Carp Reproduction Research Articles

Rearing of European catfish (Silurus glanis L.) in earthen ponds in polyculture with common carp larvae (Cyprinus carpio L.)

The aim of the present study is the production of stocking material of European catfish (Silurus glanis L.) using common carp larvae (Cyprinus carpio L.) as natural food source. The experiment was carried out in two earthen ponds (№18 and №19). The stocking material was produced through semi-artificial reproduction of European catfish and natural reproduction of common carp in two stages. The main aquaculture production indicators of the stocking material of European catfish and common carp were calculated: growth (WG, g), survival (%), total yield (kg) and average yield (kg/1000 m2). The obtained results show that the growth of European catfish in pond №19 is 69.67 g, while in pond №18 it is 58.91 g. Also, the survival rate in pond №19 is 2.8 times higher than in pond №18. After analyzing the obtained results, it can be concluded that the production indicators of the European catfish stocking material are higher in experimental pond №19.

Reproduction of grass carp (Ctenopharyngodon idella) in the Maumee River, Ohio: Part 2—Optimal river conditions for egg and larval drift

This study uses a one-dimensional steady-state hydraulic model and the Fluvial Egg Drift Simulator (FluEgg) to model the drift and dispersion of grass carp eggs and larvae in the Maumee River, Ohio, for 180 scenarios representing different combinations of 10 river flows, 6 water temperatures, and 3 spawning locations. The FluEgg simulations were used to quantify in-river suspended hatching rates (the percentage of eggs that hatch within the river and in suspension) and in-river larval retention rates (the percentage of larvae that reach the gas bladder inflation stage within the river after hatching in suspension), and identify which scenarios produce the highest likelihood of recruitment. The simulations indicate that at low flows, in-river suspended hatching and larval retention rates in the Maumee River are limited by the capacity of the flow to keep fertilized eggs in suspension, whereas at high flows, the limiting factor is the distance available for the eggs/larvae to drift in the river. A wide range of scenarios result in eggs hatching within the river, but all larvae drift into Maumee Bay prior to the gas bladder inflation stage when flows exceed the mean annual flow. The simulations were assessed in the context of the hydraulic conditions that trigger spawning and maximize egg fertilization and the nursery habitat requirements for larval grass carp. The results indicate that the Maumee River, although suitable for grass carp spawning, may not be an ideal setting for recruitment unless Maumee Bay provides adequate nursery habitat for larvae.

Review of Central-Eastern European Propagation and Larvae Nursing Method for Common Carp (Cyprinus carpio L.).

Common carp (Cyprinus carpio L.) as a cultivated fish species has huge importance all over the world. According to FAO statistics, carp is the third most widely bred freshwater pond fish species; only two other Cyprinids (silver carp and grass carp) are bred in higher amounts. Carp is native all over Asia and in a large part of Europe. As a result of human intervention, at present, carp are widespread all over the world, except for the Arctic region. Carp breeding was launched in the antique period, in the ancient Chinese Empire and the Roman Empire. The presently applied method of breeding of common carp has a long evolution. From the effectiveness point of view, the propagation and early-life nursing are crucial parts of carp production, as they provide seed stocks for the further growing section. Without effective propagation, there is no intensive carp production. Nowadays, more advanced propagation methods are available all over the world; however, in the current review, only the main milestones and production efficiency of the propagation and nursing method used in the ponds of Eastern Central Europe are discussed. In the historical overview of carp reproduction, first the natural reproduction, then the semi-extensive and intensive hatchery propagation are presented and investigated in detail. The analysis focuses on the advantages and disadvantages of the method. In particular, the different important milestones of the advanced hatchery method are shown and explained. The effectiveness is proven even with practical calculations. Not only the reproduction, but the pond nursing method is also presented and discussed, concentrating on the management of evolutionarily adapted natural feeds (Zooplankton) and their effect on the survival of fish larvae.

