Hypophthalmichthys Molitrix Valenciennes Research Articles

Progression along the invasion curve: silver carp growth slows temporally in two Missouri River tributaries

Silver carp (Hypophthalmichthys molitrix Valenciennes, 1844) have been invading North American rivers for decades, often altering zooplankton community structure and impacting native fishes. Silver carp invaded eastern South Dakota tributaries of the Missouri River in the early 2000s. Changes in dynamic rate functions can occur as invasive populations move to the latter stages of the invasion curve, but direct temporal assessments of silver carp populations are limited. Our objectives were to compare current growth of silver carp 1) between the Big Sioux and James rivers in South Dakota and 2) with previous growth recorded from the early stages of invasion (2009–2012) in these rivers. We collected silver carp in May and June of 2020–2022 using boat electrofishing and cast netting. We extracted lapilli otoliths for consensus aging from 99 and 82 silver carp from the Big Sioux and James rivers, respectively. We evaluated growth for each population using Bayesian von Bertalanffy models and compared posterior mean length at ages 2–5 to determine the probabilities of differences between rivers and with estimates from the introduction stage. Posterior estimated mean L∞ values were similar between the Big Sioux (714 mm) and James rivers (709 mm); however, the probability that the posterior mean K estimate was greater for silver carp in the James River (0.271) than the Big Sioux River (0.248) was >99.9%. Estimated mean lengths at age 2 were larger in the Big Sioux and James samples than during the introduction stage, but mean lengths at ages 3–5 were smaller. Changes in growth characteristics indicate that growth has slowed in the current establishment stage of invasion from the earlier introduction stage.

Two new records of Dactylogyrus Diesing, 1850 (Monogenea: Dactylogyridae) from cyprinids fishes farmed in Cuba

Two monogeneans species were collected from gills of Labeo, Labeo rohita (Hamilton, 1822) and silver carp, Hypophthalmichthys molitrix Valenciennes, 1844 of four localities in the country: "La Sierpe" Fish hatchery and Zaza reservoir (Sancti Spíritus province); "Carlos Manuel de Céspedes" Fish hatchery (Santiago de Cuba province); and in the Aquaculture Technologies Company, EDTA (Havana province). The two species were identified according to their morphological characteristics and morphometric measures as Dactylogyrus labei Musselius and Gussev, 1976 (Gussev, 1976) from L. rohita; and Dactylogyrus hypophthalmichthys Achmerow, 1952 from H. molitrix. The collected parasites were set in ammonium-picrate and glycerin solution, and mounted in gelatin glycerin. Drawings, digital images and morphometric data were presented for each species. These new monogeneans records for Cuba also represent a new world geographical location.

Isotopic niches of Silver Carp and two native planktivores in a large reservoir

Human-mediated biological invasions can greatly reduce native species diversity. More than 138 nonnative fishes have been introduced to the United States. Many of these nonnative species can alter ecosystem dynamics and compete with native species. The planktivorous Silver Carp (Hypophthalmichthys molitrix Valenciennes in Cuvier and Valenciennes, 1844) is a nonnative species of concern that is currently expanding its range across the Greater Mississippi River Basin in the Midwestern United States. The objective of our study was to determine the degree of potential competition among invasive Silver Carp and the native planktivores, Gizzard Shad (Dorosoma cepedianum Lesueur, 1818) and Threadfin Shad (Dorosoma petenense Günther, 1867), in Kentucky Lake, a large reservoir located in western Kentucky and Tennessee. We used data derived from N and C isotopes to model isotopic niches, calculate quantitative metrics to describe variability within and among isotopic niches and trophic positions, and qualitatively assess seasonal shifts in trophic positions. Our results suggest that in the spring, older (≥1 y old) Silver Carp share resources with older and young-of-year (YOY; <1 y old) Gizzard Shad, whereas YOY Silver Carp only share resources with YOY Gizzard Shad. Additionally, our analyses showed that older Silver Carp and older Gizzard Shad share resources in the summer. In contrast, we found no overlap in resource use between YOY Threadfin Shad and YOY or older Silver Carp. Furthermore, we provide evidence of intraspecific ontogenetic shifts in isotopic niche area and overlap between invasive and native fishes (measured by sample-size corrected standard ellipse area). If resources become limiting, invasive Silver Carp may compete with multiple life stages of Gizzard Shad in Kentucky Lake and alter foodweb dynamics.

Molecular data and phylogenetic analysis of Myxobolus pseudonobilis n. sp. infecting the gill filaments of silver carp, Hypophthalmichthys molitrix Valenciennes, 1844.

