[Objective]Implementation of the Ten-Year Fishing Ban policy may alter fish diversity and niche characteristics of dominant species in spawning grounds within the National Nature Reserve for Rare and Endemic Fish in t...[Objective]Implementation of the Ten-Year Fishing Ban policy may alter fish diversity and niche characteristics of dominant species in spawning grounds within the National Nature Reserve for Rare and Endemic Fish in the Upper Yangtze River.This study initiated continuous monitoring of natural spawning habitats from February 2022 to assess these ecological changes.[Methods]Environmental DNA(eDNA)metabarcoding was employed to analyze fish species composition,biodiversity patterns,and niche parameters of dominant species.Water sampling followed the CEN/TS 19461 standard across five monitoring transects(ZT1-ZT5).[Results]The eDNA analysis detected 45 species of fish belonging to 38 genera,13 families,and 3 orders were detected through environmental DNA(eDNA)in this survey,including 10 species endemic to the upper reaches of the Yangtze River,such as Procypris rabaudi and Myxocyprinus asiaticus.The fish community was mainly composed of bottom-dwelling,settling ovum-producing,omnivorous fish.The variation ranges of the Chao1 index,ACE index,Shannon index,and Simpson index are 736~996,719~965,1.58~3.23,and 0.83~0.99,respectively,indicating that fish species in spawning sites are abundant and community distribution uniformity is high.All indexes are highest at ZT1 monitoring points.Cluster analysis showed that,at a certain similarity level,fish community types in spawning sites could be basically divided into two groups:ZT1,ZT3,and ZT5 clustered together,and ZT2 and ZT4 clustered together,indicating similar fish community habitats.There are 9 dominant fish species in typical deep pool habitats in the reserve,with niche widths(Bi)ranging from 1.13 to 3.87.The dominant fish species are broad and medium niche fish,such as Cyprinus carpio and Hemiculter tchangi,with the niche overlap index(Oik)of some dominant fish species reaching more than 0.95.This indicates fierce competition for resources among the fish in this spawning ground.[Conclusion]The Zhutuo spawning ground demonstrates high species richness with homogeneous community structure and intense resource competition.This study establishes an eDNA-based monitoring framework that enhances conventional survey method,providing critical baseline data for adaptive management under the fishing moratorium regime.展开更多
This research was conducted to generate a primary database on ichthyofauna,distribution and diversities in the upstream and downstream segments of Sittaung River in Bago Region of Myanmar.This study contributes to the...This research was conducted to generate a primary database on ichthyofauna,distribution and diversities in the upstream and downstream segments of Sittaung River in Bago Region of Myanmar.This study contributes to the information needed on the distribution of river fish in Myanmar.Fish diversities are assessed by calculating the various diversities indices between December,2018 and November,2019.A total of 65 fish species belonging to 9 orders,23 families and 49 genera were recorded.All 65 fish species were found in upstream segment but only 60 species of them were found in downstream segment of the river.In all study sites,Shannon diversity index had value above 3 indicating that the structure of habitat was stable and balanced.Simpson’s index values were close to 1 in all sites indicating that the species richness in the region was satisfactory.The abundance all of above 5%of total catch of Mystus vittatus,M.pulcher,M.cavasius and Erethistes pusillus in their feeding habitat suggested that their upstream and downstream habitats provided suitable feeding conditions.Anguilla bengalensis,Tenualosa ilisha,Mystus gulio,Rita rita and Silonia silondia were least abundant all below 0.1%of total catch showing they could be impacted by unwise anthropogenic activities.Assessing fish species diversity is thus very important to conserve and manage and promote the health of river ecosystem that is necessary for the migration of fish species.展开更多
Decreasing fish resources in estuaries is a subject of anthropogenic activities. Studies of the spatiotemporal distribution of fish eggs and larvae can help identify the status and processes underlying recruitment in ...Decreasing fish resources in estuaries is a subject of anthropogenic activities. Studies of the spatiotemporal distribution of fish eggs and larvae can help identify the status and processes underlying recruitment in a fishery. As the fifth largest river estuary in the world, the Huanghe (Yellow) River estuary (HRE) is a typical estuary that has been seriously aff ected by human activities. Annual surveys on ichthyoplankton and environmental factors were conducted in the months of May of 2005 and 2009-2016 in the HRE to investigate the spatiotemporal distribution of fish eggs and larvae and the associated infl uencing factors. A total of 23 and 20 species of eggs and larvae, respectively, were collected. The dominant orders were Perciformes (51.2%) and Clupeiformes (25.6%). The average number of fish species eggs and larvae were 6.0 and 4.1 in average abundance of 0.91 and 0.13 ind./m^3 , respectively. The dominant species were mainly low-commercial-value small-sized fishes, such as Clupanodon punctatus , Harengula zunasi, and Acanthogobius, whereas certain traditional commercial fishes, such as Trichiurus lepturus , and Clupea pallasii, were not seen. Analysis of the fish egg and larval community revealed four temporal assemblages and two spatial assemblages. Salinity was the main factor on the spatial distribution of ichthyoplankton communities, the species number and Shannon-Weiner diversity index (H′) of the fish egg and larval community near the river mouth with lower salinity were signifi cantly lower than the community far away from the river mouth with higher salinity. In addition, increases of water temperature promoted the number and abundance of fish species eggs, and the areas of abundant prey tended to have a more diversified and abundant of ichthyoplankton species. In overall, overfishing, dam construction, and other human activities were the main drivers that led to the substantial decline in fishery resources in the HRE.展开更多
