We report here arsenic speciation in 1643 freshwater fish samples,representing 14 common fish species from 53 waterbodies in Alberta,Canada.Arsenic species were extracted from fish muscle tissue.Arsenic species in the...We report here arsenic speciation in 1643 freshwater fish samples,representing 14 common fish species from 53 waterbodies in Alberta,Canada.Arsenic species were extracted from fish muscle tissue.Arsenic species in the extracts were separated using anion-exchange high-performance liquid chromatography(HPLC)and quantified using inductively coupled plasma mass spectrometry(ICPMS).The total arsenic concentrations in fish ranged from 2.8 to 1200μg/kg(in wet weight of sample)(mean 71±101μg/kg),which are all below the 2000μg/kg(wet weight)maximum allowable total arsenic in fish,recommended by the Ontario Ministry of the Environment.In 99.7%,or 1638 of all 1643 freshwater fish samples analyzed,arsenobetaine(AsB)was detectable,with concentrations higher than the method detection limit of 0.25μg/kg(wet weight).Dimethylarsinic acid(DMA)was detectable(concentration>0.25μg/kg)in 92.1%,or 1514 of the 1643 freshwater fish samples.Inorganic arsenate(iAs^(Ⅴ))was detectable(>0.25μg/kg)in 1119 fish(i.e.,68.1% of 1643 samples).Monomethylarsonic acid(MMA)was detectable(>0.25μg/kg)in 418 fish(25.4%of 1643 samples).The concentrations of arsenic species in the 1643 fish samples varied by as much as three orders of magnitude,ranging from below the method detection limit of 0.25μg/kg to the maximum concentrations of 380μg/kg for AsB,150μg/kg for DMA,70μg/kg for iAs^(Ⅴ),and 51μg/kg for MMA.AsB made up 46.1%±26.2% of total arsenic species.Arsenic speciation patterns varied between lake whitefish,northern pike,and walleye,the three most common types of fish analyzed.The relative proportion of DMA in northern pike was larger than in lake whitefish and walleye,and conversely,the relative proportion of iAs^(Ⅴ) was lower in northern pike.Seven unknown arsenic species were detected,and their chromatographic retention time did not match with those of available arsenic standards.At least one unknown arsenic species was detected in 33.4%,or 549 of 1643 freshwater fish samples.The concentrations of unknown arsenic species were as high as 61μg/kg.Future research is necessary to identify unknown arsenic species and to determine contributing factors to the observed arsenic species patterns and concentrations.展开更多
Arsenic speciation in freshwater fish is crucial for providing meaningful consumption guidelines that allow the public to make informed decisions regarding its consumption.While marine fish have attractedmuch research...Arsenic speciation in freshwater fish is crucial for providing meaningful consumption guidelines that allow the public to make informed decisions regarding its consumption.While marine fish have attractedmuch research interest due to their higher arsenic content,research on freshwater fish is limited due to the challenges in quantifying and identifying arsenic species present at trace levels.We describe here a sensitivemethod and its application to the quantification of arsenic species in freshwater fish.Arsenic species from fish tissues were extracted using a methanol/water mixture(1:1 vol.ratio)and ultrasound sonication.Anion-exchange high-performance liquid chromatography(HPLC)enabled separation of arsenobetaine(AsB),inorganic arsenite(iAs^(Ⅲ)),dimethylarsinic acid(DMA),monomethylarsonic acid(MMA),inorganic arsenate(iAs^(Ⅴ)),and three new arsenic species.Inductively coupled plasma mass spectrometry(ICPMS)provided highly sensitive and specific detection of arsenic.A limit of detection of 0.25μg/kg(wet weight fish tissue)was achieved for the five target arsenic species:AsB,iAs^(Ⅲ),DMA,MMA,and iAs^(Ⅴ).A series of experimentswere conducted to ensure the accuracy and validity of the analytical method.The method was successfully applied to the determination of arsenic species in lakewhitefish,northern pike,and walleye,with AsB,DMA,and iAs^(Ⅴ) being frequently detected.Three new arsenic species were detected,but their chromatographic retention times did not match with those of any available arsenic standards.Future research is necessary to elucidate the identity of these new arsenic species detected in freshwater fish.展开更多
Contamination of aquatic ecosystems with heavy metals has been receiving increased worldwide attention due to their harmful effects on human health and other organisms in the environment. Most of the studies dealing w...Contamination of aquatic ecosystems with heavy metals has been receiving increased worldwide attention due to their harmful effects on human health and other organisms in the environment. Most of the studies dealing with toxic effects of metals deal with single metal species, while the aquatic organisms are typically exposed to mixtures of metals. Hence, in order to provide data supporting the usefulness of freshwater fish as indicators of heavy metal pollution, it has been proposed in the present study to investigate the bioaccumulation and depuration of chromium in the selected organs of freshwater fingerlings Cirrhinus mrigala, individually and in binary solutions with nickel. The results show that the kidney is a target organ for chromium accumulation, which implies that it is also the ＂critical＂ organ for toxic symptoms. The results further show that accumulation of nickel in all the tissues of C. mrigala is higher than that of chromium. In addition, the metal accumulations of the binary mixtures of chromium and nickel are substantially higher than those of the individual metals, indicating synergistic interactions between the two metals. Theoretically the simplest explanation for an additive joint action of toxicants in a mixture is that they act in a qualitatively similar way. The observed data suggest that C. mrigala could be suitable monitoring organisms to study the bioavailability of water-bound metals in freshwater habitats.展开更多
The aim of this study is to report the length-weight relationship parameters （a and b） for some economically important fish species from Iranian freshwaters. The length-weight relationships （LWR） are calculated fo...The aim of this study is to report the length-weight relationship parameters （a and b） for some economically important fish species from Iranian freshwaters. The length-weight relationships （LWR） are calculated for six freshwater fish species collected during 2006 and 2007 in Iran. The values of the exponent b in the LWR （W=aL^b） vary between 2.985 and 3.543. The LWR with high correlation coefficient （r^2） is significant for all the species. These parameters axe of great importance to evaluate the relative condition of populations, biology, species management and their fisheries and stock assessment. The application of the length-weight relationships presented here should be limited to the observed length ranges.展开更多
According to the three-dimensional contour maps showing the gel-forming properties of surimi derived from freshwater fish, 8 species of surimi were classified into two types. The-valley type surimi （silver carp, big-...According to the three-dimensional contour maps showing the gel-forming properties of surimi derived from freshwater fish, 8 species of surimi were classified into two types. The-valley type surimi （silver carp, big-head carp, Chinese snake head and blunt snout bream） shows easy setting, low resistance to gel collapse, high enhancement ability with two-step heating, and narrow optimum heating temperature and time area, which are of the same characteristics as the walleye pollack surimi. In contrast, the Plateau type surimi （tilapia, grass carp, mud carp and common carp） exhibits difficult setting, high resistance to gel collapse, no enhancement ability with two-step heating, and wide optimum heating temperature and time area. There are seasonal changes of gelling properties of silver carp surimi, and the setting ability of surimi gel is higher in winter and lower in summer. The marine fish meat gels and the freshwater fish meat gels have the same acceptability for inland Chinese according to the sensory evaluation results. A slight increase in sensory scorings of kamaboko gels occurred when the extract from walleye pollack muscle was added, especially in the odor scoring of silver carp kamaboko gels.展开更多
