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Aristichthys nobilis (bighead carp)
Abstract
This datasheet on Aristichthys nobilis covers Identity, Overview, Associated Diseases, Pests or Pathogens, Distribution, Dispersal, Biology & Ecology, Environmental Requirements, Natural Enemies, Impacts, Uses, Management, Genetics and Breeding, Economics, Further Information.
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Introductions of aquatic organisms into Japan are controlled only on the basis of the Convention on International Trade in Endangered Species (CITES) of Wild Fauna and Flora and the quarantine acts. Up to 1986 more than 120 exotic species have been introduced, of which only 36 were made prior to 1945. Introductions are classified into four basic categories. In this paper of those in two categories, (i) species which have spread widely over Japan and are self reproducing, and (ii) those which have been maintained for generations through artificial propagation or in confined natural waters are dealt with.
This study presents the history of the introduction of fish species into the freshwater system of Israel. Forty fish species, subspecies and hybrids were either stocked directly into freshwater bodies or raised in commercial fishponds and had access to escape routes into the natural freshwater system. Included in this study are escapees from hobbyists' aquariums but not species that were examined but did not pass the experimental stage. Of these, only five species succeeded in establishing populations, usually in local and limited areas. To minimize risks involved in the introduction of new species, Israeli policy makers must implement a clear course of action which balances the demand of local aquaculturists for new species with the need to protect the vulnerable freshwater ecosystem.
Microsatellite DNA loci have been developed from silver carp (Hypophthalmichthys molitrix) DNA for use in broodstock management and research. Here we describe how three of these loci (Hmo1, Hmo 3 and Hmo11) can be used to distinguish between silver carp and bighead carp (Aristichthys nobilis). These loci are being used in the analysis of samples collected from hatcheries in different regions of Bangladesh, in parallel with a survey of broodstock management practices. Analysis of samples from two of the hatchery areas revealed a fairly low proportion of hybrid genotypes among broodstock: this included fish which were identified as silver and bighead carp by the hatcheries. The genetic analysis suggested that while some of these fish might be F1 hybrids, others had more complex genotypes suggesting further generations of hybridization or introgression between the species. The study
Diploid and triploid hybrids with 48 and 72 chromosomes, respectively, occurred when female grass carp, Ctenopharyngodon idella, were artificially crossed with male bighead carp, Hypophthalmichthys nobilis. Diploid hybrids had a higher frequency of morphological abnormalities and were generally smaller than triploids. Lactate dehydrogenase and esterase isozymes of both parental species were expressed in the hybrids. LDH isozymes were encoded by three genetic loci, A, B and C. The C locus was active only in liver tissue. The C4 isozyme had a higher isoelectric point than the A4 or B4 isozymes.
The study aimed to determine the optimum density of free-living nematodes in feeding bighead carp, Aristichthys nobilis, larvae. In the first experiment, carp stocked at 25 larvae L−1 were fed varying levels of nematodes (50, 75, 100, 125 and 150 per ml) twice a day for 21 days from the start of exogenous feeding. Final body weight was significantly higher (P < 0.05) in larvae fed 125 and 150 nematodes per ml than in those fed 50 and 75 per ml, but survival was low (61.8 and 63.6%, respectively). Survival rate was highest in larvae fed 100 nematodes ml−1 (81.3%). Carcass analysis showed that larvae fed 125 and 150 nematodes ml−1 had significantly lower body protein and higher body lipid than those fed other nematode densities. Carcass ash was similar for larvae fed 50–100 nematodes ml−1 but it decreased significantly at the higher nematode densities. Carp larvae in a subsequent experiment were given 50, 75 and 100 nematodes ml−1 per feeding. Newly hatched Artemia was the control feed. Nematode consumption and growth of the larvae were determined. Larvae were sampled at intervals of 2–4 days and the nematodes in the gut were counted and measured. At each nematode density, the number of nematodes present in the gut of the larvae increased significantly with time. At each sampling day, the number of nematodes in the gut did not differ significantly among treatments (P > 0.05) although it tended to increase with nematode density at day 2 and day 4 but decrease at day 7 onward. The carp larvae consumed significantly shorter nematodes on day 2 and day 4 than on the succeeding sampling days regardless of nematode density. However, the length of nematodes in the gut of the larvae did not differ significantly among the nematode densities. The final body weight of larvae increased with increasing nematode density. The body weight of larvae fed 100 nematodes ml−1 did not differ significantly from that of larvae given Artemia nauplii. Results show that bighead carp larvae should be fed 100 free-living nematodes per ml at each feeding time.
