Tilapia has wide-range tolerance to salinity, and most Tilapia species can survive in both fresh water and seawater. In this study, the survival rates, absolute growth rates and instantaneous growth rates of Tilapia n...Tilapia has wide-range tolerance to salinity, and most Tilapia species can survive in both fresh water and seawater. In this study, the survival rates, absolute growth rates and instantaneous growth rates of Tilapia nilotica and Tilapia mossambica in waters with four different salinities（0‰, 10‰, 20‰, 30‰） were investigated.The results showed that the growth of T. mossambica was trended to be increased with the increased salinity, and it is suitable to be farmed in seawater; however, the growth of T. nilotica was trended to be decreased with the increased salinity, and it is suitable to be farmed in fresh water.展开更多
The concentrations of heavy metals （As, Hg, Cr, Pb and Zn） were measured in the macroalgae, macrobenthos and fish from the Tanzanian coastal marine environment in order to ascertain the biomagnification using stable...The concentrations of heavy metals （As, Hg, Cr, Pb and Zn） were measured in the macroalgae, macrobenthos and fish from the Tanzanian coastal marine environment in order to ascertain the biomagnification using stable isotopes of C and N. Macroalgae samples from the central marine areas of the Tanzanian coast had higher mean concentrations of Hg （0.17 ± 0.01 μg/g） and Cr （23.7 ± 4.15 μg/g） compared to other locations. Higher concentration of Hg （0.06 ±0.02 μg/g） was detected in the Ulva fasciata close to the Msimbazi Creek in Dares Salaam, whereas the highest concentration of Cr （45.5 ± 6.83 μg/g） was found in Ulva petrusa near Dares Salaam port. The crab Portunus pelagicus collected from Pangani river estuary contained 411.5 ± 13.04 μg/g of Zn. The other metals were uniformly distributed in macrobenthos from the entire coast. Mercury and lead in the biota were found to biomagnify along the Arius dussumieri and Lethrinus lentjan food chains as suggested by the significant positive relationships between log-pollutant concentrations in fish muscle tissues vs. 615N signatures. Zinc in muscle tissues was found to be transferred along the food webs although no biomagnification was observed. Arsenic and chromium were found to decrease with the rise of the trophic position. Metal concentrations in macroalgae, macrobenthos and fish were compared with quality guidelines values by FAO （Food and Agricultural Organization） in 1983 and they all were below permissible limits for human consumption.δ展开更多
基金Supported by Incentive Program Subsidized by Department of Science and Technology of Hebei Province(15926620H)Key Technology Research and Development Program of Science and Technology Bureau of Qinhuangdao City(201401A067,201402B043)~~
文摘Tilapia has wide-range tolerance to salinity, and most Tilapia species can survive in both fresh water and seawater. In this study, the survival rates, absolute growth rates and instantaneous growth rates of Tilapia nilotica and Tilapia mossambica in waters with four different salinities（0‰, 10‰, 20‰, 30‰） were investigated.The results showed that the growth of T. mossambica was trended to be increased with the increased salinity, and it is suitable to be farmed in seawater; however, the growth of T. nilotica was trended to be decreased with the increased salinity, and it is suitable to be farmed in fresh water.
文摘The concentrations of heavy metals （As, Hg, Cr, Pb and Zn） were measured in the macroalgae, macrobenthos and fish from the Tanzanian coastal marine environment in order to ascertain the biomagnification using stable isotopes of C and N. Macroalgae samples from the central marine areas of the Tanzanian coast had higher mean concentrations of Hg （0.17 ± 0.01 μg/g） and Cr （23.7 ± 4.15 μg/g） compared to other locations. Higher concentration of Hg （0.06 ±0.02 μg/g） was detected in the Ulva fasciata close to the Msimbazi Creek in Dares Salaam, whereas the highest concentration of Cr （45.5 ± 6.83 μg/g） was found in Ulva petrusa near Dares Salaam port. The crab Portunus pelagicus collected from Pangani river estuary contained 411.5 ± 13.04 μg/g of Zn. The other metals were uniformly distributed in macrobenthos from the entire coast. Mercury and lead in the biota were found to biomagnify along the Arius dussumieri and Lethrinus lentjan food chains as suggested by the significant positive relationships between log-pollutant concentrations in fish muscle tissues vs. 615N signatures. Zinc in muscle tissues was found to be transferred along the food webs although no biomagnification was observed. Arsenic and chromium were found to decrease with the rise of the trophic position. Metal concentrations in macroalgae, macrobenthos and fish were compared with quality guidelines values by FAO （Food and Agricultural Organization） in 1983 and they all were below permissible limits for human consumption.δ