In the present study, we combined morphological and phylogenetic methods to characterize Myxobolus pseudonobilis n. sp. infecting Hypophthalmichthys molitrix Valenciennes, 1844 from Chongqing, China. The morphology and molecular characteristics of M. pseudonobilis n. sp. were distinct from those of other previously described Myxobolus species. Mature myxospores were ovoid in frontal view with spore dimensions of 10.0±0.4 (9.3-10.9) μm in length and 8.5±0.2 (7.9-9.0) μm in width. Two polar capsules occupying approximately half of the myxospore length were unequal in size. The larger polar capsule containing 6 to 7 filament coils measured 5.2±0.3 (4.5-5.8) μm in length and 3.6±0.2 (3.2-3.9) μm in width, while the smaller capsule with 4 to 5 filament coils measured 3.9±0.3 (3.0-4.4) μm in length and 2.5±0.3 (2.1-3.6) μm in width. The comparison of molecular characteristics demonstrated similarities and genetic distances of 18S rDNA sequences of 95.19% - 98.20% and 1.82% - 5.46%, respectively, between M. pseudonobilis n. sp. and its morphologically similar species, and secondary structures were also distinctly different. Moreover, phylogenetic analysis showed that M. pseudonobilis n. sp. was clustered with other myxobolids possessing spores with a blunt anterior end and branched independently. In addition, the morphology of myxosporeans as an important indicator was discussed.

Invasive silver carp may compete with unionid mussels for algae: First experimental evidence

Abstract Unionid mussels are imperilled throughout the US, where their global diversity is highest. Silver carp (Hypophthalmichthys molitrix Valenciennes in Cuvier &amp; Valenciennes, 1844), an invasive planktivorous fish, has spread throughout Midwestern rivers and currently threatens the Great Lakes. Because silver carp remove plankton and other particles from the water column, they may compete with mussels for food resources. This would be among the first examples of a direct competitive interaction between fish and mussels. To examine the potential for competition, a 30 day tank experiment was performed with 2 year old fatmucket mussels (Lampsilis siliquoidea Barnes, 1823) and age‐1 silver carp in three treatments: fatmucket only, silver carp only and fatmucket + silver carp. All tanks were given a commercial algal‐based diet daily and dry mass of suspended particles (an estimate of available food) and NH4, NO3 and NO2 concentrations were quantified every 5 days to track food availability and changes in nutrients. Initial and final silver carp total length (mm) and mass (g), and fatmucket length (mm), height (mm) and surface area (cm2) were measured. Survival was 100% over the test duration for both species. Fatmucket grew less in the fatmucket + silver carp treatment, whereas silver carp growth was undetectable regardless of treatment. Fatmucket also exhibited increased movement in the presence of silver carp. Suspended particles did not differ among treatments. Dissolved nitrogen concentrations were higher in the silver carp treatments, suggesting that silver carp increase nutrient availability in aquatic systems. Overall, the slower growth rates observed in the fatmucket + silver carp treatment compared with the mussel‐only treatment suggest exploitative competition between invasive planktivorous silver carp and fatmucket, and this competition may contribute to additional stress on already imperilled mussels.

Morphological, histological and molecular characterization of three Myxobolus species (Cnidaria: Myxosporea) from silver carp Hypophthalmichthys molitrix Valenciennes and bighead carp Hypophthalmichthys nobilis Richardson in China

Three Myxobolus species were obtained from silver carp Hypophthalmichthys molitrix Valenciennes and bighead carp Hypophthalmichthys nobilis Richardson in China. In the present study, we supplemented their taxonomic characteristics by the morphological, histological and molecular methods. Myxobolus kiuchowensis Chen in Chen et Ma, 1998 formed small ellipsoidal plasmodia in the intestinal wall of bighead carp. Its spores appeared asymmetrical obovate in frontal view and fusiform in lateral view. Tiny mamillary protrusion in the anterior of some spores was observed. Two pyriform polar capsules were unequal. Histologically, M. kiuchowensis infected the tunica muscularis of host intestine. Myxobolus abitus Li et Nie, 1973 formed sausage–like plasmodia in the gills of silver carp. Its spores appeared oblate in frontal view and fusiform in lateral view. Two pyriform polar capsules were unequal and an obvious inter–capsule appendix was observed. Histological examination revealed that M. abitus developed in the interlamellar–epithelium of host gills. Myxobolus pavlovskii (Akhmerov, 1954) Landsberg et Lom, 1991 formed sausage–like plasmodia both in the gills of silver carp and bighead carp. Spores of M. pavlovskii were proximate oval in frontal view and fusiform in lateral view. Two pyriform polar capsules were unequal. The BLAST search indicated the SSU rDNA sequences of M. kiuchowensis and M. abitus were not identical to any sequence, however, the SSU rDNA sequences of M. pavlovskii were identical to that of M. pavlovskii recorded previously. Phylogenetic analysis showed that the present three species robustly clustered together in Cyprinid group and Asia group.