We surveyed the distribution, composition and diversity of freshwater fish in Hong Kong, China from 2002 to 2004. Sites surveyed were mainly streams, marshes and estuaries. There are ponds for aquaculture and reservoi...We surveyed the distribution, composition and diversity of freshwater fish in Hong Kong, China from 2002 to 2004. Sites surveyed were mainly streams, marshes and estuaries. There are ponds for aquaculture and reservoirs in Hong Kong but no large natural water bodies. From the 220 sites surveyed, 114 species of 37 families were found. Gobiidae (with 24 species) and Cyprinidae (21 species) were the dominant families. This survey has increased the number of freshwater fish species recorded in Hong Kong to 167. Among these, 71 (42.5%) are primary freshwater fish, 44 are brackish and 46 are vagrants. The remaining 6 species are diadromous. In Hong Kong, freshwater fish are conserved by a combination of measures. About 38% of Hong Kong’s land area is designated as country parks and/or special areas, and is managed for nature conservation and educational purposes. In addition, another 5% of land area is zoned for conservation in the statutory land use zoning system to protect them from development and incompatible land uses. Major development projects have to go through the statutory environmental impact assessment process to ensure that they will not have adverse impact as far as practicable. There are conservation action plans for important species. For example, captive-bred individuals of the endemic Hong Kong Paradise Fish Macropodus hongkongensis have been released to suitable and secure sites inside country parks and their populations are regularly monitored. Other measures such as wetland creation, restoration and enhancement programmes are also implemented for freshwater fish conservation.展开更多
[ Objective] To propose strategic conception for sustainable development of massive freshwater fish in China. [ Method] The current development status of massive freshwater fish industry in China was analyzed. On this...[ Objective] To propose strategic conception for sustainable development of massive freshwater fish in China. [ Method] The current development status of massive freshwater fish industry in China was analyzed. On this basis, strategic conception for sustainable development of massive freshwater fish in China was proposed. [Remlt] In order to solve the present problems in the massive freshwater fish industry in China, basic strategies were proposed to develop the massive freshwater fish industry in China. The fishery resources should be capitalized to promote sustainable development of resources. Consumer demand of end-market should be used to drive stable development of the whole industry chain. Consumer demand should be guided to enhance the industrial market position. Processing and distribution channels should be constructed to promote sustainable development of seed and farming industries. Consumer demand at different levels should be used to promote multi-level multi-media health culture. Brand building and operating should be performed to enhance the competitive position of the industry in international and domestic markets. [ Condusion] The study has great theoretical and practical significance for promoting development of the massive freshwater fish industry in China.展开更多
The concentrations of seven essential trace elements in 149 freshwater fish from eight fish species （European eel, bream, common carp, European catfish, roach, perch, pike and pikeperch） from five different French f...The concentrations of seven essential trace elements in 149 freshwater fish from eight fish species （European eel, bream, common carp, European catfish, roach, perch, pike and pikeperch） from five different French fishing areas from contaminated and control sites were measured by inductively coupled plasma mass spectrometry after microwave digestion under pressure. Differences in the concentration of elements in the muscles of these species were examined and the mean levels were compared for each species with previous French and European studies. The condition factor and the differences between the control and contaminated sites and between predatory and non-predatory groups, with respect to the concentration of these elements, were also studied.展开更多
With the rapid development of China’s economy,the living quality and consumption levels of people have continuously improved.As a result,freshwater fish aquaculture has emerged as an important means of meeting the gr...With the rapid development of China’s economy,the living quality and consumption levels of people have continuously improved.As a result,freshwater fish aquaculture has emerged as an important means of meeting the growing demand for high-quality aquatic products.In this context,this paper utilizes monitoring data from the sample demonstration areas of the national characteristic freshwater fish aquaculture technology system to conduct a comparative analysis of the cost and income situation of freshwater fish aquaculture from 2021 to 2022.The results are as follows:(1)In 2022,the total loss of the characteristic freshwater fish aquaculture increased by 68.04%,primarily attributed to disease losses and natural disasters;(2)In 2022,the overall cost of the characteristic freshwater fish aquaculture increased by 2.02%,with a 4.80%increase in unit costs,and the change of the aquaculture input cost mainly depended on the increase of feed costs;(3)In 2022,the overall cost margin,sales margin and marginal contribution rate of characteristic freshwater fish all decreased,and the revenue also decreased;(4)In 2022,the net profit of the characteristic freshwater fish,as well as each fish species,was highly sensitive to the price,feed cost and fry cost.Based on the research findings mentioned above,the characteristic freshwater fish industry faces problems such as high farming risks and persistently high feed costs,and this paper summarizes farming risks as disease risk,market risk and environmental risk.Therefore,to improve aquaculture efficiency and profitability,it is necessary to establish a sound fishery insurance system to enhance risk resilience,strengthen the development of the feed industry to reduce aquaculture costs and form a brand effect to play a leading role.展开更多
Dietary uptake is the major way that inorganic arsenic(iAs)enters into benthic fish;however,the metabolic process of dietborne i As in fish muscle following chronic exposure remains unclear.This was a 40-day study on ...Dietary uptake is the major way that inorganic arsenic(iAs)enters into benthic fish;however,the metabolic process of dietborne i As in fish muscle following chronic exposure remains unclear.This was a 40-day study on chronic dietborne i As[arsenite(AsⅢ)and arsenate(AsⅤ)]exposure in the benthic freshwater food fish,the crucian carp(Carassius auratus),which determined the temporal profiles of iAs metabolism and toxicokinetics during exposure.We found that an adaptive response occurred in the fish body after iAs dietary exposure,which was associated with decreased As accumulation and increased As transformation into a non-toxic As form(arsenobetaine).The bioavailability of dietary AsⅢwas lower than that of AsⅤ,probably because AsⅢhas a lower ability to pass through fish tissues.Dietary AsⅤexhibited a high potential for transformation into AsⅢspecies,which then accumulated in fish muscle.The largely produced AsⅢconsidered more toxic at the earlier stage of AsⅤexposure should attract sufficient attention to human exposure assessment.Therefore,the pristine As species and exposure duration had significant effects on As bioaccumulation and biotransformation in fish.The behavior determined for dietborne arsenic in food fish is crucial for not only arsenic ecotoxicology but also food safety.展开更多
