Fish populations have declined in many estuarine and freshwater ecosystems in part due to the loss of habitat in recent decades.Reconstructing lost habitat for larvae fish is a potential method for recovering larvae f...Fish populations have declined in many estuarine and freshwater ecosystems in part due to the loss of habitat in recent decades.Reconstructing lost habitat for larvae fish is a potential method for recovering larvae fish populations.Three-dimensional artificial floating wetlands(AFWs)on which Phragmites australis was planted were experimentally deployed to recover the lost habitat in the Changjiang(Yangtze)River estuary from May to July 2018.The AFW area was characterized by slow velocity,high transparency,low dissolved oxygen,and relatively constant water temperature.The total individuals of larvae fish in the AFW area(12122 in total)was higher than that in the non-AFW area(1250 in total),and the densities of most larvae fish species were higher in the AFW habitat than in the non-AFW area.The distributions of larvae fish species were positively influenced by habitat type because they were strongly related to the negative part of the first axis of the redundancy analysis,and Cyprinus carpio and Cyprinus auratus were inclined to habitat in the slow velocity and high transparency AFW habitat area.These results indicate that larvae fish species are inclined to inhabit the AFW habitat.The use of three-dimensional P.australis AFWs would be a potential method for enhancing the habitat of larvae fish in the degraded habitats along the estuary.展开更多
Starvation has important effects on early development of fish. It determines the survival and growth of fish larvae,and plays an important role in the dynamics of fish population and fisheries recruitment. In this rev...Starvation has important effects on early development of fish. It determines the survival and growth of fish larvae,and plays an important role in the dynamics of fish population and fisheries recruitment. In this review,we discuss the current studies about the effects of starvation on growth and development of fish larval stage. The goals of this review are to understand some adaptive mechanisms and ecological countermeasures of starved fish larvae and to provide the scientific guideline for exploring early life history processes,evaluating the nutrition condition and growth of larval fish,protecting fish resource and breeding fish larvae.展开更多
This study investigated abundance, species composition and spatial and temporal distributions of fish larvae and their relationship with some environmental variables in the Sukhothai floodplain in northern Thailand. F...This study investigated abundance, species composition and spatial and temporal distributions of fish larvae and their relationship with some environmental variables in the Sukhothai floodplain in northern Thailand. Fish larvae were collected from 33 sampling stations on 8 occasions between August 2010 and October 2013. The study collected and identified 149 296 individuals, representing 32 families and 165 taxa. The species composition of larval fish was dominated by the Cyprinidae(47.27%), Cobitidae(7.88%), Siluridae(6.67%), Bagridae(6.06%) and Mastacembelidae(3.33%) families. The mostabundant larval species were the Striped flying barb Esomus metallicus(16.90%), the Siamese mud carpHenicorhynchus siamensis(8.48%) and the Sumatran river sprat Clupeichthys goniognathus(8.31%). The greatest abundance and species diversity of larvae were found when the river flow runs onto the floodplain. PCA and nMDS analysis revealed that the samples plot is associated with temporal distribution among years. The discharge was a major factor determining fish larvae assemblage and environmental variables in the Sukhothai floodplain. Four fish larval species were positively correlated with the samples for 2013. The result of the CCA ordination plot showed that only the discharge variable was strongly correlated with fish larvae abundance, especially two cyprinid R asbora species.展开更多