Influence of zeolites on lead and cadmium content in separate links of trophic chain in hydroecosystems

Information about the influence of zeolite used as adsorbent to reduce the concentration of Lead and Cadmium in separate links of trophic chain of hydroecosystem namelyn in water, phytoplankton and muscular tissue of Silver carp is given in the article. As a sorbent we used zeolite of Sokirnitsa deposit (village Sokirnitsa, Khust district Transcarpathian region) of fraction 1.0 – 4.0 mm. Investigations were made at the Lviv research station of Institute of fisheries NAAS (Lviv oblast, Horodok region, Velykyi Lyubin). The sorption properties of natural Transcarpathian clinoptilolite towards Lead and Cadmium at dynamic conditions have been studied. The paper represents research results aimed at estimating effectiveness of removing of Lead and Cadmium ions from hydroecosystems using natural mineral–zeolite. The dynamics of heavy metals content at phytoplankton and muscular tissue of silver carp (Hypophthalmichthys molitrix Valenciennes, 1844) was studied. Measurements were perfomed in pond № 24 (12) area 0.14 hectares which is fed by waters of the river Vereshchytsia. The pond depth is 1 – 1.5 meters. Results of investigations worked out statistically combining the groups. Considerable lowering of ions content of both metals in water was determined. The lowering of cadmium content in muscular tissue of Silver carp was much noticeable than the content of Lead. Results of such investigations are rather actual and perspective and will help to reduce the content of some toxicants in water medium. Improvement of water ecosystems after use of natural sorbents will guarantee ecologically safe products of fish culture and will increase the efficiency of the branch.

Rheological Properties of Gelatin from Silver Carp Skin Compared to Commercially Available Gelatins from Different Sources

Gelatin is used as a functional ingredient in many foods, pharmaceuticals, and cosmetics as a stabilizing, thickening, and gelling agent. The rheological properties of gelatins are important in the potential functionality of gelatin. This study is designed to determine the rheological properties of gelatin extracted from the skins of silver carp (Hypophthalmichthys molitrix Valenciennes 1844). The extracted gelatin is compared with commercially available gelatins from different sources. The results indicate that the stress-strain relationship of gelatin gels remained in the linear region over a broad range of strains and stresses and gave similar elastic moduli at varying frequency, stress, and strain levels. One exception was a commercial high molecular weight fish skin gelatin that gave a lower elastic modulus indicating that its gel strength was low compared to the other gelatin samples studied. Gel strength varied between 220 and 1230 g while viscosity varied between 4.53 and 6.91 cP among the samples. Melting and gelling temperatures varied between 14.2 and 32.3 °C and 3.2 and 25.4 °C, respectively. Texture profile analysis was done at 2 deformation levels, 25% and 75%, and the results correlated well with gel strength. The correlations between hardness, cohesiveness, and gumminess and gel strength were 0.98, 0.82, and 0.99, respectively, at 25% deformation but lower at 75% deformation. The results suggest that rheological measurements might be used to quickly estimate gel strength using less material. In addition, the silver carp skin gelatin seemed to be of equal quality to some of the commercial gelatins.

Olive barb, Puntius sarana (Hamilton) is a potential candidate species for introduction into the grow-out carp polyculture system

