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The rapid growth of aquaculture over the last century has led to the widespread introduction of aquatic species to freshwater environments. Bighead carp (Cyprinidae: Hypophthalmichthys nobilis) and silver carp (Cyprinidae: Hypophthalmichthys molitrix), collectively referred to as bigheaded carp, are among the top finfishes produced in aquaculture. These filter feeders possess feeding structures that allow them to efficiently remove plankton and other particles from the water. Unfortunately, when introduced into the wild and outside their historical range, their feeding traits generally result in the exploitation and suppression of phytoplankton and zooplankton, reducing food resources for native invertebrates and vertebrates.We conducted a meta‐analysis of published experiments to examine how bigheaded carp directly and indirectly affect organisms in aquatic food webs to better understand their ecological role within ecosystems. Specifically, we addressed the following questions: (1) What is the overall magnitude and direction of bigheaded carp effects on different aquatic organisms? (2) Do bigheaded carp affect organisms in planktonic and benthic habitats? (3) Are effects similar between bighead carp and silver carp? (4) Are effects consistent among experimental arenas (i.e., mesocosm, ponds)?We detected direct and indirect effects of bigheaded carp across multiple trophic levels. Large zooplankton often exhibited the strongest negative effects, with taxa‐specific differences between carp species. The suppression of zooplankton cascaded down to primary producers, resulting in an increase in phytoplankton (i.e., indirect effect). However, we observed no compensatory increases in rotifers when large zooplankton were reduced. Growth rates of planktivorous native fishes were the slowest when stocked with bigheaded carp. Our results further indicated that egested waste from bigheaded carp appeared to subsidise (i.e., direct effect) some benthic invertebrates such as Chironomidae midges. Effects of carp on zooplankton were generally similar between mesocosms and ponds.Invasive bigheaded carp greatly restructure their surrounding food web, both positively and negatively, through a complex suite of direct and indirect effects. These changes manifested across multiple trophic levels and differing habitats. Our analysis provides a more complete understanding of how these invasive carps change their surroundings by exploiting food resources and transferring materials from planktonic to benthic habitats. Taken together, the suite of direct and indirect effects shows how an invasive species can create imbalances within aquatic ecosystems, often to the detriment of native taxa.Bigheaded carp are invasive in many countries across the globe because of their popularity in aquaculture. Our findings reaffirm the threat these planktivores pose to native freshwater organisms. [ABSTRACT FROM AUTHOR]

Alternanthera philoxeroides and Hypophthalmichthys molitrix offer significant nutritional benefits. This study evaluates the proximate composition, amino acid profile, GC-MS analysis, FT-IR spectroscopy, SEM and EDX, and color values of edible paper sheets (EPSs) derived from Alternanthera philoxeroides incorporating different levels of Hypophthalmichthys molitrix flesh. The protein content in the EPSs varied based on fish flesh incorporation, peaking at 52.66% in Ap100/Hm300 (Non-boil). Protein and carbohydrate contents showed an inverse correlation across EPSs, with the highest carbohydrate content of 60.89% in sample Ap400/Hm0 (Boil). Lipid content was also found to correlate with H. molitrix flesh content in EPSs, ranging from 1.59% to 18.41%. Amino acid analysis identified 11 types, with methionine as the most prevalent, followed by leucine, phenylalanine, and lysine. GC-MS analysis revealed 51 bioactive compounds, including carbonic acid, hentriacontane, and various fatty acids. FT-IR analysis showed characteristic bonds, while color analysis displayed L* values ranging from 24.37 to 30.97. SEM analyses depicted the microstructure, surface view, and elemental composition of the EPSs, and EDX showed an abundance of Ca, N, K, O, C, Mg, Na, P, Cl, Mn, and Fe. Therefore, EPSs prepared from A. philoxeroides and H. molitrix could offer a promising approach for effectively utilizing aquatic biomass and providing both plant and animal nutrients to consumers. [ABSTRACT FROM AUTHOR]

Fish movements in regulated rivers can be challenging to study because anthropogenic modifications, such as locks and dams, can influence animal behavior. Upper Mississippi River Lock and Dam 19 (LD 19), for example, is an invasive carp movement bottleneck due to an impassable dam. Upstream fish passage at LD19 is restricted to the lock chamber, making it an optimal location to test invasive fish deterrents that could limit further range expansion. Evaluating the effectiveness of experimental deterrents requires baseline knowledge of fish movements and suitable sample sizes of fish encountering the deterrents to ensure adequate statistical power. Some evidence indicates fish with prior upstream experience may return upstream or challenge potential deterrents at a higher rate than fish without such experience. To test how previous upstream experience could increase the rate at which fish moved upstream through a navigation lock chamber, we compared upstream passage through LD 19 using bigheaded carp captured below the dam (downstream‐origin) and two groups of bigheaded carp captured upstream from the dam: those that swam downstream on their own volition (upstream‐origin fish) and those that were captured upstream and translocated downstream of LD 19 (translocated upstream‐origin). Translocated upstream‐origin carp demonstrated the highest rate of upstream passage, with 59% of the fish detected downstream from LD 19 passing upstream during our study. In contrast, downstream‐origin carp made no upstream passages over 2 years. Fish origin was shown to influence upstream passage success. This may be an important consideration for fish passage studies and deterrent evaluations. [ABSTRACT FROM AUTHOR]

