Cirrhinus Molitorella Research Articles

Density‐dependent trophic consequences of invasive mrigal carp on native mud carp in Chinese fresh waters

Abstract Understanding the strength, direction and consequences of the trophic impacts of invasive fish on functionally analogous native fishes is important in invasion impact assessment and for informing management programmes. As functionally analogous native and invasive fishes can share prey resources, there is high potential for competitive interactions, which could affect trophic niche sizes and positions. The highly invasive mrigal carp Cirrhinus mrigala and native mud carp Cirrhinus molitorella now co‐exist in many freshwaters in southern China, raising concern on the consequences for mud carp. The trophic interactions of the two species and their consequences (for growth rates and trophic niche sizes as the isotopic niche, calculated using δ13C and δ15N) were tested in a pond enclosure experiment based on additive and substitutive treatments using fish in allopatric and sympatric contexts, with results compared with invaded wild communities. In the experiment, specific growth rates decreased significantly as fish abundance in treatments increased. These density‐dependent effects were observed in both species and were independent of whether the treatment was allopatric or sympatric. In allopatric treatments, isotopic niches of mud carp increased in size with fish number. Conversely, in sympatric treatments, mud carp isotopic niche size decreased with increased mrigal carp number. For mrigal carp, isotopic niche sizes decreased as fish number increased in both allopatric and sympatric treatments. In sympatric experiment treatments, the isotopic niches of mud carp and mrigal carp were always divergent. This was, however, in contrast to four invaded wild communities, where the isotopic niches of the two fishes always had some overlap. Experimental and field data suggest that although native mud carp could be impacted by mrigal carp, these impacts might only manifest when the species are at very high abundances and inter‐specific competitive interactions could be intense. These results also suggest the two species have mechanisms that reduce their inter‐specific interactions to minimise their competitive interactions, thus any ecological impacts from mrigal carp might manifest more from indirect than direct processes.

Niche overlap between native Cirrhinus molitorella and potential invasive competitors

Biological invasion is one of the important reasons for the decline of freshwater biodiversity in China and even in the world. The Pearl river basin is one of the most threatened areas in China by biological invasion. Over the past four decades, mrigal carp Cirrhinus mrigala and rohu Labeo rohita have invaded the Pearl river. They potentially pose a huge threat to a well-known economic species, native mud carp Cirrhinus molitorella. However, little is known about the likely habitat distributions of these two invasive species, which limits our management of them. In this study, we detected the stable isotope ratios of nitrogen and carbon for fish and quantified their niche overlap with nicheROVER in R. The result showed that the individuals of two invasive species had a higher probability to be found in niche region of native C. molitorella (i.e., 65 % for C. mrigala and 74 % for L. rohita). Moreover, to increase understanding of their habitat distributions and potential range of spread, the existing habitats data of these three fish species obtained from previous literatures and the high-resolution bioclimatic parameters from WorldClim were analyzed via Maxent model. The results stressed that niche overlap was high among species, which could have an impact on local biodiversity in future. Furthermore, the visualization of habitat distributions could help show the dynamic habitat changes of invasive and native species over time, while also provide new insights into the subsequent prevention and control for invasive species in other river regions around the world.

The feasibility of Chinese mitten crab (Eriocheir sinensis), mandarin fish (Siniperca chuatsi), and mud carp (Cirrhinus molitorella) polyculture and their effects on growth performance, water quality, antioxidant, and nonspecific immunological capacity

The feasibility of Chinese mitten crab (Eriocheir sinensis), mandarin fish (Siniperca chuatsi), and mud carp (Cirrhinus molitorella) polyculture and their effects on growth performance, water quality, antioxidant, and nonspecific immunological capacity

Paradiplozoon cirrhini n. sp. (Monogenea, Diplozoidae), a gill parasite of Cirrhinus molitorella (Cyprinidae, Labeoninae) in South China.

