A prevailing,controversial hypothesis is that fishing pressure has played a greater role than climatic and environmental drivers,in changing fish species succession and biomass fluctuation in the South China Sea(SCS)....A prevailing,controversial hypothesis is that fishing pressure has played a greater role than climatic and environmental drivers,in changing fish species succession and biomass fluctuation in the South China Sea(SCS).Based on otter trawl survey data from 1959 to 2010 in the outer Beibu Gulf(OBG),northern SCS,large seasonal and interannual variation is reported for fish species composition,the proportional abundances of dominant taxa,and fish biomass.Generalized additive models are developed to quantify relationships between fish biomass and the external factors of fishing pressure and climate change.Fishing pressure proved to be the main driver of sharp declines in demersal fish stocks,with high-value species being replaced by low-value ones over time.Abrupt decreases in fish biomass during the years of 1993 and 1998 correspond to El Nino events,with climate change possibly the main driver of proportional representation of pelagic species in fisheries trawl catch.The need to differentiate impacts of fishing and environmental drivers on fish species with different life history strategies is stressed to better understand fish community dynamics.展开更多
This paper lists 50 fish specs in the Huanghe Estuary, which belong to 9 orders, 22 families and 37 genera. The paper describes the seasonal distributions of these fish species and the succession of the important fi...This paper lists 50 fish specs in the Huanghe Estuary, which belong to 9 orders, 22 families and 37 genera. The paper describes the seasonal distributions of these fish species and the succession of the important fish species during the past 50 a. The authors discuss the main factors that have resulted in the changes in fish species diversity and the fishery resources. These include the overexploitation of the fishery and the sharp reduction in the fresh water discharges from the Huanghe River.展开更多
River-floodplain ecosystems are in delicate balance and are impacted by even minor changes in water availability. In this study, we surveyed fish assemblages and investigated environmental and landscape parameters in ...River-floodplain ecosystems are in delicate balance and are impacted by even minor changes in water availability. In this study, we surveyed fish assemblages and investigated environmental and landscape parameters in a total of 135 floodplain waterbodies (rivers, diversion canals, ponds, irrigation ditches, paddy fields, and wetlands) in the Chao Phraya River Basin in rainy (September 2014) and dry (March 2015) seasons. Factors affecting fish species richness in each type of waterbody were analyzed using generalized linear mixed models. Floodplain area around each surveyed waterbody was a major factor determining fish species richness in rivers, diversion canals, and ponds in the region. The contribution of floodplain area was equivalent to that of hydrology (current velocity, water depth) and water quality (dissolved oxygen, turbidity) in the waterbodies. The population of juvenile fishes was increased in temporarily connected floodplain waterbodies to main rivers compared with isolated waterbodies, and fluvial and lacustrine fishes were observed in the temporary inundated floodplain waterbodies during the rainy season. The high dependence of fish species richness on floodplain area in the region appeared to be a result of the use of inundated floodplains by fish species to forage and breed. Our results highlight the impact of flood control measures that reduces floodplain area. These measures must be reviewed to ensure the conservation of fish biodiversity in the Chao Phraya River Basin, one of the world’s most threatened floodplain systems.展开更多
Evaluation of spatial-temporal variability of species composition and diversity in oceanic ecosystems is not easy because it is usually difficult to obtain sufficient data quantifying such variability.In this study,we...Evaluation of spatial-temporal variability of species composition and diversity in oceanic ecosystems is not easy because it is usually difficult to obtain sufficient data quantifying such variability.In this study,we examined pelagic species diversity indicators,species richness,Shannon-Wiener index of diversity and Hurlbert's species evenness,for fish assemblages from two areas(north and south) in the North Pacific Ocean(2°±12°N,178°E±165°W) during May±July 2008.The assemblages were based on data collected by an onboard scientific observer during a commercial longline fishing trip.The species richness and Shannon-Wiener diversity index of fish assemblages in the northern area were slightly higher than those in the southern area,although these differences were not significant(t test,P.0.05).Non-parametric multidimensional scaling and analysis of similarities indicated that there were significant differences in fish assemblages between the two areas(P,0.01).展开更多