Grass carp (Ctenopharyngodon idella) are globally important in aquaculture and aquatic vegetation control. However, escaped grass carp have established invasive populations. A targeted keyword search was performed on a carp (order: Cypriniformes) literature database maintained by the U.S. Geological Survey to identify literature relevant to grass carp. Additional sources cited in reviewed documents and provided by numerous reviewers were also included. There were three focus areas designed to provide support for invasive grass carp management: (1) diet and behavior; (2) physiological constraints, toxicity, and biology; and (3) gut physiology. Each focus area provides information to guide development of potential pathways for invasive grass carp control. Information from other carp species was used to fill in gaps where grass carp information was lacking and provide additional, potential research directions. Diet-related information included food selection and aquacultural diet formulations. Behavioral information included stimuli and non-physical barriers to attract, repel, or stop movement. Physiological constraints, toxicology, reproductive control, and biological control provide a research review for control options. Gut physiology and related control pathways provide knowledge to improve toxin or pathogen delivery. This review provides a basis for developing approaches and research for controlling invasive grass carp populations, aquaculture, and native population management. [ABSTRACT FROM AUTHOR]

Fish growth is one of the most complex traits that may be influenced by many physiological processes. Among them, feeding is a necessary prerequisite to ensure the growth, development and survival of fish. In order to study the effects of feeding promoting and feeding inhibiting genes on genetic regulation of growth and starvationrefeeding, cDNA sequences of neuropeptide Y (HynNPY) and pro-opiomelanocortin (HynPOMC) genes were cloned in bighead carp (Hypophthalmichthys nobilis) in this study. By using qRT-PCR, expression levels of NPY and POMC genes were studied in hypothalamus and intestine of extreme growth and starvation-refeeding of bighead carp by setting control (feeding), starvation, and starvation-refeeding group, respectively. The full-length cDNA of NPY and POMC genes were 839 and 799 bp, encoding 96 and 218 amino acids, respectively. Phylogenetic analysis showed that NPY and POCM are highly conserved in teleosts. The expression of NPY in hypothalamus was the highest, followed by intestine and brain. The expression of POMC in intestine was the highest, followed by hypothalamus and liver. In the hypothalamus and intestine of extreme large (mean 42.4 g) and extreme small (mean 18.8 g) individuals cultured in the same pond, the expression of NPY in extremely large group was higher than that of extremely small group, while the expression of POMC in extreme small group was significantly higher than that of extreme small group. Starvation increased the expression of NPY in hypothalamus and intestine. After starvation, the expression of NPY increased in the hypothalamus and increased significantly in the intestine. After refeeding, the expression of NPY decreased in the hypothalamus and intestine. The expression of POMC in hypothalamus and intestine of starvation group increased significantly, and decreased to the level of control group after refeeding. Histological observations showed that structure of intestine in extremely large group is better than that of extremely small group, meanwhile, broken intestinal villi and leukocyte infiltration in starvation group tend to recover gradually after refeeding. In short, NPY promotes the intake of more food and POMC supresses appetite, and both of them are involved in feeding mediation of central and peripheral nerve systems of bighead carp. NPY and POMC may directly or indirectly affect the growth of bighead carp by controlling feeding behavior, intake of feed nutrition and GH secretion. These results would provide insights into further understanding of molecular mechanisms for differential growth in bighead carp and gene resources for genetic improvement. [ABSTRACT FROM AUTHOR]

Due to their invasiveness in North America, grass (Ctenopharyngodon idella), bighead (Hypophthalmichthys nobilis), and silver carp (Hypophthalmichthys molitrix) are management priorities. Comparing electrophysiological responses to olfactory cues, such as amino acids, could help identify stimuli to facilitate management efforts (i.e., repellants or baits). We assessed olfactory response magnitude to individual amino acids between fish species using electro-olfactogram recording techniques (EOG). We measured EOG responses (peak EOG magnitude) of juvenile grass (n = 21), bighead (n = 21), and silver carp (n = 22) to 10−4 molar amino acid solutions containing one of L-alanine, L-arginine, L-aspartic acid, L-asparagine, L-glutamine, or L-glutamic acid. Amino acid EOG responses differed across species; grass carp had the greatest mean EOG response. Statistical analyses showed no inter- or intra-specific differences in EOG response among amino acids. The greater EOG response of grass carp matched their selective grazing habits compared to more passive, generalist-tending, filter-feeding bighead and silver carp. All amino acids elicited significant EOG responses in all species, meaning they are candidates for future behavioral research. Such research could explore the management potential of amino acids, testing if amino acids are attractants or deterrents that could facilitate the removal of these fishes by congregating and/or directing movement. [ABSTRACT FROM AUTHOR]