This study was undertaken to determine the effects of washing and storage on the quality of Selaroides leptolepis and Aristichthys nobilis surimi kept at -20°C for 24 weeks. Surimi was prepared from unwashed, once-washed and twice-washed minces. Analyses conducted include changes in texture profile, expressible moisture, color, elasticity, moisture content, pH, salt-soluble protein, trimethylamine, total volatile basic nitrogen and thiobarbituric acid. Results showed that twice-washed surimi of both species were generally more stable than once-washed and unwashed surimi. The storage quality in terms of texture, color, elasticity, moisture content, pH and salt soluble protein values for all samples showed significant decreases during storage. There were increases in expressible moisture, trimethylamine, total volatile basic nitrogen and thiobarbituric acid.
Fish integrate their reproductive activities with seasonal environmental cycles. Certain environmental factors such as temperature, photoperiod and rainfall act as cues for the approaching favorable season for reproduction. Signals from environmental cues and endogenous physiological cycles input to the neuroendocrine system, which in turn regulates pituitary and gonadal functions. One of the main reasons for lack of ovulation and spawning in a number of cultured fish is failure of the pituitary to release gonadotropin (GtH-11), one of the hormones involved in the regulation of reproduction. GtH-U secretion in many teleosts is under a dual control, with release being stimulated by gonadotropin releasing hormone (GnRH), and inhibition by dopamine on the actions of GnRH, as well as spontaneous release of GtH-H. The inhibitor}' actions of dopamine on GtH secretion can vary in potency between species. In goldfish, carps and catfish, dopamine inhibition is very strong: injection of a dopamine blocker, such as domperidone (DOM), results in potentiation of the actions of GnRH analogs, leading to a large release of GtH-11 and ovulation. In bream and loach, dopamine inhibition is weak, injection of a high dose of GnRH analog alone is effective in stimulating GtH-H release and ovulation; however, the combination of DOM with GnRH analog results in potentiation of the GtH-11 response and shortening of the response time from injection to ovulation. In seabream, sciaenids and some other marine fish, GtH:11 secretion is not under dopaminergic inhibitory control, they are sensitive to GnRH a_haJ0gs and can be induced to ovulate and spawn by multiple injections or chronic administration of GnRH analogs.
The methods for induced spawning in Ctenopharyngodon idella are similar to those used for Cyprinus carpio, except for the maintenance of spawners and egg rinsing.-from Author
Part 1 deals with the Principles of aquaculture, including 15 Chapters (Basis of aquaculture, History of aquaculture and present state, National planning of aquaculture, Selection of sites, Selection of species, Design and construction of aquafarms, Nutrition and feeds, Reproduction and genetic selection, Health and diseases, Control of weeds, pests and predators, Economic and finacing of aquaculture, and farm management;
Part 2 deals with Aquaculture practices, including chapters on Carps, Trouts and salmons, Catfishes, Eels, Tilapias, Grey mullets and milkfish, Yellowtail, Sea-basses and sea-breams, Other finfishes, Shrimps and prawns, Crayfishes and crabs, Oysters and mussels, Clams, scallops and abalones, Integration of aquaculture with crop and livestock farming and Stocking of open waters and ranching.
Genetic improvement efforts in Israel have focused mainly on common carp (Cyprinus carpio) and tilapias and, only recently, on marine fish species. Genetic improvement of tilapias has focused on the all-male inter-specific hybrid Nile tilapia (Oreochromis niloticus) × Jordan tilapia (O. aureus). Since realized heritability for growth rate in the gilthead sea bream (Sparus aurata) was estimated to be 0.45, a mass selection program was initiated. Some efforts are being devoted to testing the benefits of crossbreeding and inter-specific hybridization with Diplodus sargus and red sea bream (Pagrus major). Genetic engineering efforts are currently directed mainly towards developing methods of producing transgenic carp and gilthead sea bream carrying exogenous GH genes. -from Author
Isocalric diets (290 kcal digestible energy/100 g) with protein levels ranging from 20 to 50% in increments of 5% were fed to bighead carp fry (3.8±0.2 mg mean body weight and 9.8±0.1 mm total length) for 7 weeks. Growth in weight and length increased as the protein level of the diet increased from 20 to 30% and decreased as the protein level increased further. Although not significantly different (P>0.05) from those of fry fed the 25% or 35% protein diet, weight gain (250 mg) and increase in total length (15.7 mm) were highest for fry fed the 30% protein diet. Feed conversion ratio, protein efficiency ratio and survival rate did not clearly indicate the required protein level. The protein requirement was determined using a static-water culture system but assessment of the water quality failed to indicate an association between ammonia concentration and protein in the diet. Further research is necessary to determine why high levels of protein resulted in depressed growth.
