The small indigenous fish species(SIS)are harvested as ensemble of different fish species of varying size and shape.An appraisal of the abundance and biomass of fish species constituting such ensemble was carried out ...The small indigenous fish species(SIS)are harvested as ensemble of different fish species of varying size and shape.An appraisal of the abundance and biomass of fish species constituting such ensemble was carried out with samples collected from fish markets ofWest Bengal,India.The data revealed that at least 22 different fish species were present varying in numbers and species combinations.The abundance and biomass of the individual fish species was negatively correlated,indicating numerical dominance of small sized species.Logarithmic regression showed a good fit of the relative abundance(y)with the species richness(x)in the samples of SIS(y=55.72ln(x)e 77.27;r^(2)=0.940),while power regression was best fit for the relative biomass of individual fish(y)with the species richness(x)in the samples of SIS(y=24.58x^(-1.54);R^(2)=0.831).In overall both species specific and individual based biomass and abundance relationships were negatively correlated.In order to ascertain the harvest and marketability of the SIS in a judicious manner,monitoring of the fish assemblages in natural habitats is recommended.展开更多
The fish Sinocyclocheilus grahami is one of the indicative and endemic species in the Dianchi Lake ecosystem. As a result of pollution and invasion of exotic fishes, the fish had disappeared from Dianchi Lake since 19...The fish Sinocyclocheilus grahami is one of the indicative and endemic species in the Dianchi Lake ecosystem. As a result of pollution and invasion of exotic fishes, the fish had disappeared from Dianchi Lake since 1986 and only a few small populations survive in springs and streams around the lake. Due to the endangered status and special scientific value, S.grahami was listed as the second class protective animal of China in 1989. The importance of S. grahami and the indigenous biodiversity of Dianchi Lake were recognized by the Global Environment Foundation （GEF） /World Bank and Yunnan Development ＆ Reform Committee. Therefore a special grant was set up to restore and conserve the indigenous biodiversity of Dianchi Lake. The artificial breeding of S. grahami is a part of the targeted activities. Two successful breeding experiments were achieved using five females plus six males up to early March 2007. Approximately 1600 eggs were collected, of which 1320 eggs fertilized using the dry-fertilizing method. The mean fertilization rate was 73%. Approximately 480 fish fry was hatched and the mean hatching rate was 36%. After 10 days of cultivation, 95% fingerlings survived and their body lengths were up to 8- 12 mm. The importance of the artificial breeding success of S. grahami could be summarized as following： effectively protecting the fish from extinction; releasing the fish fry back to appropriate water body of the lake could help to restore the indigenous biodiversity of Dianchi Lake; facilitating the shift of local fish cultivation from the present non-indigenous to the future indigenous fishery.展开更多
Erhai Lake is the second largest freshwater lake on the Yunnan Plateau, Southwest China. In recent decades, a number of exotic fish species have been introduced into the lake and the fish community has changed conside...Erhai Lake is the second largest freshwater lake on the Yunnan Plateau, Southwest China. In recent decades, a number of exotic fish species have been introduced into the lake and the fish community has changed considerably. We evaluated the status of the fish community based on surveys with multimesh gillnet, trap net, and benthic fyke-net between May 2009 and April 2012. In addition, we evaluated the change in the community using historical data （1952-2010） describing the fish community and fishery harvest. The current fish community is dominated by small-sized fishes, including Pseudorasbora parva, Rhinogobius giurinus, Micropercops swinhonis, Hemiculter leucisculus, and Rhinogobius cliffordpopei. These accounted for 87.7% of the 22 546 total specimens collected. Omnivorous and carnivorous species dominated the community. A canonical correspondence analysis （CCA） plot revealed that the distribution of fishes in the lake is influenced by aquatic plants, water temperature, pH, and season. The abundance of indigenous species has declined sharply, and a majority of endemic species have been extirpated from the lake （a decrease from seven to two species）. In contrast, the number of exotic species has increased since the 1960s to a total of 22 at present. The fishery harvest decreased initially following the 1960s, but has since increased due to the introduction of non-native fish and stocking of native fish. The fishery harvest was significantly correlated with total nitrogen, not total phosphorus, during the past 20 years. Based on our results, we discuss recommendations for the restoration and conservation of the fish resources in Erhai Lake.展开更多
Management of fed-fish culture practices,at present,stands on two broad feed categories,(i)formulated proteinaceous aquafeeds and(ii)the natural resources.Judicious use of the later is gaining popularity since it offe...Management of fed-fish culture practices,at present,stands on two broad feed categories,(i)formulated proteinaceous aquafeeds and(ii)the natural resources.Judicious use of the later is gaining popularity since it offers sustainability to fish culture.Polyculture often targets phyto-and zooplanktonic resources,but mostly ignores periphyton.This review discusses the works on feed diversification performed independently at different times.Fishes,viz.Cyprinus carpio,Labeo rohita and Amblypharyngodon mola were projected as potential candidates for resource-nutrient management with feed diversification in rice fish culture.With C.carpio the rice fish culture called Aji Gnui Assonii in terrace water-logged rice field of Apatani Plateau,Arunachal Pradesh(India)is referred as self-substrating aquaculture practice.This monoculture practice experiences high carp productivity since there remains surplus of resources below the threshold level in these rice fields.Similarly,L.rohita,explores periphytic resources in ponds when substrates are installed.As a result,filter feeders get more foraging aquatic phase intensifying the resources for exploration in pond.This concept is suggested for rice fields with water depth above 50 cm where rice stems act as substrate.With trenches or refuge canals,resource intensification may be managed for more cultivable fishes in rice fields with<50 cm water depth.This model of resource intensification further allows inclusion of Small Indigenous Fish Species(SIFs)-which are rich source of many micronutrients.Thus,integration of SIFs confers huge potentiality for intensification of nutrients,especially protein and micronutrients in rice fields.展开更多
文摘The small indigenous fish species(SIS)are harvested as ensemble of different fish species of varying size and shape.An appraisal of the abundance and biomass of fish species constituting such ensemble was carried out with samples collected from fish markets ofWest Bengal,India.The data revealed that at least 22 different fish species were present varying in numbers and species combinations.The abundance and biomass of the individual fish species was negatively correlated,indicating numerical dominance of small sized species.Logarithmic regression showed a good fit of the relative abundance(y)with the species richness(x)in the samples of SIS(y=55.72ln(x)e 77.27;r^(2)=0.940),while power regression was best fit for the relative biomass of individual fish(y)with the species richness(x)in the samples of SIS(y=24.58x^(-1.54);R^(2)=0.831).In overall both species specific and individual based biomass and abundance relationships were negatively correlated.In order to ascertain the harvest and marketability of the SIS in a judicious manner,monitoring of the fish assemblages in natural habitats is recommended.