Mercury (Hg) concentrations in the tissues (muscle, stomach, liver, gills, skin, and gonads) of five fish species (mullet Liza haematocheilus, flathead fish Platycephalus indicus, sea bass Lateolabrax japonicus, macke...Mercury (Hg) concentrations in the tissues (muscle, stomach, liver, gills, skin, and gonads) of five fish species (mullet Liza haematocheilus, flathead fish Platycephalus indicus, sea bass Lateolabrax japonicus, mackerel Scomberomorus niphonius and silver pomfret Pampus argenteus) collected from Laizhou Bay in the Bohai Sea of China were investigated. The results indicate that Hg bioaccumulation in the five fish was tissue- specific, with the highest levels in the muscle and liver, followed by the stomach and gonads. The lowest levels were found in the gills and skin. Fish at higher trophic levels (flathead fish and sea bass) exhibited higher Hg concentrations than consumers at lower trophic levels. Mercury bioaccumulation tended to be positively correlated with fish length in mullet, silver pomfret, mackerel, and flathead fish, but was negatively correlated with fish length in sea bass. The Hg concentrations in the muscles of all fish species in Laizhou Bay were within the permissible limits of food safety set by national and international criteria. However, the suggesting maximum consumption of sea bass is 263g per week for human health.展开更多
A fuzzy mathematical method is used to discriminate the similarities of pelagic fishes land- ed in the 9180 hauls by 10 light-seine information vessels in the southern Fujian waters from 1989 to 1998. The results indi...A fuzzy mathematical method is used to discriminate the similarities of pelagic fishes land- ed in the 9180 hauls by 10 light-seine information vessels in the southern Fujian waters from 1989 to 1998. The results indicate that the dominant species of the communities had an obvious alternation and the fuzzy adjacency of annual species composition varied between 0. 659 and 0. 923 with an average value of 0. 791. The fuzzy clustering analysis indicates that the annual fuzzy adjacency in general remains good although the species composition of the pelagic fishes has changed to a certain degree since 1992. This paper concludes that the community structure of pelagic fishes in the southern Taiwan Strait remains rel- atively stable and the state of fish stocks shows a good potentiality for a larger utilization.展开更多
A total number of 60 specimens of two different species of Scarus fish caught from the Red Sea coast at Jeddah (30) and Rabigh (30) cities in Saudi Arabia were examined to determine their metazoan parasitic fauna, the...A total number of 60 specimens of two different species of Scarus fish caught from the Red Sea coast at Jeddah (30) and Rabigh (30) cities in Saudi Arabia were examined to determine their metazoan parasitic fauna, their prevalences, and mean intensities. Collected parasites were identified as, Isopoda (praniza larva of Gnathia sp.), Copepoda (Hatschekia sp.) Monogenea (Diplectanum sp.) and Digenea (Lecithoclaster and Bucephalus spp). Out of 30 specimens of fish caught from Jeddah coast 13 (43.4%) were infested by 90 parasites comprising of two parasite species, praniza larva and Hatschekia sp., with prevalence of infestation 40% and 3.33%, and mean intensity 7 and 6 parasites per fish respectively. 19 (63.3%) of Scarus fish caught from Rabigh coast were infested by 205 parasites representing 4 parasite spp. Diplectanum sp. represents the most commonly encountered parasite with prevalence (53.3%) and mean intensity (10.94%), followed by (Lecithoclaster sp. then praniza larva, prevalances (16.66% and 13.3%) and mean inentisities (3.4. and 1.75) respectively. Bucephalus sp. showed the minor, prevalence (3.33%) and mean intensity (6). Generally Scarus fish species from Rabigh had higher prevalence and mean intensity (63.3% and 7.59%) than Scarus fish species from Jeddah (43.4% and 6.92%). Female fish from Jeddah showed no parasitic infestation, while males were infested (prevalence 65% and mean intensity 6.92). Female fish from Rabigh had higher prevalence (84.21) and lower intensity (6.43) than males which showed prevalence (27.27%) and intensity (19). Relationship between parasitic infestation and fish species and sex were also studied in the two different localities and discussed.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