Saprolegniasis,caused by Saprolegnia infection,is one of the most common diseases in freshwater fish.Our study aimed to determine the epidemiological characteristics of saprolegniasis in Chinese regions of high incide...Saprolegniasis,caused by Saprolegnia infection,is one of the most common diseases in freshwater fish.Our study aimed to determine the epidemiological characteristics of saprolegniasis in Chinese regions of high incidence.Saprolegnia were isolated and identified by morphological and molecular methods targeting the internal transcribed spacer(ITS)ribosomal DNA(rDNA)and building neighbor-joining(NJ)and maximum parsimony(MP)phylogenetic trees.The ITS sequences of eight isolated strains were compared with GenBank sequences and all strains fell into three clades:CLADE1(02,LP,04 and 14),CLADE2(S1),and CLADE3(CP,S2,L5 and the reference ATCC200013).Isolates 02 and LP shared 80%sequence similarity with S.diclina,S.longicaulis,S.ferax,S.mixta,and S.anomalies.Further,isolates 04 and 14 shared 80%similarity with S.bulbosa and S.oliviae.Finally,extremely high ITS sequence similarities were identified between isolates S1 and S.australis(100%);CP and S.hypogyna(96%);and S2,L5,ATCC200013 and S.salmonis(98%).This research provides insights into the identification,prevention and control of saprolegniasis pathogens and the potential development of effective drugs.展开更多
Background Opisthorchiid flukes,particularly Opisthorchis viverrini,Opisthorchis felineus,Clonorchis sinensis,and Metorchis spp.are the most common fish-borne zoonotic human liver flukes(hLFs).Liver fluke infections a...Background Opisthorchiid flukes,particularly Opisthorchis viverrini,Opisthorchis felineus,Clonorchis sinensis,and Metorchis spp.are the most common fish-borne zoonotic human liver flukes(hLFs).Liver fluke infections are more prevalent in resource-deprived and underprivileged areas.We herein estimated the prevalence of the metacercariae(MC)of major hLFs in common large freshwater fishes(lFWF)marketed for human consumption from some selected areas of Bangladesh along with detection of their molluscan vectors and reservoirs.Methods The current status of fish-borne zoonotic hLF infections in lFWF was investigated along with their molluscan vectors and mammalian reservoir hosts in Mymensingh and Kishoreganj in Bangladesh from July 2018-June 2022 using conventional and multiple molecular techniques,such as PCR,PCR-restriction fragment length polymorphism(RFLP),sequencing,and bioinformatic analyses.The infection rate of fishes was analyzed using the Z-test and the loads of MC were compared using the chi-squared(χ^(2))test.Results The MC of C.sinensis,Opisthorchis spp.,and Metorchis spp.were detected in 11 species of common and popular lFWF.In lFWF,the estimated prevalence was 18.7%and the mean load was 137.4±149.8 MC per 100 g of fish.The prevalence was the highest(P<0.05)in spotted snakehead fishes(Channa punctata,63.6%).The highest rate of infection(P<0.05)was observed with the MC of C.sinensis(11.8%).Metacercariae were almost equally(P>0.05)distributed between the head and body of fishes.The infection rate was slightly higher in cultured(19.6%)fishes.The MC of C.sinensis,O.felineus,O.viverrini,and Metorchis orientalis in fishes were confirmed using PCR,PCR-RFLP and bioinformatics.The cercariae of opisthorchiid(Pleurolophocercus cercariae)flukes were only recovered from Bithynia spp.(3.9%,42 out of 1089).The ova of hLFs from dogs(4.3%,5 out of 116)and cats(6.0%,6 out of 100),and adult flukes(M.orientalis)from ducks(41.1%113 out of 275)were detected.Conclusions The MC of hLFs are highly prevalent in fresh water fishes in Bangladesh.Reservoir hosts,such as street dogs,cats,and ducks carried the patent infection,and residents of Bangladesh are at risk.展开更多
As part of an ongoing inventory of the helminth parasites of freshwater fishes in Mexico, 570 individual fish were collected between Apr 2008 and Oct 2011 in 26 localities along the Cuatro Ciénegas region in Coah...As part of an ongoing inventory of the helminth parasites of freshwater fishes in Mexico, 570 individual fish were collected between Apr 2008 and Oct 2011 in 26 localities along the Cuatro Ciénegas region in Coahuila State, northern Mexico. Seventeen species of hosts, mostly corresponding to Nearctic freshwater elements, were studied. A total of 8324 individual worms were collected during this survey, representing 25 species of helminths, of which 9 were digeneans, 3 monogeneans, 3 acanthocephalans, 9 nematodes and 1 cestode. Most of the records in this checklist represent new host or locality records. The information provided in this checklist may be helpful for our understanding of the biodiversity and historical biogeography of this host-parasite system, because in the Cuatro Ciénegas region occur a Nearctic freshwater fish fauna, along with Neotropical and endemic elements, and from a biogeographical point of view, this may represent a transitional area.展开更多
Food and water are the main sources of human exposure to arsenic.It is important to determine arsenic species in food because the toxicities of arsenic vary greatly with its chemical speciation.Extensive research has ...Food and water are the main sources of human exposure to arsenic.It is important to determine arsenic species in food because the toxicities of arsenic vary greatly with its chemical speciation.Extensive research has focused on high concentrations of arsenic species in marine organisms.The concentrations of arsenic species in freshwater fish are much lower,and their determination presents analytical challenges.In this review,we summarize the current state of knowledge on arsenic speciation in freshwater fish and discuss challenges and research needs.Fish samples are typically homogenized,and arsenic species are extracted using water/methanol with the assistance of sonication and enzyme treatment.Arsenic species in the extracts are commonly separated using high-performance liquid chromatography(HPLC)and detected using inductively coupled plasma mass spectrometry(ICPMS).Electrospray ionization tandem mass spectrometry,used in combination with HPLC and ICPMS,provides complementary information for the identification and characterization of arsenic species.The methods and perspectives discussed in this review,covering sample preparation,chromatography separation,and mass spectrometry detection,are directed to arsenic speciation in freshwater fish and applicable to studies of other food items.Despite progress made in arsenic speciation analysis,a large fraction of the total arsenic in freshwater fish remains unidentified.It is challenging to identify and quantify arsenic species present in complex sample matrices at very low concentrations.Further research is needed to improve the extraction efficiency,chromatographic resolution,detection sensitivity,and characterization capability.展开更多
