COBIA (Rachycentron canadum)

The partial toxicity tests of copper (Cu 2+ ), zinc (Zn 2+ ) and cyanide (CN - ) for young cobia(Rachycentron canadum) fishes 45 days-old were conducted in Doson station during ten days (yr2005). These three toxic substances affected strongly the growth rate of the Cobia fish (length andweight of the body), even at the lowest treated concentration. The LC values of copper, zinc andcyanide were 0.32 mg l -1 ; over mg l -1 and 0.049 mg l -1 , respectively. Based on the statistical analysisof growth rate of cobia by determining IC25, IC50, NOEC and LOEC values, we have addressedthe safe concentrations of these two heavy metals and cyanide in the environmental aquaculturewhich must be lower than 0.025 mg Cu l -1 , 0.5 mg Zn l -1 and 0.005 mg CN l -1 , respectively. Theresult also showed that cyanide was the most toxic to Cobia, followed by copper and zinc.24. Fang, F., Xu, M., Cai, Q. & Huang, X. (2007). Analysis and comparison on level of 5 kinds ofhormones in muscles of cultured and wild fishes in Zhanjiang sea area. Journal of TropicalOceanography, 26(5), 69-72.The levels of growth hormone, estradiol, progesterone, testosterone and chorlonic gonadotropichormone in the muscles of cultured and wild Sparus macroccephalus, Plectorhynchus cinctus,Rachycentron canadum, Nibea japonica, Pampus argenteus in the Zhanjiang sea area weredetermined by radioimmunoassay (RIA). The result showed that the level of each hormone wasdifferent with different fish species, and their distributions were as follows. The highest levels ofgrowth hormone, estradiol, progesterone, testosterone and chorionic gonadotropic hormone in the 5species of cultured and wild fishes occurred in cultured and wild Nibea japonica, cultured Sparusmacroccephalus and wild Rachycentron canadum, cultured and wild Rachycentron canadum,cultured and wild Pampus argenteus, cultured Nibea japonica and wild Plectorhynchus cinctusrespectively. The level of each hormone in the cultured fish was obviously higher than the samespecies of the wild fish (p