Three different packaging materials of (37 cm × 25 cm) size (Sealed Transparent Polythene Bag (STPB) Sealed Paper Bag (SPB) (Brown envelope), Open Mouth Polythene Bag (OMPB) (Black incolour)) were used for Oreoch...Three different packaging materials of (37 cm × 25 cm) size (Sealed Transparent Polythene Bag (STPB) Sealed Paper Bag (SPB) (Brown envelope), Open Mouth Polythene Bag (OMPB) (Black incolour)) were used for Oreochromisniloticus (O), Clariasgariepinus (C) and Mormyrusrume (M). Twenty fish samples per species (averaging 250 gm) were hot smoked dried whole for 36 hours at an average temperature of 100?C. Packaged hot at the rate of 6 fishes per package for each species (three packs for each packaging treatment i.e. 18 pieces were packed while the remaining 2 pieces were used for initial bacteria load and microbial load). Microbial load (Total Viable Count (TVC), Total Coliform Count (TCC) and Total Fungi Count (TFC)) for the fresh fish was initial hot smoked and finally at the end of 12 weeks was monitored. The TVC (bacterial load) of O. niloticus dropped from (10.6 - 8.4) × 104 (fresh state-hot smoked) and M. rume (9.8 - 7.0) × 104, while C. gariepinus slightly increased from (12.4 - 12.6) × 104. After hot smoking, highest TVC of 8.6 × 104 (OMPBC), 8.3 × 104 (SPBC) and 8.2 × 104 (STPBC) were recorded in C. gariepinus among the 9 packag- ing at 12 weeks. However highest tendency for heavy TVC is in all OMPB with highest bacteria load in the OMPBC (8.6 × 104), 7.6 × 104 (OMPBO) and 6.6 × 104 (OMPBM). After 12 weeks highest ranged TFC of (0.6 - 0.7) × 104 was recorded in M. rume as against 0.2 × 104 recorded in the initial smoked for all. TCC was highest in C. gariepinus (4.0 - 4.3) × 104. Packaging did not limit the existence of micro-organisms. Six bacteria species (Micrococcus (acidiophilus, luteus), Bacillus (subtilis, cereus, aureus), Staphylococcus aureus, Streptococcus lactis, Proteus (vulgaricus, morganii), Pseudomonas aureginosa) and three fungi species (Aspergillus (niger, tamari), Rhizopusnigricans, fusariumoxysporum) were represented in all the packages. On the average five bacteria and two fungi species were represented, excepting for OMPBM and OMPBO with six bacteria species.展开更多
In September and October 2015, a new species of the family Nemacheilidae, Triplophysa tianxingensis sp. nov., was discovered from underground water in Qiubei County, Yunnan Province, China. It can be distinguished fro...In September and October 2015, a new species of the family Nemacheilidae, Triplophysa tianxingensis sp. nov., was discovered from underground water in Qiubei County, Yunnan Province, China. It can be distinguished from all other troglobiotic Triplophysa species occurring in Yunnan by the following combination of characters: eyes small, a little degenerated; barbels longer; ventral profiles greatly convex; pectoral fin short, attaining a third of the distance from the pectoral-fin base to pelvic fin base; body with many brown blotches; caudal peduncle with fin fold; caudal fin shallowly forked, and free posterior chamber of swim bladder cylindrical.展开更多
Cavefish have advanced to the forefront as excellent models for laboratory studies in developmental and evolutionary biology.The iconic Mexican characid,Astyanax mexicanus,which consists of a surface-dwelling morph an...Cavefish have advanced to the forefront as excellent models for laboratory studies in developmental and evolutionary biology.The iconic Mexican characid,Astyanax mexicanus,which consists of a surface-dwelling morph and about 30 interfertile cave-dwelling morphs,has become a major contributor to behavior,sensory biology,trait evolution,and biomedicine(Jeffery,2020).There are about 200 scientifically-described cavefish species distributed in karst areas on most continents(Proudlove,2015).Similar to A.mexicanus,a small subset of other cavefish taxa coupled with related surface-dwelling species are now serving as additional laboratory models to address a variety of important biological problems.A prime example is the cyprinid genus Sinocycloceilus,which