Polyethylene microplastics cause apoptosis via the MiR-132/CAPN axis and inflammation in carp ovarian

Microplastics (MPs) are widely distributed pollutants in the environment and accumulate in the aquatic environment due to human activities. Carp, a common edible aquatic organism, has been found to accumulate MPs in body. MicroRNA (miRNAs) is a non-coding short RNA that regulates protein expression by binding to target genes in various physiological processes such as proliferation, differentiation and apoptosis. The ovary is a crucial role in carp reproduction. In this study, we established a model of carp exposed to polyethylene microplastics (PE-MPs) in the aquatic environment to investigate the specific mechanism of PE-MPs causing ovarian injury and the involvement of miR-132/calpain (CAPN) axis. H&E stained sections revealed that PE-PMs induced inflammation in ovarian tissues and impaired oocyte development. TUNEL analysis showed an increased rate of apoptosis in ovarian cells treated with PE-PMs. RT-PCR and Western Blot assays confirmed that exposure to PE-MPs significantly decreased miR-132 expression while increasing CAPN expression at both mRNA and protein levels. The concentration of calcium ions was significantly increased in tissues, leading to CAPN enzyme activity increase. The expression of mitochondrial damage-related genes (bax, AIF, cyt-c, caspase-7, caspase-9, and caspase-3) was higher while the expression of anti-apoptotic genes (bcl-2 and bcl-xl) was lower. Protein levels of bax, AIF, caspase-3, bcl-2 and bcl-xl changed accordingly with the genetic alterations. Additionally, we discovered that PE-MPs can activate the p65 factor through the TRAF6/NF-kB pathway resulting in elevated production of pro-inflammatory factors IL-6, IL-1β and TNF-a which contribute to ovarian inflammation development. This study investigates the impact of PE-MPs on carp ovarian function and provides insights into miRNAs' role and their target genes.

Экологическая эффективность мер по сохранению водных биоресурсов и среды их обитания: аспекты правового и экономического анализа

Based on the analysis of the regulatory framework and economic assessments, the ongoing measures to prevent and minimize damage to aquatic biological resources, as well as their natural habitat, are analyzed. On the example of the Amur Region, it is shown that the selected measures related to the artificial reproduction of carp are not effective and require significant adjustments.

Fish reproduction in Krasnoarmeysk district of Saratov region in 2022

One of the main factors influencing the efficiency of reproduction of limnophilic fish is the height of water level and the duration of spring flood with uniform water heating. Work was carried out to assess the natural reproduction of fish in the area of the middle zone of the Volgograd reservoir, near the villages Akhmat and Zolotoye, Krasnoarmeysk district, Saratov region, in 2022. In total, juveniles of 11 fish species were caught in the surveyed areas in 2022. There is a significant decrease in species diversity compared to previous years. Due to the unfavorable level regime during the spawning period, very unfavorable conditions for the reproduction of fish have developed in 2022. For the first time in 6 years of research in the waters under consideration, it was possible to record the reproduction of catfish (Silurus glanis) and carp (Cyprinus carpio). In 2022, in the area near Akhmat village, an anomaly was observed: underyearlings of bleak (Alburnus alburnus), which usually dominates catches, and perch (Perca fluviatilis), which is also common in this area, were absent in the catches (despite the fact that individuals of these fish of older ages were encountered). In the water area near Zolotoye village still recorded the reproduction of Black Sea-Caspian sprat (Clupeonella cultriventris), the early larvae of which are common there in the catches and are not found in the water area near Akhmat village. In the water area near Zolotoye village underyearlings of asp (Aspius aspius) are still common, and they dominate the catches in 2022. In the water area near Akhmat village, the catches of 2022 are dominated by crucian carp (Carassius gibelio).

Grass Carp Reproduction in Small Tributaries of Harry S. Truman Reservoir, Missouri: Implications for Establishment in Novel Habitats

