Non-salmonid Fish Research Articles

Establishment and Characterization of Seven Continuous Cell Lines from Freshwater Fish

Seven continuous cell lines were established from salmonid and nonsalmonid fishes. Salmonid cell lines derived from rainbow trout Oncorhynchus mykiss and chum salmon O. keta were designated RTE and RTE-2 (rainbow trout embryo), RTT (rainbow trout tail), and SEH (“sake” or chum salmon embryo head). Nonsalmonid cell lines derived from pond smelt Hypomesus olidus, chevron snakehead Channa striata, and goldfish Carassius auratus were designated WF-1 (“wakasagi” fin), SHH (snakehead heart), and EPG (epithelioma papulosum of goldfish), respectively. Optimum growth for most of the cell lines was observed in Eagle's minimum essential medium buffered with sodium bicarbonate (26 mM) or a combination of sodium bicarbonate (8.9 mM) and tris (16 mM). Likewise, most of the cell lines showed optimum growth at the lowest NaCl concentration tested (0.116 M). Optimum growth temperatures ranged from 15 to 20°C for the salmonid cell lines and from 15 to 30°C for nonsalmonid cell lines. Except for RTT, the cell lines were heteroploid. Eleven fish viruses were used to test the susceptibility of these cell lines. Cell lines derived from salmonids developed cytopathic effects (CPE) when infected with 10 of the 11 fish viruses tested, except for RTT, which produced CPE with only 8 of the fish viruses. Six fish rhabdoviruses used in this study elicited a pronounced CPE when inoculated into nonsalmonid cell lines EPG, WF-1, and SHH. Among the new cell lines, RTE-2 showed the best potential for the isolation of fish viruses.

Comparative Growth Response of Fish Cell Lines in Different Media, Temperatures, and Sodium Chloride Concentrations.

Growth responses to three different media, temperatures, and sodium chloride concentrations in the media were determined for 13 salmonid and 14 non-salmonid fish cell lines. Most cell lines showed better growth in Eagle's MEM than in Medium 199 or in Leivobitz L-15 medium. Nine salmonid cell lines grew well in the normal sodium bicarbonate buffer in Eagle's MEM, while 11 non-salmonid cell lines grew better in Eagle's MEM buffered with either HEPES-bicarbonate or Tris-bicarbonate. Optimum temperature for growth ranged from 15 to 20°C for almost all salmonid cells and 20 to 30°C for non-salmonid cells. Most of the cell lines showed highest growth in commercial medium preparations with the lowest concentration of sodium chloride (0.116M) examined. However, three of the six cell lines derived from rainbow trout, Oncorhynchus mykiss and cell lines from eels, Anguilla japonica, showed optimum growth response at a higher sodium chloride concentration of 0.171M in the medium.

Cell-Surface-Associated Properties of Fish Pathogenic Bacteria

Abstract Pathogenicity assays showed that 33 of 42 potentially pathogenic strains of bacteria tested were virulent to rainbow trout Oncorhynchus mykiss. Regardless of their degree of virulence to fish, strains of motile Aeromonas, A. salmonicida, and Vibrio anguillarum were moderately hydrophobic. Only 46 and 25°10 of the strains were able to hemagglutinate human and trout erythrocytes, respectively. Hydrophobicity and hemagglutination were practically absent in isolates of Yersinia ruckeri. A notable number of the strains positively adhered to salmonid (51%) and nonsalmonid (55%) fish cells. Whereas the treatment of the bacteria with proteinase K or trypsin did not decrease the hydrophobicity of the isolates, within motile Aeromonas and A. salmonicida species, strains with both protease-sensitive and -resistant hemagglutinating and adhesive abilities occurred. The effects of heat and sugars on hemagglutinating and hydrophobic properties varied within all bacterial groups. Although treatment of strains wi...

Factors Influencing the Body Condition of Rainbow Trout in Small Wyoming Reservoirs

ABSTRACT Possible relations between the body condition of rainbow trout (Oncorhynchs mykiss) and the density of salmonid fishes, the abundance of non-salmonid fishes, and two measures of biological productivity—total dissolved solids and elevation above mean sea level—were assessed for 13 small (< 170 surface hectares) reservoirs in Wyoming. The mean condition of rainbow trout was positively related to total dissolved solids and negatively related to the abundance of non-salmonid fishes.