文摘The fish Sinocyclocheilus grahami is one of the indicative and endemic species in the Dianchi Lake ecosystem. As a result of pollution and invasion of exotic fishes, the fish had disappeared from Dianchi Lake since 1986 and only a few small populations survive in springs and streams around the lake. Due to the endangered status and special scientific value, S.grahami was listed as the second class protective animal of China in 1989. The importance of S. grahami and the indigenous biodiversity of Dianchi Lake were recognized by the Global Environment Foundation （GEF） /World Bank and Yunnan Development ＆ Reform Committee. Therefore a special grant was set up to restore and conserve the indigenous biodiversity of Dianchi Lake. The artificial breeding of S. grahami is a part of the targeted activities. Two successful breeding experiments were achieved using five females plus six males up to early March 2007. Approximately 1600 eggs were collected, of which 1320 eggs fertilized using the dry-fertilizing method. The mean fertilization rate was 73%. Approximately 480 fish fry was hatched and the mean hatching rate was 36%. After 10 days of cultivation, 95% fingerlings survived and their body lengths were up to 8- 12 mm. The importance of the artificial breeding success of S. grahami could be summarized as following： effectively protecting the fish from extinction; releasing the fish fry back to appropriate water body of the lake could help to restore the indigenous biodiversity of Dianchi Lake; facilitating the shift of local fish cultivation from the present non-indigenous to the future indigenous fishery.
基金Supported by the National Special Research Fund for Non-Profit Sector(Agriculture)(No.200903048-04)the Major Science and Technology Program for Water Pollution Control and Treatment of China(No.2012ZX07105-004)the State Key Program of National Natural Science Foundation of China(No.30830025)
文摘Erhai Lake is the second largest freshwater lake on the Yunnan Plateau, Southwest China. In recent decades, a number of exotic fish species have been introduced into the lake and the fish community has changed considerably. We evaluated the status of the fish community based on surveys with multimesh gillnet, trap net, and benthic fyke-net between May 2009 and April 2012. In addition, we evaluated the change in the community using historical data （1952-2010） describing the fish community and fishery harvest. The current fish community is dominated by small-sized fishes, including Pseudorasbora parva, Rhinogobius giurinus, Micropercops swinhonis, Hemiculter leucisculus, and Rhinogobius cliffordpopei. These accounted for 87.7% of the 22 546 total specimens collected. Omnivorous and carnivorous species dominated the community. A canonical correspondence analysis （CCA） plot revealed that the distribution of fishes in the lake is influenced by aquatic plants, water temperature, pH, and season. The abundance of indigenous species has declined sharply, and a majority of endemic species have been extirpated from the lake （a decrease from seven to two species）. In contrast, the number of exotic species has increased since the 1960s to a total of 22 at present. The fishery harvest decreased initially following the 1960s, but has since increased due to the introduction of non-native fish and stocking of native fish. The fishery harvest was significantly correlated with total nitrogen, not total phosphorus, during the past 20 years. Based on our results, we discuss recommendations for the restoration and conservation of the fish resources in Erhai Lake.
文摘Management of fed-fish culture practices,at present,stands on two broad feed categories,(i)formulated proteinaceous aquafeeds and(ii)the natural resources.Judicious use of the later is gaining popularity since it offers sustainability to fish culture.Polyculture often targets phyto-and zooplanktonic resources,but mostly ignores periphyton.This review discusses the works on feed diversification performed independently at different times.Fishes,viz.Cyprinus carpio,Labeo rohita and Amblypharyngodon mola were projected as potential candidates for resource-nutrient management with feed diversification in rice fish culture.With C.carpio the rice fish culture called Aji Gnui Assonii in terrace water-logged rice field of Apatani Plateau,Arunachal Pradesh(India)is referred as self-substrating aquaculture practice.This monoculture practice experiences high carp productivity since there remains surplus of resources below the threshold level in these rice fields.Similarly,L.rohita,explores periphytic resources in ponds when substrates are installed.As a result,filter feeders get more foraging aquatic phase intensifying the resources for exploration in pond.This concept is suggested for rice fields with water depth above 50 cm where rice stems act as substrate.With trenches or refuge canals,resource intensification may be managed for more cultivable fishes in rice fields with<50 cm water depth.This model of resource intensification further allows inclusion of Small Indigenous Fish Species(SIFs)-which are rich source of many micronutrients.Thus,integration of SIFs confers huge potentiality for intensification of nutrients,especially protein and micronutrients in rice fields.