Paradiplozoon cirrhini n. sp. (Monogenea, Diplozoidae) is described from the gills of mud carp, Cirrhinus molitorella (Valenciennes, 1844) (Cyprinidae, Labeoninae), collected in Wuzhou, Guangxi Province, and Conghua, Guangdong Province as part of an ongoing survey of the diplozoid fauna in the Pearl River basin of China. The new Paradiplozoon species is distinguished from congeners by the structure of median plate and its outgrowth sclerites. The ITS2 sequences of the new species differ from all known available diplozoid sequences by 22.04%-38.34%. The new species is the first diplozoid species parasitic on Labeoninae in China. Molecular phylogenetic analyses using rRNA ITS2 placed Paradiplozoon cirrhini n. sp. in a sister position to the other Chinese Paradiplozoon, implying that Labeoninae represents an early and potentially ancestral host group for China Paradiplozoon. We also provided ITS2 sequences for four other diplozoids species, namely P. megalobramae Khotenovsky, 1982, P. saurogobionis (Jiang, et al., 1985) Jiang, Wu & Wang, 1989, Sindiplozoon hunanensis Yao & Wang, 1997, and Sindiplozoon sp., and validated their phylogenetic position. The results confirm that all diplozoid species are spilt into two major clades and show monophyly of Sindiplozoon but paraphyly of Paradiplozoon.

Sex-specific markers developed by 2b-RAD and genome sequencing reveal an XX/XY sex-determination system in mud carp (Cirrhinus molitorella)

Sex-specific markers are a powerful tool for studying sex-determination mechanisms and sex-control breeding in aquaculture. Mud carp (Cirrhinus molitorella) is one of the most important edible fishes in South China and Southeast Asia, and its processed products, such as tinned foods, have a high market value. The age of first maturation for mud carp is often three years. However, the sex-determination mechanism of mud carp is still unclear, which has affected its genetic breeding and culture industrial development. In this study, we identified sex-specific markers by 2b-RAD and genome sequencing in mud carp. The whole genome of a male mud carp was sequenced, and the total size of the draft genome was 1078.7 Mb. Nine males and nine females were subjected to 2b-RAD sequencing, and 12 male-specific scaffolds were isolated. Primers were designed based on these male scaffolds, and five male-specific markers from five scaffolds successfully discriminated males from females in the broodstock populations with 100% accuracy. Furthermore, five male-specific SNPs were identified and verified by Sanger sequencing, and all of them showed female homogamety and male heterogamety. These results indicate that mud carp has a male-heterogametic XX/XY sex-determination system. To the best of our knowledge, this is the first report of practical sex-specific markers in this species. Our results will contribute to elucidating the genetic basis of sex determination and improving the efficiency of genetic breeding in mud carp.

Efficacy of Matrine, Rotenone, and Pyrethrin Against Red Imported Fire Ant Solenopsis invicta (Hymenoptera: Formicidae) and Their Impact on Aquatic Organisms.

Chemicals, including toxic bait and dusts, are the main means of controlling the red imported fire ant Solenopsis invicta (abbreviation 'RIFA'), which is a serious invasive pest. To identify environmentally friendly chemicals for controlling RIFA, we tested the toxicity and horizontal transfer of three botanical insecticides-matrine, rotenone, and pyrethrin-and their impact on aquatic organisms (i.e., three fish and one shrimp). The LD50 value of matrine, rotenone, and pyrethrin was 0.24, 50.929, and 13.590 ng/ant, respectively. Matrine, rotenone, and pyrethrin had effective horizontal transfer and caused significant secondary mortality. After exposure to donor workers, 90.75%, 90.75%, and 100% of recipient workers in the 0.025% matrine, 1.0% rotenone, and 0.3% pyrethrin dust treatments, respectively, died within 48 h. Furthermore, 0.025% matrine dust caused significant tertiary mortality (49.5%). Tertiary mortality caused by 1.0% rotenone and 0.3% pyrethrin dusts was very low, only 7.75% and 18.5%, respectively. In a field trial, the comprehensive mortality effect of 0.05% matrine, 1.50% rotenone, and 0.375% pyrethrin dust was 74.96%, 30.10%, and 29.27%, respectively, after 14 d of treatment. Matrine had low toxicity to the fish Hypophthalmichthys molitrix, and 37.5 mg/L pyrethrin had low toxicity to the fish Cirrhinus molitorella, H. molitrix, and Oreochromis niloticus. However, rotenone was highly toxic to all three fish. The shrimp Neocaridina denticulate was not sensitive to matrine, rotenone, or pyrethrin. Matrine dust has highly effective horizontal transfer, and 0.05% matrine dust has great potential for managing RIFA in organic farms, aquaculture farms of H. molitrix, and water resource regions.