The mercury content in 158 fishes and 28 mussels in the Second Songhua river were detected. The range of mercury concentrations in fishes and mussels was 0.02-0.66 mg/kg and 0.002-0.056 mg/kg, respectively. The histor...The mercury content in 158 fishes and 28 mussels in the Second Songhua river were detected. The range of mercury concentrations in fishes and mussels was 0.02-0.66 mg/kg and 0.002-0.056 mg/kg, respectively. The history change of mercury content in fishes was analyzed in this paper. From upstream to downstream, the average mercury concentrations in fishes increased with the increase of the distance to the headstream, then decreased in the downstream of Wujiazhan town (sampling site). The fact illuminated that the source of mercury contamination was mercury in sediment. In the different species of fishes, the mercury concentration in Parasiburus asvtus was the highest and the order of mercury distribution in fishes was: the mercury value in fishes in the river bottom >that in fishes in the surface and that in predacious fishes>that in herbivorous fishes. In the investigation, there were amount of fishes whose mercury value exceeded the criterion for that in fishes that suggested that the mercury contamination in the Second Songhua River have not completely been eliminated until now.展开更多
The survey in the, Huanghe River estuary indicated that the 85 fish species found there comprised three faunal elements: warm-water species (29.4%), warm-temperate species (55.3%) and cpld-temperate species. (15.3%). ...The survey in the, Huanghe River estuary indicated that the 85 fish species found there comprised three faunal elements: warm-water species (29.4%), warm-temperate species (55.3%) and cpld-temperate species. (15.3%). The seasonal changes of fish species, density and bipmass are obvious. The total biomass is highest (7699t) in August and lowest(489 t) in January. Setipinna taty has mean density of 9278 indiv/km2, and is the most important species constituting 25.5% of the total weight of fish caught. Trichiurus haumela was a dominant species in the 1950s, but no one was caught in this survey. There were obvious changes of the dominant fish species during the recent three decades. The demersal fish biomass has dropped greatly to only 1/10 in over 50 years since 1930.展开更多
This study was aim to determined the levels of some heavy metals in the gills, liver, stomach, kidney, bones and flesh of four fish species (Tilapia zilli, Clarias anguillaris, Synodentis budgetti and Oreochronmis nil...This study was aim to determined the levels of some heavy metals in the gills, liver, stomach, kidney, bones and flesh of four fish species (Tilapia zilli, Clarias anguillaris, Synodentis budgetti and Oreochronmis niloticus) collected at River Benue in Vinikilang, Adamawa State, Nigeria for analysis of Cu, Zn, Co, Mn, Fe, Cr, Cd, Ni and Pb. These metals were chosen because at higher concentrations there might be toxic to the fish and by extension humans that depends on such fish as food. The concentrations of the metals were carried out using Flame Atomic Absorption Spectrophotometer (AAS, Unicam 969). Large differences in trace metal concentrations were observed between different tissues within each fish. The highest concentration of Fe (12.65 μg/g) was recorded in gill of Synodentis budgetti, while the lowest value of 0.68 μg/g was recorded in the flesh of Oreochronmis niloticus. The liver of Synodentis budgetti accumulates significant higher levels of Mn and Cd than other species;Fe and Zn was highest in the stomach of Tilapia zilli, while Clarias angullaris shows more of Cr, Pb, Cd and Co. The stomach of Synodentis budgetti accumulate significant higher levels of Fe than other species;Zn was highest in the stomach of Tilapia zilli, while Clarias angullaris shows more of Mn, Cr, Cu, Cd and Pb. Similarly, the bone of Synodentis budgettiaccumulates significant higher levels of Mn and Cd than other species;Zn and Fe were highest in the bone of Tilapia zilli, while Clarias angullaris shows more of Cr, Pb, Ni, and Co. The highest levels of Fe (12.65 μg/g) observed in this study was recorded in the gill of Synodentis budgetti and it was below the high residue concentrations of Fe (34 - 107 ppm) in fish samples. Based on the above results, it can therefore be concluded that metals bioaccumulation in the entire fish species study did not exceeds the permissible limits set for heavy metals by FAO, FEPA and WHO.展开更多
The lower Mississippi River(LMR) has been heavily modified for multiple human purposes such as navigation, flood control, and bank stabilization. However, the LMR simultaneously supports a diverse fish fauna that incl...The lower Mississippi River(LMR) has been heavily modified for multiple human purposes such as navigation, flood control, and bank stabilization. However, the LMR simultaneously supports a diverse fish fauna that includes recreational and commercial fisheries. Due to river training and diversion structures constructed during the past 80 years, the historic characteristics of the LMR have been drastically altered and have likely influenced fishes and fisheries in the system. One common restoration measure used throughout the LMR has been to "notch" wing-dike structures that close secondary(side) river channels. Dike notching allows year-round flows through secondary channels, which enhances habitat diversity and promotes biological productivity at the ecosystem scale. Although notching is presumed good for LMR fishes and other biota, few studies have examined its effects on fish assemblages. In this study, fish assemblages were sampled at seven LMR secondary channels spanning from river kilometer(rkm) 628(Louisiana-Mississippi, U.S.A.) upstream to rkm 1504(Missouri-Kentucky, U.S.A.). Four secondary channels were termed "permanent"(i.e.,with notched dikes) while three secondary channels were termed "temporary"(i.e., without notched dikes).Fishes were sampled by boat-mounted electrofishing conducted during falling and low stages from1995—1997. Fish assemblages differed between permanent and temporary secondary channels, and varied somewhat between falling and low stages. Gizzard shad(Dorosoma cepedianum), threadfin shad(D. petenense), and white bass(Morone chrysops) demonstrated consistent preferences for low-current conditions associated with temporary secondary channels. Conversely, blue catfish(Ictalurus furcatus), flathead catfish(Pylodictis olivaris), and freshwater drum(Aplodinotus grunniens) were more associated with permanent secondary channels. Future restoration strategies in the LMR should consider dike notching and resultant maintenance of permanent secondary channels in selected river reaches. However, temporary secondary channels also contain unique fish species, and also appear to be important sites of riverine primary production. Restoration strategies should consider a balance of both secondary channel types, which should support the greatest biodiversity for the LMR ecosystem.展开更多
This paper puts forward a construction method based on ontology for the Pearl River Basin fish production, to facilitate the domain knowledge analysis and information retrieval. By converting the concepts and terms in...This paper puts forward a construction method based on ontology for the Pearl River Basin fish production, to facilitate the domain knowledge analysis and information retrieval. By converting the concepts and terms in domain ordinally, the fish production ontology was constructed with the definition of classes, properties, instances, and relationships. The developed ontology model of the fish production knowledge is proposed and applied in the system of fish diseases diagnosis primarily. The research lays the semantic foundation for the further efficient knowledge management and practical application.展开更多