Fermentation has been found as an effective method to decrease the hypersensitive reactions of consumers by freshwater fish,but the reason is not clear.Therefore,the aim of this study was to investigate the impact of ...Fermentation has been found as an effective method to decrease the hypersensitive reactions of consumers by freshwater fish,but the reason is not clear.Therefore,the aim of this study was to investigate the impact of pH and acid-activated proteases on the decrease of immunological properties of parvalbumin from freshwater fish,by the indicators of SDS-polyacrylamide gel electrophoresis,western blotting,enzyme-linked immunosorbent assay,surface hydrophobicity and circular dichroism.The results showed that black carp(Mylopharyngodon piceus)had the highest level of immunological properties reflected by quantitation,the content of linear epitopes and conformational epitopes of parvalbumin,and IgE-binding rate.Afterwards,purified parvalbumin from black carp was obtained with purity higher than 95%.Then,for acidification and enzyme models,it indicated that acid-activated proteases were the reason for the decrease of immunological properties.Ulteriorly,the mechanism on the level of protein structure was provided,which showed the decrease ofα-helix and the increase ofβ-turn and random coil,as well as the decrease of surface hydrophobicity had joint contribution for the breaking of conformational epitopes.This study could provide a novel guidance for the decrease of immunological properties of fish and promote fish processing industry further.展开更多
Data on the mercury concentration in freshwater and marine fish and seafood on the territory of Russia are presented. The level and pattern of the fish and seafood consumption in various regions of Russia are found fr...Data on the mercury concentration in freshwater and marine fish and seafood on the territory of Russia are presented. The level and pattern of the fish and seafood consumption in various regions of Russia are found from the analysis of open statistics. Regions with the maximum and minimum consumption of fish products are established. Mercury intake from these products in a human organism is calculated. It is shown that at the current level and pattern of the diet in Russia fish cannot be a source of high mercury concentrations in a human organism.展开更多
Most fish exhibit remarkable morphological diversity,which is often influenced by genetic variation and ecological pressures.Consequently,these are the outcomes of organisms’responses to their environment.Meanwhile,m...Most fish exhibit remarkable morphological diversity,which is often influenced by genetic variation and ecological pressures.Consequently,these are the outcomes of organisms’responses to their environment.Meanwhile,modern morphometrics can quantify shape variation within species of the same group.This study aims to determine the body shape variation of Glossogobius giuris from Lake Mainit,Agusan Del Norte,Philippines.60 adult,uniform-sized fish samples were collected and subjected to standardized laboratory procedures.Further,the samples were digitized for 16 homologous landmark points and loaded into Symmetry Asymmetry Geometric Data(SAGE)Software.Across the tested factors—individuals,sides,and individual x sides—result shows that shape variations among individuals were highly significant(F=2.1045,p<0.0001),along with among males(F=3.2711,p<0.0001).Females exhibited higher Fluctuating Asymmetry(FA)(F=18.99,p<0.0001)compared to males(F=7.0964,p<0.0001).It suggests morphological shape differences across the sexes,and the shape variation observed could be a response to environmental perturbations.Shape variations were associated with swimming,food hunting,and predator defense.Moreover,Principal Component Analysis(PCA)demonstrates higher scores of FA in females(81.96%)than in males(74.76%).It was noticed that females had a high fluctuating asymmetry.It might be due to various physiological and ecological pressures compared to males.The observed levels of directional and fluctuating asymmetry in males and females,respectively,may indicate sex-linked morphological and developmental processes,which are important to consider in ecological or evolutionary contexts.Thus,utilizing geometric morphometrics can depict subtle differences across the same populations.展开更多
The establishment of water circulation aquaculture system realized the hi- erarchical use of nitrogen, phosphorus and other eutrophic substances in aquaculture wastewater and the recirculation use of water resource. H...The establishment of water circulation aquaculture system realized the hi- erarchical use of nitrogen, phosphorus and other eutrophic substances in aquaculture wastewater and the recirculation use of water resource. However, no research has been reported on the detailed calculation of the relationship between the area of aquaculture pond and purification pond. In this study, referring to the absorption ability of aquatic plants to pollutants in aquaculture wastewater and pollutant generation and discharge coefficient in aquaculture pond, based on the general rules of water quality management in freshwater aquaculture system, a calculation mode was es- tablished to investigate the relationship between the area of aquaculture pond and purification pond in freshwater recirculation aquaculture system, which was feasible to explain related cases and would provide theoretical basis to reduce the economic costs in the construction of water circulation aquaculture system and realize the bal- ance between the ecological benefits and the economic benefits.展开更多
In the present study, the effects of season on fatty acid composition, total lipids, and ω3/ω6 ratios of northern pike muscle lipids in Klzlhrmak River （Klrlkkale, Turkey） were investigated. A total of 35 differen...In the present study, the effects of season on fatty acid composition, total lipids, and ω3/ω6 ratios of northern pike muscle lipids in Klzlhrmak River （Klrlkkale, Turkey） were investigated. A total of 35 different fatty acids were determined in gas chromatography. Among these, palmitic, oleic, and palmitoleic acids had the highest proportion. The main polyunsaturated fatty acids （PUFAs） were found to be docosahexaenoic acid, eicosapentaenoic acid, and arachidonic acid. There were more PUFAs than monounsaturated fatty acids （MUFA） in all seasons. Similarly, the percentages of ω3 fatty acids were higher than those of total ω6 fatty acids in the fatty acid composition. ω3/ω6 ratios were calculated as 1.53, 1.32, 1.97, and 1.71 in spring, summer, autumn and winter, respectively. Overall, we found that the fatty acid composition and ω3/ω6 fatty acid ratio in the muscle of northern pike were significantly influenced by season.展开更多
Silver carp,Hypopthalmichthys molitrix is one of the most economically valuable fish species in Bangladesh.However,its production is often hindered by parasite-induced mortality.The present study reports the intensity...Silver carp,Hypopthalmichthys molitrix is one of the most economically valuable fish species in Bangladesh.However,its production is often hindered by parasite-induced mortality.The present study reports the intensity of parasitic infestation in 216 specimens of H.molitrix collected from different fish markets in Rajshahi City,Bangladesh.Nine different parasite species (Trichodina pediculatus,Dactylogyrus vastator,Ichthyophthirius multifilis,Gyrodactylus elegans,Lernaea sp.,Apiosoma sp.,Myxobolus rohitae,Camallanus ophiocephali,and Pallisentis ophiocephali) were recovered from the gill,skin,stomach,and intestine of host fish.The highest level of infection was observed for host skin,while lower levels were observed for host gill,stomach,and intestine.The results also revealed that the intensity of parasite infection in different organs of H.molitrix varied with the season.In particular,the highest levels of infection were recorded during the winter period (November-February),when fish are most susceptible to parasites.The findings of the study will help in the management and conservation of H.molitrix.展开更多
基金supported by Alberta Health,Alberta Innovates,the Canada Research Chairs program,the Canadian Institutes of Health Research,and the Natural Sciences and Engineering Research Council of Canada.