Characterization of structures and gel properties of ultra-high-pressure treated-myofibrillar protein extracted from mud carp (Cirrhinus molitorella) and quality characteristics of heat-induced sausage products

This study aimed to understand the effects of ultra-high pressure (UHP) treatment on the protein structures and gel properties of myofibrillar protein (MP), and the secondary structure and quality of sausage gels developed by Cirrhinus molitorella. MP was treated with 100, 200, and 300 MPa for 3, 9, and 15 min separately. Observations suggested that UHP treatment improved MP aggregation α-helix and β-Sheet converted to random coil in MP structures as pressure increased. Myosin heavy chain (180 kDa) and actin (48 kDa) are the most important protein bands in C. molitorella MP. When the pressure reached to 300 MPa for 9 min during UHP-thermal processing, the gel strength, water holding capacity, and the chewiness and hardness of fish sausage gels reached to the peak value of 1,296.8 g cm, 83.60%, 3864.02 g/mm and 2169.94 g, respectively. 300 MPa for 9 min was the optimum UHP condition to modify the conformation to improve gel properties of MP, and to improve the quality characteristics of heat-induced sausage gels. Collectively, UHP had the potential in expanding the application of fish protein in food industry by modifying MP structure, as well as in developing novel fish products.

Epidemiological characterization of Clonorchis sinensis infection in humans and freshwater fish in Guangxi, China

BackgroundClonorchiasis is a widespread yet neglected foodborne disease with over 85% of all cases found in China. Guangxi province, located in southeastern China, ranks among the highest endemic provinces. We explore the epidemiological status and determinants of Clonorchis sinensis (C. sinensis) infection in humans and freshwater fish in Guangxi, China.MethodsData on C. sinensis infection in humans from January 2008 to December 2017were extracted from the China Information System for Disease Control and Prevention. An active surveillance of C. sinensis infection in fish was conducted in 2016–2017. County level data including potential environmental, social-economical and behavioral determinants was also collected. Univariate and multivariate logistic regression models were used to explore the determinants of C. sinensis infection in humans and fish. Simple and multiple zero-inflated Poisson regression models were fit to assess the associated factors of clonorchiasis in humans at the county level.ResultsTotally, 4526 C. sinensis cases were reported between 2008 and 2017, with an annual prevalencerate of 0.96/100,000 persons. Of 101 counties in Guangxi, 97 reported at least 1 case. Among 2,098 fish samples, 203 (9.7%) from 70 counties contained C. sinensis. The rate was higher in small fish including Pseudorasbora parva (45.3%), Misgurnus anguillicaudatus (41.2%), Hemicculter leuciclus (34.5%), unclassified small fishes (30.9%), Cyprinidae (20.0%), Cirrhinus molitorella (16.4%), Carassius auratus (13.6%) and Cyprinus carpio (13.3%), while it was lower in fish species that are usually used in preparing raw fish dishes including Ctenopharyngodon idellus (3.6%), Spinibarbus denticulatus (3.7%), Monopterus albus (6.4%), Cyprinus carpio (4.4%), Oreochromis mossambicus (3.3%) and Spualiobarbus Curriculus (6.6%). The C. sinensis infection in fish was only associated with fish species. The estimated human clonorchiasis prevalence at the county level was positively associated with raw fish consumption habits and certain rivers.ConclusionsClonorchiasis is highly prevalent in both humans and freshwater fish in Guangxi. Environmental, social-economic and behavioral determinants contribute to the high prevalence as well as the significant differential distribution by county. Regular surveillance should be implemented for clonorchiasis to demonstrate the change in epidemiology and burden, which will benefit the design of interventions.

Colonization of Lactobacillus rhamnosus GG in Cirrhinus molitorella (Mud Carp) Fingerling: Evidence for Improving Disease Resistance and Growth Performance

The use of probiotic bacteria can not only enhance the nutritional utilization of fish feeds to produce more biomass but can also provide a practically “safer” alternative to the fish farming industry to reduce the abuse of antibiotics and drugs. This study investigated the possibility of colonizing Lactobacillus rhamnosus strain GG (LGG) to the intestine of Cirrhinus molitorella (mud carp) fingerling. Colonization of LGG was observed in gut tissue after 14 days of administration with a diet supplemented with 1 × 108 CFU/mL LGG. Moreover, growth performance parameters of the LGG-supplemented diet group, including relative weight gain, feed conversion ratio and feed efficiency, were found about two-fold higher than the control group after 60 days. In addition, fish fed with an LGG-supplemented diet for 60 days showed substantial resistance against the infection of pathogenic bacterial Aeromonas hydrophila, with a relative survival rate of up to 57% compared to the control group. In summary, the results indicated that LGG as dietary supplement for mud carp fingerling can enhance nutrition utilization and better protect fish against the infection of Aeromonas hydrophila. The results provide an insight to the fish farming industry, encouraging a reduction in the use of antibiotics and drugs and the production of “safer” mud carp for the market at a manageable cost.