The measurements for the quality of the water were made at eight stations of Adügüzel Dam, Yenice Regulator, Sarayköy Bridge, Feslek Regulator, Yenipazar Bridge, Aydιn Bridge, Koçarlι Bridg...The measurements for the quality of the water were made at eight stations of Adügüzel Dam, Yenice Regulator, Sarayköy Bridge, Feslek Regulator, Yenipazar Bridge, Aydιn Bridge, Koçarlι Bridge, Söke Regulator located at the Buyuk Menderes River, Turkey. The study was conducted for the period between 2000-2013 for the months of February, April, June, August, October and December. The results received were analyzed for temperature, pH, EC, Cl<sup>-</sup>, Na, Ca<sup>2+</sup>, Mg<sup>2+</sup>, K<sup>+</sup>, , TDS, TH and SS aquaculture. The results of the analyses revealed that although the water pollution in the river showed variations throughout the year, in fact the samples obtained at various locations displayed high levels of pollutants. The “Regulation on Turkish Water Pollution Control” was made use of in classifying the parameters of the water in this study. These parameters were compared with the WHO Guidelines and TS-266. Among the 8 Dams that were included in the study, the best quality of water was measured in the Adügüzel Dam, which gave the lowest values;and the levels were measured to be higher in the Saraykoy Station than those of the other dams. There was a severe drought in Menderes Basin in 2007, and therefore the highest annual values were measured for the year 2007. In those years, the levels of the irrigation water decreased as low as 4255 m<sup>3</sup>/ha. The SPSS 21 Statistical Analysis Program was made use of in analyzing the data of the study. The One-Way Anova and Tukey Multiple Comparison tests were also used for the analyses of the data as well. The p < 0.05 level was accepted as being significant in the analyses. The distribution of the data was performed by using the Box-plot Graphs. Furthermore, the effects on fish species and the pollution in Büyük Menderes River were also examined in the study.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
The transboundary Mekong River is shared by six SE Asia countries (China, Myanmar, Thailand, Lao PDR, Cambodia, and Vietnam). In this paper the livelihoods of farmers and fishers of Lao PDR, Cambodia and Vietnam are e...The transboundary Mekong River is shared by six SE Asia countries (China, Myanmar, Thailand, Lao PDR, Cambodia, and Vietnam). In this paper the livelihoods of farmers and fishers of Lao PDR, Cambodia and Vietnam are examined to assess impacts of Mekong River development and modernization projects on the rural peoples of the Mekong River and Delta. A high proportion of the 190 million rural people of the Mekong basin are dependent on the diverse and abundant resources of the Mekong River and its tributaries for food security and basic necessities, livelihoods, and cultural identities. Although rice farming and fisheries occupations are primary income sources, many livelihoods involve a diversity of on-farm and off-farm activities. Agricultural specialization and intensification and hydropower dam construction on the Mekong main stem and tributaries are altering traditional rural patterns of household food security, income, and cultural ways of living at an increasingly rapid pace. Rural transformation projects must better assess how these modernization efforts change the ecology of the Mekong River and in turn affect the capacity of rural people to adapt in ways that ensure food security and improve household livelihoods. It will be critical that development efforts recognize, value, and invest in rural people’s roles in producing a stable, affordable food system and managing the integrity of river ecosystems upon which future prosperity depends. Interventions are needed to prevent degradation of the Mekong Basin soil and water resources from large-scale agricultural intensification, water diversion and overbuilding of hydropower dams which are threats to small-scale land holdings and farmers and fishers capacities to provide daily food for their own consumption and to feed SE Asia’s growing urban populations.展开更多
Dam removal is becoming an effective approach for aquatic biodiversity restoration in damming river in order to balance the aquatic ecosystem conservation with large-scale cascade damming. However, the effects of dam ...Dam removal is becoming an effective approach for aquatic biodiversity restoration in damming river in order to balance the aquatic ecosystem conservation with large-scale cascade damming. However, the effects of dam removal on fish communities in Asian mountainous rivers, which are dominated by Cypriniformes fishes, are still not well known. To determine whether dam removal on a mountainous river benefit restoration of fish diversity, we investigated the response of fish assemblage to dam removal using a before-after-control-impact design in two tributaries of the Lancang River(dam removal river: the Jidu River, and control river: the Fengdian River). Fish surveys were conducted one year prior to dam removal(2012) and three years(2013–2015) following dam removal. We observed rapidly and notably spatio-temporal changes in fish biodiversity metrics and assemblage structure, occurring in the Jidu River within the first year after dam removal. Overall, fish species richness, density and Shannon-Wiener diversity all increased immediately in above-and below-dam sites, and maintained a stable level in subsequent years, compared to unchanged situation in the control river. All sites in the Jidu River experienced shifts in fish composition after dam removal, with the greatest temporal changes occurred in sites below-and above-the former dam, resulting in a temporal homogenization tendency in the dam removed river. These findings suggest that dam removal can benefit the recovery of habitat conditions and fish community in Asian mountainous rivers, but the results should be further evaluated when apply to other dammed rivers since the dam age, fluvial geomorphology and situation of source populations could all affect the responses of fish assemblages.展开更多