Bigheaded carp Hypophthalmichthys spp. are invasive species native to Asia expanding in the Mississippi River Basin in North America. An understanding of spatiotemporal distribution and aggregation of invasive carp is key to establishing when and where to focus surveillance designed to monitor expansion, and to managing harvest programs designed to curb population densities. We applied a two-stage hurdle model to assess three aspects of bigheaded carp ecology: distribution, relative abundance, and aggregation. Stage 1 was a binary 0/1 model that represented fish presence (p), and stage 2 was a truncated count distribution that had no zeros and included counts ≥ 1 only (C). Estimates of p and C varied temporally and spatially, but not in harmony and sometimes in opposing directions, indicating temporal and spatial swings in fish distributions and aggregations. Intense fish aggregations in channels in spring shown by low p's and high C's, eventually scattered by summer and fall as shown by high p's and low C's. An alternative but complementary interpretation of our observations is that p indexes incidence of aggregations and C indexes size of aggregations. Partitioning catch into its zero and nonzero components provided insight into population ecology that can inform development of monitoring and management of harvesting programs targeted at lessening potential effects of the invasion. [ABSTRACT FROM AUTHOR]

Grass carp (Ctenopharyngodon idella) are globally important in aquaculture and aquatic vegetation control. However, escaped grass carp have established invasive populations. A targeted keyword search was performed on a carp (order: Cypriniformes) literature database maintained by the U.S. Geological Survey to identify literature relevant to grass carp. Additional sources cited in reviewed documents and provided by numerous reviewers were also included. There were three focus areas designed to provide support for invasive grass carp management: (1) diet and behavior; (2) physiological constraints, toxicity, and biology; and (3) gut physiology. Each focus area provides information to guide development of potential pathways for invasive grass carp control. Information from other carp species was used to fill in gaps where grass carp information was lacking and provide additional, potential research directions. Diet-related information included food selection and aquacultural diet formulations. Behavioral information included stimuli and non-physical barriers to attract, repel, or stop movement. Physiological constraints, toxicology, reproductive control, and biological control provide a research review for control options. Gut physiology and related control pathways provide knowledge to improve toxin or pathogen delivery. This review provides a basis for developing approaches and research for controlling invasive grass carp populations, aquaculture, and native population management.

Due to their invasiveness in North America, grass (Ctenopharyngodon idella), bighead (Hypophthalmichthys nobilis), and silver carp (Hypophthalmichthys molitrix) are management priorities. Comparing electrophysiological responses to olfactory cues, such as amino acids, could help identify stimuli to facilitate management efforts (i.e., repellants or baits). We assessed olfactory response magnitude to individual amino acids between fish species using electro-olfactogram recording techniques (EOG). We measured EOG responses (peak EOG magnitude) of juvenile grass (n = 21), bighead (n = 21), and silver carp (n = 22) to 10−4 molar amino acid solutions containing one of L-alanine, L-arginine, L-aspartic acid, L-asparagine, L-glutamine, or L-glutamic acid. Amino acid EOG responses differed across species; grass carp had the greatest mean EOG response. Statistical analyses showed no inter- or intra-specific differences in EOG response among amino acids. The greater EOG response of grass carp matched their selective grazing habits compared to more passive, generalist-tending, filter-feeding bighead and silver carp. All amino acids elicited significant EOG responses in all species, meaning they are candidates for future behavioral research. Such research could explore the management potential of amino acids, testing if amino acids are attractants or deterrents that could facilitate the removal of these fishes by congregating and/or directing movement.

Preservation of the nutritional value of fish and the useful qualities of its rich composition is extremely important. The urgent task of the food industry is to develop and create quality food products that meet modern production trends and compete in domestic and foreign markets. This scientific paper describes studies aimed at assessing the specific weight (%) of essential nutrients (glycogen, proteins, and lipids) in particular organs and tissues of different size and mass groups of the hybrid of silver and bighead carp experimental ponds and reservoirs of Ukraine. To achieve the goal in the research process, fish farming, biochemical (study of total protein, lipids, and carbohydrates), and statistical (mathematical processing of research results) research methods were used. In all size and mass groups of the hybrid of silver and bighead carp from ponds and reservoirs in 2017, 2018, and 2019, mostly satisfactory values of general metabolism indicators were found - glycogen, proteins, and lipids in the liver, gills, and muscles of fish. In annual fish of winter ponds, total protein and glycogen content in all organs and tissues was slightly reduced. The organisms of biennial fish from feeding ponds were characterized by fluctuations in the content of glycogen in the liver (it was the highest in fish, 3.28 - 3.33%). Significant fluctuations in the total protein content of muscle, liver, and gills and a slight excess of glycogen in the liver and lipids in the gills of three-year-olds were observed in the reservoirs. The difference found in the availability of essential nutrients in the body of the studied fish indicates a change in the intensity and direction of their metabolic processes. However, their physiological condition at the time of the study was within normal limits. [ABSTRACT FROM AUTHOR]

The aim of the present research is to study the efficacy of rosemary oil as an anesthetic for bighead carp (Hypophthalmichthys nobilis Richardson, 1845) and as an anesthetic used for transport of fingerlings. The fish used in the experiment have an average body weight (BW, g) of 42.13±17.90 and an average total length (TL, cm) of 16.54±2.32. Five treatments are conducted with five experimental concentrations: 0.20 ml.l-1, 0.30 ml.l-1, 0.40 ml.l-1, 0.50 ml.l-1 and 0.60 ml.l-1. For each concentration 10 fish are used or a total of 50 fish. For the transport experiment, 3 concentrations are used: 0.06 ml.l-1, 0.08 ml.l-1 and 0.10 ml.l-1. The applied stocking density is 3 fish/l. A total of 60 fish are used for each concentration or a total of 180 fish. The established results, for the first experiment, show that at concentration of 0.60 ml.l-1 the induction of anesthesia is the fastest (3.46 min). From all tested concentrations the recovery time is the shortest at the lowest concentration - 2.16 min (p≤0.001). The concentration of 0.10 ml.l-1 of rosemary oil can be used for transport of bighead carp fingerlings for a period from 1 to 2 hours. The concentration of 0.08 ml.l-1 can be applied when the duration of the transport is from 1 to 3 hours. [ABSTRACT FROM AUTHOR]

