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1.
The dynamics of development and production of Thelohanellus hovorkai (Myxozoa) were examined to investigate factors inducing haemorrhagic thelohanellosis in carp, Cyprinus carpio L. Fresh actinospores of T. hovorkai were harvested from the oligochaete alternate host, Branchiura sowerbyi, and used for infection experiments with myxosporean-free carp. Visualization of actinospores by fluorescent labelling revealed that sporoplasms penetrated the gill filaments of carp immersed in an actinospore suspension as early as 30 min post-exposure (PE). Plasmodia of T. hovorkai developed in the connective tissues of various organs and matured 3-5 weeks PE; dispersion of myxospores from degenerate plasmodia occurred 5-7 weeks PE. Challenges with a high dose of actinospores (4.5 x 10(6) spores per fish) resulted in the onset of disease, which was more easily achieved by the oral intubation of actinospores than by immersion in an actinospore suspension. Actinosporean-free B. sowerbyi were exposed to different densities of myxospores (10(4)-10(6) spores per oligochaete) and subsequently reared at different temperatures (15, 20, 25 degrees C). At 20 and 25 degrees C, actinospore releases were first detected 40-43 days PE, with multiple peaks of release (max. 7 x 10(5) actinospores day(-1)) during the next 60 days. We concluded that the developmental cycle of T. hovorkai was completed within 3-5 months at 20-25 degrees C, and that the ingestion of large numbers of actinospores orally, possibly by feeding on infected oligochaetes, resulted in a disease condition in carp. 相似文献
2.
The life cycle of the histozoic myxozoan parasite Henneguya nuesslini was investigated in two salmonid host species. Naive brown trout, Salmo trutta, and brook trout, Salvelinus fontinalis, were experimentally infected in two trials by triactinomyxon type actinospores from naturally infected Tubifex tubifex. In exposed common carp, Cyprinus carpio, no myxospore production was detected. The parasite formed cysts with mature myxospores in the connective tissue of the fish 102 days post-exposure. The morphology of both actinosporean and myxosporean stages was described by light microscopy and a 1417-bp fragment of the 18S rDNA gene was sequenced. Sequence analysis confirmed the absolute congruence of the two developmental stages and assisted in determining species identity. Host range, tissue specificity and myxospore measurements provided sufficiently distinctive features to confirm species validity and were thus crucial for identification. The triactinomyxon spores had 16 secondary germ cells, unique dimensions, a very opaque sporoplasm matrix and three conspicuously protruding, pyriform polar capsules. This is the first record of a Henneguya sp. life cycle with a triactinomyxon-type actinospore, which suggests a close relationship with the Myxobolus group and a polyphyletic origin of the genus Henneguya. 相似文献
3.
This study provides detailed information on the invertebrate hosts of Myxobolus pseudodispar (Myxozoa) and explores the susceptibility range of several species and analyses the relevance of the species composition of an oligochaete population. Our findings demonstrate that the oligochaete host range of M. pseudodispar is similarly wide as the number of vertebrate host species. Besides Tubifex tubifex and Limnodrilus hoffmeisteri, Psammoryctides barbatus and Psammoryctides moravicus were also found to be susceptible invertebrate hosts. The genetic characterization of the mitochondrial 16S rDNA of T. tubifex sensu lato revealed that lineages I, II and III are susceptible to M. pseudodispar, whereas T. tubifex lineage VI seems to be non‐susceptible. T. tubifex lineage V and L. hoffmeisteri specimens were positive in a M. pseudodispar‐specific PCR, but in most cases, the release of mature actinospores could not be detected. Hence, these non‐susceptible oligochaetes likely serve as `biological filters` as they remove myxospores from the sediment without producing actinospores. Together with the phylogenetic analysis of the susceptible and non‐susceptible oligochaete hosts on the basis of mt 16S rDNA sequences, the route of the development of M. pseudodispar in the oligochaete hosts was tracked by in situ hybridization. According to our findings, the gut epithelia seem to be a portal of entry of the sporoplasms, where the development of the parasite also takes place. The basal lamina seems to be involved in the migration of the parasite, and the worm’s cellular immune response is activated by the infection. 相似文献
4.