Artificial fish nests are set in Lukou section and Hengyang section of Xiangjiang River from March 20 to May 10, 2019. The structure of artificial fish nest is bamboo frame, with the size of 2.5 m × 5.0 m × ...Artificial fish nests are set in Lukou section and Hengyang section of Xiangjiang River from March 20 to May 10, 2019. The structure of artificial fish nest is bamboo frame, with the size of 2.5 m × 5.0 m × 4 and a unit frame area of 60 m<sup>2</sup>. A total of 58,201 eggs were collected by 24 monitoring times, of which 30,441 were from Lukou and 27,760 from Hengyang. 3831 fish eggs identify 8 fish species using morphological or molecular biological methods. The results showed that the number of eggs peaked from the 8<sup>th</sup> day to the 24<sup>th</sup> day after the nest entered the water, and then decreased rapidly. There was significant negative correlation between egg number in per m<sup>2</sup> fish nest and days of fish nest (P < 0.01). The economic benefits of artificial fish nests were RMB 11.81 million. The artificial fish nest can not only increase the population of fish, but also has significant economic benefits.展开更多
Length-weight relationships and condition factors are among the commonly used parameters to link the length of a fish to its weight. The present study was initiated to find out the growth patterns and overweight statu...Length-weight relationships and condition factors are among the commonly used parameters to link the length of a fish to its weight. The present study was initiated to find out the growth patterns and overweight status of 15 fish species in the Loémé basin in Mayombe, Republic of Congo. In the period from February 2020 to September 2021, sampling was carried out in eight stations, following a standardised capture method using four gillnets of 10, 12, 15, and 25 mm mesh size and a hawk net of 1.90 m radius with 10 mm mesh size. Length-weight relationships were calculated according to P = aLS<sup>b</sup> and the condition factor, using K = (P/LS<sup>b</sup>)* 100. A total of 1153 specimens representing 15 species, 10 genera and 6 families were recorded. The number of specimens ranged from 10 to 214 for Chrysichthys auratus and Enteromius camptacanthus, respectively. The allometry coefficient b minimum of 2.697 for Chromidotilapiamelaniae and maximum of 3.589 for Garraornata, with a mean of 3.03 ± 0.2 is significantly not different from 3 at the 0.05 probability threshold and indicates isometric growth for almost all species, except for E. camptacanthus where b = 2.858 was statistically different from 3 at the same threshold. The positive and high values of the coefficients of determination r<sup>2</sup> = 0.787-0.989 of the species, obtained during this study, suggest that weight increases with size in the fish of the Loémé basin. The average condition factor varies from 0.524 ± 0.064 for G. ornata to 4.917 ± 0.440 for C. melaniae.展开更多
Fish is rich </span><span style="font-size:10.0pt;font-family:"">in</span><span style="font-size:10.0pt;font-family:""> essential nutrients but can remain a potent...Fish is rich </span><span style="font-size:10.0pt;font-family:"">in</span><span style="font-size:10.0pt;font-family:""> essential nutrients but can remain a potential source of food poisoning. A study was</span><span style="font-size:10.0pt;font-family:"">,</span><span style="font-size:10.0pt;font-family:""> therefore</span><span style="font-size:10.0pt;font-family:"">,</span><span style="font-size:10.0pt;font-family:""> carried out with the general objective of highlighting the probable biological and chemical dangers associated with the <span>consumption of fish and freshwater fruits from </span></span><span style="font-size:10.0pt;font-family:"">the </span><span style="font-size:10.0pt;font-family:"">Guéssabo river. The</span><span style="font-size:10.0pt;font-family:""> present study was conducted on 50 carp fish, 50 mackerel f</span><span style="font-size:10.0pt;font-family:"">i</span><span style="font-size:10.0pt;font-family:"">sh, 50 frog</span><span style="font-size:10.0pt;font-family:"">s</span><span style="font-size:10.0pt;font-family:""> and 50 mol<span>lusks caught in the Guéssabo River. Microorganisms were enumerated by</span> conventional tests and heavy metals were investigated by Inductively Coupled Plasma Optical Emission Spectrometry. The enumeration showed high levels of thermotolerant Coliforms (2.5 × 10<sup>4</sup>), Enterobacteriaceae (3.4 × 10<sup>4</sup>), <i>S</i>. <i>aureus</i> (2.3 × 10<sup>3</sup>) and Yeast/Molds (2.1 × 10<sup>4</sup>), in all samples the standards were not in conformity with the required standards. High levels of Al (7230 μg/kg) and Cd (21.57 μg/kg) were observed in carp fish and these values are <span>above the standard. In conclusion</span></span><span style="font-size:10.0pt;font-family:"">,</span><span style="font-size:10.0pt;font-family:""> the fish caught in the Guéssabo River</span><span style="font-size:10.0pt;font-family:""> could be a health risk factor for the consumer.展开更多
The Luapula River has received mining discharges from Lubumbashi and Kipushi Gecamines for several decades and from the CHEMAF company since 2005. It also received mining waste from SODIMICO. The Luapula River has Lak...The Luapula River has received mining discharges from Lubumbashi and Kipushi Gecamines for several decades and from the CHEMAF company since 2005. It also received mining waste from SODIMICO. The Luapula River has Lake Banguelo as its source in Zambia and flows into Lake Moero, which is located on the border between Zambia and the Democratic Republic of Congo. The objective of this study is to assess the health safety of the fish from the Luapula River. Fish samples were collected in August 2015 at the site of the locality of Kasenga located downstream of the mining activities (n = 14) and presumed to be polluted. On the other hand, reference fish samples were taken upstream of any mining activity of the Panda, Kasungwe and Congo Rivers at the sections located near their sources and presumed not to be polluted by mining wastes. (n = 11). Ten Metal Trace Elements (MTE) were assayed at the laboratory of the Congolese Control Office (OCC) of Lubumbashi and at the laboratory of the Catholic University of Leuven in Belgium using ICP-OES and ICP-MS. To assess and evaluate the health safety of fish from the Luapula River, the concentrations of fish samples from the Luapula River were compared with the concentrations of the reference fish samples from the Panda Kasungwe and Congo rivers by the Wilcoxon test. The concentrations of fish samples from the Congo River were also compared with the maximum acceptable metal trace element concentrations established by the FAO, WHO, EU (European Union) and other regulatory bodies. as reported by Akoto et al. The results of this study showed that the fish from the Luapula River is contaminated in Cd, Cu, Ni and Pb, and are not fit for human consumption. The results obtained will be brought to attention of the decision-makers of the Province of Haut-Katanga, so that measures can be taken to ban metallurgical factories to drump their mining wastes into waterways.展开更多