文摘We report here arsenic speciation in 1643 freshwater fish samples,representing 14 common fish species from 53 waterbodies in Alberta,Canada.Arsenic species were extracted from fish muscle tissue.Arsenic species in the extracts were separated using anion-exchange high-performance liquid chromatography(HPLC)and quantified using inductively coupled plasma mass spectrometry(ICPMS).The total arsenic concentrations in fish ranged from 2.8 to 1200μg/kg(in wet weight of sample)(mean 71±101μg/kg),which are all below the 2000μg/kg(wet weight)maximum allowable total arsenic in fish,recommended by the Ontario Ministry of the Environment.In 99.7%,or 1638 of all 1643 freshwater fish samples analyzed,arsenobetaine(AsB)was detectable,with concentrations higher than the method detection limit of 0.25μg/kg(wet weight).Dimethylarsinic acid(DMA)was detectable(concentration>0.25μg/kg)in 92.1%,or 1514 of the 1643 freshwater fish samples.Inorganic arsenate(iAs^(Ⅴ))was detectable(>0.25μg/kg)in 1119 fish(i.e.,68.1% of 1643 samples).Monomethylarsonic acid(MMA)was detectable(>0.25μg/kg)in 418 fish(25.4%of 1643 samples).The concentrations of arsenic species in the 1643 fish samples varied by as much as three orders of magnitude,ranging from below the method detection limit of 0.25μg/kg to the maximum concentrations of 380μg/kg for AsB,150μg/kg for DMA,70μg/kg for iAs^(Ⅴ),and 51μg/kg for MMA.AsB made up 46.1%±26.2% of total arsenic species.Arsenic speciation patterns varied between lake whitefish,northern pike,and walleye,the three most common types of fish analyzed.The relative proportion of DMA in northern pike was larger than in lake whitefish and walleye,and conversely,the relative proportion of iAs^(Ⅴ) was lower in northern pike.Seven unknown arsenic species were detected,and their chromatographic retention time did not match with those of available arsenic standards.At least one unknown arsenic species was detected in 33.4%,or 549 of 1643 freshwater fish samples.The concentrations of unknown arsenic species were as high as 61μg/kg.Future research is necessary to identify unknown arsenic species and to determine contributing factors to the observed arsenic species patterns and concentrations.
基金supported by Alberta Health,Alberta Innovates,the Canada Research Chairs Program,the Canadian Institutes of Health Research,and the Natural Sciences and Engineering Research Council of Canada。
文摘Arsenic speciation in freshwater fish is crucial for providing meaningful consumption guidelines that allow the public to make informed decisions regarding its consumption.While marine fish have attractedmuch research interest due to their higher arsenic content,research on freshwater fish is limited due to the challenges in quantifying and identifying arsenic species present at trace levels.We describe here a sensitivemethod and its application to the quantification of arsenic species in freshwater fish.Arsenic species from fish tissues were extracted using a methanol/water mixture(1:1 vol.ratio)and ultrasound sonication.Anion-exchange high-performance liquid chromatography(HPLC)enabled separation of arsenobetaine(AsB),inorganic arsenite(iAs^(Ⅲ)),dimethylarsinic acid(DMA),monomethylarsonic acid(MMA),inorganic arsenate(iAs^(Ⅴ)),and three new arsenic species.Inductively coupled plasma mass spectrometry(ICPMS)provided highly sensitive and specific detection of arsenic.A limit of detection of 0.25μg/kg(wet weight fish tissue)was achieved for the five target arsenic species:AsB,iAs^(Ⅲ),DMA,MMA,and iAs^(Ⅴ).A series of experimentswere conducted to ensure the accuracy and validity of the analytical method.The method was successfully applied to the determination of arsenic species in lakewhitefish,northern pike,and walleye,with AsB,DMA,and iAs^(Ⅴ) being frequently detected.Three new arsenic species were detected,but their chromatographic retention times did not match with those of any available arsenic standards.Future research is necessary to elucidate the identity of these new arsenic species detected in freshwater fish.
文摘Contamination of aquatic ecosystems with heavy metals has been receiving increased worldwide attention due to their harmful effects on human health and other organisms in the environment. Most of the studies dealing with toxic effects of metals deal with single metal species, while the aquatic organisms are typically exposed to mixtures of metals. Hence, in order to provide data supporting the usefulness of freshwater fish as indicators of heavy metal pollution, it has been proposed in the present study to investigate the bioaccumulation and depuration of chromium in the selected organs of freshwater fingerlings Cirrhinus mrigala, individually and in binary solutions with nickel. The results show that the kidney is a target organ for chromium accumulation, which implies that it is also the ＂critical＂ organ for toxic symptoms. The results further show that accumulation of nickel in all the tissues of C. mrigala is higher than that of chromium. In addition, the metal accumulations of the binary mixtures of chromium and nickel are substantially higher than those of the individual metals, indicating synergistic interactions between the two metals. Theoretically the simplest explanation for an additive joint action of toxicants in a mixture is that they act in a qualitatively similar way. The observed data suggest that C. mrigala could be suitable monitoring organisms to study the bioavailability of water-bound metals in freshwater habitats.
文摘The aim of this study is to report the length-weight relationship parameters （a and b） for some economically important fish species from Iranian freshwaters. The length-weight relationships （LWR） are calculated for six freshwater fish species collected during 2006 and 2007 in Iran. The values of the exponent b in the LWR （W=aL^b） vary between 2.985 and 3.543. The LWR with high correlation coefficient （r^2） is significant for all the species. These parameters axe of great importance to evaluate the relative condition of populations, biology, species management and their fisheries and stock assessment. The application of the length-weight relationships presented here should be limited to the observed length ranges.