contains 75 closely related surface and cave species endemic to the karst massifs of southwestern China(Jiang et al.,2019,2023;Ma et al.,2019).Comparative studies of Chinese and Mexican cavefish can be used to address a host of questions concerning the convergence and divergence of cave related traits.In the future,other Chinese cavefish species,such as the cave loach,as well as the more recently discovered European cavefishes,are likely to join the current group of excellent laboratory models.This special issue of Zoological Research presents the results of current research on these diverse cavefish species.In addition to recent research using cavefish models in laboratory studies,this issue also covers new research on cavefish in the wild.展开更多
Community structure of fish in relation to environmental variation was investigated in Nanji Islands National Nature Reserve (NINNR). In order to test this relationship, we delineated 25 survey stations with bottom tr...Community structure of fish in relation to environmental variation was investigated in Nanji Islands National Nature Reserve (NINNR). In order to test this relationship, we delineated 25 survey stations with bottom trawling and measured environmental variables. Samples were taken from November 2013 (autumn), February 2014 (winter), May 2014 (spring) and September 2014 (summer). We found a very strong correlation in space and time between temperature and salinity;abundance and biomass in winter;depth and DO in summer then a strong correlation was found respectively between temperature and biomass;salinity and biomass in winter too and finally a moderate correlation between depth and biomass in spring, (P-value < 0.01) with positive correlation (that the other variable or factor has a tendency to increase). We also found out a negative correlation (P-value < 0.05), respectively between salinity and DO;DO and chlorophyll in summer;temperature and salinity;salinity and DO in spring period (mean that the other variable or factor has a tendency to decrease). A negative correlation observed between temperature, salinity and chlorophyll in winter, spring and autumn period were due by a temperature and salinity window open for species blooms through the movement of the TWC and Jiangzhe coastal current close to shore. By comparing diversity of fish species with environmental factors, the community structure of fish varied significantly as physicochemical parameters changed between different stations for each season. As results and according to the species referencing of environmental factors;species diversity, abundance and evenness vary among different stations, corresponding to significant differences of environmental factors (e.g. physicochemical parameters and chlorophyll-a concentration in different sites). Species richness of microfauna was negatively correlated with salinity levels. Furthermore, they were related to the fish community according to the results. This may be due to the fish community’s adaptability in these different variations of environmental factors, but only tolerant members remaining.展开更多
Accurate species identification is a key component of biodiversity research.DNA barcoding is an effective molecular method used for fish species identification.We aimed to study the DNA barcoding of fish in Zhoushan c...Accurate species identification is a key component of biodiversity research.DNA barcoding is an effective molecular method used for fish species identification.We aimed to study the DNA barcoding of fish in Zhoushan coastal waters,explore the differences and applicability of two gene fragments(12S rRNA and COI)of DNA barcoding in fish species identification,and established a comprehensive fish barcoding reference database.Two hundred and eighty-seven captured fish samples from Zhoushan coastal waters were identified using morphological characteristics and DNA barcoding.A total of 26412S rRNA sequences(belonging to eight orders,31 families,55 genera,and 66 species)and 188 COI sequences(belonging to seven orders,30 families,48 genera,and 58 species)were obtained.The lengths of the 12S rRNA sequences ranged from 165 to 178 bp,and the guanine-cytosine(GC)content was 45.37%.The average 12S rRNA interspecific and intraspecific genetic distances(K2P)were 0.10%and 26.66%,respectively.The length of the COI sequence ranged 574–655 bp,and the content of GC was 45.97%.The average 12S rRNA interspecific and intraspecific genetic distances(K2P)were 0.16%and 27.45%,respectively.The