A preliminary study of parasite diversity in the anadromous Kamchatkan mikizha Parasalmo mykiss mykiss (Osteichthyes: Salmoniformes: Salmonidae)

The study of parasites associated with the anadromous mikizha from several rivers of the Western Kamchatka has revealed 44 parasite species. The majority of parasites (59%) belong to marine and estuarine-marine species. Lecithophyllum bothryophorum, Echinorhynchus leidyi and plerocercoids of the family Litobothriidae were found for the first time in anadromous fish entering into Asian continental watersheds. It has been revealed that only a few specimens of the anadromous mikizha feed in fresh waters. Most of feeding fish consume a minor amount of food, and this feeding is occasional. Young forms of intestinal parasites of the freshwater and estuarine-freshwater groups (Neoechinorhynchus spp., Crepidostomum spp., Cucullanus truttae, Eubothrium salvelinf) come into anadromous fishes mainly before their entering in fresh waters.     

Analysis of microsatellite variation in the rainbow trout (Parasalmo (Oncorhynchus) mykiss) from Kamchatka

Genetic variation of Kamchatka rainbow trout Parasalmo (O.) mykiss was examined using 10 microsatellite DNA loci, and phylogeographic comparison with other representatives of the species across the distribution range was performed. It was demonstrated that Kamchatka populations differed from other geographic groups of rainbow trout in a number of microsatellite loci. These populations also displayed distinct clustering and were characterized by lower genetic diversity. Analysis of a set of 26 different microsatellite loci (personal and literature data) demonstrated that most of the populations within the Kamchatka region were separated from one another, characterized by marked geographic differentiation, and affiliation to certain river basins. In Kamchatka rainbow trout, with high degree of probability, three geographic clusters (northwestern, southwestern, and eastern) were identified. In general, analysis of microsatellite DNA supported the data on low genetic diversity of the Kamchatka group Parasalmo (O.) mykiss, based on the variation estimates for a number of genes of nuclear and mitochondrial DNA, and allozyme loci.     

Genetic divergence of mykizha (Parasalmo (Oncorhynchus) mykiss) from Kamchatka inferred from restriction analysis and sequencing of mtDNA cytochrome b gene

The populations of mykizha Parasalmo (O.) mykiss from western and eastern coasts of Kamchatka were studied by restriction analysis of a fragment of fish mitochondrial genome that included the control region and the region of the cytochrome b gene (cytb). The restriction patterns obtained with five enzymes (MspI; Tru1I; RsaI; BsuRI; DdeI) were identical in all studied individuals. Sequencing of the cytb gene showed high similarity between all samples (99.6-100%). In general, the geographical group of mykiss from Kamchatka is monophyletic with low genetic divergence at the population level. Shantarian mykiss originates most likely from that native to Kamchatka.     

Survey of parasites in threatened stocks of coho salmon (Oncorhynchus kisutch) in Oregon by examination of wet tissues and histology

We are conducting studies on the impacts of parasites on Oregon coastal coho salmon (Oncorhynchus kistuch). An essential first step is documenting the geographic distribution of infections, which may be accomplished by using different methods for parasite detection. Thus, the objectives of the current study were to (1) identify parasite species infecting these stocks of coho salmon and document their prevalence, density, and geographic distribution; (2) assess the pathology of these infections; and (3) for the first time, determine the sensitivity and specificity of histology for detecting parasites compared with examining wet preparations for muscle and gill infections. We examined 576 fry, parr, and smolt coho salmon in total by histology. The muscle and gills of 219 of these fish also were examined by wet preparation. Fish were collected from 10 different locations in 2006-2007. We identified 21 different species of parasites in these fish. Some parasites, such as Nanophyetus salmincola and Myxobolus insidiosus, were common across all fish life stages from most basins. Other parasites, such as Apophallus sp., were more common in underyearling fish than smolts and had a more restricted geographic distribution. Additional parasites commonly observed were as follows: Sanguinicola sp., Trichodina truttae , Epistylis sp., Capriniana piscium, and unidentified metacercariae in gills; Myxobolus sp. in brain; Myxidium salvelini and Chloromyxum majori in kidney; Pseudocapillaria salvelini and adult digenean spp. in the intestine. Only a few parasites, such as the unidentified gill metacercariae, elicted overt pathologic changes. Histology had generally poor sensitivity for detecting parasites; however, it had relatively good specificity. We recommend using both methods for studies or monitoring programs requiring a comprehensive assessment of parasite identification, enumeration, and parasite-related pathology.     