AbstractSubstantial work has been conducted to estimate the river length required for recruitment of invasive Grass Carp Ctenopharyngodon idella and bigheaded carps (Bighead Carp Hypophthalmichthys nobilis and Silver Carp H. molitrix); however, the distance upstream and size of stream required for spawning remain unclear. Adult Grass Carp are regularly captured in Harry S. Truman Reservoir, Missouri, although there have been only unconfirmed sightings of Silver Carp. Fertile diploid Grass Carp are used legally for vegetation control in Missouri; however, it is uncertain whether Grass Carp in Harry S. Truman Reservoir are the result of natural reproduction or escapees. We used ichthyoplankton tows and environmental DNA (eDNA) to investigate which carp species were present in the reservoir basin and to determine whether these carps were spawning in reservoir tributaries. Grass Carp eggs were collected in four of five tributaries during June 2014. We did not detect eggs, larvae, or eDNA of Bighead Carp or Silver Carp. The occurrence of Grass Carp eggs generally coincided with rapid increases in discharge and turbidity. These tributaries may be the smallest rivers worldwide in which spawning of Grass Carp has been documented. We infer from the developmental stages captured and the distance from the reservoir that sufficient river length exists for egg survival. These results have broad implications concerning the establishment of Grass Carp in other novel habitats, including other reservoirs and lake basins, smaller rivers, and the Laurentian Great Lakes ecosystem.

Common carp reproduction in winter using heated water in temporal climate of Uzbekistan

In December 2022, 10 females and 2 males of common carp (Common carp) from ponds (water temperature 10°C) were placed in RAS pools and 2 females and 2 males (control group) were placed in an open pond in Uzbeki-stan. In January, the water temperature was increased by 1°C in two days in the RAS for two weeks. Since January 20, the water temperature was 22-24°C for two weeks. The fish had weigh 2950 – 3980 (average 3235) g. From February 3th, 4 females and 2 males were injected with the pituitary gland according to the routine methods and ripe eggs and milt were obtained, ripe eggs (920 g) were incubated in Zuger apparatus. Fertility was 90%, Feb-ruary 7th, the beginning of hatching of the larvae was determined. The yield of larvae from eggs was 64%. Injected at the same time, 2 females and 2 males from the control group of carp did not produce ripe eggs and milt at all.

Artificial reproduction of royal carp (Cyprinus carpio)

The aim of this study was to establish an experimental protocol for the artificial reproduction of royal carp ‘Cyprinus carpio’ with the hormonal induction of spawning. For this purpose, we conducted this study at an aquaculture farm in Khemis Meliana (Ain Defla, Algeria). The study included six royal carp broodstock, 4 females and 2 males. Hormone injection was performed in the dorsal muscle under the fin. The induction of carp was done successively in females by GnRH at a dose of 3 mg/kg and in males by hCG at a dose of 500 IU per kg weight. Fertilisation was done artificially by the dry method. After incubation of eggs, a binocular magnifying glass was used to check the condition of eggs and the development of the embryos over time. The results obtained show that the artificial reproduction of this species was possible, with success of ovulation and fertilisation, and hatching and growth of the larvae. Stripping was done after 24 h of hormonal stimulation at a temperature of 21°C. Disaggregation of eggs was performed efficiently with whole milk. The total number of eggs was 552,000 eggs with a weight of 1104 g. The average latency time was 22 hours. The hatching rate after 3 days of incubation on artificial spawning grounds at 21±1°C was 441,600 larvae (80%). Larvae food follow-up started from the 3rd day post-hatching with a combination natural food (rotifers) and artificial food. At the end of this experiment, we can conclude that it is possible to improve reproduction through the proper use of hormonal stimulation techniques and by improving feeding and abiotic factors that are dominant in fish farming.

Establishment of invasive Black Carp (Mylopharyngodon piceus) in the Mississippi River basin: identifying sources and year classes contributing to recruitment

Black Carp (Mylopharyngodon piceus) was imported to the USA to control aquaculture pond snails. This species has escaped captivity and occurs in parts of the Mississippi River, several tributaries, and floodplain lakes, which is concerning due to potential competition with native fishes and predation on native mussels, many of which are imperiled. However, Black Carp captures have primarily been incidental by commercial fishers, and evidence of reproduction in the wild is limited. The objectives of this study were to assess relative abundance of aquaculture-origin and wild Black Carp using ploidy and otolith stable isotope analysis, identify spatial extent of natural reproduction using otolith microchemistry, assess age distributions of wild and aquaculture-source Black Carp to infer years in which natural reproduction occurred and timing of aquaculture escapement or introductions, and estimate size and age at maturation to assess whether recruitment to adulthood has occurred. Results revealed that Black Carp are established in parts of the Mississippi River basin based on findings that: (1) non-captive Black Carp primarily consist of fertile, naturally-reproduced fish, (2) reproduction has occurred in several rivers, (3) multiple year classes of wild fish are present, and (4) wild fish have recruited to adulthood. Multiple introductions or escapements of aquaculture-source fish into the wild, including both fertile and functionally sterile individuals, were also inferred. Individual growth appears to be rapid, although considerable variation was observed among fish. Additional study is suggested to refine understanding of where and when Black Carp reproduction is occurring in the Mississippi River basin.