Invasion, spread and predominance of alien invasive fishes were studied in 950-km-long stretch of the Yamuna River. The fish yield ranged between 32 t/km/yr to 240 t/km/yr and the catch of alien invasive fishes domina...Invasion, spread and predominance of alien invasive fishes were studied in 950-km-long stretch of the Yamuna River. The fish yield ranged between 32 t/km/yr to 240 t/km/yr and the catch of alien invasive fishes dominated over local fishes in the fishery, which was over 96% at Etawah. The calculated Invasion Coefficient Index (Ixi) of alien invasive fishes was in the range of 0.12 to 0.31 indicating a major loss to the local fish diversity. The calculated Pearson’s correlation coefficient was found to have positive correlation of 0.757 and 0.710 for common carp and tilapia respectively with locally captured Indian major carps (IMC). The results of this study highlighted how unintentional spread of alien invasive fishes due to rapid aquaculture diversification and intensification has invaded into the Yamuna River causing severe loss to the local fishery. The invasion of alien fishes has been mapped for the Yamuna River at different locations using GIS tools. The results of this study invite attention on the management and sustainability of the local fishery and ecosystem health of the river.展开更多
文摘[Objective]Implementation of the Ten-Year Fishing Ban policy may alter fish diversity and niche characteristics of dominant species in spawning grounds within the National Nature Reserve for Rare and Endemic Fish in the Upper Yangtze River.This study initiated continuous monitoring of natural spawning habitats from February 2022 to assess these ecological changes.[Methods]Environmental DNA(eDNA)metabarcoding was employed to analyze fish species composition,biodiversity patterns,and niche parameters of dominant species.Water sampling followed the CEN/TS 19461 standard across five monitoring transects(ZT1-ZT5).[Results]The eDNA analysis detected 45 species of fish belonging to 38 genera,13 families,and 3 orders were detected through environmental DNA(eDNA)in this survey,including 10 species endemic to the upper reaches of the Yangtze River,such as Procypris rabaudi and Myxocyprinus asiaticus.The fish community was mainly composed of bottom-dwelling,settling ovum-producing,omnivorous fish.The variation ranges of the Chao1 index,ACE index,Shannon index,and Simpson index are 736~996,719~965,1.58~3.23,and 0.83~0.99,respectively,indicating that fish species in spawning sites are abundant and community distribution uniformity is high.All indexes are highest at ZT1 monitoring points.Cluster analysis showed that,at a certain similarity level,fish community types in spawning sites could be basically divided into two groups:ZT1,ZT3,and ZT5 clustered together,and ZT2 and ZT4 clustered together,indicating similar fish community habitats.There are 9 dominant fish species in typical deep pool habitats in the reserve,with niche widths(Bi)ranging from 1.13 to 3.87.The dominant fish species are broad and medium niche fish,such as Cyprinus carpio and Hemiculter tchangi,with the niche overlap index(Oik)of some dominant fish species reaching more than 0.95.This indicates fierce competition for resources among the fish in this spawning ground.[Conclusion]The Zhutuo spawning ground demonstrates high species richness with homogeneous community structure and intense resource competition.This study establishes an eDNA-based monitoring framework that enhances conventional survey method,providing critical baseline data for adaptive management under the fishing moratorium regime.
文摘This research was conducted to generate a primary database on ichthyofauna,distribution and diversities in the upstream and downstream segments of Sittaung River in Bago Region of Myanmar.This study contributes to the information needed on the distribution of river fish in Myanmar.Fish diversities are assessed by calculating the various diversities indices between December,2018 and November,2019.A total of 65 fish species belonging to 9 orders,23 families and 49 genera were recorded.All 65 fish species were found in upstream segment but only 60 species of them were found in downstream segment of the river.In all study sites,Shannon diversity index had value above 3 indicating that the structure of habitat was stable and balanced.Simpson’s index values were close to 1 in all sites indicating that the species richness in the region was satisfactory.The abundance all of above 5%of total catch of Mystus vittatus,M.pulcher,M.cavasius and Erethistes pusillus in their feeding habitat suggested that their upstream and downstream habitats provided suitable feeding conditions.Anguilla bengalensis,Tenualosa ilisha,Mystus gulio,Rita rita and Silonia silondia were least abundant all below 0.1%of total catch showing they could be impacted by unwise anthropogenic activities.Assessing fish species diversity is thus very important to conserve and manage and promote the health of river ecosystem that is necessary for the migration of fish species.
基金Supported by the National Natural Science Foundation of China—Shandong Provincial Joint Fund for Marine Science Research Centers(No.U1606404)the National Key Basic Research Program of China(973 Program)(No.2015CB453301)the National Marine Public Welfare Research Project of China(No.201405007)
文摘Decreasing fish resources in estuaries is a subject of anthropogenic activities. Studies of the spatiotemporal distribution of fish eggs and larvae can help identify the status and processes underlying recruitment in a fishery. As the fifth largest river estuary in the world, the Huanghe (Yellow) River estuary (HRE) is a typical estuary that has been seriously aff ected by human activities. Annual surveys on ichthyoplankton and environmental factors were conducted in the months of May of 2005 and 2009-2016 in the HRE to investigate the spatiotemporal distribution of fish eggs and larvae and the associated infl uencing factors. A total of 23 and 20 species of eggs and larvae, respectively, were collected. The dominant orders were Perciformes (51.2%) and Clupeiformes (25.6%). The average number of fish species eggs and larvae were 6.0 and 4.1 in average abundance of 0.91 and 0.13 ind./m^3 , respectively. The dominant species were mainly low-commercial-value small-sized fishes, such as Clupanodon punctatus , Harengula zunasi, and Acanthogobius, whereas certain traditional commercial fishes, such as Trichiurus lepturus , and Clupea pallasii, were not seen. Analysis of the fish egg and larval community revealed four temporal assemblages and two spatial assemblages. Salinity was the main factor on the spatial distribution of ichthyoplankton communities, the species number and Shannon-Weiner diversity index (H′) of the fish egg and larval community near the river mouth with lower salinity were signifi cantly lower than the community far away from the river mouth with higher salinity. In addition, increases of water temperature promoted the number and abundance of fish species eggs, and the areas of abundant prey tended to have a more diversified and abundant of ichthyoplankton species. In overall, overfishing, dam construction, and other human activities were the main drivers that led to the substantial decline in fishery resources in the HRE.