Asian carps continue to expand their range in North America, necessitating efforts to limit the spread and establishment of reproducing populations. Mississippi River Lock and Dam 19 is a high-head dam that represents a population 'pinch-point' as passage through the lock chamber is the only means by which fishes can complete upstream movement. As such, this location could be a pivotal control point for minimizing the spread of invasive fishes in the Upper Mississippi River and a possible candidate site for installation of deterrent measures. Our objectives were (1) to study the timing (i.e., weekly and diel) and behavior of fishes in the downstream lock approach, (2) evaluate the relation of presence in the downstream lock approach with environmental factors and lock operation, and (3) identify any upstream or downstream passage events through the lock chamber and the relation between these events and the operation of the lock. Acoustic transmitters were surgically implanted into 262 Asian carps and 216 native fishes to monitor fish activity on a telemetry receiver array deployed around and within the lock for 622 days during 2017–2018. One hundred eighty-six telemetered fish were detected in the downstream lock approach. We documented 14 upstream Asian carp passages and 10 upstream native fish passages; these passages coincided with a specific sequence of large vessel lockages. The results of this study advance our understanding of fish presence and behavior at a Mississippi River mainstem lock and dam and inform the development and testing of deterrent systems at this location or at similar pinch-point lock and dams. [ABSTRACT FROM AUTHOR]

Invasive bigheaded carps, genus Hypophthalmichthys, are spreading throughout the Mississippi River basin. To explore the efficacy of a consumer-based market (i.e., invasivorism) to manage them, we developed a conceptual model and evaluated three harvest approaches--direct contracted removal, volume-based incentives ("fisher-side" control), and set-quota harvest ("market-side" control). We quantified the efficacy of these approaches and potential population impact in the Illinois River. Contracted removal was effective for suppressing small populations at the edge of the range but cannot support a market. "Fisher-side" removals totaled 225,372 kg in one year. However, participation was low, perhaps due to reporting requirements for fishers. The "market-side", set-quota approach removed >1.3 million kg of bigheaded carp in less than 6 months. Larger, older fish were disproportionately harvested, which may hinder the ability to suppress population growth. Total density declined in one river reach, and harvest may reduce upstream movement toward the invasion fronts. With sufficient market demand, harvest may control bigheaded carp. However, lack of processing infrastructure and supply chain bottlenecks could constrain harvest, particularly at low commodity prices. Given the geographical scale of this invasion and complicated harvest logistics, concerns about economic dependence on invasivorism that encourage stock enhancement are likely unmerited. [ABSTRACT FROM AUTHOR]

Summary: Bighead carp Hypophthalmichthys nobilis and silver carp Hypophthalmichthys molitrix (together, the bigheaded carps) are invasive fishes in North America that have resulted in substantial negative effects on native fish communities and aquatic ecosystems. Movement and behavior of adult bigheaded carps has been studied previously using telemetry, while similar studies with juvenile bigheaded carps have yet to be attempted. Recent technological advances in telemetry transmitters has increased the availability of tags sufficiently small enough to implant in juvenile carps. However, the effects of surgical implantation of telemetry tags on juvenile bigheaded carps have not been evaluated. We determined tag retention and survival associated with surgical implantation of acoustic telemetry tags into juvenile bighead carp (range 128–152 mm total length) at three temperatures (13, 18, and 23°C). In addition, we assessed the effect of surgically implanted transmitters on the fitness, defined as changes in weight or critical swimming speed, of carp implanted with transmitters. Survival was high among tagged fish (85%) with 47% of tags retained at the conclusion of the 45‐day study. No substantial decline in fitness of the fish was observed in tagged fish compared to untagged fish. [ABSTRACT FROM AUTHOR]

BACKGROUND To evaluate their fat reduction effect, common carp fish protein hydrolysates (FPH) were made using four methods: the conventional enzymatic process, a microwave‐intensified enzymatic process, the conventional alkaline hydrolysis process, and a microwave‐intensified alkaline hydrolysis process. RESULTS: The efficiency of protein extraction was significantly enhanced by microwave intensification. The oil‐holding capacities of FPH produced by these four processes were all lower than that of raw fish protein. The water‐holding capacities of FPH produced by these four processes were all higher than that of raw fish protein. The FPH from the four processes and raw fish protein were used in the preparation of deep‐fried kamaboko. The fat content of deep‐fried kamaboko was drastically reduced from approximately 160 g kg−1 to about 50 g kg−1 by replacing 20 g kg−1 fish mince with FPH, regardless of the process. Texture profile analysis (TPA) of deep‐fried kamaboko found no significant difference in hardness and brittleness among all the deep‐fried kamaboko samples. The similar interior protein cross‐linking micro‐structure of all these samples further explained the TPA finding. CONCLUSION: With the involvement of FPH in the formulation, the fat content of deep‐fried kamaboko can be significantly reduced from approximately 160 to 50 g kg−1, without a change in its texture. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Hypophthalmichthys molitrix (Silver Carp) is an invasive fish that threatens ecosystem function by consuming basal food web resources. In this study we quantify gut contents of 83 Silver Carp in the mainstem reservoir ecosystem of Kentucky Lake, Kentucky, Tennessee River Valley, United States. Silver Carp guts contained phytoplankton (63.5%), zooplankton (33.8%) and heterotrophic flagellates (2.7%) based on volume. Additionally, we compare existing literature on Silver Carp diet and trophic position (i.e., stable isotope information). Our study indicates that Silver Carp are planktivorous and consume organisms within multiple lower trophic levels across a range of habitats. However, we show that Silver Carp diets differ at finer taxonomic scales and suggest these differences may be driven by forage availability. To our knowledge, this is the first study to quantify diets of Silver Carp within a mainstem reservoir ecosystem designed for flood storage with a comparison to existing Silver Carp diet literature. The results of this study may be useful in predicting ecological implications of Silver Carp invasion across a diversity of habitats. [ABSTRACT FROM AUTHOR]