Decreasing fish resources in estuaries is a subject of anthropogenic activities. Studies of the spatiotemporal distribution of fish eggs and larvae can help identify the status and processes underlying recruitment in ...Decreasing fish resources in estuaries is a subject of anthropogenic activities. Studies of the spatiotemporal distribution of fish eggs and larvae can help identify the status and processes underlying recruitment in a fishery. As the fifth largest river estuary in the world, the Huanghe (Yellow) River estuary (HRE) is a typical estuary that has been seriously aff ected by human activities. Annual surveys on ichthyoplankton and environmental factors were conducted in the months of May of 2005 and 2009-2016 in the HRE to investigate the spatiotemporal distribution of fish eggs and larvae and the associated infl uencing factors. A total of 23 and 20 species of eggs and larvae, respectively, were collected. The dominant orders were Perciformes (51.2%) and Clupeiformes (25.6%). The average number of fish species eggs and larvae were 6.0 and 4.1 in average abundance of 0.91 and 0.13 ind./m^3 , respectively. The dominant species were mainly low-commercial-value small-sized fishes, such as Clupanodon punctatus , Harengula zunasi, and Acanthogobius, whereas certain traditional commercial fishes, such as Trichiurus lepturus , and Clupea pallasii, were not seen. Analysis of the fish egg and larval community revealed four temporal assemblages and two spatial assemblages. Salinity was the main factor on the spatial distribution of ichthyoplankton communities, the species number and Shannon-Weiner diversity index (H′) of the fish egg and larval community near the river mouth with lower salinity were signifi cantly lower than the community far away from the river mouth with higher salinity. In addition, increases of water temperature promoted the number and abundance of fish species eggs, and the areas of abundant prey tended to have a more diversified and abundant of ichthyoplankton species. In overall, overfishing, dam construction, and other human activities were the main drivers that led to the substantial decline in fishery resources in the HRE.展开更多
A study on the assemblage composition and vertical distribution of larval fish was conducted in the southern area of the Moroccan Atlantic coast in Autumn 2011. A total of I 680 fish larvae taxa were identified from 2...A study on the assemblage composition and vertical distribution of larval fish was conducted in the southern area of the Moroccan Atlantic coast in Autumn 2011. A total of I 680 fish larvae taxa were identified from 21 families. The majority of the larvae were present in the upper layers. Clupeids were the most abundant larvae taxa followed by Myctophidae, Gadidae and Sparidae, hence the larval fish assemblages （LFA） were variable in different depth layers. Total fish larvae showed a preference for surface layers, and were mainly found above 75 m depth, with some exceptions. The maximum concentration of fish larvae was concentrated up to 25 m essentially above the thermocline, where chlorophyll a and mesozooplankton were abundant. Spatially, neritic families were located near the coast and at some offshore stations especially in the northern part, while oceanic families were more distributed towards offshore along the study area. Cluster analysis showed a segregation of two groups of larvae. However, a clear separation between neritic families and oceanic families was not found. Multivariate analysis highlighted the relationship between the distribution of larvae of different families and environmental parameters. Temperature and salinity seem to have been the factors that acted on associations offish larvae. Day/night vertical distributions suggest there was not a very significant vertical migration, probably due to adequate light levels for feeding.展开更多
[Objective] The paper was to explore the species composition, number distribution and seasonal dynamics of fish eggs and larvae in Liaodong Bay in 2008. The protection and exploitation status of spawning ground in Lia...[Objective] The paper was to explore the species composition, number distribution and seasonal dynamics of fish eggs and larvae in Liaodong Bay in 2008. The protection and exploitation status of spawning ground in Liaodong Bay was analyzed, and the corresponding protection measures were put forward. [Methods] The species composition of fish eggs and larvae in spawning ground of Liaodong Bay was investigated by horizontal trawling associated with vertical trawling with zooplankton net in May, July, September and October in 2008. [Result] It was found that 7 724 eggs and 229 larvae of fishes belonging to 32 taxa were collected, in which 29 taxa were identified as species, belonging to 9 genera, 21 families and 28 orders, 2 taxa were identified to only family level, and one failed to be identified. The main spawning groups were Cynoglossus joyneri, Engraulis japonicus, Johnius belengerii, Larimichthys polyactis, Konosirus punctatus, Sardinella zunasi, and Scomberomorus niphonius, and the main spawning ground was found in northern waters and Changxing Island waters in Liaodao Bay. There was slightly less spawning species in 2008 compared with 1998, especially the number of fish eggs and larvae decreased greatly. [Conclusion] The effective measures for protection of spawning grounds in Liaodong Bay are suggested, including control of fishing intensity, development of artificial reefs, establishment of germplasm resources reserves, and standardization of compensation standards for marine ecological damage.展开更多