minimum interspecific genetic distances of 12S rRNA and COI(1.23%and 1.86%)were both greater than their maximum intraspecific genetic distances(2.42%and 8.66%).Three molecular analyses(NJ tree,ABGD,and GMYC)were performed to accurately identify and delineate species.Clustering errors occurred when the 12S rRNA sequences were delimited using the NJ tree method,and the delimitation results of ABGD and GMYC are consistent with the final species identification results.Our results demonstrate that DNA barcoding based on 12S rRNA and COI can be used as an effective tool for fish species identification,and 12S rRNA has good application prospects in the environmental DNA(eDNA)metabarcoding of marine fish.展开更多
基金The Science and Technology Basic Resources Investigation Program of China under contract No.2017FY201405the Open Research Fund Program of Guangxi Key Lab of Mangrove Conservation and Utilization under contract No.GKLMC-201403+2 种基金the National Natural Science Foundation of China under contract No.41666008the Fund of Key Laboratory of Open-Sea Fishery Development,Ministry of Agriculture of China under contract No.LOF 2018-01the Natural Science Foundation of Guangxi under contract No.2016GXNSFDA380035
文摘A prevailing,controversial hypothesis is that fishing pressure has played a greater role than climatic and environmental drivers,in changing fish species succession and biomass fluctuation in the South China Sea(SCS).Based on otter trawl survey data from 1959 to 2010 in the outer Beibu Gulf(OBG),northern SCS,large seasonal and interannual variation is reported for fish species composition,the proportional abundances of dominant taxa,and fish biomass.Generalized additive models are developed to quantify relationships between fish biomass and the external factors of fishing pressure and climate change.Fishing pressure proved to be the main driver of sharp declines in demersal fish stocks,with high-value species being replaced by low-value ones over time.Abrupt decreases in fish biomass during the years of 1993 and 1998 correspond to El Nino events,with climate change possibly the main driver of proportional representation of pelagic species in fisheries trawl catch.The need to differentiate impacts of fishing and environmental drivers on fish species with different life history strategies is stressed to better understand fish community dynamics.
基金National Natural Science Foundation of China under contract No. 3963260.
文摘This paper lists 50 fish specs in the Huanghe Estuary, which belong to 9 orders, 22 families and 37 genera. The paper describes the seasonal distributions of these fish species and the succession of the important fish species during the past 50 a. The authors discuss the main factors that have resulted in the changes in fish species diversity and the fishery resources. These include the overexploitation of the fishery and the sharp reduction in the fresh water discharges from the Huanghe River.
文摘River-floodplain ecosystems are in delicate balance and are impacted by even minor changes in water availability. In this study, we surveyed fish assemblages and investigated environmental and landscape parameters in a total of 135 floodplain waterbodies (rivers, diversion canals, ponds, irrigation ditches, paddy fields, and wetlands) in the Chao Phraya River Basin in rainy (September 2014) and dry (March 2015) seasons. Factors affecting fish species richness in each type of waterbody were analyzed using generalized linear mixed models. Floodplain area around each surveyed waterbody was a major factor determining fish species richness in rivers, diversion canals, and ponds in the region. The contribution of floodplain area was equivalent to that of hydrology (current velocity, water depth) and water quality (dissolved oxygen, turbidity) in the waterbodies. The population of juvenile fishes was increased in temporarily connected floodplain waterbodies to main rivers compared with isolated waterbodies, and fluvial and lacustrine fishes were observed in the temporary inundated floodplain waterbodies during the rainy season. The high dependence of fish species richness on floodplain area in the region appeared to be a result of the use of inundated floodplains by fish species to forage and breed. Our results highlight the impact of flood control measures that reduces floodplain area. These measures must be reviewed to ensure the conservation of fish biodiversity in the Chao Phraya River Basin, one of the world’s most threatened floodplain systems.