Arne Levsen 《Aquarium Sciences and Conservation》2001,3(4):301-311
The parasitic fish nematode Camallanus cotti has been reported from a number of freshwater fish species around the world. Its wide geographical distribution seems mainly
to be the result of anthropogenic dissemination due to extensive ornamental fish trade. In most reports it is assumed that
C. cotti's life cycle involves cyclopoid copepods as intermediate host and various freshwater fishes as final host. However, the species'
relatively frequent and persistent occurrence in aquaria worldwide strongly indicates flexibility in its life cycle, i.e.
the ability to infect the final host directly. The present study has shown that under aquaria conditions, without any presence
of copepods, C. cotti is able to infect various phylogenetically distant fish species directly for at least three generations. It was further shown
that the infective free-living first-stage larvae may survive for more than three weeks in the host-external environment and
that their host-attracting behaviour is not precluding direct transmission to the final fish host. Any treatment for C. cotti under aquaculture or aquarium conditions should be directed towards both individual infected fish hosts as well as the free-living
larvae on the substrate.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
5.
Effects of Co‐stocking Smallmouth Buffalo,Ictiobus bubalus,with Channel Catfish,Ictalurus punctatus 
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下载免费PDF全文 Charles C. Mischke Matt J. Griffin David J. Wise Terrence E. Greenway 《Journal of the World Aquaculture Society》2016,47(2):212-219
Proliferative gill disease (PGD) in catfish is caused by the myxozoan Henneguya ictaluri. The complex life cycle requires Dero digitata as the oligochaete host. Efforts to control PGD by eradicating D. digitata have been unsuccessful. Smallmouth buffalo, Ictiobus bubalus, (SMB) are opportunistic bottom feeders and a putative option for controlling D. digitata. In 2011, 15 ponds (0.4 ha) were stocked with 5000 channel catfish, Ictalurus punctatus; 7 of these 15 ponds were also stocked with 300 SMB fingerlings. There were no differences in benthic invertebrate numbers or water quality variables between ponds with or without SMB. At harvest, there were no differences in percent survival, total weight, or catfish feed conversion ratio. In the second year, 18 ponds (0.4 ha) were stocked with 6000 channel catfish. Half the ponds were also stocked with 300 SMB. Sentinel fish were used to estimate disease severity, and pond water was collected for molecular estimation of H. ictaluri actinospore concentrations. Similar to the first year, there were no differences between treatments in any variable tested, including PGD severity in sentinel fish and parasite concentrations in pond water. Under these study conditions, presence of SMB did not have a measureable effect on PGD incidence, parasite density, or overall catfish production. 相似文献
6.
Sandra L. Marín Juan Carvajal Andrs Manríquez Melinka Mancilla 《Aquaculture (Amsterdam, Netherlands)》2009,295(1-2):138-141
Galaxias maculatus, the common jollytail, is a native smelt fish with a lacustrine or diadromous life cycle. In Chile, the rearing cycle of this fish includes a freshwater and a marine phase. Several diseases and parasites reported for the freshwater phase could be avoided by rearing the fish in salty or brackish water. Nonetheless, this alternative could result in Caligus rogercresseyi infections. The objective of this study was to evaluate experimentally the capacity of C. rogercresseyi to infect the common jollytail and the effects this parasite may cause to the fish. Prevalence and intensity of experimental C. rogercresseyi infections on G. maculatus were estimated and the effects of this parasitosis on the fish were evaluated on fish survival, weight loss, swimming behavior, and skin damage. Two experiments were carried out with adult fish taken from the Maullín Estuary. Fish were acclimatized to a salinity of 32 ppt and divided into two groups of 20 fish each. The experimental group was infected with copepodid stages of C. rogercresseyi and the other was used as a control. The fish were kept in individual tanks until observing ovigerous female copepods. C. rogercresseyi recognizes G. maculatus as a host under experimental conditions and optimal salinity for the parasite. Results show that under experimental condition copepodid stage can successfully infect the fish, developing to the adult stage, mating, and producing eggs (females). C. rogercresseyi caused alterations in fish behavior, superficial body damage, weight loss, and mortality. Rearing the common jollytail in salty water should take into consideration measures to control these infections as they can damage fish and affect surrounding wild fish populations. There are no records of this parasite in natural common jollytail populations; however, our understanding of the ecological role played by the common jollytail in C. rogercresseyi transmissions among sympatric host species could be greatly improved through further research related to host preferences and epidemiological data for different sympatric host species. 相似文献
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8.