To reduce the pressure on aquatic resources due to the use of fishmeal in fish feed, the mastery and use of alternative sources of fishmeal in all stages of fish development are essential. Five diets including 4 exper...To reduce the pressure on aquatic resources due to the use of fishmeal in fish feed, the mastery and use of alternative sources of fishmeal in all stages of fish development are essential. Five diets including 4 experimental and one control diet were considered. Experimental diets of post-larvae were developed from unconventional ingredients in which fishmeal was completely replaced by a mixture of brewer’s yeast, chicken viscera and maggots. These foods were tested on Clarias gariepinus post-larvae with an initial average weight of 80 ± 1 mg. 1500 fish individuals were equally distributed in 15 concrete basins with a volume of 500 L forming five treatments in triplicate. Fish individuals were fed, manually at a ration rate of 20%, four times per day. The specific growth rates were 8.38%/day in imported food and 6.35%/day in the experimental food receiving 45.5% of protein from unconventional meal. Similar results were obtained with the feed consumption index. These encouraging results show that it is possible to partially or completely replace fishmeal in catfish feed and obtain an economically profitable production. The recovery of waste such as chicken viscera, brewer’s yeast and soybean meal in fish food formulation as tested in this study is a good contribution to environmental sanitation.展开更多
The goal of this study was to determine the short-term effects of the quality (UV-A/UV-B ratio) and quantity (irradiance) of natural ultraviolet radiation (UVR) on the apoptosis levels in Yellow perch (Perca flavescen...The goal of this study was to determine the short-term effects of the quality (UV-A/UV-B ratio) and quantity (irradiance) of natural ultraviolet radiation (UVR) on the apoptosis levels in Yellow perch (Perca flavescens) larvae. Apoptosis, or programmed cell death, is an essential event in many physiological processes as well as in pathological conditions. Western blots were used to measure the expression of several key proteins of the apoptotic cascade, such as p53, Bax, Bcl-2, and PARP-1, whereas specific apoptotic DNA fragmentation was measured by an ELISA assay. We predicted that higher UVR exposure would be related to higher levels of apoptosis. Our results showed that specific apoptotic DNA fragmentation was reduced by visible light + UV-A as well as by visible light + UV-A and UV-B treatments although it was not significantly affected by light quantity. However, the expression of p53, Bax/Bcl-2 ratio and PARP-1 were not significantly affected in larvae by the quantity or the quality of the light after two days of exposure. Altogether our results suggest that UVR may modulate the apoptotic process in Yellow perch larvae proposing an interesting role for this stressor on the early development of living organism under natural exposure condition.展开更多
The present study deals with the effect of exogenous treatment of O. niloticus females with L-thyroxine (T4) on the development of the digestive system during larval rearing, and its subsequent effect on larval growth...The present study deals with the effect of exogenous treatment of O. niloticus females with L-thyroxine (T4) on the development of the digestive system during larval rearing, and its subsequent effect on larval growth and survival. The development of the digestive tract and accessory glands was investigated histologically and histochemically in the developing O. niloticus larvae, from control and T4-treated spawners. During yolk-sac absorption, the digestive system of the fish underwent further differentiation and the rudimentary alimentary canal became segmented into four different histological regions: the buccopharynx, oesophagus, stomach and intestine. The injection of females O. niloticus with thyroxine (1 or 10 μg T4/g BW) greatly enhanced the development of the digestive tract and accessory glands of larvae as indicated by the quantitative and qualitative changes of the mucus composition from