Samples of the Auburn University populations of bighead carp (Aristichthys nobilis), silver carp (Hypothalmichthys molitrix) and their reciprocal hybrids were surveyed for isozyme varibility at 23 loci. Allelic variation in loci encoding for alcohol dehydrogenase, creatine kinase, lactate dehydrogenase, malate dehydrogenase (NAD-dependent) and superoxide dismutase was found to differentiate the two species. Reciprocal hybrids could not be distinguished electrophoretically. Isozyme banding patterns indicate these hybrids were diploid. These hybrids were fertile, and they produced large numbers of F2 progeny. The bighead carp population had 4% of its loci polymorphic, whereas the silver carp were polymorphic at 17% of their loci. The bighead carp evaluated in this study as well as those in previously reported studies of cultured carp, have a degree of homozygosity that is probably related to the hatchery procedures for propagating these species.
During June and July 1998, at least three Arkansas fish farms polyculturing bighead carp Hypophthalmichthys nobilis with channel catfish Ictalurus punctatus suffered major losses of catfish associated with massive infestations by the crustacean parasite Lernaea cyprinacea. The channel catfish had few adult Lernaea attached to their skin, but there were 8-50 Lernaea copepodids on the surface of each catfish gill filament. The copepodids were found grazing on the gill tissue, and their feeding activity was associated with gill damage including epithelial hyperplasia, telangiectasis, and hemorrhage. Bighead carp in the same ponds were reported to have had numerous adult Lernaea on their skin but did not die during the epizootic. It is possible that the filter-feeding apparatus of the carp captured the copepodids, thus preventing heavy infestation of the gill filaments. Lernaea copepodids have not been implicated previously in fish losses resulting from parasite damage to the gills. The loss of catfish in these cases is likely to be due to their polyculture with the bighead carp, a species that provides an excellent host for adult Lernaea.
Bighead carp is one of the most important freshwater filter-feeding fish of Chinese aquaculture. In recent decades, there have been a number of contradictory conclusions on the digestibility of algae by bighead carp based on the results from gut contents and digestive enzyme analysis or radiolabelled isotope techniques. Phytoplankton in the gut contents of bighead carp (cultured in a large net cage in Lake Donghu) were studied during March–May. In biomass, the dominant phytoplankters in the fore-gut contents were the centric diatom Cyclotella (average 54.5%, range 33.8–74.3%) and the dinoflagellate Cryptomonas (average 22.8%, range 6.8–55.8%). Phytoplankton in water samples were generally present in proportionate amounts in samples from the fore-guts of bighead carp. The size of most phytoplankton present in the intestine of bighead carp was between 8 and 20 μm in length. Bighead carp was also able to collect particles (as small as 5–6 μm) much smaller than their filtering net meshes, suggesting the importance of mucus in collecting small particles. Examination of the change in the integrity of Cyclotella on passage through the esophagus of bighead carp indicated that disruption of the algal cell walls is principally by the pharyngeal teeth, explaining the previous contradictory conclusions.
In a series of trials, larvae of common carp (Cyprinus carpio L.), silver carp (Hypophthalmichthys molitrix Rich.), grass carp (Ctenopharyngodon idella Val.) and bighead carp (Aristichthys nobilis Rich.) were transferred directly from a diet of zooplankton to a dry, compound feed. The dry diet was based on a previously described diet of yeast and freeze-dried animal tissues. Common carp larvae showed the best growth on live zooplankton (46.3 mg individual weight after 14 days) compared to fish fed solely on dry feed (13.8 mg). Transfer of common carp larvae to dry diet when they reached 4.27 mg significantly improved growth, but no dependence was observed on two diets tested. Grass carp larvae grew equally well on live food and on the best compound diet (8.7 mg after 15 days), but fish transferred to dry diet at 4.3 mg showed significantly improved growth. The growth rate, however, depended on the diet (12.9–23.5 mg). Silver carp grew better when fed solely on dry diet (23.5 mg), compared to live zooplankton (15.8 mg after 15 days), but this was due to an insufficient supply of suitable live food. Transfer of fish at 6.8 mg to dry diet improved the growth only slightly, and dependence on the kind of dry diet was observed. Bighead carp larvae showed better growth on live zooplankton (42.2 mg after 15 days) than on the best compound diet (18.6 mg). Fish transferred at 5.6 mg to dry diets showed good growth, but high mortality was observed. It was concluded that common carp larvae are the most “difficult” to raise solely on dry diet, whereas silver carp larvae are the “easiest”. The present study has shown that the transfer of four cyprinids to dry diet improved their growth rate and that the transfer is possible at the individual wet weight of 5–6 mg.