Predator-Prey Interactions between Nonnative Juvenile Largemouth Bass (Micropterus salmoides) and Local Candidate Prey Species in the Pearl River Delta: Predation Capacity, Preference and Growth Performance.

An ontogenetic dietary shift is crucial for the survival and growth of piscivorous largemouth bass (LB). However, there is much to learn about the predator-prey interaction during the switching process. We carried out a series of indoor experiments to examine the predation capacity, predation preference, and growth performance of exotic juvenile LB feeding on candidate prey species in the Pearl River Delta. The widely distributed oriental river prawn (Macrobranchium nipponense), barcheek goby (Ctenogobius giurinus), western mosquitofish (Gambusia affinis), silver carp (Hypophthalmichthys molitrix), and mud carp (Cirrhinus molitorella), with relatively similar total lengths, were selected as potential prey based on their availability and habitat use. Our results show that predation capacity and preference varied quantitatively and qualitatively among prey species. The number of oriental river prawns killed was significantly less than that of fish species, comparing the 1st hour with the 24th hour (p < 0.01). The feeding rhythm of LB varied significantly from crayfish to fish. Numerically, Jacobs’ selection index reinforced LB’s special preference for predating G. affinis. Although there were obvious variations in predation capacity and feed selection, no statistically significant growth differences were detected among LB groups feeding on live M. nipponense, G. affinis, H. molitrix, and C. molitorella (p < 0.05). These findings suggest that the successful ontogenetic dietary shift of juvenile LB may depend on the availability and vulnerability of local fish species. Further study on the reproductive phenology of potential fish prey may help to predict LB’s establishment.

Characteristics and differences of microplastics ingestion for farmed fish with different water depths, feeding habits and diets

Microplastics have become a potential hazard to the quality and safety of aquatic products although there are few reports on microplastics distribution related to water depth, feeding habits and diets in aquaculture ponds. In this study, five aquaculture fish species (Ctenopharyngodon idella, Hypophthalmichthys molitrix, Cirrhinus molitorella, Oreochromis niloticus and Pelteobagrus fulvidraco) were selected and their accumulation of microplastics was measured and classified. We found that the water depth, feeding habits and diets led to large differences in microplastics accumulation. The bottom-dwelling omnivorous fish had the largest ingestion of microplastics and ranked as P. fulvidraco>O. niloticus>C. molitorella，the herbivore C. idella in the middle benthic layer and the upper-layer filter-feeder H. molitrix had the lowest ingestion. The detection frequency in the gastro-intestinal tracts for C. idella, H. molitrix, C. molitorella, O. niloticus, and P. fulvidraco were 93.33%, 91.67%, 87.50%, 92.86%, and 90.91%, and detection frequencies for gills were 86.67%, 100%, 87.5%, 100%, and 81.82%, respectively. Fibers presented the dominant shape (91.92%) and blue was the primary particle color in the majority of the samples (77.39%) and 0.5–2 mm particles dominated. The plastics were composed of olefins, acrylic, rayon, polyester, polyethylene and polypropylene. Our study first reported the relationship between MPs accumulation and water depth, feeding habits and diets in aquaculture ponds, which also has a certain correlation with the fish size.

Indigenous Fish-Based Assessment of Genotoxic Potentials of the Helong Reservoir in Guangzhou, China.

The present study was conducted to assess the genotoxic potential of water from the Helong Reservoir, which was designated as a strategic drinking water source by the Guangdong Provincial Government of China in October 2016. Four kinds of common indigenous fish samples (Labeo rohita, Cirrhinus molitorella, red tilapia, and Oreochromis niloticus) were collected at 6 sampling sites during the period from July to November 2020. Fish from the clean drinking water source of the upper reaches of the Liuxihe Reservoir in Guangzhou were collected as the control. Both the alkaline single cell gel electrophoresis assay and the micronucleus test were used to detect DNA damage and the micronucleus rate in erythrocytes of fish samples, respectively. The results indicated that there was a significant increase in comet tail length, Olive tail moment, and micronucleus rates of all fish samples compared with those of the control (p < 0.05). The order of sensitivity to DNA damage and micronucleus formation was Labeo rohita > Cirrhinus molitorella > red tilapia > Oreochromis niloticus. The results of the 2 kinds of experiments were in perfect agreement with each other. We conclude that there are obvious genotoxic effects from the water in the Helong Reservoir. As a strategic drinking water source, the safety of the Reservoir water quality should be considered. The local government should put the restoration of the Helong Reservoir water quality on the agenda as soon as possible. Environ Toxicol Chem 2021;40:1919-1927. © 2021 SETAC.