In vivo and in vitro aging of common carp Cyprinus carpio sperm after multiple hormonal application and stripping of males

The present study was designed to evaluate sperm phenotypic variables during in vivo and in vitro storage following multiple sperm stripping in common carp (Cyprinus carpio L.). Each male was injected 3 times with carp pituitary 3days apart. Sperm was stored in vivo in the body cavity for 0.5days (Fresh sperm) and 3days (Old sperm) after hormonal stimulation. Then sperm was collected and diluted with a carp extender at a ratio of 1:1, and stored in vitro on ice for 0, 3, and 6days. The phenotypic parameters, including the number of total motile spermatozoa, number of fast motile spermatozoa, number of motile spermatozoa, percentage of fast motile spermatozoa, and percentage of spermatozoa motility were the major components of principal component analysis (PCA). In general, Fresh sperm from the first stripping showed slightly better quality than Old sperm from the second and third stripping, especially in the phenotypic parameters of a number of total spermatozoa and a number of total motile spermatozoa (P < 0.05). The highest kinetic and quantitative spermatozoa variables were obtained in Fresh and Old sperm just after sperm collection (0-day storage in vitro), and then they were decreased during the period of in vitro storage up to 6days (P < 0.05). However, the fertilization, hatching, and malformation rates from Fresh sperm were similar compared with the Old sperm. Sperm could be stripped 0.5days post hormonal treatment and stored in vitro up to 6days with good fertilization performance (fertility, hatching, and malformation rates were 92.5%, 91.5%, and 1.3%, respectively). Therefore, our results suggested that multiple hormonal treatments with multiple stripping could be used in artificial reproduction in common carp.

Tandem Mass Tagging-Based Quantitative Proteomics Analysis Reveals Damage to the Liver and Brain of Hypophthalmichthys molitrix Exposed to Acute Hypoxia and Reoxygenation.

Aquaculture environments frequently experience hypoxia and subsequent reoxygenation conditions, which have significant effects on hypoxia-sensitive fish populations. In this study, hepatic biochemical activity indices in serum and the content of major neurotransmitters in the brain were altered markedly after acute hypoxia and reoxygenation exposure in silver carp (Hypophthalmichthys molitrix). Proteomics analysis of the liver showed that a number of immune-related and cytoskeletal organization-related proteins were downregulated, the ferroptosis pathway was activated, and several antioxidant molecules and detoxifying enzymes were upregulated. Proteomics analysis of the brain showed that somatostatin-1A (SST1A) was upregulated, dopamine-degrading enzyme catechol O methyltransferase (COMT) and ferritin, heavy subunit (FerH) were downregulated, and the levels of proteins involved in the nervous system were changed in different ways. In conclusion, these findings highlight that hypoxia–reoxygenation has potential adverse effects on growth, locomotion, immunity, and reproduction of silver carp, and represents a serious threat to liver and brain function, possibly via ferroptosis, oxidative stress, and cytoskeleton destruction in the liver, and abnormal expression of susceptibility genes for neurodegenerative disorders in the brain. Our present findings provide clues to the mechanisms of hypoxia and reoxygenation damage in the brain and liver of hypoxia-sensitive fish. They could also be used to develop methods to reduce hypoxia or reoxygenation injury to fish.

The role of hydraulic and geomorphic complexity in predicting invasive carp spawning potential: St. Croix River, Minnesota and Wisconsin, United States.