Monitoring ichthyoplankton is useful for identifying reproductive fronts and spawning locations of bigheaded carps (Hypophthalmichthys spp.). Unfortunately, sorting and identifying ichthyoplankton to monitor for bigheaded carp reproduction is time consuming and expensive. Traditional methods require frequent egg-larvae sampling, sorting of all samples to obtain presumptively identified bigheaded carp, and genetic validation of presumptively identified eggs. Quantitative PCR (qPCR) has the potential to streamline this process by identifying samples that likely do or do not contain a target species. Our objective was to develop a genetic screening tool using qPCR with the duplex assays SCTM4/5 and BHTM1/2 to prioritize samples that have a higher likelihood of containing bigheaded carp eggs or larvae. We used tandem ichthyoplankton samples collected for monitoring bigheaded carps in the Upper Mississippi, Illinois, and St. Croix rivers to evaluate the effectiveness of qPCR as a screening tool. Samples with > 10,000 copies of DNA had 100% occurrence of bigheaded carp eggs or larvae in the traditionally sorted samples, whereas samples with < 10 copies of DNA had 0% occurrence of ichthyoplankton from these invasive species. We used a logistic regression model to calculate the probability of finding bigheaded carp eggs or larvae based upon the number of DNA copies; 406 copies corresponded with a 50% probability of having bigheaded carp ichthyoplankton present in a sample. These data can be used to inform management actions (i.e., control, containment) for these invasive fishes, and this tool could be adapted for monitoring for reproduction of other aquatic invasive species. [ABSTRACT FROM AUTHOR]

Knowledge of environments used during early life history and movement patterns of Bighead Carp (Hypophthalmichthys nobilis) and Silver Carp (H. molitrix), collectively termed bigheaded carps, in the Upper Mississippi River (UMR) would be valuable for informing control measures to limit further population expansion and impacts of these species. Lock and Dam 19 (LD19) is a high-head dam on the UMR that delineates downriver areas where bigheaded carps are well established from upriver pools where these species are less abundant and evidence of reproduction and recruitment are limited. Principal natal environments supporting recruitment of emerging bigheaded carp populations in the UMR are unknown. The objectives of this study were to (1) infer environments occupied during early-life stages by bigheaded carps collected in UMR Pools 19-21 during 2013-2014 using otolith microchemistry and stable isotope analyses, and (2) use early-life environment assignments and capture location to identify individuals that passed through LD19. Differences in multivariate water chemistry signatures (Sr:Ca, Ba:Ca and δ18O) among the UMR, its tributaries, and the Missouri and Middle Mississippi rivers enabled development of a classification model for inferring early-life environment of bigheaded carps. Multiple sources of recruits, including from tributaries, have contributed to upriver expansion of bigheaded carps in the UMR. Sustainable control of bigheaded carps upstream of LD19 will likely require efforts to control local recruitment and immigration from downriver. The frequency of bigheaded carps collected in Pool 19 that were downstream of LD19 during early life suggests that bigheaded carps upstream of LD19 still predominantly consisted of immigrants from downriver during 2013-2014. Otolith chemistry provides an approach for assessing the extent to which changes in abundance of bigheaded carps upstream of LD19 are associated with local recruitment or immigration from downriver. [ABSTRACT FROM AUTHOR]

Fish herding (driving fish into nets) is used by commercial fishers to increase harvest of invasive bigheaded carp (Hypophthalmichthys spp.), yet has not been widely adopted for fisheries monitoring purposes. We conducted an experiment to assess whether fish herding using percussive sound or electrical stimuli can enhance catch rates and detection of bigheaded carp and other fishes in surface-to-bottom gill nets. Catch rates (fish net set−1) from traditional gill net sets where no herding method was applied were compared to sets combined with either sound stimuli (physical impacts to the boat hull and water surface to produce percussive sound) or electricity produced from a pulsed-DC electrofisher to manipulate fish movements. For most species, herding increased catch rates and detection probability compared to control sets. Sound stimuli increased catch rates of Silver Carp (Hypophthalmichthys molitrix) by over three times, whereas electrical stimuli increased catch rates by over six times. Catch of Bighead Carp (Hypophthalmichthys nobilis) was highest in nets paired with sound stimuli. Herding methods also reduced the number of samples required to attain target detection probabilities for bigheaded carp. Herding techniques combined with gill netting may be a valuable option for targeted bigheaded carp sampling, especially when electrofishing or netting alone is ineffective for these evasive fishes. Synergistic methods may provide a cost effective means of improving detection probabilities for bigheaded carp at their invasion front or other locations where densities are low and uncertainty of capture is high. [ABSTRACT FROM AUTHOR]