predominantly neutral to a mixture of neutral and acid mucosubstances, or acid mucosubstances occurred during the rearing period for the larvae produced from T4-treated females. This may be due to the direct effect of exogenous thyroxine, which might have been transferred from maternal circulation into the oocytes and larvae, on the synthesis of proteins, which increased with larval development. Thus, thyroxine directly or indirectly improved O. niloticus larval growth, since a marked increase in both, length and weight of larvae occurred during the experimental period. In addition, larvae from treated females also gave a significantly higher survival rate than that of control. It could be concluded that exogenous T4 in maternal circulation might have been transferred into oocytes and larvae. The transferred thyroid hormone appears to play some role in the early development of larvae and may confer a distinct advantage for the growth of the offspring of the Nile tilapia, O. niloticus.展开更多
基金Supported by the National Key R&D Program of China(Nos.2019YFD0901202,2018YFD0900905)the China Postdoctoral Science Foundation(No.2018M632887)。
文摘Fish populations have declined in many estuarine and freshwater ecosystems in part due to the loss of habitat in recent decades.Reconstructing lost habitat for larvae fish is a potential method for recovering larvae fish populations.Three-dimensional artificial floating wetlands(AFWs)on which Phragmites australis was planted were experimentally deployed to recover the lost habitat in the Changjiang(Yangtze)River estuary from May to July 2018.The AFW area was characterized by slow velocity,high transparency,low dissolved oxygen,and relatively constant water temperature.The total individuals of larvae fish in the AFW area(12122 in total)was higher than that in the non-AFW area(1250 in total),and the densities of most larvae fish species were higher in the AFW habitat than in the non-AFW area.The distributions of larvae fish species were positively influenced by habitat type because they were strongly related to the negative part of the first axis of the redundancy analysis,and Cyprinus carpio and Cyprinus auratus were inclined to habitat in the slow velocity and high transparency AFW habitat area.These results indicate that larvae fish species are inclined to inhabit the AFW habitat.The use of three-dimensional P.australis AFWs would be a potential method for enhancing the habitat of larvae fish in the degraded habitats along the estuary.
文摘Starvation has important effects on early development of fish. It determines the survival and growth of fish larvae,and plays an important role in the dynamics of fish population and fisheries recruitment. In this review,we discuss the current studies about the effects of starvation on growth and development of fish larval stage. The goals of this review are to understand some adaptive mechanisms and ecological countermeasures of starved fish larvae and to provide the scientific guideline for exploring early life history processes,evaluating the nutrition condition and growth of larval fish,protecting fish resource and breeding fish larvae.
基金Supported by the Agricultural Research Development Agency(Public Organization)
文摘This study investigated abundance, species composition and spatial and temporal distributions of fish larvae and their relationship with some environmental variables in the Sukhothai floodplain in northern Thailand. Fish larvae were collected from 33 sampling stations on 8 occasions between August 2010 and October 2013. The study collected and identified 149 296 individuals, representing 32 families and 165 taxa. The species composition of larval fish was dominated by the Cyprinidae(47.27%), Cobitidae(7.88%), Siluridae(6.67%), Bagridae(6.06%) and Mastacembelidae(3.33%) families. The mostabundant larval species were the Striped flying barb Esomus metallicus(16.90%), the Siamese mud carpHenicorhynchus siamensis(8.48%) and the Sumatran river sprat Clupeichthys goniognathus(8.31%). The greatest abundance and species diversity of larvae were found when the river flow runs onto the floodplain. PCA and nMDS analysis revealed that the samples plot is associated with temporal distribution among years. The discharge was a major factor determining fish larvae assemblage and environmental variables in the Sukhothai floodplain. Four fish larval species were positively correlated with the samples for 2013. The result of the CCA ordination plot showed that only the discharge variable was strongly correlated with fish larvae abundance, especially two cyprinid R asbora species.