- To understand the ecological factors behind the decline of functionally important threatened species with complex life cycles, many different life‐cycle stages need to be investigated. The highly threatened unionoid freshwater mussels, with their complex life cycle, including a parasitic stage on host fish, often have a large influence on biodiversity and ecosystem functioning.
- The overall aim of the present article is to summarize and discuss the impact of two articles published in Aquatic Conservation: Marine and Freshwater Ecosystems (AQC) on biotic interactions and adaptation of a threatened unionoid mussel (Margaritifera margaritifera) to its host fish (Salmo trutta).
- The two AQC publications described research on the influence of population size and density of mussels and host fish, and host–parasite interactions between mussels and their host fish, on the recruitment of juvenile mussels.
- The results from these publications filled gaps in knowledge and resulted in recommendations and incentives for conservation. The results and method development have been used in practical conservation work with threatened mussel species and have been implemented and cited in management handbooks. The outcome of the publications has been implemented in large conservation and restoration projects, and in several recent scientific publications.
- Specifically, the results from one publication showed that ecological parameters such as mussel and host fish density and population size influenced recruitment of the threatened freshwater pearl mussel. The results from the second publication showed that understanding host–parasite interactions is important for comparing the suitability of host fish strains, and that host fish strains differ in their suitability for mussel infestations. In combination, the articles show that integrating ecological parameters of threatened mussels and their host fish with host–parasite interaction experiments can be an important influence on conservation recommendations, adaptive management and national management programmes for threatened species.
9.
The development of Myxobolus bramae Reuss 1906, a myxosporean parasite of the gills of common bream Abramis brama L., was studied in experimentally infected oligochaetes. In five experiments, uninfected Tubifex tubifex (Müller) and Limnodrilus hoffmeisteri Claparéde were exposed to mature myxospores of M. bramae . In four experiments triactinomyxon type actinospores developed in Tubifex specimens but no infection was found in Limnodrilus . Actinospores were released from oligochaetes 70–81 days after initial exposure. At that time pansporocysts containing eight actinospores were located in the gut epithelium of experimental oligochaetes, but free actinosporean stages were also found in their gut lumen. Each actinospore had three pyriform polar capsules and a barrel-shaped sporoplasm with 32 secondary cells. The spore body joined the three caudal projections with a stout style. The total length of the actinospore was 139 μm on the average. 相似文献
10.
Jens‐Eike Taeubert Marco Denic Bernhard Gum Michael Lange Juergen Geist 《水产资源保护:海洋与淡水生态系统》2010,20(7):728-734
- 1. The complex life cycle of endangered European freshwater pearl mussel Margaritifera margaritifera L. involves an obligatory parasitic phase on a host fish. Knowledge on the host–parasite interaction and on the suitability of different host fish species and strains is required both for the management of wild fish and mussel populations as well as for improving the efficiency of captive breeding methods.
- 2. In this study, the suitability of different salmonid strains for hosting glochidia was tested, including Danube salmon (Hucho hucho L.) and three brown trout (Salmo trutta L.) strains from inside and outside the freshwater pearl mussel distribution range. All brown trout strains as well as Danube salmon were successfully infected with freshwater pearl mussel glochidia and encystment of mussel larvae was detected.