文摘The mercury content in 158 fishes and 28 mussels in the Second Songhua river were detected. The range of mercury concentrations in fishes and mussels was 0.02-0.66 mg/kg and 0.002-0.056 mg/kg, respectively. The history change of mercury content in fishes was analyzed in this paper. From upstream to downstream, the average mercury concentrations in fishes increased with the increase of the distance to the headstream, then decreased in the downstream of Wujiazhan town (sampling site). The fact illuminated that the source of mercury contamination was mercury in sediment. In the different species of fishes, the mercury concentration in Parasiburus asvtus was the highest and the order of mercury distribution in fishes was: the mercury value in fishes in the river bottom >that in fishes in the surface and that in predacious fishes>that in herbivorous fishes. In the investigation, there were amount of fishes whose mercury value exceeded the criterion for that in fishes that suggested that the mercury contamination in the Second Songhua River have not completely been eliminated until now.
文摘The survey in the, Huanghe River estuary indicated that the 85 fish species found there comprised three faunal elements: warm-water species (29.4%), warm-temperate species (55.3%) and cpld-temperate species. (15.3%). The seasonal changes of fish species, density and bipmass are obvious. The total biomass is highest (7699t) in August and lowest(489 t) in January. Setipinna taty has mean density of 9278 indiv/km2, and is the most important species constituting 25.5% of the total weight of fish caught. Trichiurus haumela was a dominant species in the 1950s, but no one was caught in this survey. There were obvious changes of the dominant fish species during the recent three decades. The demersal fish biomass has dropped greatly to only 1/10 in over 50 years since 1930.
文摘This study was aim to determined the levels of some heavy metals in the gills, liver, stomach, kidney, bones and flesh of four fish species (Tilapia zilli, Clarias anguillaris, Synodentis budgetti and Oreochronmis niloticus) collected at River Benue in Vinikilang, Adamawa State, Nigeria for analysis of Cu, Zn, Co, Mn, Fe, Cr, Cd, Ni and Pb. These metals were chosen because at higher concentrations there might be toxic to the fish and by extension humans that depends on such fish as food. The concentrations of the metals were carried out using Flame Atomic Absorption Spectrophotometer (AAS, Unicam 969). Large differences in trace metal concentrations were observed between different tissues within each fish. The highest concentration of Fe (12.65 μg/g) was recorded in gill of Synodentis budgetti, while the lowest value of 0.68 μg/g was recorded in the flesh of Oreochronmis niloticus. The liver of Synodentis budgetti accumulates significant higher levels of Mn and Cd than other species;Fe and Zn was highest in the stomach of Tilapia zilli, while Clarias angullaris shows more of Cr, Pb, Cd and Co. The stomach of Synodentis budgetti accumulate significant higher levels of Fe than other species;Zn was highest in the stomach of Tilapia zilli, while Clarias angullaris shows more of Mn, Cr, Cu, Cd and Pb. Similarly, the bone of Synodentis budgettiaccumulates significant higher levels of Mn and Cd than other species;Zn and Fe were highest in the bone of Tilapia zilli, while Clarias angullaris shows more of Cr, Pb, Ni, and Co. The highest levels of Fe (12.65 μg/g) observed in this study was recorded in the gill of Synodentis budgetti and it was below the high residue concentrations of Fe (34 - 107 ppm) in fish samples. Based on the above results, it can therefore be concluded that metals bioaccumulation in the entire fish species study did not exceeds the permissible limits set for heavy metals by FAO, FEPA and WHO.
基金Supported by the Financial from the U.S.Army Corps of Engineers-Lower Mississippi Valley Division,Vicksburg,Mississippi,U.S.A.
文摘The lower Mississippi River(LMR) has been heavily modified for multiple human purposes such as navigation, flood control, and bank stabilization. However, the LMR simultaneously supports a diverse fish fauna that includes recreational and commercial fisheries. Due to river training and diversion structures constructed during the past 80 years, the historic characteristics of the LMR have been drastically altered and have likely influenced fishes and fisheries in the system. One common restoration measure used throughout the LMR has been to "notch" wing-dike structures that close secondary(side) river channels. Dike notching allows year-round flows through secondary channels, which enhances habitat diversity and promotes biological productivity at the ecosystem scale. Although notching is presumed good for LMR fishes and other biota, few studies have examined its effects on fish assemblages. In this study, fish assemblages were sampled at seven LMR secondary channels spanning from river kilometer(rkm) 628(Louisiana-Mississippi, U.S.A.) upstream to rkm 1504(Missouri-Kentucky, U.S.A.). Four secondary channels were termed "permanent"(i.e.,with notched dikes) while three secondary channels were termed "temporary"(i.e., without notched dikes).Fishes were sampled by boat-mounted electrofishing conducted during falling and low stages from1995—1997. Fish assemblages differed between permanent and temporary secondary channels, and varied somewhat between falling and low stages. Gizzard shad(Dorosoma cepedianum), threadfin shad(D. petenense), and white bass(Morone chrysops) demonstrated consistent preferences for low-current conditions associated with temporary secondary channels. Conversely, blue catfish(Ictalurus furcatus), flathead catfish(Pylodictis olivaris), and freshwater drum(Aplodinotus grunniens) were more associated with permanent secondary channels. Future restoration strategies in the LMR should consider dike notching and resultant maintenance of permanent secondary channels in selected river reaches. However, temporary secondary channels also contain unique fish species, and also appear to be important sites of riverine primary production. Restoration strategies should consider a balance of both secondary channel types, which should support the greatest biodiversity for the LMR ecosystem.