The Spring-Run Ecotype of the Steelhead Trout Parasalmo (Oncorhynchus) mykiss (Walbaum, 1792) (Salmonidae,Salmoniformes) in the Kamchatka Peninsula

Russian Journal of Marine Biology - A seasonal spring-run (vernal) ecotype of the Steelhead Trout Parasalmo (Oncorhynchus) mykiss (Walbaum, 1792) has been found in western Kamchatka for the first...     

The development of a new system of genetic markers for Kamchatka mykiss <Emphasis Type="Italic">Parasalmo (Onchorhynchus) mykiss</Emphasis>

Two new SCAR (Sequence Characterized Amplified Region) and ISSR (Inter Simple Sequence Repeats or Inter-Microsatellite-PCR) gene marker systems were developed for genetic analysis of populations of Kamchatka mykiss Parasalmo (O.) mykiss and other salmonids. Both systems demonstrated a high level of variability between newborn populations of mykiss, and, despite the initial species specificity, can be used for analysis of other salmonids with a complex population structure.     

Reproduction of mykiss <Emphasis Type="Italic">Parasalmo mykiss</Emphasis> in the Kol river (Western Kamchatka) and its controlling factors

For the first time, special traits of the reproduction of mykiss Parasalmo mykiss in Kamchatka are studied: dates of spawning, localization, topography and hydrology of spawning grounds, structure and fractional composition of ground of redds, duration of incubation and larval period, and thermal conditions. Possibilities of reproduction of mykiss are constrained by a narrow range of variation of spawning conditions. Spawning occurs only in tundra rivers and tributaries. The principal factor limiting reproduction of mykiss is temperature, namely a rapid warming of water in May and attaining of a necessary sum of degree-days (over 500, from the middle of May until the middle of July) during spawning and the period of incubation. Presence of water bodies of the tundra type with their special thermal conditions predetermine a possibility of reproduction of mykiss in Kamchatka and its present-day comparatively narrow area in Asia.     

A new species of myxozoan (Myxosporea) from the brain and spinal cord of rainbow trout (Oncorhynchus mykiss) from Idaho

A new species of Myxosporea, Myxobolus neurotropus n. sp., is described from the brain and spinal cord of rainbow trout (Oncorhynchus mykiss) from Duncan Creek, Owyhee County, Idaho. Spores are oval, have 2 pyriform polar capsules, and possess a thick spore wall (sutural rim) with a short intracapsular offshoot. The mean spore dimensions are length 11.8 microm, width 10.8 microm, and thickness 8.8 microm. This myxozoan is compared to other described Myxobolus species found in cranial tissues of salmonids in terms of spore morphology and phylogenetic analysis. Because it is found in brain and spinal cord, it is encountered while performing screening tests for Myxobolus cerebralis, the causative agent of salmonid whirling disease. Where chronic inflammation and granulomatous lesions are associated with M. cerebralis, histological examination shows no host response to M. neurotropus n. sp. A diagnostic polymerase chain reaction (PCR) test is included as an aid in properly identifying the species.     

Allozyme variability and genetic divergence of Pacific trout (species Parasalmo) from western Kamchatka

Genetic variation in several populations of Parasalmo (Onchorhyncus) mykiss from Kamchatka was examined on the basis of data obtained by the author and results from literature. Three (sSOD-1*, LDH-C*, and EST-1*) out of 44 protein-coding loci were highly polymorphic. Low-frequency alternative alleles occurred at sAAT-1,2*, LDH-A2*, EST-5*, IDDH-1,2*, and sMDH-1,2*. The results of the present work and comparison with evidence on North American species indicated that, in the Kamchatka part of the range, P. mykiss is represented by several populations carrying unique alleles and forming a genetically independent group. Gene exchange between North American and Western Kamchatka populations is mainly determined by straying in the feeding stock of the American coastal form entering the Sea of Okhotsk. The genetic divergence and mean heterozygosities in the Kamchatka populations were low (D magnitude of 0.0002-0.0275; HS magnitude of 0.011-0.0371). The difference between the Western Kamchatka populations from the North American coastal form was so small (D magnitude of 0.0109-0.0241) that these forms clustered together. Genetic divergence of the Kamchatka populations and the inland North American P. mykiss is an order of magnitude higher (D magnitude of 0.1973-0.2367).     