- 3. One brown trout strain originating from the natural pearl mussel distribution range was identified as the most suitable host, revealing the highest fish‐weight‐normalized infection rates and highest glochidial growth rates, whereas endemic Danube salmon was least suitable. Under natural conditions, the role of Danube salmon may be attributed to the long‐distance dispersal of glochidia in the Danube system, whereas sedentary brown trout appear to be the most important hosts at a local scale.
- 4. Successful infection of suitable hosts and the maintenance of these host–parasite systems in calcareous water were demonstrated in this study. These results indicate that neither the infection process nor the encystment phase of freshwater pearl mussels is dependent on low lime concentrations.
- 5. The results of this study suggest that careful selection and management of appropriate host fish strains is mandatory for sustainable conservation management of freshwater pearl mussel populations. Copyright © 2010 John Wiley & Sons, Ltd.
11.
Life cycle inference and phylogeny of Ortholinea labracis n. sp. (Myxosporea: Ortholineidae), a parasite of the European seabass Dicentrarchus labrax (Teleostei: Moronidae), in a Portuguese fish farm 下载免费PDF全文
下载免费PDF全文 L F Rangel S Rocha G Casal R Castro R Severino C Azevedo F Cavaleiro M J Santos 《Journal of fish diseases》2017,40(2):243-262
Ortholinea labracis n. sp. is described and its life cycle is inferred from a Southern Portuguese fish farm, with basis on microscopic and molecular procedures. This myxosporean parasite infects the urinary bladder of the European seabass Dicentrarchus labrax and the intestinal epithelium of a marine oligochaete of the genus Tectidrilus. Myxospores subspherical in valvular view and ellipsoidal in sutural view measuring 7.6 ± 0.3 (6.8–8.7) μm in length, 7.2 ± 0.2 (6.7–7.7) μm in width and 6.5 ± 0.4 (5.8–7.7) μm in thickness. Two polar capsules, 3.0 ± 0.2 (2.6–3.4) μm long and 2.4 ± 0.1 (2.0–2.9) μm wide, located at the same level, but with divergent orientation and opening to opposite sides of the suture line. Sequencing of the SSU rRNA gene revealed a similarity of 100% between the analysed myxospores and triactinomyxon actinospores. The phylogenetic setting of O. labracis n. sp. shows subgrouping in correlation with tissue tropism, but identifies this parasite as another exception to the main division of Myxosporea into the main freshwater and marine lineages. 相似文献
12.
Invasive Chinese pond mussel Sinanodonta woodiana threatens native mussel reproduction by inducing cross‐resistance of host fish 下载免费PDF全文
下载免费PDF全文 Seth W. Donrovich Karel Douda Věra Plechingerová Kateřina Rylková Pavel Horký Ondřej Slavík Huan‐Zhang Liu Martin Reichard Manuel Lopes‐Lima Ronaldo Sousa 《水产资源保护:海洋与淡水生态系统》2017,27(6):1325-1333
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C M J Delannoy R N Zadoks M Crumlish D Rodgers F A Lainson H W Ferguson J Turnbull M C Fontaine 《Journal of fish diseases》2016,39(1):13-29
Streptococcus agalactiae infections in fish are predominantly caused by beta‐haemolytic strains of clonal complex (CC) 7, notably its namesake sequence type (ST) 7, or by non‐haemolytic strains of CC552, including the globally distributed ST260. In contrast, CC23, including its namesake ST23, has been associated with a wide homeothermic and poikilothermic host range, but never with fish. The aim of this study was to determine whether ST23 is virulent in fish and to identify genomic markers of fish adaptation of S. agalactiae. Intraperitoneal challenge of Nile tilapia, Oreochromis niloticus (Linnaeus), showed that ST260 is lethal at doses down to 102 cfu per fish, whereas ST23 does not cause disease at 107 cfu per fish. Comparison of the genome sequence of ST260 and ST23 with those of strains derived from fish, cattle and humans revealed the presence of genomic elements that are unique to subpopulations of S. agalactiae that have the ability to infect fish (CC7 and CC552). These loci occurred in clusters exhibiting typical signatures of mobile genetic elements. PCR‐based screening of a collection of isolates from multiple host species confirmed the association of selected genes with fish‐derived strains. Several fish‐associated genes encode proteins that potentially provide fitness in the aquatic environment. 相似文献
15.