Despite the longstanding presence of grass carp Ctenopharyngodon idella in the Upper Mississippi River (UMR) watershed, information regarding their populations remains largely unknown, in part because capture is difficult. Occupancy models are a popular wildlife assessment tool to account for imperfect detections but have been slow to be adopted in fisheries. Herein, we used occupancy modelling to evaluate the influence of two environmental covariates (river discharge and water temperature) on grass carp occupancy, extinction, colonization, and detection at nine sites within south‐eastern Iowa rivers from April to October 2014 and 2015. Grass carp were detected at least once at all but one site. The most parsimonious model indicated that grass carp colonization probability increased from 0.15 to 0.67 with increases in river discharge. In contrast, occupancy (0.20), extinction (0.29), and detection (0.50) probabilities were temporally constant. Models indicated that water temperatures did not influence grass carp extinction or colonization probabilities relative to river discharge. Cumulative grass carp detection probability approached 1.0, whereas conditional occupancy estimates were less than 0.1 when using five or more sampling transects. The use of a robust design occupancy model allowed us to estimate site occupancy rates of grass carp corrected for imperfect detections, while demonstrating the importance of river discharge for site colonization. These results can be used to assess the distribution of a cryptic fish while helping to guide grass carp sampling and removal efforts. [ABSTRACT FROM AUTHOR]

Invasive bigheaded carps, genus Hypophthalmichthys, are spreading throughout the Mississippi River basin. To explore the efficacy of a consumer-based market (i.e., invasivorism) to manage them, we developed a conceptual model and evaluated three harvest approaches—direct contracted removal, volume-based incentives (“fisher-side” control), and set-quota harvest (“market-side” control). We quantified the efficacy of these approaches and potential population impact in the Illinois River. Contracted removal was effective for suppressing small populations at the edge of the range but cannot support a market. “Fisher-side” removals totaled 225,372 kg in one year. However, participation was low, perhaps due to reporting requirements for fishers. The “market-side”, set-quota approach removed >1.3 million kg of bigheaded carp in less than 6 months. Larger, older fish were disproportionately harvested, which may hinder the ability to suppress population growth. Total density declined in one river reach, and harvest may reduce upstream movement toward the invasion fronts. With sufficient market demand, harvest may control bigheaded carp. However, lack of processing infrastructure and supply chain bottlenecks could constrain harvest, particularly at low commodity prices. Given the geographical scale of this invasion and complicated harvest logistics, concerns about economic dependence on invasivorism that encourage stock enhancement are likely unmerited.

The respiratory process of silver carp, a typical filter-feeding fish, works in conjunction with its feeding mechanism when it filters plankton from water. In the present study, a variety of parameters associated with breathing and feeding of silver carp were measured in response to decreases in dissolved oxygen (DO) levels when the fish were fed microalgae Chlorella ellipsoidea. This approach enabled exploration of the relationship between breathing and feeding in starved or non-starved carp while filtering microalgae particles at different DO levels. The results showed that (1) in the no-feeding group (starved group), respiratory frequency (f R ) and oxygen consumption rate (VO 2 ) of fish did not show significant differences among DO levels of 0.89 to 7.43 mg·L −1 ( P  > 0.05). Normal DO levels (5.28–7.43 mg L −1 ) did not significantly affect respiratory stroke volume (V S.R ), gill ventilation (V G ), V G /VO 2 , filtration rate (FR) or filtering efficiency (E) of fish ( P  > .05).When DO levels declined to 4.14 mg L −1 , the V S.R , V G and V G /VO 2 of fish began to increase significantly ( P  < .05), while the FR and E of fish began to decrease significantly ( P  < .05). There are no significant differences in the clearance rate (CR) of fish among DO levels of 3.17 to 7.43 mg L −1 ( P  > .05). The oxygen extraction efficiency (EO 2 ) of fish increased significantly with decline of DO levels from 7.43 mg L −1 to 0.89 mg·L −1 ( P  < .05). (2) In the feeding group (non-starved group), normal DO levels (5.28–7.43 mg L −1 ) did not affect significantly the f R , VO 2 , V S.R , V G and V G /VO 2 of fish ( P  > .05), but these parameters began to increase significantly, while DO levels declined to 3.17 mg L −1 ( P  < .05). With the decline of DO levels, EO 2 , FR and CR of fish increased and reached the peak at a DO level of 3.17 mg L −1 , and these parameters later began to decrease, while DO levels further declined to 1.90 mg L −1 . The E of fish decreased significantly when DO levels declined from 7.43 mg L −1 to 0.89 mg L −1 ( P  < .05). (3) The f R , VO 2 , V G , V G /VO 2 , FR and CR of fish in the no-feeding group were significantly higher than those in the feeding group at DO levels ranging from 4.14 to 7.43 mg L −1 ( P  < .05), while the EO 2 and E of fish in the no-feeding group were significantly lower than those in the feeding group at DO levels of 3.17 to 7.43 mg L −1 and 5.28 to 7.43 mg L −1 , respectively ( P  < .05). In addition, an anti-filtering response appeared at DO levels of 1.90 mg L −1 and 0.89 mg L −1 in both groups. [ABSTRACT FROM AUTHOR]