文摘According to the three-dimensional contour maps showing the gel-forming properties of surimi derived from freshwater fish, 8 species of surimi were classified into two types. The-valley type surimi （silver carp, big-head carp, Chinese snake head and blunt snout bream） shows easy setting, low resistance to gel collapse, high enhancement ability with two-step heating, and narrow optimum heating temperature and time area, which are of the same characteristics as the walleye pollack surimi. In contrast, the Plateau type surimi （tilapia, grass carp, mud carp and common carp） exhibits difficult setting, high resistance to gel collapse, no enhancement ability with two-step heating, and wide optimum heating temperature and time area. There are seasonal changes of gelling properties of silver carp surimi, and the setting ability of surimi gel is higher in winter and lower in summer. The marine fish meat gels and the freshwater fish meat gels have the same acceptability for inland Chinese according to the sensory evaluation results. A slight increase in sensory scorings of kamaboko gels occurred when the extract from walleye pollack muscle was added, especially in the odor scoring of silver carp kamaboko gels.
基金the comprehensive ecological baseline survey programme of the Department of Agriculture ,Fisheries and Conservation
文摘We surveyed the distribution, composition and diversity of freshwater fish in Hong Kong, China from 2002 to 2004. Sites surveyed were mainly streams, marshes and estuaries. There are ponds for aquaculture and reservoirs in Hong Kong but no large natural water bodies. From the 220 sites surveyed, 114 species of 37 families were found. Gobiidae (with 24 species) and Cyprinidae (21 species) were the dominant families. This survey has increased the number of freshwater fish species recorded in Hong Kong to 167. Among these, 71 (42.5%) are primary freshwater fish, 44 are brackish and 46 are vagrants. The remaining 6 species are diadromous. In Hong Kong, freshwater fish are conserved by a combination of measures. About 38% of Hong Kong’s land area is designated as country parks and/or special areas, and is managed for nature conservation and educational purposes. In addition, another 5% of land area is zoned for conservation in the statutory land use zoning system to protect them from development and incompatible land uses. Major development projects have to go through the statutory environmental impact assessment process to ensure that they will not have adverse impact as far as practicable. There are conservation action plans for important species. For example, captive-bred individuals of the endemic Hong Kong Paradise Fish Macropodus hongkongensis have been released to suitable and secure sites inside country parks and their populations are regularly monitored. Other measures such as wetland creation, restoration and enhancement programmes are also implemented for freshwater fish conservation.
基金supported by the grants of the China Spark Program (2006EA770019)National Special Research Fund for Public Welfare (Agriculture) of China (200903028)+2 种基金the 11th Five-year Plan for Key Construction Academic Subject (Zoology) of Hunan Province (07-A-2)Production-Teaching-Research Demonstration Base Project of Colleges and Universities of Hunan Province (2008-2010)Technology Innovation Platform of Colleges and Universities of Hunan Province for Conservation and Use of Living Aquatic Resources (2010-2012)
文摘[ Objective] To propose strategic conception for sustainable development of massive freshwater fish in China. [ Method] The current development status of massive freshwater fish industry in China was analyzed. On this basis, strategic conception for sustainable development of massive freshwater fish in China was proposed. [Remlt] In order to solve the present problems in the massive freshwater fish industry in China, basic strategies were proposed to develop the massive freshwater fish industry in China. The fishery resources should be capitalized to promote sustainable development of resources. Consumer demand of end-market should be used to drive stable development of the whole industry chain. Consumer demand should be guided to enhance the industrial market position. Processing and distribution channels should be constructed to promote sustainable development of seed and farming industries. Consumer demand at different levels should be used to promote multi-level multi-media health culture. Brand building and operating should be performed to enhance the competitive position of the industry in international and domestic markets. [ Condusion] The study has great theoretical and practical significance for promoting development of the massive freshwater fish industry in China.
文摘The concentrations of seven essential trace elements in 149 freshwater fish from eight fish species （European eel, bream, common carp, European catfish, roach, perch, pike and pikeperch） from five different French fishing areas from contaminated and control sites were measured by inductively coupled plasma mass spectrometry after microwave digestion under pressure. Differences in the concentration of elements in the muscles of these species were examined and the mean levels were compared for each species with previous French and European studies. The condition factor and the differences between the control and contaminated sites and between predatory and non-predatory groups, with respect to the concentration of these elements, were also studied.
基金funded by the special project of National Characteristic Freshwater Fish Industrial Technology System for construction of modern agricultural industrial technology system(No.CARS-46)。
文摘With the rapid development of China’s economy,the living quality and consumption levels of people have continuously improved.As a result,freshwater fish aquaculture has emerged as an important means of meeting the growing demand for high-quality aquatic products.In this context,this paper utilizes monitoring data from the sample demonstration areas of the national characteristic freshwater fish aquaculture technology system to conduct a comparative analysis of the cost and income situation of freshwater fish aquaculture from 2021 to 2022.The results are as follows:(1)In 2022,the total loss of the characteristic freshwater fish aquaculture increased by 68.04%,primarily attributed to disease losses and natural disasters;(2)In 2022,the overall cost of the characteristic freshwater fish aquaculture increased by 2.02%,with a 4.80%increase in unit costs,and the change of the aquaculture input cost mainly depended on the increase of feed costs;(3)In 2022,the overall cost margin,sales margin and marginal contribution rate of characteristic freshwater fish all decreased,and the revenue also decreased;(4)In 2022,the net profit of the characteristic freshwater fish,as well as each fish species,was highly sensitive to the price,feed cost and fry cost.Based on the research findings mentioned above,the characteristic freshwater fish industry faces problems such as high farming risks and persistently high feed costs,and this paper summarizes farming risks as disease risk,market risk and environmental risk.Therefore,to improve aquaculture efficiency and profitability,it is necessary to establish a sound fishery insurance system to enhance risk resilience,strengthen the development of the feed industry to reduce aquaculture costs and form a brand effect to play a leading role.
基金the Special Fund for AgroScientific Research in the Public Interest of China(No.201503108)the Science and Technology Project of Hunan Province(No.2017WK2091)。
文摘Dietary uptake is the major way that inorganic arsenic(iAs)enters into benthic fish;however,the metabolic process of dietborne i As in fish muscle following chronic exposure remains unclear.This was a 40-day study on chronic dietborne i As[arsenite(AsⅢ)and arsenate(AsⅤ)]exposure in the benthic freshwater food fish,the crucian carp(Carassius auratus),which determined the temporal profiles of iAs metabolism and toxicokinetics during exposure.We found that an adaptive response occurred in the fish body after iAs dietary exposure,which was associated with decreased As accumulation and increased As transformation into a non-toxic As form(arsenobetaine).The bioavailability of dietary AsⅢwas lower than that of AsⅤ,probably because AsⅢhas a lower ability to pass through fish tissues.Dietary AsⅤexhibited a high potential for transformation into AsⅢspecies,which then accumulated in fish muscle.The largely produced AsⅢconsidered more toxic at the earlier stage of AsⅤexposure should attract sufficient attention to human exposure assessment.Therefore,the pristine As species and exposure duration had significant effects on As bioaccumulation and biotransformation in fish.The behavior determined for dietborne arsenic in food fish is crucial for not only arsenic ecotoxicology but also food safety.