基金supported by the National Natural Science Foundation of China (2006AA10Z239)the National Key Technology R&D Program of China (2006BAD10A0501)
文摘This paper puts forward a construction method based on ontology for the Pearl River Basin fish production, to facilitate the domain knowledge analysis and information retrieval. By converting the concepts and terms in domain ordinally, the fish production ontology was constructed with the definition of classes, properties, instances, and relationships. The developed ontology model of the fish production knowledge is proposed and applied in the system of fish diseases diagnosis primarily. The research lays the semantic foundation for the further efficient knowledge management and practical application.
文摘The measurements for the quality of the water were made at eight stations of Adügüzel Dam, Yenice Regulator, Sarayköy Bridge, Feslek Regulator, Yenipazar Bridge, Aydιn Bridge, Koçarlι Bridge, Söke Regulator located at the Buyuk Menderes River, Turkey. The study was conducted for the period between 2000-2013 for the months of February, April, June, August, October and December. The results received were analyzed for temperature, pH, EC, Cl<sup>-</sup>, Na, Ca<sup>2+</sup>, Mg<sup>2+</sup>, K<sup>+</sup>, , TDS, TH and SS aquaculture. The results of the analyses revealed that although the water pollution in the river showed variations throughout the year, in fact the samples obtained at various locations displayed high levels of pollutants. The “Regulation on Turkish Water Pollution Control” was made use of in classifying the parameters of the water in this study. These parameters were compared with the WHO Guidelines and TS-266. Among the 8 Dams that were included in the study, the best quality of water was measured in the Adügüzel Dam, which gave the lowest values;and the levels were measured to be higher in the Saraykoy Station than those of the other dams. There was a severe drought in Menderes Basin in 2007, and therefore the highest annual values were measured for the year 2007. In those years, the levels of the irrigation water decreased as low as 4255 m<sup>3</sup>/ha. The SPSS 21 Statistical Analysis Program was made use of in analyzing the data of the study. The One-Way Anova and Tukey Multiple Comparison tests were also used for the analyses of the data as well. The p < 0.05 level was accepted as being significant in the analyses. The distribution of the data was performed by using the Box-plot Graphs. Furthermore, the effects on fish species and the pollution in Büyük Menderes River were also examined in the study.
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.
文摘The transboundary Mekong River is shared by six SE Asia countries (China, Myanmar, Thailand, Lao PDR, Cambodia, and Vietnam). In this paper the livelihoods of farmers and fishers of Lao PDR, Cambodia and Vietnam are examined to assess impacts of Mekong River development and modernization projects on the rural peoples of the Mekong River and Delta. A high proportion of the 190 million rural people of the Mekong basin are dependent on the diverse and abundant resources of the Mekong River and its tributaries for food security and basic necessities, livelihoods, and cultural identities. Although rice farming and fisheries occupations are primary income sources, many livelihoods involve a diversity of on-farm and off-farm activities. Agricultural specialization and intensification and hydropower dam construction on the Mekong main stem and tributaries are altering traditional rural patterns of household food security, income, and cultural ways of living at an increasingly rapid pace. Rural transformation projects must better assess how these modernization efforts change the ecology of the Mekong River and in turn affect the capacity of rural people to adapt in ways that ensure food security and improve household livelihoods. It will be critical that development efforts recognize, value, and invest in rural people’s roles in producing a stable, affordable food system and managing the integrity of river ecosystems upon which future prosperity depends. Interventions are needed to prevent degradation of the Mekong Basin soil and water resources from large-scale agricultural intensification, water diversion and overbuilding of hydropower dams which are threats to small-scale land holdings and farmers and fishers capacities to provide daily food for their own consumption and to feed SE Asia’s growing urban populations.
基金the National Natural Science Foundation of China(No.41501574)the National Key Research and Development Program of China(No.2016YFA0601601)+1 种基金the Yunnan Applied Basic Research Projects(No.2016FB079)the National Science and Technology Support Program of China(No.2013BAB06B03)
文摘Dam removal is becoming an effective approach for aquatic biodiversity restoration in damming river in order to balance the aquatic ecosystem conservation with large-scale cascade damming. However, the effects of dam removal on fish communities in Asian mountainous rivers, which are dominated by Cypriniformes fishes, are still not well known. To determine whether dam removal on a mountainous river benefit restoration of fish diversity, we investigated the response of fish assemblage to dam removal using a before-after-control-impact design in two tributaries of the Lancang River(dam removal river: the Jidu River, and control river: the Fengdian River). Fish surveys were conducted one year prior to dam removal(2012) and three years(2013–2015) following dam removal. We observed rapidly and notably spatio-temporal changes in fish biodiversity metrics and assemblage structure, occurring in the Jidu River within the first year after dam removal. Overall, fish species richness, density and Shannon-Wiener diversity all increased immediately in above-and below-dam sites, and maintained a stable level in subsequent years, compared to unchanged situation in the control river. All sites in the Jidu River experienced shifts in fish composition after dam removal, with the greatest temporal changes occurred in sites below-and above-the former dam, resulting in a temporal homogenization tendency in the dam removed river. These findings suggest that dam removal can benefit the recovery of habitat conditions and fish community in Asian mountainous rivers, but the results should be further evaluated when apply to other dammed rivers since the dam age, fluvial geomorphology and situation of source populations could all affect the responses of fish assemblages.
文摘Artificial fish nests are set in Lukou section and Hengyang section of Xiangjiang River from March 20 to May 10, 2019. The structure of artificial fish nest is bamboo frame, with the size of 2.5 m × 5.0 m × 4 and a unit frame area of 60 m<sup>2</sup>. A total of 58,201 eggs were collected by 24 monitoring times, of which 30,441 were from Lukou and 27,760 from Hengyang. 3831 fish eggs identify 8 fish species using morphological or molecular biological methods. The results showed that the number of eggs peaked from the 8<sup>th</sup> day to the 24<sup>th</sup> day after the nest entered the water, and then decreased rapidly. There was significant negative correlation between egg number in per m<sup>2</sup> fish nest and days of fish nest (P < 0.01). The economic benefits of artificial fish nests were RMB 11.81 million. The artificial fish nest can not only increase the population of fish, but also has significant economic benefits.