基金Supported by the National Natural Science Foundation of China—Shandong Provincial Joint Fund for Marine Science Research Centers(No.U1606404)the National Key Basic Research Program of China(973 Program)(No.2015CB453301)the National Marine Public Welfare Research Project of China(No.201405007)
文摘Decreasing fish resources in estuaries is a subject of anthropogenic activities. Studies of the spatiotemporal distribution of fish eggs and larvae can help identify the status and processes underlying recruitment in a fishery. As the fifth largest river estuary in the world, the Huanghe (Yellow) River estuary (HRE) is a typical estuary that has been seriously aff ected by human activities. Annual surveys on ichthyoplankton and environmental factors were conducted in the months of May of 2005 and 2009-2016 in the HRE to investigate the spatiotemporal distribution of fish eggs and larvae and the associated infl uencing factors. A total of 23 and 20 species of eggs and larvae, respectively, were collected. The dominant orders were Perciformes (51.2%) and Clupeiformes (25.6%). The average number of fish species eggs and larvae were 6.0 and 4.1 in average abundance of 0.91 and 0.13 ind./m^3 , respectively. The dominant species were mainly low-commercial-value small-sized fishes, such as Clupanodon punctatus , Harengula zunasi, and Acanthogobius, whereas certain traditional commercial fishes, such as Trichiurus lepturus , and Clupea pallasii, were not seen. Analysis of the fish egg and larval community revealed four temporal assemblages and two spatial assemblages. Salinity was the main factor on the spatial distribution of ichthyoplankton communities, the species number and Shannon-Weiner diversity index (H′) of the fish egg and larval community near the river mouth with lower salinity were signifi cantly lower than the community far away from the river mouth with higher salinity. In addition, increases of water temperature promoted the number and abundance of fish species eggs, and the areas of abundant prey tended to have a more diversified and abundant of ichthyoplankton species. In overall, overfishing, dam construction, and other human activities were the main drivers that led to the substantial decline in fishery resources in the HRE.
基金Supported by the Moroccan-Norwegian scientific team that participated in the survey on aboard the R/V Dr Fridtjof Nansen in the context of the regional project CCLME“Canary Current Large Marine Ecosystem”
文摘A study on the assemblage composition and vertical distribution of larval fish was conducted in the southern area of the Moroccan Atlantic coast in Autumn 2011. A total of I 680 fish larvae taxa were identified from 21 families. The majority of the larvae were present in the upper layers. Clupeids were the most abundant larvae taxa followed by Myctophidae, Gadidae and Sparidae, hence the larval fish assemblages （LFA） were variable in different depth layers. Total fish larvae showed a preference for surface layers, and were mainly found above 75 m depth, with some exceptions. The maximum concentration of fish larvae was concentrated up to 25 m essentially above the thermocline, where chlorophyll a and mesozooplankton were abundant. Spatially, neritic families were located near the coast and at some offshore stations especially in the northern part, while oceanic families were more distributed towards offshore along the study area. Cluster analysis showed a segregation of two groups of larvae. However, a clear separation between neritic families and oceanic families was not found. Multivariate analysis highlighted the relationship between the distribution of larvae of different families and environmental parameters. Temperature and salinity seem to have been the factors that acted on associations offish larvae. Day/night vertical distributions suggest there was not a very significant vertical migration, probably due to adequate light levels for feeding.
基金Supported by Special Fund for Scientific Research(Marine)in the Public Interest(201405010)
文摘[Objective] The paper was to explore the species composition, number distribution and seasonal dynamics of fish eggs and larvae in Liaodong Bay in 2008. The protection and exploitation status of spawning ground in Liaodong Bay was analyzed, and the corresponding protection measures were put forward. [Methods] The species composition of fish eggs and larvae in spawning ground of Liaodong Bay was investigated by horizontal trawling associated with vertical trawling with zooplankton net in May, July, September and October in 2008. [Result] It was found that 7 724 eggs and 229 larvae of fishes belonging to 32 taxa were collected, in which 29 taxa were identified as species, belonging to 9 genera, 21 families and 28 orders, 2 taxa were identified to only family level, and one failed to be identified. The main spawning groups were Cynoglossus joyneri, Engraulis japonicus, Johnius belengerii, Larimichthys polyactis, Konosirus punctatus, Sardinella zunasi, and Scomberomorus niphonius, and the main spawning ground was found in northern waters and Changxing Island waters in Liaodao Bay. There was slightly less spawning species in 2008 compared with 1998, especially the number of fish eggs and larvae decreased greatly. [Conclusion] The effective measures for protection of spawning grounds in Liaodong Bay are suggested, including control of fishing intensity, development of artificial reefs, establishment of germplasm resources reserves, and standardization of compensation standards for marine ecological damage.