Specific features of ecology of chars of the genus <Emphasis Type="Italic">Salvelinus</Emphasis> (Salmonidae) from the basin of Lake Kronotskoe (Kamchatka) according to parasitological data

A parasitological study was performed of chars of the genus Salvelinus inhabiting Lake Kronotskoe (Kamchatka Peninsula)—S. malma, S. albus, S. schmidtii, and S. kronocius, as well as of juvenile Salvelinus spp. Twenty-three species of parasites, including six species new for the lake, Hennequya zschokkei, Protteocephalus longicollis, Diphyllobothrium dendriticum, Crepidostomum sp., Echinorhynchus salmonis, and Paracanthobdella livanowi, were found. With consideration of published data, in chars of this water body, 28 species of parasites were recorded, including seven species (N. cf. pungitius, B. luciopercae, Crepidostomum sp., Cr. fausti, Cr. cf. cooperi, Eubothrium crassium, and Proteocephalus sp.), whose presence or species identification in the lake ecosystem need confirmation. Two species (N. rutili and Diphyllobothrium sp.) are removed from the list. Parasites common for all species of chars were revealed. They include Myxobolus arcticus, E. salvelini, D. ditretum, Crepidostotum sp., Cr. farionis, Cr. metoecus, Cystidicola farionis, Cucullanus truttae, Philonema oncorhynchi, and Salmincola carpionis. Cluster analysis of the fauna of parasites of different species of chars demonstrated considerable differences in infestation, which indicates differences between them in preference for food items and occupied biotopes and thereby supports the ecological differentiation of chars in the basin of Lake Kronotskoe. S. albus and S. kronocius are most similar in parasitofauna, which is determined by their predation; S. malma as a benthophage is infected by the same species of parasites, but considerably less intensively. Extremely high indices of population numbers of some parasite species are considered as a manifestation of the Krebs cycle in parasites under the conditions of an isolated lake.     

On joint spawning of anadromous and resident mykiss <Emphasis Type="Italic">Parasalmo mykiss</Emphasis> in rivers of Western Kamchatka

The fact of joint spawning of anadromous and resident mykiss Parasalmo mykiss is reliably recorded in the basin of the Kol River (Western Kamchatka). The obtained data on relationships of these forms during spawning indicate to their conspecificity. This species should be protected as a whole, in all diversity of its forms.     

Genetic divergence of sympatric charrs of the genus Salvelinus from Nachikinskoe Lake (Kamchatka)

We studied genetic differentiation of two charr species, Dolly Varden Salvelinus malma malma Walbaum and resident lacustrine charr Salvelinus sp., which sympatrically inhabit Nachikinskoe Lake (the Bol'shaya River basin) in southwestern Kamchatka Peninsula. Using restriction analysis (RFLP), three mitochondrial DNA fragments (ND1/ND2, ND5/ND6, and Cytb/D loop) amplified in polymerase chain reaction (PCR) were compared. The divergence of the mtDNA sequences between Salvelinus sp. and S. malma malma was 2.8%; Salvelinus sp. and S. taranetzi, 0.36%; Salvelinus sp. and S. krogiusae, 0.21%; Salvelinus sp. and S. alpinus, 3.0%. These results point to reproductive isolation of charrs in Nachikinskoe Lake and support the earlier suggestion on a close relationship between Salvelinus sp., S. taranetzi, and S. krogiusae.     

In vitro effect of rainbow trout (Oncorhynchus mykiss) serum in Tylodelphys sp. (trematoda, Diplosromatidae) metacercariae]

Here, it has been described that normal fresh sera from rainbow trout (Oncorhynchus mykiss) were able to lyse Tylodelphys sp. metacercariae isolated from Galaxias maculatus (Jenyns, 1842) (Teleostei, Galaxiidae) brain. This effect was time dependent, and progressively increased since 1 h up to 18 h incubation. There were oscillations in the ability of different sera samples to lyse these parasites. Similar values were achieved with other salmonid sera, and also with normal human sera pool. The lytic activity was abolished by heat-inactivated sera, by zymosan treatment and by incubation in the presence of EDTA. However, the mean values obtained in the presence of EGTA-Mg++ did not significantly differ from those found with sera as a source of complement. The results of this study suggested the role of complement alternative pathway on Tylodephys sp. in vitro lysis, under our experimental conditions.     