The effects of bighead carp Hypophthalmichthys nobilis on native planktivores in the USA is unknown. The objectives of this study were to experimentally test for competitive interactions between age-0 bighead carp and age-0 paddlefish Polyodon spathula. Differences among water chemistry variables, invertebrate densities, and relative growth of fish were assessed in mesocosms. Water chemistry variables were similar among treatments throughout the experiment and only exhibited a temporal effect. Zooplankton density declined in mesocosms after fish were introduced. In general, zooplankton densities did not differ among treatments but did differ from the control. The relative growth of paddlefish was negative in the paddlefish and paddlefish–bighead carp treatments. The relative growth of bighead carp was negative in the bighead carp treatment but positive in the paddlefish–bighead carp treatment. Age-0 paddlefish exhibited the greatest decrease in relative growth in mesocosms with bighead carp. Bighead carp exhibited the greatest increase in relative growth in mesocosms with paddlefish. These data suggest that bighead carp have the potential to negatively affect the growth of paddlefish when food resources are limited.
Grass carp (Ctenopharyngodon idella) and bighead carp (Hypophthalmichthys nobilis) larvae fed freshwater rotifers (Brachionus rubens) were consistently longer and heavier at the end of the 3-week feeding trials than those fed the other foods tested. The final length of grass carp fed nematodes (Panagrellus sp.) was the lowest of the live foods tested, however, the length of bighead carp fed Panagrellus was not significantly different from those fed brine shrimp nauplii Artemia salina. Growth of grass carp fed the two commercial dry diets (Ewos Larvstart and Fry Feed Kyowa A) was less than those fed the three live foods. Bighead carp grew well on the commercial diets, but results were somewhat inconsistent.Construction of a simple, inexpensive airlift sponge filter is described. This filter provided adequate water quality, resulting in excellent survival at densities as high as 57 individuals/l with no addition of freshwater. The airlift sponge filter has great potential for intensive larval rearing.
Growth of second-year triploid and diploid bighead carp, Hypophthalmichthys nobilis, was compared in a 189- to 190-day yield trial; the fish were grown separately in 0.04-ha earthen ponds at 625/ha and were also grown communally in 0.05-ha earthen ponds at 640ha. When grown communally, bighead carp were polycultured with channel catfish, Ictalurus punctatus (7,50Oha), and grass carp, Cienopharyngodon idella (40/ha); when they were grown separately, they were polycultured with grass carp at 501ha. When cultured separately, diploids were longer (526 vs 499 mm) and heavier (1,645 vs 1,427 g) than the triploids at harvest, but the differences were not significant (P 5 0.05). When cultured communally, the diploids were significantly longer (519 vs 485 mm) and heavier (1,621 vs 1,321 g) than their triploid counterparts at harvest. Ploidy of all bighead carp was determined after fish were harvested, and 7.9% of the presumed triploids that were stocked separately were actually diploids. Growth of the triploids appeared to be acceptable for commercial use where diploid bighead carp are banned. The efficiency of producing triploid bighead carp must be improved if they are to be cultured in states where bighead carp are illegal.
Sexual maturation in bighead carp Aristichthys nobilis reared without supplemental feeding in floating cages in Laguna de Bay was observed year-round. Percent maturation ranged from 3 to 94 % in females and 0 to 82 % in males from July 1985 to July 1986. High maturation rates in both sexes occurring in March 1986 were positively correlated with high inorganic turbidity in the lake. Low natural food productivity (phyto-and zooplankton) during high turbidity did not negatively affect fish growth. Fish may have deended partly on susended particles as additional food sources when production of more suitable food (zooplankton) was low. Increased production of natural food as a result of water clearing by seawater intrusion during May to September did not enhance growth and maturation of the fish. There was a low negative correlation between chlorinity and percent maturation of both sexes.
Abstract— Alternative fish species that can be cultured together with catfish Ictalurus punctatus provide an opportunity to diversify caffish farms. A 2-yr study was conducted in 0.10-ha earthen ponds to evaluate the effect of bighead carp (BHC) stocking density on growth, yield, dressout yield, and net returns. Initially, bighead carp (average weight of 22 g) were stocked at rates of 380, 750, or 1,130 fishha in ponds with catfish. Caffish were cultured under commercial conditions by stocking caffish at a density of 12,500/ha, aerating nightly and feeding at an average rate of 82 kgha per d. Stocking rates for 2-yr-old fish were reduced to 77, 260, and 435/ha in the second growing season. There were no significant differences among treatments (P > 0.05) in summer growth of bighead carp in either year. Bighead carp stocked at 1,130 fishha had significantly higher yields than those stocked at 380/ha, but did not reach minimum market size of 2.2 kg during the first year (P > 0.05). There were no significant differences (P > 0.05) in caffish growth, yield, survival, or feed conversion ratios due to the bighead carp stocking densities. Partial budget analysis indicated that net benefits were positive for all three treatments over a range of prevailing prices of bighead carp. Bighead carp production in catfish ponds is economically feasible over a wide range of prices. Given the market risk of producing smaller fish at the higher density, the medium density is the preferred stocking density of fingerling bighead carp in catfish ponds.