Since they were first introduced to the United States more than 50 years ago, invasive carp have rapidly colonized rivers of the Mississippi River Basin, with detrimental effects on native aquatic species. Their continued range expansion, and potential for subsequent invasion of the Great Lakes, has led to increased concern for the susceptibility of as-yet uncompromised lotic and lentic systems in the central United States. Because invasive carp eggs and larvae must drift in the river current for the first several days following spawning, numerical drift modeling has emerged as a useful technique for determining whether certain river systems and reaches have the potential to support suspension-to-hatching survival of invasive carp eggs, a critical first step in recruitment. Here we use one such numerical modeling approach, the Fluvial Egg Drift Simulator (FluEgg), to estimate bighead carp (Hypophthalmichthys nobilis) egg hatching success and larval retention in a 47.8-kilometer (km) reach of the multi-thread St. Croix River, Minnesota and Wisconsin, United States. We explore three approaches for obtaining the hydraulic data required by FluEgg, parameterizing the model with either (a) field hydraulic data collected within the main channel during a high-flow event, or hydraulic data output from a one-dimensional hydrodynamic model with both (b) steady, and (c) unsteady flows. We find that the three approaches, along with the range of water temperatures and discharge used in simulations, produce vastly different predictions of streamwise transport and in-river egg hatching probability (0% for field data, 0 to 96% for steady-state hydraulic modeling, and 1.8 to 65% for unsteady modeling). However, all FluEgg simulations, regardless of the source of hydraulic data, predicted that no larvae reach the gas bladder inflation stage within the study reach where nursery habitat is abundant. Overall, these results indicate that the lower St. Croix River is suitable for invasive carp spawning and egg suspension until hatching for a range of discharge and water temperatures. These results highlight the role of complex channel hydraulics and morphology, particularly multi-thread reaches, and their inclusion in ecohydraulic-suitability modeling to determine susceptibility of river systems for invasive carp reproduction. Our work also emphasizes the scientific value of multi-dimensional hydrodynamic models that can capture the spatial heterogeneity of flow fields in geomorphically complex rivers. This work may help to guide management efforts based on the targeted monitoring and control and improve invasive carp egg and larvae sampling efficiency.

До апробації галицького масиву коропа

Purpose. To evaluate the reproductive indicators and exterior characteristics of the breeding brood stock of the Galician carp group at the original farms, namely farms "Korop" and "Dzherelo", State Enterprise "Lviv Experimental Station". Methodology. The study was conducted according to generally accepted methods in fish farming and breeding using statistical processing and data analysis. The productive features of the Galician carp were improved by the method of mass selection and directional selection. The tasks of the selection were to obtain a breeding stock of the Galician group, which will ensure the production of offspring with high individual weight in the first year of life. Findings. The age of maturity in brood Galician carp was 3-4 years in males and 4-5 years in females. After pituitary stimulation in the conditions of industrial reproduction, a positive reaction of the brood fish was established, which exceeded 92%. When forming breeding stocks of Galician carp in the first year of life, the intensity of selection was 15%. Directional selection on the basis of average individual weight started on the second year of life. The intensity of selection of age-1+ Galician carp group was 50%, then this parameter exceeded 85%. Reproduction of the Galician carp group occurred in spawning ponds and in industrial conditions. Working fertility of females was 1256.0 ± 132.80 thousand eggs, relative fertility - 127.5 ± 5.52 thousand eggs/kg, which was quite high in comparison with the Ukrainian framed carp. During the reproduction of Galician carp in ponds, the yield of three-day-old larvae from one nest amounted to 241 thousand individuals. According to the obtained data, based on the exterior indicators, the Galician carp group is characterized by a high-backed physique and fleshy structure, which is preserved throughout life. In view of the conducted study, the Galician carp group fully complies with the requirements of the Regulation on approbation of selection achievements in animal husbandry and can be submitted to the relevant authorities for consideration and approval as an intrabreed type of Ukrainian framed and scaly carp breeds. Originality. The analysis of reproductive indicators of the breeding brood stock of Galician carp will serve as a basis for the presentation of this group in the status of intrabreed type and its approval as a selection achievement. Practical value. The obtained results will contribute to the expansion of the Galician carp group both in the aquaculture of Ukraine and abroad. Breeding brood material as an object of selection will be involved in work with framed carp mixes. Key words: breeding, carp, inventory, grading, crossbreeding, organization of spawning, reproduction.