I. Thibault R. D. Hedger J. J. Dodson J.‐C. Shiao Y. Iizuka W.‐N. Tzeng 《Ecology of Freshwater Fish》2010,19(3):348-360
Thibault I, Hedger RD, Dodson JJ, Shiao J‐C, Iizuka Y, Tzeng W‐N. Anadromy and the dispersal of an invasive fish species (Oncorhynchus mykiss) in Eastern Quebec, as revealed by otolith microchemistry. Ecology of Freshwater Fish 2010: 19: 348–360. © 2010 John Wiley & Sons A/S Abstract – Rainbow trout (Oncorhynchus mykiss) is invading rivers bordering the St. Lawrence Estuary (Quebec, Canada). Some rivers in Eastern Quebec support self‐sustaining populations while adult vagrants are frequently captured in rivers where no reproduction has been confirmed. We hypothesised that the development of anadromy has promoted the species dispersal. Otolith Sr:Ca analyses revealed that although all fish captured in the upstream stocking region were freshwater residents, both anadromous and freshwater resident phenotypes were found downstream in Eastern Quebec. The proportion of fish exhibiting the anadromous life cycle increased with the distance from the stocking zone. Eastern Quebec steelhead migrated to sea at the same age but at a larger size than steelhead within their native range. Age at first reproduction was similar to that observed in native populations. The development of the anadromous life cycle enables this species to colonise new rivers following long‐distance migrations along the St. Lawrence Estuary corridor. 相似文献
16.
Completion of the Pacific bluefin tuna Thunnus orientalis (Temminck et Schlegel) life cycle 总被引：1，自引：0，他引：1
Yoshifumi Sawada Tokihiko Okada Shigeru Miyashita Osamu Murata & Hidemi Kumai 《Aquaculture Research》2005,36(5):413-421
Tuna aquaculture is currently dependent on the wild capture of juveniles for production. The development of hatchery technology for bluefin and other tunas would be a major step forward in improving sustainability of their aquaculture. The present study overviews the technology in the life cycle completion of the Pacific bluefin tuna (PBT) Thunnus orientalis (Temminck et Schlegel) under aquaculture conditions in Kinki University, and the problems to be solved for the establishment of tuna hatchery technology. On 23 June 2002, broodstock of PBT that were artificially hatched and reared spontaneously spawned in captivity. The resulting eggs hatched and were subsequently reared to the juvenile stage. The spawning fish were the result of a research project started in 1987 to rear wild‐caught juvenile PBT that were several months old. Fertilized eggs were obtained from these fish in 1995 and 1996. Resulting juveniles (the artificially hatched first generation) were reared to maturity and spawned in 2002. Over the summer of 2002, 1.63 million eggs from these fish were used for a mass rearing experiment, and 17 307 juveniles were produced and transferred to an open sea net cage. Of these artificially hatched second‐generation PBT, 1100 grew to approximately 95 cm total length and 14 kg body weight in 22 months. This procedure means the completion of PBT life cycle under aquaculture conditions, which was first attained among large tuna species. The problems awaiting solution in PBT hatchery production are their unpredictable spawning in captivity, to improve survival during the first 10 days post hatch, to reduce cannibalism in larval and juvenile stages, and to solve collision problem causing high mortality during the juvenile stage. 相似文献
17.