基金Supported by the China National Fishery Observer Programthe Shanghai Leading Academic Discipline Project (No. S30702)
文摘Evaluation of spatial-temporal variability of species composition and diversity in oceanic ecosystems is not easy because it is usually difficult to obtain sufficient data quantifying such variability.In this study,we examined pelagic species diversity indicators,species richness,Shannon-Wiener index of diversity and Hurlbert's species evenness,for fish assemblages from two areas(north and south) in the North Pacific Ocean(2°±12°N,178°E±165°W) during May±July 2008.The assemblages were based on data collected by an onboard scientific observer during a commercial longline fishing trip.The species richness and Shannon-Wiener diversity index of fish assemblages in the northern area were slightly higher than those in the southern area,although these differences were not significant(t test,P.0.05).Non-parametric multidimensional scaling and analysis of similarities indicated that there were significant differences in fish assemblages between the two areas(P,0.01).
基金Supported by the National Natural Science Foundation of China for International or Regional Research Cooperation and Exchange Project(No.31061160187)the National Natural Science Foundation of China for Creative Research Group(No.41121064)
文摘Mercury (Hg) concentrations in the tissues (muscle, stomach, liver, gills, skin, and gonads) of five fish species (mullet Liza haematocheilus, flathead fish Platycephalus indicus, sea bass Lateolabrax japonicus, mackerel Scomberomorus niphonius and silver pomfret Pampus argenteus) collected from Laizhou Bay in the Bohai Sea of China were investigated. The results indicate that Hg bioaccumulation in the five fish was tissue- specific, with the highest levels in the muscle and liver, followed by the stomach and gonads. The lowest levels were found in the gills and skin. Fish at higher trophic levels (flathead fish and sea bass) exhibited higher Hg concentrations than consumers at lower trophic levels. Mercury bioaccumulation tended to be positively correlated with fish length in mullet, silver pomfret, mackerel, and flathead fish, but was negatively correlated with fish length in sea bass. The Hg concentrations in the muscles of all fish species in Laizhou Bay were within the permissible limits of food safety set by national and international criteria. However, the suggesting maximum consumption of sea bass is 263g per week for human health.
基金This project is funded by the Fujian Department of Fisheries (Min Shui Ke 1998-08).
文摘A fuzzy mathematical method is used to discriminate the similarities of pelagic fishes land- ed in the 9180 hauls by 10 light-seine information vessels in the southern Fujian waters from 1989 to 1998. The results indicate that the dominant species of the communities had an obvious alternation and the fuzzy adjacency of annual species composition varied between 0. 659 and 0. 923 with an average value of 0. 791. The fuzzy clustering analysis indicates that the annual fuzzy adjacency in general remains good although the species composition of the pelagic fishes has changed to a certain degree since 1992. This paper concludes that the community structure of pelagic fishes in the southern Taiwan Strait remains rel- atively stable and the state of fish stocks shows a good potentiality for a larger utilization.
文摘A total number of 60 specimens of two different species of Scarus fish caught from the Red Sea coast at Jeddah (30) and Rabigh (30) cities in Saudi Arabia were examined to determine their metazoan parasitic fauna, their prevalences, and mean intensities. Collected parasites were identified as, Isopoda (praniza larva of Gnathia sp.), Copepoda (Hatschekia sp.) Monogenea (Diplectanum sp.) and Digenea (Lecithoclaster and Bucephalus spp). Out of 30 specimens of fish caught from Jeddah coast 13 (43.4%) were infested by 90 parasites comprising of two parasite species, praniza larva and Hatschekia sp., with prevalence of infestation 40% and 3.33%, and mean intensity 7 and 6 parasites per fish respectively. 19 (63.3%) of Scarus fish caught from Rabigh coast were infested by 205 parasites representing 4 parasite spp. Diplectanum sp. represents the most commonly encountered parasite with prevalence (53.3%) and mean intensity (10.94%), followed by (Lecithoclaster sp. then praniza larva, prevalances (16.66% and 13.3%) and mean inentisities (3.4. and 1.75) respectively. Bucephalus sp. showed the minor, prevalence (3.33%) and mean intensity (6). Generally Scarus fish species from Rabigh had higher prevalence and mean intensity (63.3% and 7.59%) than Scarus fish species from Jeddah (43.4% and 6.92%). Female fish from Jeddah showed no parasitic infestation, while males were infested (prevalence 65% and mean intensity 6.92). Female fish from Rabigh had higher prevalence (84.21) and lower intensity (6.43) than males which showed prevalence (27.27%) and intensity (19). Relationship between parasitic infestation and fish species and sex were also studied in the two different localities and discussed.