Do brook charr (Salvelinus fontinalis) from insular Newfoundland have different parasites than their mainland counterparts?

Based on the published literature, comparison of the metazoan parasite faunas of brook char (Salvelinus fontinalis) from freshwater localities in northeastern North America reveals that hosts in insular Newfoundland have fewer parasite species recorded from them. Of 45 parasite species or taxa, only 20 are common to the island and the mainland. Twenty-three parasite species have been reported from the mainland but not from the island, with most of the taxa being types common to non-salmonid fishes. Two species, the copepod Ergasilus luciopercarum and the digenean Tetracotyle, have been reported from charr on the island but not from the northeastern mainland. It is suggested that the primary reason for the difference in the structure of the assemblages is the lack of contact brook charr in Newfoundland have with percid, cyprinid, centrarchid, esocid, and catostomid fishes and their parasites.

サケ亜目魚類Ｉ型コラーゲンのサブユニット組成

It was previously shown that among fishes in the suborder Salmonoidei, chum salmon and rainbow trout which belong to Salmonidae possessed the skin Type I collagens with a subunit composition of α1α2α3, contrasted to the collagen with (α1)2α2 of ayu which belongs to Plecoglossidae. In this study, soluble skin and/or muscle Type I collagens were isolated from seven fish species in Salmonoidei and characterized with respect to their subunit composition.Chromatographic and electrophoretic analyses revealed the existence of α1α2α3 heterotrimers in the skin Type I collagens of three other salmonid fishes (Japanese char, masu salmon, and coho salmon) and their α3 chains were distinct in chromatographic behaviour on CM-cellulose from those of many other teleosts. The muscle Type I collagen of Japanese char, however, was composed virtually of an (α1)2α2 heterotrimer, although the possible presence in trace amounts of an α1α2α3 heterotrimer could not be excluded; the same result was previously obtained for the muscle Type I collagen of chum salmon. These composite results indicated the tissue-specificexpression in salmonid fish of a Type I collagen α3 gene. On the other hand, the skin or muscle Type I collagens of several non-salmonid fishes (capelin, Japanese smelt, ayu, and icefish) were found to lack an α3 chain characteristic of many groups of teleosts and existed as (α1)2α2 heterotrimers.

Effects of Cortisol Implants on the PKX Myxosporean Causing Proliferative Kidney Disease in Rainbow Trout, Salmo gairdneri

The myxosporean (PKX) that causes proliferative kidney disease in salmonid fishes is found primarily in the kidney interstitium of clinically affected fish, where it invokes a severe inflammatory response. Incomplete spores are observed in the lumen of kidney tubules in recovering fish. PKX-infected rainbow trout, Salmo gairdneri, were immunosuppressed with cortisol implants to determine if a reduction in renal interstitial inflammation would enhance the development of the parasite. Immunosuppression of these fish was indicated by high plasma cortisol levels, chronic mortality due to opportunistic pathogens, and depressed leucocrits when compared to infected fish not receiving cortisol implants. Cortisol-treated PKX-infected fish had 20 times the density of interstitial PKX compared with nontreated fish, but showed less interstitial inflammation. All of the former group examined at 4 wk postimplantation exhibited intraluminal sporogonic forms of PKX, whereas no sporogonic forms were detected in the nontreated fish. Suppression of the inflammatory response clearly enhanced the parasite's ability to reach the sporogonic stage, but did not induce complete development of the spore. Possibly the kidney tubules of rainbow trout do not provide the proper physiological environment for complete sporulation of PKX and a nonsalmonid fish may be the primary host.

Effects of Urban Development on Fish Population Dynamics in Kelsey Creek, Washington

Abstract A 30-month study of the comparative dynamics of the fish populations inhabiting Kelsey Creek, located in the City of Bellevue, Washington, and a nearby pristine control stream suggest that urban development has resulted in a restructuring of the fish community. Environmental perturbations, including habitat alteration, increased nutrient loading, and degradation of the intragravel environment appeared to have a greater impact on coho salmon Oncorhynchus kisutch and nonsalmonid fish species than on cutthroat trout Salmo clarki. Although the total biomass (g/m2) of fish in each stream was similar, its composition differed markedly. Ages 0 and I cutthroat trout were the majority of the fish community inhabiting Kelsey Creek, whereas the control stream supported a diverse assemblage of salmonids of various ages and numerous nonsalmonids. The rapid growth and greater biomass of salmonids in Kelsey Creek (a 2-year mean of 3.51 g/m2 versus 2.03 g/m2 in the control stream) resulted in a total annual net ...

