The eggs and fries from grass carps and common carps were treated with different concentrations chromium in water body.It was found that toxic effects was caused at the concentration of more than 2mg/L groups treated with Cr.The fries lethal rate of 10 mg Cr/L groups reached to 30% during 168h.The eggs hatching rate of grass carps and common carps descended 46% and 88.9% respectively.The fries lethal rate of grass carps in 15 mg Cr/L group was 100% and the eggs hatching rate was zero.The endurance to chromium of two kinds of fish has no significantly.

The reproductive biology and artificial breeding technology were studied in Hemibarbus maculates Bleeker.In the experiment,the age and minimal size at maturity,fecundity,gonadal development,spawning time and temperature,and morphological distinguishment of sex were understood in Hemibarbus maculates Bleeker.In artificial breeding,the effects of various hormones on spawn induction of the fish were compared in the fish with spawning success of 100%,fertilization rate of 95.3%,hatching rate of 95%.About 1412 00 individuals of fry were obtained.

Neojifu tilapia ( Oreochromis niloticus ) fry with body length varying from 0.7 cm to 1.9cm were fed diets containing different levels ofestradiol benzoate (EB) hormone to induce feminization ofXY neofemales for YY super males twice a daily from July 12th to October 21 st of 2009 and from May 1 st to November 6th of 2010. The fish fed the diet containing EB at a dose of 100 mg·kg^-1 were found to have 80.0% of females in 26 d, 93.4% of females in 36 d, 93.9% of females in 46 d, and 94.0% of females in 59 d and reared for 102 d, 25.2%, 38.6%, 39.1%, and 39.2% higher than that in the control group (54.8%), respectively. There was 83.1% of females in the fish fed the diet containing 200 ·kg^-1 EB for 24 d and reared for 188 d, 36.2% higher compared with the control group (46.9%), and very significant differences by X2 test in the two experiments (P〈0.001). There were no significant differences in the survival rate between the test fish and the control ones, and no abnormal fish were observed. It was found that the final body weight and final total length were very sig- nificantly and significantly smaller in the fish in the two experimental groups than those in the control group(P〈0.01, P〈0.05). There was no significant difference in growth between the experimental sex non-reversal males and the control males (P〉0.50). Thus, it is optimization of feminization protocol that neojifu tilapia fry are fed a diet containing EB at a dose of 200 mg·kg^-1 for about 35 d.

Light intensity as one of the most important environmental parameters has been shown to significantly influence growth and survival of larval or juvenile fish. The juvenile (with body weight of 10.10-+ 0.8g) masu salmon Oncorhynchus masou masou were reared in polyethylene tanks (80 cm diameter, 60 cm tank depth with water level of 40 cm) with a flowing freshwater at light intensity of 1200 lx, 600 lx, and 300 lx)at ambient temperature of 12.1 - 13.9℃ for 50 days to evaluate the effects of light intensity on growth performance. The light intensity was found to influence specific growth rate(SGR ), condition factor(CF) and coefficient variation (CV) significantly (P〈 0.01 ). The juveniles reared in high light intensity ( 1200 lx) had significantly higher SGR and CF than the juveniles reared under light intensity of 600 lx and 300 lx did. However, there was the lower CV under 1200 lx than under the other two light regimes. Correspondingly, the juveniles reared in high light intensity ( 1200 lx) showed significantly higher feeding intake compared to the animals under light intensity of 600 lx and 300 lx, indicating that increasing light intensity led to the positive effects for the growth in the juveniles. These findings contribute valuable information to the continuing development of juvenile culture of the juvenile masu salmon.

we researched the water chemistry,plankton and fishes of the ovulation space of salmon in the middle and low section of Huma river from sept.24,1999 to sept.28.