文摘Length-weight relationships and condition factors are among the commonly used parameters to link the length of a fish to its weight. The present study was initiated to find out the growth patterns and overweight status of 15 fish species in the Loémé basin in Mayombe, Republic of Congo. In the period from February 2020 to September 2021, sampling was carried out in eight stations, following a standardised capture method using four gillnets of 10, 12, 15, and 25 mm mesh size and a hawk net of 1.90 m radius with 10 mm mesh size. Length-weight relationships were calculated according to P = aLS<sup>b</sup> and the condition factor, using K = (P/LS<sup>b</sup>)* 100. A total of 1153 specimens representing 15 species, 10 genera and 6 families were recorded. The number of specimens ranged from 10 to 214 for Chrysichthys auratus and Enteromius camptacanthus, respectively. The allometry coefficient b minimum of 2.697 for Chromidotilapiamelaniae and maximum of 3.589 for Garraornata, with a mean of 3.03 ± 0.2 is significantly not different from 3 at the 0.05 probability threshold and indicates isometric growth for almost all species, except for E. camptacanthus where b = 2.858 was statistically different from 3 at the same threshold. The positive and high values of the coefficients of determination r<sup>2</sup> = 0.787-0.989 of the species, obtained during this study, suggest that weight increases with size in the fish of the Loémé basin. The average condition factor varies from 0.524 ± 0.064 for G. ornata to 4.917 ± 0.440 for C. melaniae.
文摘Fish is rich </span><span style="font-size:10.0pt;font-family:"">in</span><span style="font-size:10.0pt;font-family:""> essential nutrients but can remain a potential source of food poisoning. A study was</span><span style="font-size:10.0pt;font-family:"">,</span><span style="font-size:10.0pt;font-family:""> therefore</span><span style="font-size:10.0pt;font-family:"">,</span><span style="font-size:10.0pt;font-family:""> carried out with the general objective of highlighting the probable biological and chemical dangers associated with the <span>consumption of fish and freshwater fruits from </span></span><span style="font-size:10.0pt;font-family:"">the </span><span style="font-size:10.0pt;font-family:"">Guéssabo river. The</span><span style="font-size:10.0pt;font-family:""> present study was conducted on 50 carp fish, 50 mackerel f</span><span style="font-size:10.0pt;font-family:"">i</span><span style="font-size:10.0pt;font-family:"">sh, 50 frog</span><span style="font-size:10.0pt;font-family:"">s</span><span style="font-size:10.0pt;font-family:""> and 50 mol<span>lusks caught in the Guéssabo River. Microorganisms were enumerated by</span> conventional tests and heavy metals were investigated by Inductively Coupled Plasma Optical Emission Spectrometry. The enumeration showed high levels of thermotolerant Coliforms (2.5 × 10<sup>4</sup>), Enterobacteriaceae (3.4 × 10<sup>4</sup>), <i>S</i>. <i>aureus</i> (2.3 × 10<sup>3</sup>) and Yeast/Molds (2.1 × 10<sup>4</sup>), in all samples the standards were not in conformity with the required standards. High levels of Al (7230 μg/kg) and Cd (21.57 μg/kg) were observed in carp fish and these values are <span>above the standard. In conclusion</span></span><span style="font-size:10.0pt;font-family:"">,</span><span style="font-size:10.0pt;font-family:""> the fish caught in the Guéssabo River</span><span style="font-size:10.0pt;font-family:""> could be a health risk factor for the consumer.
文摘The Luapula River has received mining discharges from Lubumbashi and Kipushi Gecamines for several decades and from the CHEMAF company since 2005. It also received mining waste from SODIMICO. The Luapula River has Lake Banguelo as its source in Zambia and flows into Lake Moero, which is located on the border between Zambia and the Democratic Republic of Congo. The objective of this study is to assess the health safety of the fish from the Luapula River. Fish samples were collected in August 2015 at the site of the locality of Kasenga located downstream of the mining activities (n = 14) and presumed to be polluted. On the other hand, reference fish samples were taken upstream of any mining activity of the Panda, Kasungwe and Congo Rivers at the sections located near their sources and presumed not to be polluted by mining wastes. (n = 11). Ten Metal Trace Elements (MTE) were assayed at the laboratory of the Congolese Control Office (OCC) of Lubumbashi and at the laboratory of the Catholic University of Leuven in Belgium using ICP-OES and ICP-MS. To assess and evaluate the health safety of fish from the Luapula River, the concentrations of fish samples from the Luapula River were compared with the concentrations of the reference fish samples from the Panda Kasungwe and Congo rivers by the Wilcoxon test. The concentrations of fish samples from the Congo River were also compared with the maximum acceptable metal trace element concentrations established by the FAO, WHO, EU (European Union) and other regulatory bodies. as reported by Akoto et al. The results of this study showed that the fish from the Luapula River is contaminated in Cd, Cu, Ni and Pb, and are not fit for human consumption. The results obtained will be brought to attention of the decision-makers of the Province of Haut-Katanga, so that measures can be taken to ban metallurgical factories to drump their mining wastes into waterways.
文摘Invasion, spread and predominance of alien invasive fishes were studied in 950-km-long stretch of the Yamuna River. The fish yield ranged between 32 t/km/yr to 240 t/km/yr and the catch of alien invasive fishes dominated over local fishes in the fishery, which was over 96% at Etawah. The calculated Invasion Coefficient Index (Ixi) of alien invasive fishes was in the range of 0.12 to 0.31 indicating a major loss to the local fish diversity. The calculated Pearson’s correlation coefficient was found to have positive correlation of 0.757 and 0.710 for common carp and tilapia respectively with locally captured Indian major carps (IMC). The results of this study highlighted how unintentional spread of alien invasive fishes due to rapid aquaculture diversification and intensification has invaded into the Yamuna River causing severe loss to the local fishery. The invasion of alien fishes has been mapped for the Yamuna River at different locations using GIS tools. The results of this study invite attention on the management and sustainability of the local fishery and ecosystem health of the river.