Characteristics of a new herpesviral isolate from salmonid fish.

The characteristics of virus (strain H-83) isolated from apparently healthy masu salmon (Oncorhynchus masou) were investigated. The isolate replicated in line cells derived from salmonid fish but not in those from non-salmonid fish. Cell monolayers infected with the virus showed cytopathic effect characterized by syncytia with intranuclear inclusion bodies and many metachromatic granules in the cytoplasm. Enveloped virions were estimated to be approximately 250nm in diameter and possessed hexagonal nucleocapsides of 103 to 118nm. The physicochemical and morphological features indicated that the strain H-83 is a herpesvirus. Viral antigens were detected in the cytoplasm and membrane of virus-infected cells by immunofluorescent antibody test. Cross neutralization test among strain H-83 and two other herpesviruses, Herpesvirus salmonis and Oncorhynchus masou virus (OMV), indicated that these three viruses were serologically different from each other. Further, the restriction endonuclease cleavage analysis of viral DNA showed that the cleavage pattern of the strain H-83 DNA was similar to that of OMV, while apparently distinct from H. salmonis.

Suitability of Vertical Slot and Denil Fishways for Passing North-Temperate, Nonsalmonid Fish

A vertical slot fishway and two Denil fishways (of 10 and 20% slope) built into a weir on the Lesser Slave River (55°18′N, 115°45′W) were studied from May 12 to June 25, 1984, to determine how effectively these designs pass north-temperate, nonsalmonid fishes. Thousands of spottail shiner (Notropis hudsonius), substantial numbers (&gt; 100) of northern pike (Esox lucius), longnose sucker (Catostomus catostomus), white sucker (Catostomus commersoni), immature yellow perch (Perca flavescens), and lesser numbers of burbot (Lota lota), adult yellow perch, lake whitefish (Coregonus clupeaformis), and trout-perch (Percopsis omiscomaycus) ascended the fishways. Walleye (Stizostedion vitreum) and goldeye (Hiodon alosoides), although probably moving extensively through the river, did not use the fishways. Although high water levels allowed most fish to surmount the weir, of those that chose the fishway, pike strongly preferred to ascend the Denil fishways and the two sucker species preferred to ascend the vertical slot. Therefore, a combination of several different fishways may be required for the most efficient passage of a wide variety of species. Plasma glucose and lactate measurements on pike revealed that ascending the Denil fishways was only moderately stressful for these fish.

The taxonomy of Gyrodactylus (Monogenea) parasitizing certain salmonid fishes of North America, with a description of Gyrodactylus nerkae n. sp.

Specimens of Gyrodactylus Nordmann, 1832, both newly collected and deposited type material, from cultured and wild salmonid fishes from various localities in North America, are compared and five species are recognized: G. salmonis Yin and Sproston, 1948 status emended, on Salmo clarki, S. salar, S. aguabonita, S. gairdneri, S. trutta, Salvelinus fontinalis, S. namaycush, and Oncorhynchus kisutch from several localities throughout the continent; Gyrodactylus nerkae n. sp. on O. nerka from Vancouver Island; G. colemanensis Mizelle and Kritsky, 1967 on Salmo gairdneri from California, Arkansas, and insular Newfoundland, S. fontinalis from Nova Scotia and Ontario, and S. trutta, S. namaycush, and S. fontinalis × S. namaycush from Ontario; G. avalonia Hanek and Threlfall, 1969 on S. gairdneri from Nova Scotia; and G. brevis Crane and Mizelle, 1967 on S. gairdneri from California. Gyrodactylus salmonis, G. nerkae, and G. colemanensis are considered specific to salmonid fishes, whereas G. avalonia and G. brevis are considered "accidental" infections, acquired from nonsalmonid fishes. A diagnostic key to the five species is provided and gyrodactyliasis, as a disease of cultured salmonids in North America, is discussed briefly.

Diseases of farmed fish: non-salmonids including eels and crustacea.

All cultured fish are subject to very similar parasitic and bacterial conditions. These disease outbreaks are often stress mediated due to adverse environmental factors. The non-salmonid fishes are affected by a number of specific viral diseases which may vary from mild skin infections to systemic conditions resulting in high mortality. Nutritional diseases may be associated with dietary deficiencies or inclusion of toxic products in artificial feeds.