Light Trapping Reveals Multiple Bigheaded Carp Spawns Upstream of Lock and Dam 19 in the Upper Mississippi River

AbstractThe Silver Carp Hypophthalmichthys molitrix and Bighead Carp H. nobilis are two species of invasive bigheaded carp currently invading North American rivers and watersheds. Bigheaded carp were accidentally introduced into the lower Mississippi River basin in the early 1970s and have since invaded many water bodies in the Midwestern United States. Evidence of bigheaded carp reproduction and recruitment in the upper Mississippi River upstream of Lock and Dam 19 (LD19) at Keokuk, Iowa, thought to be a critical constriction point to their upstream establishment, has been limited to a few isolated detections of eggs, larvae, and juvenile life stages since 2012. Therefore, a more comprehensive assessment of bigheaded carp reproduction in this critical management zone was needed. We used quadrafoil light traps (n = 1,387) deployed during May–September 2016–2018 in Pools 17–19 of the Mississippi River to monitor for advanced larval bigheaded carp in low‐velocity habitats. Throughout the sampling period, we captured 1,747 larval and 35 postlarval bigheaded carp (N = 1,782). Bigheaded carp were collected on 15 sampling events that spanned from May 31, 2016, to September 13, 2018, with associated hatch dates estimated to represent 10 unique reproductive events from May 2016 to September 2018. The individual captures and backdated hatch estimates revealed a protracted spawning period of up to seven events in 2016, one event in 2017, and two events in 2018. Bigheaded carp were only captured in Pool 19, possibly due to the drifting requirements for egg maturation and the low‐velocity downstream reach of Pool 19. This research provides confirmation that bigheaded carp spawned upstream of LD19 are capable of transitioning past the yolk sac stage upstream of this bottleneck to more advanced larval stages. Knowledge of reproduction and larval retention and the field‐based evidence of protracted spawning fill critical research gaps needed for the management of bigheaded carp.

Influence of antioxidants on the growth performance, gonadosomatic index and biochemical properties of gonad and fertilization success in koi carp (Cyprinus carpioL.)

Adult koi carp (Cyprinus carpio L.) were fed with feed supplemented with vitamin C at 200 mg/kg feed (T1), 400 mg/kg feed (T2) and 600 mg/kg feed (T3), and vitamin E at 200 mg/kg feed (T4), 400 mg/kg feed (T5) and 600 mg/kg feed (T6) at ad libitum for 60 days. Control (without vitamin inclusion) was also maintained. Observations were made on the growth performance, GSI and biochemical composition of gonads such as crude protein, crude fat, cholesterol and carotenoid once in 15 days. At the end of the experiment, fertilization was done to record the fertilization and hatching rate. The difference in the values was noticed among the male and female koi carp. Fish supplemented with vitamin E at 200 mg/kg feeexhibited higher growth in both male and female fish, and the fertilization rate and hatching rate were also higher in that group, and the values were significantly different (p < 0.05) and showed linear and quadratic trends. Inclusion of vitamin C at 600 mg/kg feed had shown higher lipid and carotenoid contents of female koi carp (p<0.05). Hence, the results revealed that supplementing vitamin C and E in the diet is necessary for the successful reproduction of koi carp.

Bigheaded Carp Spatial Reproductive Dynamics in Illinois and Wabash River Tributaries

AbstractFisheries managers are devoting considerable effort, time, and funding toward limiting the spread of invasive Bighead Carp Hypophthalmichthys nobilis and Silver Carp H. molitrix (hereafter, “bigheaded carps”). A better understanding of factors that influence spatial patterns of bigheaded carp reproduction can help fisheries managers to prevent their spread. To examine factors that influence spatial patterns of reproduction, we sampled ichthyoplankton by using drift nets and push nets in three tributaries of the Illinois and Wabash rivers during March–September 2016–2018. We compared relative abundances of bigheaded carp eggs and larvae among tributaries by using CPUE. Abiotic data were analyzed from individual study tributaries and were pooled among tributaries with substantial versus minimal evidence of bigheaded carp reproduction. In total, 5,689 larval bigheaded carp were captured during three sampling seasons. Of the six study tributaries, we captured the most bigheaded carp larvae in the Sangamon River, followed by the Little Wabash, Embarras, Spoon, Mackinaw, and Vermilion rivers. Based on previous literature, we investigated differences in watershed area, discharge, water temperature, turbidity, and free‐flowing stretches of river in our study tributaries. In general, tributaries with greater relative abundances of bigheaded carp eggs and larvae had larger watersheds, greater discharge, lower Secchi depths (higher turbidity), and longer free‐flowing stretches than those with minimal evidence of reproduction. This study provides a thorough investigation of bigheaded carp reproduction in six large‐river tributaries and will help fisheries managers to better monitor and mediate the spread of these invaders by facilitating the prioritization of potential monitoring locations.