The compatibility of olive barb, Puntius sarana (Hamilton) with major carps was studied in grow-out carp polyculture system for one year in a set of nine earthen ponds of 0.08 ha each. Three different species combinations evaluated were Control: catla (Catla catla Ham.), silver carp (Hypophthalmichthys molitrix Valenciennes), rohu (Labeo rohita Hamilton) and mrigal (Cirrhinus mrigala Hamilton) at 0.5:0.5:1:1; T1: catla, silver carp, rohu and olive barb at 0.5:0.5:1:1 and T2: catla, silver carp, mrigal and olive barb at 0.5:0.5:1:1 at combined density of 7500 fingerlings/ha. While survival levels of the carps did not differ significantly in treatments (P>0.05), silver carp recorded highest survival levels (94–96%) followed by olive barb (87–90%), mrigal (72–74%), rohu (72–73%) and catla (67–69%). The specific growth rate (SGR) and average harvested body weight (ABW) of catla and silver carp did not differ significantly among the treatments revealing their competition with mrigal or olive barb to be minimum. In absence of rohu in T2, both mrigal and olive barb showed higher SGR and ABW revealing minimal competition between these two species, while their lower performance in presence of rohu in Control and T1 indicated inter-specific competition with the latter. Such olive barb–rohu inter-specific competition, however, failed to yield significant effect on growth of rohu as revealed from its non-significant SGR difference in presence and absence of olive barb. The lower FCR (2.54±0.06) and higher treatment biomass production (3418.4±95.0 kg ha−1 year−1) in T1 with rohu–olive barb combination compared to T2 with mrigal–olive barb (2.84±0.11; 3155.1±104.7 kg ha−1 year−1) indicated feasibility and advantage of culturing rohu with olive barb rather than mrigal in carp polyculture. Further, similar biomass production in Control and T1 also indicated feasibility of replacing mrigal with olive barb in the grow-out carp polyculture system.

Introduction of jundia Rhamdia quelen (Quoy &amp; Gaimard) and Nile tilapia Oreochromis niloticus (Linnaeus) increases the productivity of carp polyculture in southern Brazil

Fish polyculture is based on the assumption that each species has its own feeding niche and may increase the maximum standing crop of a pond by exploring a wider range of available food and ecological niches. In order to identify the better species ratio and to introduce jundia (JN) (Rhamdia quelen Quoy & Gaimard) and Nile tilapia (NT) (Oreochromis niloticus Linnaeus) in to the carp polyculture practiced in South Brazil, a 162-day experiment was conducted, in 12 250-m2 earthen ponds (1.2 m deep). Treatment I (T-I) contained 35% common carp, Cyprinus carpio (L.) (CC); 35% grass carp, Ctenopharyngodon idella Valenciennes (GC); 15% silver carp, Hypophthalmichthys molitrix Valenciennes (SC); and 15% bighead carp, Aristichthys nobilis Richardson (BC). Treatment II (T-II) consisted of three ponds stocked at the following ratio: 17.5% CC, 35% GC, 15% SC, 15% BC and 17.5% JN. Treatment III (T-III) consisted of three ponds with 35% CC, 35% GC, 7.5% SC, 7.5% BC and 15% NT. Treatment IV (T-IV) consisted of three ponds with 17.5% CC, 35% GC, 7.5% SC, 7.5% BC%, 17.5% JN and 15% NT. No significant correlation was found between the treatments with different species ratio and water quality parameters. The final weight of different species, in different treatments, was statistically different. The major result was the clear positive effect on growth parameters observed by the introduction of JN and/or NT in to the carp polyculture. The yield per hectare was 2083.33±183 kg ha−1 for polyculture with carp species; 2476.67±139.88 kg ha−1 following the introduction of JN only; 2801.67±111.42 kg ha−1 for isolated introduction of NT; and 2506.67±422.31 kg ha−1 for simultaneous introduction of JN and NT. The introduction of JN and/or NT had a positive effect on growth parameters when compared with carp-only polyculture. The reduction in CC ratio also had a positive effect on growth parameters.

Changes in the plankton community following introduction of filter‐feeding planktivorous fish

1. We conducted enclosure experiments in a shallow eutrophic lake, in which a biomass gradient of the filter‐feeding planktivore, silver carp, Hypophthalmichthys molitrix Valenciennes, was created, and subsequent community changes in both zooplankton and phytoplankton were examined.2. During a summer experiment, a bloom of Anabaena flos‐aquae developed (≈ 8000 cells mL−1) solely in an enclosure without silver carp. Concurrent with, or slightly preceding the Anabaena bloom, the number of rotifer species and their abundance increased from seven to twelve species (1700–14 400 organisms L−1) after the bloom in this fish‐free enclosure. Protozoans and bacteria were generally insensitive to the gradient of silver carp biomass.3. During an autumn experiment, on the other hand, large herbivorous crustaceans were more efficient than silver carp in suppressing the algae, partly because the lower water temperature (≈ 24 °C) inhibited active feeding of this warm‐water fish and also formation of algal colonies. Heterotrophic nanoflagellate and bacterial densities were also influenced negatively by the crustaceans.4. Correspondence analysis (CA) was applied to the weekly community data of zooplankton and phytoplankton. A major effect detected in the zooplankton community was the presence/absence of silver carp rather than the biomass of silver carp, whereas that in the phytoplankton community was the fish biomass before the Anabaena bloom, but shifted to the presence/absence of the fish after the bloom.