With the increment of dropped days, the number of glochidium in the gills of five species offish decreased. The parasitic number of dropped glochidium in the same day was obviously different. At the first day, the parasitic number of the Ctenopharyngodon idellus was most, and the following were Aristichthys nobilis, Carassius auratus, Pelteobagrus fulvidraco, Hypophthalmichthys molitrix. From the second day to the seventh day, the parasitic number of the Ctenopharyngodon idellus was most and the following were Carassius auratus, Aristichthys nobilis, Pelteobagrus fulvidraco, Hypophthalmichthys molitrix. After the eighth day, the parasitic number of the Carassius auratus was most, and the following were Ctenopharyngodon idellus, Aristichthys nobilis, Pelteobagrus fulvidraco, Hypophthalmichthys molitrix. The longest time that the glochidium can parasite in the gills of the five species of fish were: Carassius auratus:\l days, Ctenopharyngodon idellus, Aristichthys nobilis and Pelteobagrus fulvidraco: 11 days, Hypophthalmichthys molitrix: 8 days. The abortion rate of glochidium after 30 days, 60 days and 90 days parasitic increased with the increment of days, and the abortion rate of the same specie of fish with the same parasitic day increased after 30 days, 60 days and 90 days. But the abortion rate of 30 days occupied 80% of the 90 days. The five species of fish with the same paratisic day were different also after 30 days, 60 days and 90 days.The glochidium grew to juveniles according anomaly after 90 days parasitic. At the temperature of 10 1 , the juveniles began to drop and it continued 22 days before all the glochidium dropped. Every aquarium was in the same dropping time in the main from the beginning to the last. The climactic dropping time of the juveniles of the first day parasitic was the fifth day after the juveniles appeared, and the climactic dropping time of the juvenilesof the second day parasitic was the sixth day. The climactic dropping time of the third day to the seventh day lagged about 1-2 days. The dropping number and dropping rates of juveniles decreased with the increment of the dropping days of glochidium. From the first day to the third day, the dropping number and dropping rates of glochidium in the gills of Carassius auratus are 1.1, 0.8, 0.5 and 0.36, 0.27, 0.20; and that of Aristichthys nobilis are 18.3, 2.6, 1.6 and 17.26, 13.00, 10.00; and that of Hypophthalmichthys molitrix are 27.1, 18.5, 12.9 and 7.13, 6.56, 5.33; and that of Ctenopharyngodon idellus are 190.3, 136.9, 57.6 and 30.11, 26.33, 18.11; and that of Pelteobagrus fulvidraco are 101.6, 70.8, 37.2 and 61.21, 55.31, 32.07. 7 days after dropping, the glochidium can still parasite in the gills of Carassius auratus, Aristichthys nobilis, Ctenopharyngodon idell...