Observations were made on the growth of microphagous silver carp and bigheads in a tank housed under a horticultural polythene tunnel. It is suggested that the species may be of interest for cultivation and might also be useful in removing nutrients from eutrophic waters in the United Kingdom.
The effects of different types of feed, given singly or in combination, on the growth and survival of bighead carp, Arislichlhys nobilis Richardson, larvae reared for a period of 12 weeks were determined. Growth was highest for fish fed with the combination of Moina and artificial feed followed by fish fed with artificial feed alone. Significantly lower (P < 0.05) growth was found in fish fed with green water +Moina+ artificial feed; green water + artificial feed; green water +Moina and Moina alone, in a descending order. Carp larvae reared in green water alone did not survive after the fifth day of feeding. Specific growth rales ranging from 0.59% day−1 to 2.75% day−1 were exhibited by fish in all the remaining six treatments.Although green water alone did not support the growth of the larvae, enhanced survival rates were observed when green water was given in combination with other feeds. Survival rate was highest in fish fed with the combination of green water, Moina and artificial feed, but was not significantly different (P > 0.01) from those given Moina+ artificial feed. Consequently, normalized biomass index was significantly high (P < 0.05) in fish fed with the combination of green water, Moina and artificial feed.
Incidental and/or uncontrolled hybridization between silver carp (Hypophthalmichthys molitrix) and bighead (Aristichthys nobilis) represents a serious problem in Czechoslovak aquaculture. This fact affects fitness traits very negatively in successive generations of hybrids. To solve this problem, 1076 individuals in a total of both H. molitrix. A. nobilis, and their hybrids in 12 groups from six rearing facilities were analysed. Twelve protein systems representing 21 presumptive loci were studied to analyse the electrophoretic patterns of their products using horizontal starch gel electrophoresis of blood and tissue extracts. Both species displayed identical electrophoretic patterns in MYO-I*, LDH-A*, LDH-B*, sMDH-1*, sIDHP-3*, GPI-1*, and CK-I* loci. For a reliable differentiation of both species products of the following nine loci are applicable ALB*, PA*, TF, sMDH-2*, SOD*, NDH*, MYO-IF, MYO-III*, and CK-2*. In addition, some polymorphic variants in slDHP-1*, sIDHP-2*, LDH-C*, EST-II*, and GPI-2* loci are of use as auxillary markers while the other variants are common to both species. A high level of gene introgression was evident through hybridization between both species. All groups declared previously as ‘H. molifrix’ were actually confirmed biochemically to be H. molitrix. However, all groups declared as ‘A. nobilis’ were proved to be a mixture of A. nobilis and its hybrids of different level with H. molitrix. This suggests it is impossible to distinguish between A. nobilis and hybrids using their external morphology only.
— Bighead carp Hypophthalmichthys nobilis have been raised in the United States for two decades and sold through the livehaul market, but their profitability in monoculture has not been evaluated. Three studies were conducted in 0.10-ha earthen ponds to evaluate the effect of bighead carp stocking density on growth, yield, dressout yield. and net returns. Initially, bighead carp (average weight of 0.36 kg) were stocked at rates of 500, 320, or 130 fish/ha with three replicates of each treatment. Stocking rates for 2-yr-old fish (average weight of 2.45 kg) were reduced to 320, 220, or 130 fish/ha in the second year. Net yields of bighead carp stocked at 500 fish/ha (963 kg/ha) were significantly higher (P < 0.05) than net yields at the 320 fishha density (771 kg/ha), and these were significantly greater (P < 0.05) than net yields at 130 fish/ha (369 kg/ha) in the first growing season. Net yields in the second growing season were not significantly different (P > 0.05) among densities. There were no significant differences (P > 0.05) among treatments in yearly growth which ranged from 11–17 g/d in the first and from 6–13 g/d in the second growing season. Dressout percentages for whole-dressed, steak, shank fillet, and shank fillets with white meat only did not differ with stocking density (P > 0.05). Enterprise and partial budget analysis indicated that monoculture of bighead carp in fertilized ponds is profitable only in the short run at average livehaul market prices, because revenues exceeded variable but not fixed costs. The negative net returns, when all costs were accounted for, indicated that it is not profitable to construct ponds solely for monoculture of bighead carp.
