Adult rice field eels with 125.52±27.99 g body weight corresponding to 44.79±5.93 cm in length were maturity cultured in a 5 m^2 cement tank without mud for three months with density 30 eels/m^2.Eel broodsto...Adult rice field eels with 125.52±27.99 g body weight corresponding to 44.79±5.93 cm in length were maturity cultured in a 5 m^2 cement tank without mud for three months with density 30 eels/m^2.Eel broodstocks were fed with three types of food including:sea fish(T1),commercial pellet food(T2)and mixed food—50%sea fish and 50%commercial pellet food(T3).Result showed that the maximum gonadosomatic index(GSI)of female eels fed by sea fish(2.89%±0.67%)was higher than both commercial pellet food(1.62%±0.62%)and mixed food(2.03%±0.82%)(P<0.05),while,GSI of male eels was 1.27%±0.31%,0.68%±0.23%and 1.14%±0.41%(P>0.05).Maturity rate of female fed by sea fish(88.91%±9.64%)was higher than commercial pellet food(61.12%±9.64%)(P<0.05).The maturity rate of male eels was rather low and there was not significantly different among treatments(P>0.05).Then.the eels were induced for spawning with two kinds of hormones,including T1:human chorionic ganadotropin(HCG)at 1,500 IU/kg,T2:luteinzing hormone-releasing hormone(LHRH-a)at 150μg/kg and domperidon 10 mg/kg,and T3:control without hormone.The results of spawning induction methods showed that the reproduction rate of female eels induced by LHRH-a and HCG hormones were higher than that by natural reproduction method(P<0.05).Others,the survival rate of fry eels after 5 d using natural reproduction method(92.65%±2.54%)was higher than both using LHRH-a(67.77%±1.91%)and HCG(68.65%±1.23%)hormones(P<0.05).The average diameter of eggs was 3.40-3.41 mm and the length of newly hatched eels was 1.72±0.19 cm.展开更多
The diversity of aquatic resources in Thi Nai Lagoon decreased due to the lack of harmonious use and integrated long-term planning on the use of living resources.There remained a lack of mechanisms and regulations for...The diversity of aquatic resources in Thi Nai Lagoon decreased due to the lack of harmonious use and integrated long-term planning on the use of living resources.There remained a lack of mechanisms and regulations for coordination of activities in the lagoon by Binh Dinh Provincial People’s Committee(PPC).The aim of the study was to investgate the aquatic species and water quality in Thi Nai Lagoon,Vietnam.Data were collected at 23 different points on Thi Nai Lagoon,with three replicates at each point.There were 106 species of fish presented on the lagoon and in different sizes,including 17 mollusc species and 15 crustaceans species.In the dry season,there were 167 phytoplankton species in five divisions,10 classes in 39 orders in 59 families including 77 genus.Zooplankton had eight chordata in 10 classes of 18 orders including 44 families,64 genus and 102 species.Arthropoda had the largest number of species,78 species,accounting for 76.5%of total species.In the rainy season,only 48 species of Arthropoda,Cnidaria,Annelida,Chaetognatha and Rotifer were affected and some were not encountered in the wet season,such as mollusca and chordata.While water quality variables were still good for aquaculture,within permitted limits of TCVN standard and criteria,there were still problems caused by production discharges and living activities of inhabitants around the lagoon,such as sedimentary matters.展开更多
文摘Adult rice field eels with 125.52±27.99 g body weight corresponding to 44.79±5.93 cm in length were maturity cultured in a 5 m^2 cement tank without mud for three months with density 30 eels/m^2.Eel broodstocks were fed with three types of food including:sea fish(T1),commercial pellet food(T2)and mixed food—50%sea fish and 50%commercial pellet food(T3).Result showed that the maximum gonadosomatic index(GSI)of female eels fed by sea fish(2.89%±0.67%)was higher than both commercial pellet food(1.62%±0.62%)and mixed food(2.03%±0.82%)(P<0.05),while,GSI of male eels was 1.27%±0.31%,0.68%±0.23%and 1.14%±0.41%(P>0.05).Maturity rate of female fed by sea fish(88.91%±9.64%)was higher than commercial pellet food(61.12%±9.64%)(P<0.05).The maturity rate of male eels was rather low and there was not significantly different among treatments(P>0.05).Then.the eels were induced for spawning with two kinds of hormones,including T1:human chorionic ganadotropin(HCG)at 1,500 IU/kg,T2:luteinzing hormone-releasing hormone(LHRH-a)at 150μg/kg and domperidon 10 mg/kg,and T3:control without hormone.The results of spawning induction methods showed that the reproduction rate of female eels induced by LHRH-a and HCG hormones were higher than that by natural reproduction method(P<0.05).Others,the survival rate of fry eels after 5 d using natural reproduction method(92.65%±2.54%)was higher than both using LHRH-a(67.77%±1.91%)and HCG(68.65%±1.23%)hormones(P<0.05).The average diameter of eggs was 3.40-3.41 mm and the length of newly hatched eels was 1.72±0.19 cm.
文摘The diversity of aquatic resources in Thi Nai Lagoon decreased due to the lack of harmonious use and integrated long-term planning on the use of living resources.There remained a lack of mechanisms and regulations for coordination of activities in the lagoon by Binh Dinh Provincial People’s Committee(PPC).The aim of the study was to investgate the aquatic species and water quality in Thi Nai Lagoon,Vietnam.Data were collected at 23 different points on Thi Nai Lagoon,with three replicates at each point.There were 106 species of fish presented on the lagoon and in different sizes,including 17 mollusc species and 15 crustaceans species.In the dry season,there were 167 phytoplankton species in five divisions,10 classes in 39 orders in 59 families including 77 genus.Zooplankton had eight chordata in 10 classes of 18 orders including 44 families,64 genus and 102 species.Arthropoda had the largest number of species,78 species,accounting for 76.5%of total species.In the rainy season,only 48 species of Arthropoda,Cnidaria,Annelida,Chaetognatha and Rotifer were affected and some were not encountered in the wet season,such as mollusca and chordata.While water quality variables were still good for aquaculture,within permitted limits of TCVN standard and criteria,there were still problems caused by production discharges and living activities of inhabitants around the lagoon,such as sedimentary matters.