The present study is based on the processing of bioapatite (BAp) of sintered fish scales, i.e. heat treated fish scales at 900°C, by the cryogenic grinding technique. It shows that BAp formed by cryogenic grinding of sintered fish scales became purer and nanosized. Earlier studies had reported that nanosized bioapatite increases the resorbability and bioactivity for tissue replacement and regeneration like bones and dental tissues of human beings. Energy dispersive X-ray spectroscopy of sintered fish scale BAp con- firmed the presence of tetracalcium phosphate with Ca/P ratio of 1.97. Field emission scanning electron microscopy and dynamic light scattering (DLS) showed microsized particles. The sintered fish scales when cryoground showed the formation of nanosized particles as revealed by transmission electron microscopy and DLS. The Fourier transform infrared spectroscopy results of sintered and cryoground BAp had similar functional groups, but cryoground BAp showed greater purity. [ABSTRACT FROM AUTHOR]

Length-weight relations (LWRs) were estimated for 46 fish species representing 8 families and 29 genera from the lower sections of Jialing River, a tributary of Yangtze River basin, south-western China: Opsariichthys bidens Günther, 1873; Squaliobarbus curriculus (Richardson, 1846); Ancherythroculter kurematsui (Kimura, 1934); Chanodichthys mongolicus (Basilewsky, 1855); Hemiculter tchangi Fang, 1942; Pseudolaubuca sinensis Bleeker, 1864; Pseudolaubuca engraulis (Nichols, 1925); Parabramis pekinensis (Basilewsky, 1855); Xenocypris davidi Bleeker, 1871; Xenocypris fangi Tchang, 1930; Hypophthalmichthys nobilis (Richardson, 1845); Hypophthalmichthys molitrix (Valenciennes, 1844); Sarcocheilichthys nigripinnis (Günther, 1873); Sarcocheilichthys sinensis Bleeker, 1871; Squalidus argentatus (Sauvage et Dabry de Thiersant, 1874); Coreius heterodon (Bleeker, 1864); Coreius guichenoti (Sauvage et Dabry de Thiersant, 1874); Rhinogobio typus Bleeker, 1871; Rhinogobio cylindricus Günther, 1888; Saurogobio dabryi Bleeker, 1871; Saurogobio gymnocheilus Lo, Yao et Chen, 1998; Gobiobotia filifer (Garman, 1912); Xenophysogobio boulengeri (Tchang, 1929); Onychostoma simum (Sauvage et Dabry de Thiersant, 1874); Spinibarbus sinensis (Bleeker, 1871); Procypris rabaudi (Tchang, 1930); Parabotia fasciata Dabry de Thiersant, 1872; Parabotia bimaculata Chen, 1980; Leptobotia elongata (Bleeker, 1870); Leptobotia taeniops (Sauvage, 1878); Leptobotia rubrilabris (Dabry de Thiersant, 1872); Leptobotia microphthalma Fu et Ye, 1983; Jinshaia sinensis (Sauvage et Dabry de Thiersant, 1874); Pseudobagrus vachellii (Richardson, 1846); Pseudobagrus pratti (Günther, 1892); Tachysurus nitidus (Sauvage et Dabry de Thiersant, 1874); Tachysurus dumerili (Bleeker, 1864); Hemibagrus macropterus Bleeker, 1870; Liobagrus nigricauda Regan, 1904; Liobagrus marginatus (Günther, 1892); Silurus asotus Linnaeus, 1758; Silurus meridionalis Chen, 1977; Glyptothorax fokiensis (Rendahl, 1925); Glyptothorax sinensis (Regan, 1908); Siniperca chuatsi (Basilewsky, 1855); Siniperca knerii Garman, 1912. Data were monthly collected from May 2013 to October 2016. The values of coefficient a ranged from 0.0046 to 0.0237, and the values of exponent b ranged from 2.66 to 3.26. The length-weight relations of two species have not been previously reported. [ABSTRACT FROM AUTHOR]