The use of Panagrellus redivivus as live feed for bighead carp and Asian catfish larvae was tested. In experiment 1, carp larvae were given Artemia nauplii (control) or Panagrellus twice daily for 21 days. A third treatment consisted of unfed larvae. The same three treatments were used in experiment 2 plus another with a commercial entomopathogenic nematode (EPN). Bighead carp larvae given Panagrellus in experiment 1 had much lower growth and survival than those fed Artemia nauplii. This could be due to low nematode density (5–30 mL−1 water) during feeding. The unfed larvae had 100% mortality by days 11–13. In experiment 2, growth and survival of carp larvae given Artemia nauplii (5–10 mL−1) and Panagrellus (50 mL−1) did not differ significantly (P > 0.05). All unfed larvae had died by day 13, while larvae fed EPN were all dead by day 8. Two experiments on Asian catfish were likewise conducted. In experiment 1, the catfish larvae were fed Tubifex (ad libitum), Panagrellus (50–100 mL−1 per feeding) orArtemia (5 nauplii mL−1 per feeding) three times daily for 14 days. In experiment 2, larvae were fed Artemia alone (10 nauplii mL−1 per feeding), Panagrellus alone (100 mL−1 per feeding), or their combination with a 38% protein dry diet twice daily. For both experiments, catfish larvae fed Panagrellus had significantly lower growth and survival than those fed Tubifex or Artemia. The combination of Panagrellus and dry diet created little improvement in the growth and survival of catfish larvae.
Twenty-month-old bighead carp, Aristichthys nobilis (Richardson), were fed prepared dry diets for 20 months in cages in Laguna de Bay, Philippines, to determine the effect on reproductive performance. The experimental diets were similar in composition except for the combinations of vitamins being tested. Diet 1 was supplemented with vitamins A, E and C; diets 2, 3 and 4 each lacked one of the supplementary vitamins; and diet 5 did not include any vitamin supplementation. Bighead carp that relied solely on natural food without a prepared diet served as a control. The total of six treatments each had two replicates. Results showed that the onset of gonad maturation was 2–3 months earlier in the fish that were fed the prepared diets regardless of vitamin supplementation, when compared with the fish that were fed natural food (control). Moreover, the prepared diets enhanced egg hatchability which was significantly higher in fish that were fed diet 1 (+ vitamins A, E and C, 80.5 ± 18.1%) and diet 3 (– vitamin E, 78.5 ± 1.1%) than in those fish that were fed natural food (control) (36.5 ± 31.3%). Mean number of 3-day-old larvae was highest in fish fed on diet 1 (34 525 ± 1732), followed closely by fish that were fed diet 3 (32 420 ± 3909). A low number of 3-day-old larvae was obtained from fish fed the natural diet (14 490 ± 4331) as well as in fish that were fed diet 2 (– vitamin A, 14 347 ± 4863), diet 4 (– vitamin C, 21 407 ± 5840) and diet 5 (– vitamin A, E and C, 12 191 ± 1439). Other criteria for reproduction such as relative fecundity, fertilization rate, and hatching rate did not differ significantly (P > 0.05) among treatments. The addition of vitamins also had no significant effects on weight gain of adult fish.
Using a limnocorral study, Microcystis grazing by silver carp, bighead and tilapia was examined in an eutrophic shallow lake permanently infested with a Microcystis bloom. Twelve fingerlings of each fish species were introduced into the limnocorrals placed in the lake, in triplicate, and their grazing effects were examined over a period until the limnocorral bloom declined substantially and remained unchanged. Introduction of fish, regardless of species, into the limnocorrals resulted in sharp reductions (60–93%) of the initial Microcystis population on day 3 or 7. Maximum gross and net clearance of Microcystis were by silver carp followed by bighead and tilapia. Short-term high retention of Microcystis by tilapia indicated that the clearance effect did not last long due to a high rate of defaecation of undigested Microcystis. Nearly 6–180% nutrient enrichment of the limnocorrals was attributable to the defaecation of test fishes suggesting their ichthyoeutrophication potentials, which were in the following order: tilapia>bighead>silver carp. It is concluded that silver carp is most suitable for clearing Microcystis in the lake because of its minimal ichthyoeutrophication effect.