The potency of curcumin and the thyroxine hormone to support the antioxidant activity during reproduction in common carp (Cyprinus carpio L)

In the reproductive period, the female fish experiences an increase in metabolism due to the variety of reproductive activities, including the synthesis of vitellogenin. High metabolic activity with insufficient availability of endogenous antioxidants can increase free radical production. The measurement of free radical levels can be determined by calculating the concentration of malondialdehyde. This study was conducted to know the potency of curcumin and thyroxine hormone supplementation to support the antioxidant activity during the reproduction period. Our study used female broodstock of common carp as the experimental animal. In this study, we used forty female broodstock divided into 8 groups of treatment. The results showed that supplementation of curcumin and thyroxine hormone during the reproduction period has the potency to support the antioxidant activity.

Suitability of an Upper Mississippi River Tributary for Invasive Carp Reproduction

AbstractInvasive carp are expanding throughout the upper Mississippi River basin and are of great concern due to their potential economic and ecological impacts. Identification of spawning locations provides critical information on recruitment sources to evaluate potential management strategies. Our objective was to create and validate a spawning habitat suitability model of the Des Moines River, Iowa, during low‐, average‐, and high‐water‐level conditions. Backwater availability, abundance of hardpoints (structures that create turbulence), river gradient and sinuosity, water temperature, and continuously free‐flowing river lengths were used as model parameters. The model was compared to back‐calculated spawning locations from invasive carp eggs collected in 2014–2015. Turbulent hardpoints, river sinuosity, and gradient were not significant predictors of invasive carp spawning locations, and backwater availability in the 25 river kilometers downstream of each reach was inversely correlated with invasive carp spawning locations. Invasive carp eggs were not caught in 2014 despite optimal spawning conditions, revealing that spawning may have high interannual variation. This study suggests that predicting invasive carp reproduction may require variables in addition to those currently proposed.

ОЦЕНКА УСЛОВИЙ И ЭФФЕКТИВНОСТИ ВОСПРОИЗВОДСТВА ВОДНЫХ БИОЛОГИЧЕСКИХ РЕСУРСОВ ОЗЕРА ЦАЦА В УСЛОВИЯХ АНТРОПОГЕННОЙ НАГРУЗКИ НА ЕГО ЭКОСИСТЕМУ

The paper presents for the first time the results of long-term observations of the conditions and efficiency of the natural reproduction of aquatic biological resources in Lake Tsatsa in-cluded in the Sarpinsky lakes system. In a comparative aspect, the data from studying the commercial fish natural reproduction during 2016-2019 are presented (according to the juvenile fish yield). There has been considered the species composition, as well as the changes of juvenile abundance on the spawning grounds of Lake Tsatsa under different hydraulicity of spring floods during the observed period. The species composition of the main commercial fish juveniles is represented by 10 species. The most stable natural reproduction (high productivity of juveniles) was observed in roach, rudd and perch. Over the entire observation period, the number of roach juveniles dominated by 1.23-3.87 thousand sp./ha. The abundance of pike perch, pike, silver bream and tench has also remained stable for four years, but with the lower quantitative characteristics. The analysis of data on the productivity of juveniles showed that the water regime had the most significant effect on the natural reproduction of carp in Lake Tsatsa. The efficiency of its natural reproduction increases significantly in a high-water year (by 6-32 times) compared with dry years. The influence of hydrological and temperature regimes on the efficiency of natural reproduction of commercial fish has been shown. The terms of spawning of the most abundant commercial fish species are given. The main factors of the anthropogenic impact affecting the ecosystem of Lake Tsatsa and reducing the abundance of the aquatic biological resources reserves due to their natural reproduction have been determined. The data obtained in the course of the research will help solving the problem of amending and supplementing the fishing rules, since there were no terms (periods) in the rules for placing a ban on catching aquatic biological resources for this reservoir