Lucelia Tessaro Talita Sarah Mazzoni Robie Allan Bombardelli Arno Juliano Butze Irani Quagio‐Grassiotto 《Aquaculture Research》2019,50(12):3507-3518
The reproductive dynamics of a species is important information to have for the maintenance and reproduction of animals in captivity, for either commercial or conservation purposes. Steindachneridion melanodermatum is an endemic fish that has been reproduced by breeding protocols, but knowledge related to the maturation and reproductive cycle of this species is scarce. The purpose of this research was to observe different parameters related to the reproductive biology of males born in captivity over a 24‐month period to determine the first maturation and reproductive activity of S. melanodermatum males maintained in captivity. Body development changes (weight and length) were observed, and gonadosomatic index (GSI) and plasma sex steroids (testosterone and 17β‐estradiol) were measured monthly. Phases of the reproductive cycle were detected based on macroscopic changes and histological observations of the testes. The obtained data were correlated, demonstrating that the GSI values accompanied testis development and sex steroid peaks. Additionally, immunohistochemistry was performed for the detection of KI‐67, 3β‐HSD and Vasa protein. Our data analysis indicated that the first maturity in males bred in captivity occurred after one year (at 22‐month‐old fish), with a reproductive period occurring from September to November, which is the spring season in the southern hemisphere. 相似文献
18.
Heavy loads of parasitic freshwater pearl mussel (Margaritifera margaritifera L.) larvae impair foraging,activity and dominance performance in juvenile brown trout (Salmo trutta L.) 下载免费PDF全文
下载免费PDF全文 Karl Filipsson Tina Petersson Johan Höjesjö John J. Piccolo Joacim Näslund Niklas Wengström E. Martin Österling 《Ecology of Freshwater Fish》2018,27(1):70-77
The life cycle of the endangered freshwater pearl mussel (Margaritifera margaritifera) includes a parasitic larval phase (glochidia) on the gills of a salmonid host. Glochidia encystment has been shown to affect both swimming ability and prey capture success of brown trout (Salmo trutta), which suggests possible fitness consequences for host fish. To further investigate the relationship between glochidia encystment and behavioural parameters in brown trout, pairs (n = 14) of wild‐caught trout (infested vs. uninfested) were allowed to drift feed in large stream aquaria and foraging success, activity, agonistic behaviour and fish coloration were observed. No differences were found between infested and uninfested fish except for in coloration, where infested fish were significantly darker than uninfested fish. Glochidia load per fish varied from one to several hundred glochidia, however, and high loads had significant effects on foraging, activity and behaviour. Trout with high glochidia loads captured less prey, were less active and showed more subordinate behaviour than did fish with lower loads. Heavy glochidia loads therefore may negatively influence host fitness due to reduced competitive ability. These findings have implications not only for management of mussel populations in the streams, but also for captive breeding programmes which perhaps should avoid high infestation rates. Thus, low levels of infestation on host fish which do not affect trout behaviour but maintains mussel populations may be optimal in these cases. 相似文献
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Nematode parasites infecting the starry batfish Halieutaea stellata (Vahl) (Lophiiformes: Ogcocephalidae) from the East and South China Sea 下载免费PDF全文
下载免费PDF全文 The starry batfish Halieutaea stellata (Vahl) is a small, benthic fish found in Indo‐West Pacific Oceans. However, our present knowledge of the helminth parasites of this fish is still fragmentary. In this study, a total of 29 fish collected from the East and South China Sea were examined to determine the prevalence, intensity and species composition of helminth parasites in H. stellata. Using morphological and molecular approaches, four species of nematodes were found parasitic in this fish host, including the adults and fourth‐stage larvae of Raphidascaroides nipponensis Yamaguti 1941; adults and third‐stage larvae of Raphidascaris lophii (Wu 1949), third‐ and fourth‐stage larvae of Hysterothylacium larval type IV‐A of Shamsi, Gasser & Beveridge 2013 and third‐stage larvae of Hysterothylacium amoyense (Hsü 1993). Halieutaea stellata represents a new host record for the three last‐named nematodes. Raphidascaroides nipponensis with the highest prevalence (82.5%) and intensity (mean = 13.5) of infection was considered as the dominant parasite species in H. stellata. The detailed morphology of the different developmental stages of the four nematode species was studied using light and scanning electron microscopy. All nematode species were also genetically characterized by sequencing and analysing the internal transcribed spacer (ITS) of the ribosomal DNA. This study provides further data on the occurrence of nematode parasites in H. stellata and also contributes to facilitate an accurate and rapid diagnosis of the infection by these little‐known nematodes. 相似文献