Effects of intraperitoneal injections of LHRH-a and domperidone (DOM), given singly or in combination at two injections, on oocyte maturation, ovulation and spawning in bighead carp, Aristichthys nobilis, were investigated. Results were compared with the existing protocol using HCG + LHRH-a at 1800 IU and 20 μg/kg BW, respectively, to induce spawning in bighead carp. Oocyte diameter of fish at 6 h after the second injection of LHRH-a + DOM and HCG + LHRH-a had significantly increased to 7.0% and 7.5% respectively, as compared to the 0 h group (P<0.05); fish injected with LHRH-a, DOM or saline had significantly lower increases (1.0%, 2.0%, and 3.0%, respectively). Ovulation was induced in 75% and 60% of fish injected with LHRH-a + DOM and HCG + LHRH-a, respectively. In contrast, fish treated with LHRH-a, DOM or saline did not ovulate. Total eggs spawned, and fertilization and hatching rates did not differ significantly (P<0.05) between the two groups with ovulated fish. Although injection protocols using LHRH-a + DOM and HCG + LHRH-a were equally effective in inducing spawning of bighead carp, the former had a lower combined cost than the latter.
Comparative karyological studies on Chinese carps (Ctenopharyngodon idella, Aristichthys nobilis, Hypophthalmichthys molitrix) were carried out to determine the possiblities of hybridization. The diploid chromosome number, the morphological distribution of chromosomes, the arm ratio, the total and relative lengths of chromosomes, the total length of chromosome sets, and the number of arms were determined. Cross-breeding of grass carp and bighead was tested, and resulted in viable progeny. Karyological analyses of the F1 hybrid generation were made. The hybrid proved to be triploid.
Bighead carp were introduced into Arkansas in 1973 to improve water clarity in production ponds. Bighead carp subsequently escaped aquaculture facilities in the early 1980's and dispersed into the Mississippi and Missouri rivers. The first documentation of bighead carp reproduction in the Mississippi River system was in 1989. The population has increased in the Missouri River as is evident in their increased proportion in the commercial harvest since 1990. The effect of this exotic planktivore on native ecosystems of the U.S. has not been examined. Basic biological data on bighead carp Hypophthalmichthys nobilis in the Missouri River are needed to predict potential ecological problems and provide a foundation for manipulative studies. The objectives of this study were to assess age, growth, and gonadal characteristics of bighead carp in the Missouri River. Adult bighead carp in our sample varied from age 3 to age 7 and length varied from 475 to 1050mm. There was a large variation in length at age, and overall bighead carp exhibited fast growth. For example, mean back-calculated length at age 3 was 556mm. The sample was dominated by bighead carp from the 1994 year class. There was no difference in gonad development (i.e., gonadal somatic index, egg diameter) between winter and spring samples. Length of male bighead carp and GSI were not significantly correlated; however, females exhibited a positive linear relationship between length and GSI. In each ovary, egg diameter frequencies exhibited a bimodal distribution, indicating protracted spawning. Mean fecundity was 226213, with a maximum fecundity of 769964. Bighead carp in the Missouri River have similar life history characteristics to Asian and European populations. They have become well established in the Missouri River and it is likely that dispersal and population density will increase.
Lipids have a complex role in the nutritional value of food. Some polyunsaturated fatty acids, characterized as essential,
are extremely important for human health. This is primarily related to α-linolenic acid (18:3n-3), eicosapentaenoic acid (20:5n-3)
and docosahexaenoic acid (22:6n-3). Content of polyunsaturated n-3 fatty acids is usually much higher in lipids of marine
fish than in freshwater fish. Previous investigations have shown that muscle tissue of silver carp and bighead carp from fish
farms may be a rich source of essential fatty acids. Because of that, the objective of this work was to examine contents and
composition of fatty acids and total lipids in the muscle tissue of silver and bighead carp, with the aim to find out whether
there are significant differences in this respect between the two species and to what extent the harvest season can influence
the composition of lipids in these freshwater fish. This study showed that there is no significant difference either in the
content of polyunsaturated n-3 and n-6 fatty acids, or in the n-6/n-3 fatty acid ratio in these two fish species. The lipids
of both the silver and bighead carp from the spring harvest have significantly higher contents of the n-3 acids and a significantly
lower n-6/n-3 ratio than fish from the autumn harvest.
Bighead carp (Aristichthys nobilis Oshima) fry of various ages (11, 18, and 35 days post-hatch) were exposed to the low salinities encountered during the annual intrusion of seawater in Laguna Lake, Philippines. Practical indices of salinity tolerance assessed the effect of a 96 h direct exposure to low salinities (0–16). Mean (MST) and median survival times (MST50) of fry decreased as salinity of rearing medium increased. Younger fry were less able to tolerate exposure to these salinities than their older cohorts. Median lethal salinity after 96 h (MLS) revealed higher tolerance among 35–day old fry (7.6) than 11 (2.3) and 18–day old fry (6.0), demonstrating that survival in saline water depends on their age at initial exposure to low salinities. Mean body weight of 18–day old fry reared in 0 and 2 for 3 and 4 weeks was higher than for those reared in 4 and 6 for the same period. Growth over these periods was inversely related with the range of salinities tested. These results demonstrate that, despite their known stenohalinity, bighead carp fry possess some degree of osmoregulatory capability, allowing them to survive and grow in lakes subjected periodically to saltwater inflow.