基金This work is financially supported by the National Key Technology R&D Program(Grant No.2013BAD13B03).
文摘Saprolegniasis,caused by Saprolegnia infection,is one of the most common diseases in freshwater fish.Our study aimed to determine the epidemiological characteristics of saprolegniasis in Chinese regions of high incidence.Saprolegnia were isolated and identified by morphological and molecular methods targeting the internal transcribed spacer(ITS)ribosomal DNA(rDNA)and building neighbor-joining(NJ)and maximum parsimony(MP)phylogenetic trees.The ITS sequences of eight isolated strains were compared with GenBank sequences and all strains fell into three clades:CLADE1(02,LP,04 and 14),CLADE2(S1),and CLADE3(CP,S2,L5 and the reference ATCC200013).Isolates 02 and LP shared 80%sequence similarity with S.diclina,S.longicaulis,S.ferax,S.mixta,and S.anomalies.Further,isolates 04 and 14 shared 80%similarity with S.bulbosa and S.oliviae.Finally,extremely high ITS sequence similarities were identified between isolates S1 and S.australis(100%);CP and S.hypogyna(96%);and S2,L5,ATCC200013 and S.salmonis(98%).This research provides insights into the identification,prevention and control of saprolegniasis pathogens and the potential development of effective drugs.
基金funded by the Ministry of Education(MoE)and Ministry of Science and Technology(MoST),The Government of Bangladeshsupported by the JSPS Core-to-Core Program(JSJSCCB20200010).
文摘Background Opisthorchiid flukes,particularly Opisthorchis viverrini,Opisthorchis felineus,Clonorchis sinensis,and Metorchis spp.are the most common fish-borne zoonotic human liver flukes(hLFs).Liver fluke infections are more prevalent in resource-deprived and underprivileged areas.We herein estimated the prevalence of the metacercariae(MC)of major hLFs in common large freshwater fishes(lFWF)marketed for human consumption from some selected areas of Bangladesh along with detection of their molluscan vectors and reservoirs.Methods The current status of fish-borne zoonotic hLF infections in lFWF was investigated along with their molluscan vectors and mammalian reservoir hosts in Mymensingh and Kishoreganj in Bangladesh from July 2018-June 2022 using conventional and multiple molecular techniques,such as PCR,PCR-restriction fragment length polymorphism(RFLP),sequencing,and bioinformatic analyses.The infection rate of fishes was analyzed using the Z-test and the loads of MC were compared using the chi-squared(χ^(2))test.Results The MC of C.sinensis,Opisthorchis spp.,and Metorchis spp.were detected in 11 species of common and popular lFWF.In lFWF,the estimated prevalence was 18.7%and the mean load was 137.4±149.8 MC per 100 g of fish.The prevalence was the highest(P<0.05)in spotted snakehead fishes(Channa punctata,63.6%).The highest rate of infection(P<0.05)was observed with the MC of C.sinensis(11.8%).Metacercariae were almost equally(P>0.05)distributed between the head and body of fishes.The infection rate was slightly higher in cultured(19.6%)fishes.The MC of C.sinensis,O.felineus,O.viverrini,and Metorchis orientalis in fishes were confirmed using PCR,PCR-RFLP and bioinformatics.The cercariae of opisthorchiid(Pleurolophocercus cercariae)flukes were only recovered from Bithynia spp.(3.9%,42 out of 1089).The ova of hLFs from dogs(4.3%,5 out of 116)and cats(6.0%,6 out of 100),and adult flukes(M.orientalis)from ducks(41.1%113 out of 275)were detected.Conclusions The MC of hLFs are highly prevalent in fresh water fishes in Bangladesh.Reservoir hosts,such as street dogs,cats,and ducks carried the patent infection,and residents of Bangladesh are at risk.
基金Fishes were obtained under the collecting permit Pesca de Fomento No.DGOPA.00889.280211.-0349 issued by SAGARPA to H.Espinosa P.This paper was funded in part by grants from CONACyT No.83043 and 178830)the Program PAPIIT-UNAM IN 202111 to G.Pérez-Ponce De León.
文摘As part of an ongoing inventory of the helminth parasites of freshwater fishes in Mexico, 570 individual fish were collected between Apr 2008 and Oct 2011 in 26 localities along the Cuatro Ciénegas region in Coahuila State, northern Mexico. Seventeen species of hosts, mostly corresponding to Nearctic freshwater elements, were studied. A total of 8324 individual worms were collected during this survey, representing 25 species of helminths, of which 9 were digeneans, 3 monogeneans, 3 acanthocephalans, 9 nematodes and 1 cestode. Most of the records in this checklist represent new host or locality records. The information provided in this checklist may be helpful for our understanding of the biodiversity and historical biogeography of this host-parasite system, because in the Cuatro Ciénegas region occur a Nearctic freshwater fish fauna, along with Neotropical and endemic elements, and from a biogeographical point of view, this may represent a transitional area.
基金This work was supported by Alberta Health,Alberta Innovates,the Canada Research Chairs Program,the Canadian Institutes of Health Research,and the Natural Sciences and Engineering Research Council of Canada.
文摘Food and water are the main sources of human exposure to arsenic.It is important to determine arsenic species in food because the toxicities of arsenic vary greatly with its chemical speciation.Extensive research has focused on high concentrations of arsenic species in marine organisms.The concentrations of arsenic species in freshwater fish are much lower,and their determination presents analytical challenges.In this review,we summarize the current state of knowledge on arsenic speciation in freshwater fish and discuss challenges and research needs.Fish samples are typically homogenized,and arsenic species are extracted using water/methanol with the assistance of sonication and enzyme treatment.Arsenic species in the extracts are commonly separated using high-performance liquid chromatography(HPLC)and detected using inductively coupled plasma mass spectrometry(ICPMS).Electrospray ionization tandem mass spectrometry,used in combination with HPLC and ICPMS,provides complementary information for the identification and characterization of arsenic species.The methods and perspectives discussed in this review,covering sample preparation,chromatography separation,and mass spectrometry detection,are directed to arsenic speciation in freshwater fish and applicable to studies of other food items.Despite progress made in arsenic speciation analysis,a large fraction of the total arsenic in freshwater fish remains unidentified.It is challenging to identify and quantify arsenic species present in complex sample matrices at very low concentrations.Further research is needed to improve the extraction efficiency,chromatographic resolution,detection sensitivity,and characterization capability.