Comparative Protein Analysis of Non-salmonid Fish Rhabdoviruses

SUMMARY On the basis of gel precipitation, reactions with rabbit anti-pike fry rhabdovirus sera, a recent virus isolate (V75/94) from pike fry, and the grass carp rhabdovirus were found to be indistinguishable from pike fry rhabdovirus. The proteins of these viruses were compared to those of spring viraemia of carp virus. In ‘rocket’ immunoelectrophoresis the pike fry rhabdoviruses and the grass carp rhabdovirus showed up to 4 lines with homologous antiserum in which the precipitates formed by the G and M proteins were fused. With this antiserum, spring viraemia of carp virus gave only one precipitation are which was formed by the N protein. All the viruses are very similar to vesicular stomatitis virus with respect to the mol. wt., localization and phosphorylation of structural proteins. In polyacrylamide-SDS slab gels the viruses showed minor differences in the migration of their respective NS proteins.

Neutralization and Enhancement of Infectivity of Non-salmonid Fish Rhabdoviruses by Rabbit and Pike Immune Sera

SUMMARY Plaque neutralization assays were carried out using the rhabdoviruses of pike fry (2 isolates), spring viraemia of carp and grass carp. When rabbit anti-pike fry rhabdovirus sera were used, no neutralizing activity was observed but plaque counts increased with heat-inactivated sera or sera that had been stored at -20 °C for prolonged periods. Antibody binding to the virus was demonstrated by gradient centrifugation experiments. The use of immune serum alone or in combination with anti-rabbit gamma globulin serum resulted in aggregation of radioactive virus. Aggregation was also observed when anti-rabbit gamma globulin serum was added under neutralization test conditions. Addition of non-inactivated guinea-pig serum to mixtures of pike fry rhabdovirus and rabbit antiserum to spring viraemia of carp virus resulted in strong neutralization, whereas this antiserum alone or in the presence of inactivated guinea-pig serum gave an increase in plaque numbers. The increase in plaque number and the complement-dependent neutralization phenomena were weak or absent in the homologous spring viraemia of carp virus system. Immunization of pike with pike fry rhabdovirus resulted in an increase in virus neutralizing activity which could be attributed to the macroglobulin fraction of the serum. After immunizations over a period of 6 months with virus antigens, no further increase in neutralizing activity was observed. Pike sera showed 50% plaque reduction at concentrations between 0.017 and 0.3%. Using these sera it could be demonstrated that the grass carp virus and the V 75/94 isolate from pike fry were indistinguishable from the original pike fry rhabdovirus, whereas spring viraemia of carp virus was different.

Furunculosis in Nonsalmonids

Natural furunculosis infection in a group of bait and other nonsalmonid fishes in southern Ontario is described. The source of infection, although not positively identified, appears to have been derived from an adjacent stream or from infected crayfish.

The Movements and Population Densities of Roach (Rutilus rutilus (L.)) and Gudgeon (Gobio gobio (L.)) in the River Mole

The movements of coarse (i.e. non-salmonid) fish have been little studied, although recently Williams (1965) has produced evidence to show that in the Thames most of the roach, perch (Percafluviatilis L.) and dace (Leuciscus leuciscus (L.)) ranged over a limited area. Lelek (1962) tentatively concluded that gudgeon were not tied to one part of a river, being free to move into any area where food was available, but he subsequently formed the opinion (Lelek, private communication) that the sections of river in which he worked were perhaps too small to satisfy the requirements of the species. His colleague, Lusk (1963), who worked on a larger section of river, found that 770 of the gudgeon he marked were still in the same area 100 days later and concluded that they occupied a 'home range' (Gerking 1953). Other evidence also points to the restricted movements of native fish; Worthington (1950) quotes marking experiments carried out by Le Cren in Windermere which indicated that perch showed little movement along the shore line and that there was a strong tendency for artificially displaced fish to return to their original locations. Catches taken in a trap for upstream migrants (Fishery Officer's report to Lancashire River Board, 1951) show that, apart from an occasional chub (Squalius cephalus (L.)) which appeared to move in response-to increases in water flow, very few coarse fish travelled upstream from spring to early winter except between 17 and 30 May, when there was a marked movement of roach which might have been associated with spawning. Roach spawning migrations are mentioned by Yarrel (1841) and, according to Svardson (1952), they migrate into shallow water before spawning. Hartley (1947) reported a similar phenomenon although he regarded it as unproven because his data came from traps whose catching power was possibly dependent on an activity factor in the fish. The present investigation was carried out partly in the River Mole and partly in a convoluted channel built in the laboratory to conduct experiments in an attempt to explain the field observations. A preliminary analysis of the movements of roach in the river has already been published (Stott 1961) and these data are further examined in this paper together with data for gudgeon. Mark-recapture estimates of population densities have also been made from the movement data.