文摘To reduce the pressure on aquatic resources due to the use of fishmeal in fish feed, the mastery and use of alternative sources of fishmeal in all stages of fish development are essential. Five diets including 4 experimental and one control diet were considered. Experimental diets of post-larvae were developed from unconventional ingredients in which fishmeal was completely replaced by a mixture of brewer’s yeast, chicken viscera and maggots. These foods were tested on Clarias gariepinus post-larvae with an initial average weight of 80 ± 1 mg. 1500 fish individuals were equally distributed in 15 concrete basins with a volume of 500 L forming five treatments in triplicate. Fish individuals were fed, manually at a ration rate of 20%, four times per day. The specific growth rates were 8.38%/day in imported food and 6.35%/day in the experimental food receiving 45.5% of protein from unconventional meal. Similar results were obtained with the feed consumption index. These encouraging results show that it is possible to partially or completely replace fishmeal in catfish feed and obtain an economically profitable production. The recovery of waste such as chicken viscera, brewer’s yeast and soybean meal in fish food formulation as tested in this study is a good contribution to environmental sanitation.
文摘The goal of this study was to determine the short-term effects of the quality (UV-A/UV-B ratio) and quantity (irradiance) of natural ultraviolet radiation (UVR) on the apoptosis levels in Yellow perch (Perca flavescens) larvae. Apoptosis, or programmed cell death, is an essential event in many physiological processes as well as in pathological conditions. Western blots were used to measure the expression of several key proteins of the apoptotic cascade, such as p53, Bax, Bcl-2, and PARP-1, whereas specific apoptotic DNA fragmentation was measured by an ELISA assay. We predicted that higher UVR exposure would be related to higher levels of apoptosis. Our results showed that specific apoptotic DNA fragmentation was reduced by visible light + UV-A as well as by visible light + UV-A and UV-B treatments although it was not significantly affected by light quantity. However, the expression of p53, Bax/Bcl-2 ratio and PARP-1 were not significantly affected in larvae by the quantity or the quality of the light after two days of exposure. Altogether our results suggest that UVR may modulate the apoptotic process in Yellow perch larvae proposing an interesting role for this stressor on the early development of living organism under natural exposure condition.
文摘The present study deals with the effect of exogenous treatment of O. niloticus females with L-thyroxine (T4) on the development of the digestive system during larval rearing, and its subsequent effect on larval growth and survival. The development of the digestive tract and accessory glands was investigated histologically and histochemically in the developing O. niloticus larvae, from control and T4-treated spawners. During yolk-sac absorption, the digestive system of the fish underwent further differentiation and the rudimentary alimentary canal became segmented into four different histological regions: the buccopharynx, oesophagus, stomach and intestine. The injection of females O. niloticus with thyroxine (1 or 10 μg T4/g BW) greatly enhanced the development of the digestive tract and accessory glands of larvae as indicated by the quantitative and qualitative changes of the mucus composition from predominantly neutral to a mixture of neutral and acid mucosubstances, or acid mucosubstances occurred during the rearing period for the larvae produced from T4-treated females. This may be due to the direct effect of exogenous thyroxine, which might have been transferred from maternal circulation into the oocytes and larvae, on the synthesis of proteins, which increased with larval development. Thus, thyroxine directly or indirectly improved O. niloticus larval growth, since a marked increase in both, length and weight of larvae occurred during the experimental period. In addition, larvae from treated females also gave a significantly higher survival rate than that of control. It could be concluded that exogenous T4 in maternal circulation might have been transferred into oocytes and larvae. The transferred thyroid hormone appears to play some role in the early development of larvae and may confer a distinct advantage for the growth of the offspring of the Nile tilapia, O. niloticus.