基金financially supported by the earmarked fund for Jiangsu Key R&D Project(BE2021319)Jiangsu Natural Science Fund(BK20170185)+1 种基金the earmarked fund for Jiangsu Agricultural Industry Technology System(JATS[2022]507)China Agricultures Research System(CARS-45).
文摘Fermentation has been found as an effective method to decrease the hypersensitive reactions of consumers by freshwater fish,but the reason is not clear.Therefore,the aim of this study was to investigate the impact of pH and acid-activated proteases on the decrease of immunological properties of parvalbumin from freshwater fish,by the indicators of SDS-polyacrylamide gel electrophoresis,western blotting,enzyme-linked immunosorbent assay,surface hydrophobicity and circular dichroism.The results showed that black carp(Mylopharyngodon piceus)had the highest level of immunological properties reflected by quantitation,the content of linear epitopes and conformational epitopes of parvalbumin,and IgE-binding rate.Afterwards,purified parvalbumin from black carp was obtained with purity higher than 95%.Then,for acidification and enzyme models,it indicated that acid-activated proteases were the reason for the decrease of immunological properties.Ulteriorly,the mechanism on the level of protein structure was provided,which showed the decrease ofα-helix and the increase ofβ-turn and random coil,as well as the decrease of surface hydrophobicity had joint contribution for the breaking of conformational epitopes.This study could provide a novel guidance for the decrease of immunological properties of fish and promote fish processing industry further.
文摘Data on the mercury concentration in freshwater and marine fish and seafood on the territory of Russia are presented. The level and pattern of the fish and seafood consumption in various regions of Russia are found from the analysis of open statistics. Regions with the maximum and minimum consumption of fish products are established. Mercury intake from these products in a human organism is calculated. It is shown that at the current level and pattern of the diet in Russia fish cannot be a source of high mercury concentrations in a human organism.
文摘Most fish exhibit remarkable morphological diversity,which is often influenced by genetic variation and ecological pressures.Consequently,these are the outcomes of organisms’responses to their environment.Meanwhile,modern morphometrics can quantify shape variation within species of the same group.This study aims to determine the body shape variation of Glossogobius giuris from Lake Mainit,Agusan Del Norte,Philippines.60 adult,uniform-sized fish samples were collected and subjected to standardized laboratory procedures.Further,the samples were digitized for 16 homologous landmark points and loaded into Symmetry Asymmetry Geometric Data(SAGE)Software.Across the tested factors—individuals,sides,and individual x sides—result shows that shape variations among individuals were highly significant(F=2.1045,p<0.0001),along with among males(F=3.2711,p<0.0001).Females exhibited higher Fluctuating Asymmetry(FA)(F=18.99,p<0.0001)compared to males(F=7.0964,p<0.0001).It suggests morphological shape differences across the sexes,and the shape variation observed could be a response to environmental perturbations.Shape variations were associated with swimming,food hunting,and predator defense.Moreover,Principal Component Analysis(PCA)demonstrates higher scores of FA in females(81.96%)than in males(74.76%).It was noticed that females had a high fluctuating asymmetry.It might be due to various physiological and ecological pressures compared to males.The observed levels of directional and fluctuating asymmetry in males and females,respectively,may indicate sex-linked morphological and developmental processes,which are important to consider in ecological or evolutionary contexts.Thus,utilizing geometric morphometrics can depict subtle differences across the same populations.
基金Supported by Special Fund for the Construction of Modern Agricultural Industry Technology System(CARS-46)Special Fund for Basic Research and Operating Expenses of Central-level Research Institutes(2007JBFA03)~~
文摘The establishment of water circulation aquaculture system realized the hi- erarchical use of nitrogen, phosphorus and other eutrophic substances in aquaculture wastewater and the recirculation use of water resource. However, no research has been reported on the detailed calculation of the relationship between the area of aquaculture pond and purification pond. In this study, referring to the absorption ability of aquatic plants to pollutants in aquaculture wastewater and pollutant generation and discharge coefficient in aquaculture pond, based on the general rules of water quality management in freshwater aquaculture system, a calculation mode was es- tablished to investigate the relationship between the area of aquaculture pond and purification pond in freshwater recirculation aquaculture system, which was feasible to explain related cases and would provide theoretical basis to reduce the economic costs in the construction of water circulation aquaculture system and realize the bal- ance between the ecological benefits and the economic benefits.
文摘In the present study, the effects of season on fatty acid composition, total lipids, and ω3/ω6 ratios of northern pike muscle lipids in Klzlhrmak River （Klrlkkale, Turkey） were investigated. A total of 35 different fatty acids were determined in gas chromatography. Among these, palmitic, oleic, and palmitoleic acids had the highest proportion. The main polyunsaturated fatty acids （PUFAs） were found to be docosahexaenoic acid, eicosapentaenoic acid, and arachidonic acid. There were more PUFAs than monounsaturated fatty acids （MUFA） in all seasons. Similarly, the percentages of ω3 fatty acids were higher than those of total ω6 fatty acids in the fatty acid composition. ω3/ω6 ratios were calculated as 1.53, 1.32, 1.97, and 1.71 in spring, summer, autumn and winter, respectively. Overall, we found that the fatty acid composition and ω3/ω6 fatty acid ratio in the muscle of northern pike were significantly influenced by season.
基金Project supported by the Universiti Kebangsaan Malaysia (UKM)through Young Researcher Incentive Grant (No. GGPM-2011-057)UKM Research Grant (No. UKM-OUP-FST-2012)
文摘Silver carp,Hypopthalmichthys molitrix is one of the most economically valuable fish species in Bangladesh.However,its production is often hindered by parasite-induced mortality.The present study reports the intensity of parasitic infestation in 216 specimens of H.molitrix collected from different fish markets in Rajshahi City,Bangladesh.Nine different parasite species (Trichodina pediculatus,Dactylogyrus vastator,Ichthyophthirius multifilis,Gyrodactylus elegans,Lernaea sp.,Apiosoma sp.,Myxobolus rohitae,Camallanus ophiocephali,and Pallisentis ophiocephali) were recovered from the gill,skin,stomach,and intestine of host fish.The highest level of infection was observed for host skin,while lower levels were observed for host gill,stomach,and intestine.The results also revealed that the intensity of parasite infection in different organs of H.molitrix varied with the season.In particular,the highest levels of infection were recorded during the winter period (November-February),when fish are most susceptible to parasites.The findings of the study will help in the management and conservation of H.molitrix.
