Objective: To evaluate the suitability of Palaemon adspersus (P. adspersus) as a bio-indicator for 4 and 10 days of cadmium toxicity bioassays. Methods: Four and ten days experiments were designed. CdCl2·2?H2O wa...Objective: To evaluate the suitability of Palaemon adspersus (P. adspersus) as a bio-indicator for 4 and 10 days of cadmium toxicity bioassays. Methods: Four and ten days experiments were designed. CdCl2·2?H2O was dissolved in distilled water and a stock solution was made. At 4-day bioassay, the larvae of Baltic prawns were exposed to nominal concentrations of 0, 0.02, 0.05, 0.1, 0.5, 1.0 and 5.0 mg/L of Cd for 4 days. The 4-day LC50 was calculated by the probit analysis. At 10-day bioassay, the concentrations of 0.05, 0.1, 0.5, 1.0, 5.0, 10.0 and 20.0 mg/L were introduced into each of the jars in triplicate treatments and 0 mg/L as control. Each tank containing 20 larvae was exposed to test solutions. Results: Results from probit analysis showed that the 96-h LC50 value was 0.14 mg/L for Cd. The 10 days bioassays were conducted with nominal concentrations of 0, 0.05, 0.1, 0.5, 1.0, 5.0, 10.0 and 20.0 mg/L Cd. Mortality increased in parallel with the increase in concentrations of Cd on Zoea – I stage of P. adspersus and time of exposure. The toxicity rate of the organism is concentration-dependent. All organisms except the control group died at the end of 10 days. Less than 25% of the animals survived at the 5 days of the exposure to concentrations of 0.5 mg/kg Cd or more. Only 20% of the organisms survived at the 7 days of the exposure to concentrations of 0.1 mg/kg Cd or less in seawater with clean sediment. Conclusions: The results showed that Cd was highly toxic to P. adspersus. When the larvae were exposed to concentrations of Cd, they become slightly excited and swam erratically, probably due to stress. However, behavioural and swimming patterns in control groups were normal, and there was not any mortality during the course of the experiment.展开更多
Objective:To describe the growth,reproductive biology and abundance of the population of invasive shrimps Palaemon elegans(P.elegans)in one of the branches of Garmat Ali river at Basrah,Southern Iraq.Methods:Monthly s...Objective:To describe the growth,reproductive biology and abundance of the population of invasive shrimps Palaemon elegans(P.elegans)in one of the branches of Garmat Ali river at Basrah,Southern Iraq.Methods:Monthly samples of the prawn P.elegans were collected with a bottom hand net(40 cm,0.5 mm mesh)hauled over a distance of 10 m.A simple random sampling was conducted monthly between December 2012 and November 2013.Results:Seasonal changes were observed in the composition of the population of the species during the study year with the highest abundance in 2013 and the lowest abundance for the males was reported in January and for the females occurred in June.Salinity showed a significant correlation with the abundance of shrimps at the sampling site.The largest female measured 67.90 mm while the corresponding value for males was 61.31 mm.The proportion of ovigerous adults rose during spring season to peak on about July and ovigerous prawns were taken in all months of the year.The sex ratio indicated a preponderance of females over males in all months in the study period.Each females produced around 36-1324 eggs and the incubation period lasted for 11-14 days at 17-29°C.Conclusions:The results of the present study indicate that this species has a wide distribution range,high density,and great reproduction potential.This study reveals the lack of researches on this species in environments of Shatt Al-Arab river and its branches.Thus,P.elegans has most likely formed a permanent population in all the brackish waters in Basrah area.展开更多
基金Supported by the University of Sinop,Fisheries Faculty,Department of Hydrobiology(Grant No.S.049).
文摘Objective: To evaluate the suitability of Palaemon adspersus (P. adspersus) as a bio-indicator for 4 and 10 days of cadmium toxicity bioassays. Methods: Four and ten days experiments were designed. CdCl2·2?H2O was dissolved in distilled water and a stock solution was made. At 4-day bioassay, the larvae of Baltic prawns were exposed to nominal concentrations of 0, 0.02, 0.05, 0.1, 0.5, 1.0 and 5.0 mg/L of Cd for 4 days. The 4-day LC50 was calculated by the probit analysis. At 10-day bioassay, the concentrations of 0.05, 0.1, 0.5, 1.0, 5.0, 10.0 and 20.0 mg/L were introduced into each of the jars in triplicate treatments and 0 mg/L as control. Each tank containing 20 larvae was exposed to test solutions. Results: Results from probit analysis showed that the 96-h LC50 value was 0.14 mg/L for Cd. The 10 days bioassays were conducted with nominal concentrations of 0, 0.05, 0.1, 0.5, 1.0, 5.0, 10.0 and 20.0 mg/L Cd. Mortality increased in parallel with the increase in concentrations of Cd on Zoea – I stage of P. adspersus and time of exposure. The toxicity rate of the organism is concentration-dependent. All organisms except the control group died at the end of 10 days. Less than 25% of the animals survived at the 5 days of the exposure to concentrations of 0.5 mg/kg Cd or more. Only 20% of the organisms survived at the 7 days of the exposure to concentrations of 0.1 mg/kg Cd or less in seawater with clean sediment. Conclusions: The results showed that Cd was highly toxic to P. adspersus. When the larvae were exposed to concentrations of Cd, they become slightly excited and swam erratically, probably due to stress. However, behavioural and swimming patterns in control groups were normal, and there was not any mortality during the course of the experiment.
文摘Objective:To describe the growth,reproductive biology and abundance of the population of invasive shrimps Palaemon elegans(P.elegans)in one of the branches of Garmat Ali river at Basrah,Southern Iraq.Methods:Monthly samples of the prawn P.elegans were collected with a bottom hand net(40 cm,0.5 mm mesh)hauled over a distance of 10 m.A simple random sampling was conducted monthly between December 2012 and November 2013.Results:Seasonal changes were observed in the composition of the population of the species during the study year with the highest abundance in 2013 and the lowest abundance for the males was reported in January and for the females occurred in June.Salinity showed a significant correlation with the abundance of shrimps at the sampling site.The largest female measured 67.90 mm while the corresponding value for males was 61.31 mm.The proportion of ovigerous adults rose during spring season to peak on about July and ovigerous prawns were taken in all months of the year.The sex ratio indicated a preponderance of females over males in all months in the study period.Each females produced around 36-1324 eggs and the incubation period lasted for 11-14 days at 17-29°C.Conclusions:The results of the present study indicate that this species has a wide distribution range,high density,and great reproduction potential.This study reveals the lack of researches on this species in environments of Shatt Al-Arab river and its branches.Thus,P.elegans has most likely formed a permanent population in all the brackish waters in Basrah area.