"Salmon Poisoning" Disease. II. Second Intermediate Host Susceptibility Studies

The fishes Cottus perplexus, Lampetra richardsoni, L. tridentata, and Richardsonius balteatus and the Pacific giant salmander, Dicamptodon ensatus, all from western Oregon streams, were found naturally infected with metacercariae of Nanophyetus salmincola, the salmon poisoning fluke. This is the first report of natural infections in an animal other than a fish and in nonsalmonid fishes. Fourteen species of fishes were experimentally infected: Salmo gairdneri, S. salar, S. trutta, Salvelinus fontinalis, S. namaycush, Lampetra richardsoni, Cottus perplexus, Carassius auratus, Richardsonius balteatus, Catostomus macrocheilus, Lepomis macrochirus, Gasterosteus a. aculeatus, G. a. microcephalus, and Gambusia affinis. This extends the number of salmonid and nonsalmonid fishes susceptible to experimental infection. Cysts from all five of the naturally infected animals and from 12 of the 14 experimentally infected fishes were given to hamsters by stomach tube. In all instances except one (probably because of low dosage), the identification of the parasites as N. salmincola was confirmed by recovery of adult flukes from the hamsters. The possibility that N. schikhobalowi from Far Eastern Siberian humans, dogs, cats, and foxes, Vulpes vulpes, and N. salmincola are synonymous is discussed. Nanophyetus salmincola, the salmon poisoning fluke, requires three hosts for the completion of its life cycle. The first intermediate host is Oxytrema silicula, a stream snail found only in Oregon west of the Cascade Mountains, north to the Olympic Peninsula in Washington, and in northern California. The second intermediate hosts are fishes in which the cercariae encyst. The definitive hosts are fish-eating mammals such as canids, raccoons, mink, lynx, and the skunk. The fluke is a vector for Neorickettsia helminthoeca, the etiologic agent of salmon poisoning disease, a usually fatal illness of canids. Salmon poisoning disease was reviewed by Philip (1955), and the life cycle of the parasite was studied by Bennington and Pratt (1960). On the basis of the initial work of Donham et al. (1926) and Simms et al. (1931a, b), and in the absence of reports to the contrary, it has long been believed that salmonids were the only species of fish capable of serving as Received for publication 19 August 1965. *This investigation was supported by Public Health Service Research Grant 1-ROI-AI0659901, from the NIAID. Technical Paper No. 2030, Oregon Agricultural Experiment Station. A contribution from the Pacific Cooperative Water Pollution and Fisheries Research Laboratories. This study is a part of a thesis submitted by the senior author to the Graduate School of Oregon State University in partial fulfillment of the requirements for the degree of Master of Science. second intermediate hosts for N. salmincola. Donham et al. (1926) did not find this parasite in the following nonsalmonid fishes (scientific names were not given) taken in western Oregon: two whitefish, two smelt, one chub, one sea bass, one silver perch, and five suckers. Simms et al. (1931b) were unable to find the parasite in the following nonsalmonid fishes (numbers examined not given) from western Oregon streams: Micropterus dolomieui, smallmouth bass; Thaleichthys pacificus, eulachon or Columbia River smelt; Catostomus macrocheilus, large-scale sucker; Mylocheilus caurinu , peamouth; and Acipenser transmontanus, white sturgeon. Pernot (1911) examined one mudcat (scientific name not given) and found it uninfected. The only attempts to experimentally infect nonsalmonid fishes with N. salmincola were those of Bennington and Pratt (1960). By placing fish and infected snails together in aquaria, they infected two speckled dace, Rhinichthys osculus, one riffle sculpin, Cottus gulosus (probably perplexus in view of present knowledge of the distribution of these fishes in Oregon), and two goldfish, Carassius