Developmental morphology and growth in early stages of laboratory-reared Cirrhinus molitorella and C. microlepis (Cypriniformes: Cyprinidae)

The morphological developments in laboratory-reared larval and juvenile Cirrhinus molitorella and larval C. microlepis were described, and ontogenies (including yolk sizes and absorptions, fin-ray and myomere numbers, allometric changes in the snout, upper jaw, head and pre-anal lengths, maximum body depth, eye diameter and melanophore distributions) were compared. Body lengths (BL) just after hatching were smaller in C. molitorella [3.3 ± 0.1 (mean ± SD) mm] than in C. microlepis (4.4 ± 0.1 mm), and subsequent increase in body lengths were slower in C. molitorella than in C. microlepis. Yolk sizes just after hatching were correspondingly smaller in C. molitorella than in C. microlepis and the yolks were completely absorbed by ca. 95 hours after hatching in the former and ca. 118 hours in the latter. In C. molitorella, fin-rays started appearing at a smaller size than in C. microlepis, with full complements attained by 14.4 mm BL (day 35) in the former, while they did not attain by 16.4 mm BL (day 20) in the latter. Allometric changes started in smaller sizes in C. molitorella than in C. microlepis. Total myomeres were 38–41 in C. molitorella and 39–43 in C. microlepis. Melanophore distributions progressed similarly in both species, except for a darker deposition on the caudal peduncle of C. molitorella of ca. 7–10 mm BL. Larvae of these species were identifiable mainly by differences in fin-ray numbers and allometries by size.

Laboratory study on fish behavioral response to meandering flow and riffle-pool sequence driven by deflectors in straight concrete flood channels

Sectional channelization of natural rivers for flood mitigation causes discontinuity of the riverine corridor, leading to unfavorable conditions for fish movement in the longitudinal direction. To minimize the negative effects, hydraulic structures (e.g. deflectors) are proposed as potential restoration measures in concrete flood channels. In this study, indoor flume experiments were carried out to assess the variation of flow field (velocity magnitude, turbulent kinetic energy, and Reynolds stress) and bed morphology with the inclusion of deflectors. The flow and sediment regimes were then compared in the presence or absence of deflectors. The experimental results indicated that deflectors triggered a non-uniform flow pattern and stimulated riffle-pool sequence formation through local scouring and subsequent deposition. To better understand the response of predaceous chub (Parazacco spilurus) and mud carp (Cirrhinus molitorella) to deflectors, fish trajectories, distribution, and number of transits were analyzed using a video monitoring system. The results suggested that fish responded differently to the baseline (without deflector) and deflector scenarios: (1) fish struggled against the oncoming current when crossing the physical barrier in the channelized section; (2) fish moved and rested in the diverse habitats created by deflectors. Additionally, the presence of sediments in the channel bed was essential in attracting fish to the channelized section. Therefore, it was concluded that using deflectors at appropriate intervals and allowing the existence of sediments in flood channel sections can benefit fish movement and enhance channel naturalization.

Characterization and spatial distribution of microplastics in two wild captured economic freshwater fish from north and west rivers of Guangdong province

As a new type of pollutant, microplastics are of emerging widespread concern, while amount of research done in freshwater environments and organisms is litter compared to that in marine. Following this reality, the categories of MPs in two economic freshwater fish at 25 sites from 11 cities in the north and west rivers of Guangdong province were documented. Here, 76 individuals belong Oreochromis niloticus and Cirrhinus molitorella were investigated and microplastics were found in the GITs of 43.4% and gills of 25%. The average abundances of microplastics have significant difference between Oreochromis niloticus (0.015 items/ g) and Cirrhinus molitorella (0.031 items/g), while no difference by individual (~1.9 items). The plastics were dominated by white in color (61%), fragment in shape (67%), and lass than 1 mm in size (74%). The spatial distribution of microplastics revealed that there are significant differences between different cities in average abundances, and the highest average abundances of MPs were found in Zhanjiang city (4.25 items/individual) and Guangzhou city (0.044 items/g), respectively. Our results fully proved that the microplastics was widely ingested by wild fish species and suggested that the abundance and distribution of microplastics are positively related with the development of economy, tourism, industry, agriculture, and fishery.