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Three different packaging materials of (37 cm × 25 cm) size (Sealed Transparent Polythene Bag (STPB) Sealed Paper Bag (SPB) (Brown envelope), Open Mouth Polythene Bag (OMPB) (Black incolour)) were used for Oreochromisniloticus (O), Clariasgariepinus (C) and Mormyrusrume (M). Twenty fish samples per species (averaging 250 gm) were hot smoked dried whole for 36 hours at an average temperature of 100?C. Packaged hot at the rate of 6 fishes per package for each species (three packs for each packaging treatment i.e. 18 pieces were packed while the remaining 2 pieces were used for initial bacteria load and microbial load). Microbial load (Total Viable Count (TVC), Total Coliform Count (TCC) and Total Fungi Count (TFC)) for the fresh fish was initial hot smoked and finally at the end of 12 weeks was monitored. The TVC (bacterial load) of O. niloticus dropped from (10.6 - 8.4) × 104 (fresh state-hot smoked) and M. rume (9.8 - 7.0) × 104, while C. gariepinus slightly increased from (12.4 - 12.6) × 104. After hot smoking, highest TVC of 8.6 × 104 (OMPBC), 8.3 × 104 (SPBC) and 8.2 × 104 (STPBC) were recorded in C. gariepinus among the 9 packag- ing at 12 weeks. However highest tendency for heavy TVC is in all OMPB with highest bacteria load in the OMPBC (8.6 × 104), 7.6 × 104 (OMPBO) and 6.6 × 104 (OMPBM). After 12 weeks highest ranged TFC of (0.6 - 0.7) × 104 was recorded in M. rume as against 0.2 × 104 recorded in the initial smoked for all. TCC was highest in C. gariepinus (4.0 - 4.3) × 104. Packaging did not limit the existence of micro-organisms. Six bacteria species (Micrococcus (acidiophilus, luteus), Bacillus (subtilis, cereus, aureus), Staphylococcus aureus, Streptococcus lactis, Proteus (vulgaricus, morganii), Pseudomonas aureginosa) and three fungi species (Aspergillus (niger, tamari), Rhizopusnigricans, fusariumoxysporum) were represented in all the packages. On the average five bacteria and two fungi species were represented, excepting for OMPBM and OMPBO with six bacteria species.
基金supported by the National Science Foundation of China(31272335,30970326)National Science and Technology Support Program(2013BAB06B03)+1 种基金China Huaneng Group Science&Technology Program(HNKJ13-H17-03)Power Construction Corporation of China Science & Technology Program:Ecological Safety Monitoring System Research in Hydroelectric Developed Watershed(DJ-ZDXM-2014-03)
文摘In September and October 2015, a new species of the family Nemacheilidae, Triplophysa tianxingensis sp. nov., was discovered from underground water in Qiubei County, Yunnan Province, China. It can be distinguished from all other troglobiotic Triplophysa species occurring in Yunnan by the following combination of characters: eyes small, a little degenerated; barbels longer; ventral profiles greatly convex; pectoral fin short, attaining a third of the distance from the pectoral-fin base to pelvic fin base; body with many brown blotches; caudal peduncle with fin fold; caudal fin shallowly forked, and free posterior chamber of swim bladder cylindrical.
文摘Cavefish have advanced to the forefront as excellent models for laboratory studies in developmental and evolutionary biology.The iconic Mexican characid,Astyanax mexicanus,which consists of a surface-dwelling morph and about 30 interfertile cave-dwelling morphs,has become a major contributor to behavior,sensory biology,trait evolution,and biomedicine(Jeffery,2020).There are about 200 scientifically-described cavefish species distributed in karst areas on most continents(Proudlove,2015).Similar to A.mexicanus,a small subset of other cavefish taxa coupled with related surface-dwelling species are now serving as additional laboratory models to address a variety of important biological problems.A prime example is the cyprinid genus Sinocycloceilus,which contains 75 closely related surface and cave species endemic to the karst massifs of southwestern China(Jiang et al.,2019,2023;Ma et al.,2019).Comparative studies of Chinese and Mexican cavefish can be used to address a host of questions concerning the convergence and divergence of cave related traits.In the future,other Chinese cavefish species,such as the cave loach,as well as the more recently discovered European cavefishes,are likely to join the current group of excellent laboratory models.This special issue of Zoological Research presents the results of current research on these diverse cavefish species.In addition to recent research using cavefish models in laboratory studies,this issue also covers new research on cavefish in the wild.