Abstract: Bigheaded carp (Cyprinidae: Hypophthalmichthys spp.) were brought to North America for aquaculture and eventually escaped captivity. Since their liberation, they have dispersed northward through the Mississippi River Basin and its tributaries. Although bigheaded carp are omnivorous filter‐feeding planktivores, their predatory effects on zooplankton are of principal concern because many native fishes feed on planktonic invertebrates during some phase of their life history. The aim of our study was to quantify the magnitude of effect of bighead carp (Hypophthalmichthys nobilis) on zooplankton body size and daily secondary production across a range of body lengths. We conducted an experiment where we compared responses of zooplankton in the presence of a native fish assemblage (control, n = 5 ponds) and a native fish assemblage plus bighead carp (invaded, n = 5 ponds). The experiment lasted 3 months (June–September, 2014) and was conducted in clay‐lined ponds (0.04 ha. wetted area; 1.5–1.75 m water depths). We quantified the predatory effects of bighead carp on overall changes to the size structure of zooplankton assemblages, body lengths of zooplankton taxa and taxa‐specific changes to standing crop biomass and daily secondary production. The size structure of zooplankton assemblage shifted towards smaller invertebrates in the presence of bighead carp. Bighead carp reduced the individual body sizes of Diaphanosoma (Sididae) (−19%) and Daphnia (Daphniidae) (−9%) after 3 months. Moreover, the standing crop biomass (−92% to 98%) and daily production (−65% to 74%) of Diaphanosoma, Daphnia and Calanoida were reduced in the presence of bighead carp. Bighead carp reduced immature copepod nauplii by 75% when compared to controls and may have affected recruitment to the adult stage. Our experiment indicated that the magnitude of predation by bighead carp increased with zooplankton body size, although rotifers and nauplii were exceptions to this pattern. The combined effects of reduced body sizes of some taxa and direct predation on immature and adult life stages of larger taxa suggest that bighead carp may be affecting zooplankton demographics through additional mechanisms such as reduced egg production, mate limitation, and recruitment. [ABSTRACT FROM AUTHOR]

Soy is one of the best sources of food for fish culture, high protein content, omega-3 fatty acids and unsaturated fat, which support and ensure healthy growth and development, starting from the earliest stages of life. This study evaluated the influence of technology management soy milk on growth performance of juvenile carp during postembryonal development. The results showed that the use of soy milk significantly influenced the quality and quantity of the fish material. Total increase growth and survival was significantly higher in the experimental ponds (B2, B3, B4), as compared to the control pond (B1). Biological material has developed under normal conditions without the development of pathological conditions, technological or human factors that affect the proper conduct of the experiment. Physico-chemical parameters of the water, except for short periods of thermal variation, were placed in the optimal range for the growth of silver carp. The implementation of this feed-and-feed technology for the development of the trophic base, originally and widely applied in Southeast Asia, determines the optimization of fish production in ecological conditions and lower production costs, without adversely modifying the quality of technological water, stimulation of planktonic biomass and superior assimilation of food. In this technology of silver carp larval stage feeding (Hypophthalmichthys molitrix Valenciennes, 1844) did not involve the administration of organic fertilizers, only pre-starter feeds were used, water supply level and flow rate from the pre-emergence basins was used to maintain the quality of the technological water. Growth and survival gains in the experimental ponds (average weight 0.52-0.63-0.74 g / ex, S 60-65-70%), compared to the control pond (average weight 0.25g / ex, S 40%), which shows that the application of supplementary feeding technology to soy milk, ensures a higher growth and survival rate, better assimilation of food, stimulation of planktonic biomass and maintaining optimal quality of physical-chemical parameters of water, which recommends the introduction and application of this wide-scale technology within the framework of the fisheries, with the strict observance of the way of preparing and administering this nutritional supplement. [ABSTRACT FROM AUTHOR]

This article studied the effect of different salts and heating temperature on the binding of silver carp volatile compounds and myosin. The binding ability of myosin was determined by measuring the relative headspace concentration of the volatile compounds in the presence of each myosin using solid-phase microextraction and GC/MS analysis. The results showed that: after treated with KCl and NaCl solution, the binding force between myosin and this four volatile compounds whole decreased; after treated with MgCl2 and CaCl2, the binding force between myosin and hexanal, heptanal, 1-octene-3-alcohol decreased, and when its concentration were beyond 2.5 mol·L−1, the binding force between myosin and hexanol increased. After treated with different temperature, the binding force between myosin and hexanal, heptanal, 1-octene-3-alcohol whole decreased and moreover, the higher the heating temperature the lower the binding force. On the contrary, the binding force between myosin and hexanol increased with the rose of heating temperature. Practical applications Silver carp ( Hypophthalmichthysmolitrix) was selected as the preferred materials to product freshwater-fish surimi because of its good gel-forming ability. However, its application in surimi products is restricted due to the inherent smell thus reducing the value of the processing. Myosin which composed the important part of the meat is not only influence the surimi texture but also influence the release of volatile compounds. Hence, it is extremely essential to research the interaction between volatile compounds and fish protein. [ABSTRACT FROM AUTHOR]

In the Mississippi River Basin of North America, invasive bigheaded carp (silver carp Hypophthalmichthys molitrix and bighead carp H. nobilis, also referred to as Asian carp) have spread rapidly over the past several decades. In the Illinois River, an important tributary of the Upper Mississippi River, reproduction appears to be sporadic and frequently unsuccessful, yet bigheaded carp densities in this river are among the highest recorded on the continent. Understanding the causative factors behind erratic recruitment in this commercially-harvested invasive species is important for both limiting their spread and managing their harvest. We analyzed weekly catch records from 15 years of a standardized monitoring program to document the emergence of age-0 bigheaded carp in relation to environmental conditions. The appearance of age-0 fish was generally linked to hydrographic attributes, which probably serve as a cue for spawning. However, we found profound differences in the number of age-0 fish among years, which varied by as much as five orders of magnitude in successive years. The strong link between summer flooding and age-0 fish production we observed emphasizes the importance of understanding the hydrologic context in which sustained invasions occur. Despite evidence of sporadic recruitment, bigheaded carp populations in the Illinois River appear to be consistent or increasing because of particularly strong, episodic year classes.