Distributions of and Correlations between Cd, Cr, and Hg Concentrations in Suspended Particles and Sediment in Aquaculture Ponds and in Cirrhinus molitorella Tissues

Distributions of and Correlations between Cd, Cr, and Hg Concentrations in Suspended Particles and Sediment in Aquaculture Ponds and in Cirrhinus molitorella Tissues

Freshwater fish biodiversity in the Leizhou Peninsula of China

Leizhou Peninsula is located in the Indo-Burma biodiversity hotspot. However, information about freshwater fish species in this peninsula is very scarce. Based on surveys and a literature review, a total of 100 freshwater fish species (92 native and eight non-native) within seven orders, 21 families and 70 genera, have been recorded in the Leizhou Peninsula. Four species, Mud Carp (Cirrhinus molitorella), common carp (Cyprinus carpio), South Sharpbelly (Pseudohemiculter dispar), and Helmet Catfish (Cranoglanis bouderius) are listed as threatened species in red list of IUCN. Sand mining, aquaculture pollution, non-native aquatic species, and overfishing are the greatest threats to freshwater fish biodiversity of Leizhou Peninsula. For better sustainable development, conservation efforts should be focused on the establishment of protected areas, improvement of sustainable fishery management and control of non-native species. This study provides management recommendations that will be useful for freshwater fish biodiversity conservation and fishery management in Leizhou Peninsula.

Organophosphorus flame retardants in fish from Rivers in the Pearl River Delta, South China

Twelve organophosphorus flame retardants (PFRs) were detected in the muscle of 3 species of fish, mud carp (Cirrhinus molitorella), tilapia (Tilapia nilotica), and plecostomus (Hypostomus plecostomus), from rivers in the Pearl River Delta (PRD) region. The total concentrations of PFRs in the mud carp, tilapia, and plecostomus ranged from 2.3 to 16, 3.4 to 16, and 3.5 to 30 ng/g wet weight (ww), respectively. Generally, tris(2-ethylhexyl) phosphate (TEHP), tris (2-chloro-isopropyl) phosphate (TCPP), tris (2-chloroethyl) phosphate (TCEP), and tri-n-butyl phosphate (TnBP) were the dominant compounds of the PFRs, collectively accounting for up to 90% of the total PFR levels. Concentrations of PFRs were significantly higher in the plecostomus than in the mud carp and tilapia (p < 0.05), which could be explained by differences in habitat and feeding habits of the fish species. High concentrations of PFRs were found mainly in the Guangzhou section of the Pearl River (site P1, P2, and P3) and site B3, which was similar to our previous study of PFRs in sediment from the Pearl River Delta, indicating a relatively high level of PFRs pollution in these regions. The estimated daily intake (EDI) of total PFRs from consumption of fish was 17 ng/kg bw/day to 98 ng/kg bw/day for adults and children, which was three to four orders of magnitude lower than reference dose values.

The current distribution of invasive mrigal carp (Cirrhinus mrigala) in Southern China, and its potential impacts on native mud carp (Cirrhinus molitorella) populations

Invasive species are a major and growing threat to China’s native freshwater biodiversity. They have caused species extinctions, biodiversity loss, and environmental changes. Mrigal carp (Cirrhinus mrigala), one of the most widespread and invasive of freshwater fish species, now occurs in major rivers throughout southern China. We report the current (to 2017) distribution of mrigal carp throughout southern China, and experiments with temperature, water quality and food availability, that assess possible impacts of this species on populations of native mud carp (C. molitorella)”. In the wild, the mud carp to mrigal carp weight ratio was 1:1.65. Mrigal carp were a dominant species in some rivers of southern China, such as Liuxi River, Zengjiang River and the Zhaoqing section of Xijiang River. Manipulative experiments reveal mrigal carp to be more tolerant of colder temperature, more eutrophic conditions, and lower dissolved oxygen levels than mud carp. In food-limited experiments, mrigal carp displayed no direct aggression towards mud carp, but they did snatch food from them, and excluded them from eating. Mud carp growth was curtailed in the presence of mrigal carp in food-limited treatments, with a growth rate 2.71%, only 17.02% of that in treatments where carp were fed to satiation. In satiation treatments, mrigal carp also grew up to 2.21 times faster than mud carp. Our results indicate that mrigal carp will outcompete mud carp for resources and habitat, and that both its distribution and population will increase in the future.

Effect of drying temperature and presalting methods on the quality and N-nitrosamine formation of dried mud carp (Cirrhinus molitorella )

Effect of drying temperature and presalting methods on the quality and N-nitrosamine formation of dried mud carp (<i>Cirrhinus molitorella</i> )