文摘Community structure of fish in relation to environmental variation was investigated in Nanji Islands National Nature Reserve (NINNR). In order to test this relationship, we delineated 25 survey stations with bottom trawling and measured environmental variables. Samples were taken from November 2013 (autumn), February 2014 (winter), May 2014 (spring) and September 2014 (summer). We found a very strong correlation in space and time between temperature and salinity;abundance and biomass in winter;depth and DO in summer then a strong correlation was found respectively between temperature and biomass;salinity and biomass in winter too and finally a moderate correlation between depth and biomass in spring, (P-value < 0.01) with positive correlation (that the other variable or factor has a tendency to increase). We also found out a negative correlation (P-value < 0.05), respectively between salinity and DO;DO and chlorophyll in summer;temperature and salinity;salinity and DO in spring period (mean that the other variable or factor has a tendency to decrease). A negative correlation observed between temperature, salinity and chlorophyll in winter, spring and autumn period were due by a temperature and salinity window open for species blooms through the movement of the TWC and Jiangzhe coastal current close to shore. By comparing diversity of fish species with environmental factors, the community structure of fish varied significantly as physicochemical parameters changed between different stations for each season. As results and according to the species referencing of environmental factors;species diversity, abundance and evenness vary among different stations, corresponding to significant differences of environmental factors (e.g. physicochemical parameters and chlorophyll-a concentration in different sites). Species richness of microfauna was negatively correlated with salinity levels. Furthermore, they were related to the fish community according to the results. This may be due to the fish community’s adaptability in these different variations of environmental factors, but only tolerant members remaining.
基金Supported by the Zhejiang Provincial Key Research and Development Program (No.2021C02047)。
文摘Accurate species identification is a key component of biodiversity research.DNA barcoding is an effective molecular method used for fish species identification.We aimed to study the DNA barcoding of fish in Zhoushan coastal waters,explore the differences and applicability of two gene fragments(12S rRNA and COI)of DNA barcoding in fish species identification,and established a comprehensive fish barcoding reference database.Two hundred and eighty-seven captured fish samples from Zhoushan coastal waters were identified using morphological characteristics and DNA barcoding.A total of 26412S rRNA sequences(belonging to eight orders,31 families,55 genera,and 66 species)and 188 COI sequences(belonging to seven orders,30 families,48 genera,and 58 species)were obtained.The lengths of the 12S rRNA sequences ranged from 165 to 178 bp,and the guanine-cytosine(GC)content was 45.37%.The average 12S rRNA interspecific and intraspecific genetic distances(K2P)were 0.10%and 26.66%,respectively.The length of the COI sequence ranged 574–655 bp,and the content of GC was 45.97%.The average 12S rRNA interspecific and intraspecific genetic distances(K2P)were 0.16%and 27.45%,respectively.The minimum interspecific genetic distances of 12S rRNA and COI(1.23%and 1.86%)were both greater than their maximum intraspecific genetic distances(2.42%and 8.66%).Three molecular analyses(NJ tree,ABGD,and GMYC)were performed to accurately identify and delineate species.Clustering errors occurred when the 12S rRNA sequences were delimited using the NJ tree method,and the delimitation results of ABGD and GMYC are consistent with the final species identification results.Our results demonstrate that DNA barcoding based on 12S rRNA and COI can be used as an effective tool for fish species identification,and 12S rRNA has good application prospects in the environmental DNA(eDNA)metabarcoding of marine fish.