The bighead carp (Aristichthys nobilis) and the silver carp (Hypophthalmichthys molitrix) were introduced into Brazil in 1979 from China for the aquaculture programs conducted by the Centro de Pesquisas e Treinamento em Aquicultura (CEPTA), Pirassununga, SP. Hybrids between bighead carp females and silver carp males were obtained in 1989.Reported here are the cytogenetic analysis of parental lines and hybrids, including Ag-stained NORs and C-banding patterns. The two species and hybrids have 2n = 48 chromosomes, consisting of 12 pairs of meta-submetacentrics and 12 pairs of subtelocentrics. The Ag-NOR pattern, which consisted of four pairs of nucleolus organizers in both species and the conventional Giemsa staining of chromosomes were ineffective for the cytogenetic characterization of the hybrids and of the two parental species.C-bands, in contrast, were effective markers in the characterization of the karyotypes of the two species and of their hybrids because of the presence of distinct heterochromatin blocks in one chromosome pair of A. nobilis. This chromosome marker was useful in the identification of the parental haploid sets in the hybrids.
Bighead carp (10.5 months old) stocked in cages in Laguna de Bay were assigned the following feeding treatments: 1. 40% protein diet, 2. 20% protein diet, and 3. no artificial diet (control), to determine the effects of feeding on growth and reproduction. The fish were fed for 15 months. Growth was monitored for the first 9 months and fish were induced to spawn in the succeeding months. Both weight gain and increase in total length did not differ significantly (P > 0.05) among treatments. Results of the induced spawning showed that fish fed the 40%-protein diet had the highest mean total weight of eggs/female, total number of eggs/spawning, and number of eggs/kg body weight. Fish fed the 20%-protein diet had intermediate values while the control fish had the lowest values for the same parameters. However, mean fertilization rates (54–58%) and hatching rates (61–78%) were not significantly different (P > 0.05) among treatments. The mean number of 3-day old fry of fish fed the 20%-protein diet (48 085) was lower than that of fish fed the 40%-protein diet (86 806). The control fish gave a significantly low (P < 0.05) number of 3-day old fry (37 469). When deprived of food for up to 10 days, fry of the fed broodstock had a lower mortality rate than fry of the control fish.
Analysis of intestinal contents of silver carp (Hypophthalmichthys molitrix) and bighead carp (Aristichthys nobilis) showed that silver carp consumed primarily phytoplankton while bighead carp consumed large quantities of zooplankton and detritus in addition to phytoplankton. The size of particles filtered by the bighead carp was larger (17–3,000 μm) than that filtered by silver carp (8–100 μm). Artificial feed was readily consumed by bighead carp but not by silver carp. No growth difference was indicated for silver carp in fertilized ponds and ponds receiving artificial feed. Growth of bighead carp increased substantially with the addition of artificial feed. Silver carp grew more rapidly in cages than bighead carp.
The effect of filter feeding fishes, silver carp: Hypophthalmichthys molitrix, bighead carp: Aristichthys nobilis, and a hybrid of these two species on water quality in irrigation reservoirs has been studied by means of field surveys and enclosures experiments. The concentration of particles that are liable to clog an irrigation system was reduced in the reservoirs that were stocked with filter feeding fish. The filter feeding fish reduced the concentration of filamentous algae, prevented bluegreen algae blooms, and also reduced the concentration of zooplankton, mainly of copepoda and cladocera in the reservoirs.Experiments in enclosures indicated that the concentration of chlorophyll-a was not always reduced in the presence of the filter feeding fish, but that the alga population was shifted to a smaller sized species. Blooms of bluegreen algae occurred only in the enclosures without fish. During periods of bloom, the corresponding concentration of chlorophyll-a was also significantly higher in the enclosures without filter feeding fish. Zooplankton concentration in the enclosures with no fish was much higher (up to 10 times or higher) as compared to those enclosures with filter feeding fish. In general, the presence of filter feeding fish improved the quality of irrigation water by the removal of large suspended particles.
The status of introduced fish species in Malaysia
- K J Ang
- T E Gopinath R Chua
Acceptability of selected zooplankton and phytoplankton for growing larvae/fry of bighead carp (Aristichthys nobilis)
- S F Baldia
- Pantastico
- J P Baldia