Flavobacterium oncorhynchi sp. nov., a new species isolated from rainbow trout (Oncorhynchus mykiss)

Eighteen isolates of a Gram-negative, catalase and oxidase-positive, rod-shaped bacterium, recovered from diseased rainbow trout (Oncorhynchus mykiss), were characterized, using a polyphasic taxonomic approach. Studies based on comparative 16S rRNA gene sequence analysis showed that that the eighteen new isolates shared 99.2-100% sequence similarities. Phylogenetic analysis revealed that isolates from trout belonged to the genus Flavobacterium, showing the highest sequence similarities to F. chungangense (98.6%), F. frigidimaris (98.1%), F. hercynium (97.9%) and F. aquidurense (97.8%). DNA-DNA reassociation values between the trout isolates (exemplified by strain 631-08(T)) and five type strains of the most closely related Flavobacterium species exhibited less than 27% similarity. The G+C content of the genomic DNA was 33.0 mol%. The major respiratory quinone was observed to be menaquinone 6 (MK-6) and iso-C(15:0), C(15:0) and C(16:1) ω7c the predominant fatty acids. The polar lipid profile of strain 631-08(T) consisted of phosphatidylethanolamine, unknown aminolipids AL1 and AL3, lipids L1, L2, L3 and L4 and phospholipid PL1. The novel isolates were differentiated from related Flavobacterium species by physiological and biochemical tests. On the basis of the evidence from this polyphasic study, it is proposed that the isolates from rainbow trout be classified as a new species of the genus Flavobacterium, Flavobacterium oncorhynchi sp. nov. The type strain is 631-08(T) (= CECT 7678(T) = CCUG 59446(T)).     

Peculiarities of the parasitofauna of Atlantic salmon parr (Salmo salar L.), brown trout (Salmo truttae L.), and char (Salvelinus alpinus L.) in the Utsjoki River system (Northern Finland)

Data on the parasite diversity in Salmonidae fish parr from different parts of the Utsjoki River obtained during 1993-1995 and 2006-2007 are presented. Three fish species, Salmo salar L., S. truttae L., and Salvelinus alpinus L., were examined on the presence of helminthes. Twenty species of salmon parasites were found, the majority of which are the parasites with complicated life cycles. Infusorians C apriniana piscium, myxosporidia Chloromyxum januaricus and Myxobolus neurobius, metacercaria of the genera Diplostomum and Apatemon, and the nematode Raphidascaris acus larvae were the most numerous in salmon parasite fauna. Brown trout had the most number of specific parasite species, whereas char was infested by protozoan parasites only.     

Phylogenetic revision of the Charis cleonus complex (Lepidoptera: Riodinidae)

Abstract.  A revision of the Charis cleonus group of Neotropical riodinid butterflies is presented, including discussions on the taxonomy, biogeography and biology of its species, and illustrations of the adults and male and female genitalia (where known) of all taxa. We recognize twenty-two species, including nineteen new species: C. ariquemes sp.n., C. brasilia sp.n., C. breves sp.n., C. cacaulandia sp.n., C. cuiaba sp.n., C. humaita sp.n., C. ipiranga sp.n., C. iquitos sp.n., C. ma sp.n., C. manicore sp.n., C. manu sp.n., C. matic sp.n., C. maues sp.n., C. negro sp.n., C. palcazu sp.n., C. rocana sp.n., C. santarem sp.n., C. tapajos sp.n and C. tefe sp.n. A cladistic analysis using thirty-six characters of male and female genitalia and external facies generated a single most parsimonious cladogram highlighting the existence of two clades, the major and cleonus subgroups. As each species largely occupies a parapatric range, this cladogram provides the opportunity to reassess historical relationships among areas of endemism in the Amazon basin.     

Echinorhynchus brayi n. sp. (Acanthocephala: Echinorhynchidae) from Pachycara crassiceps (Roule) (Zoarcidae), a deep-sea fish

Echinorhynchus brayi n. sp. (Palaeacanthocephala: Echinorhynchidae) is described from Pachycara crassiceps (Roule) (Zoarcidae) from the Porcupine Seabight, Northeast Atlantic. The new species closely resembles E. canyonensis Huffman & Kliever, 1977, a parasite of a Pacific zoarcid, but has longer lemnisci, larger eggs and larger testes. E. brayi n. sp. can be readily differentiated from the ten other Echinorhynchus spp. recorded from deep-sea fishes (E. abyssicola, E. gadi, E. longiproboscis, E. malacocephali, E. melanoglaeae, E. muraenolepisi, E. petrotschenkoi, E. sebastolobi, E. trachyrinci and E. truttae), because it has fewer hooks per longitudinal row.     

Different susceptibility of two aquatic vertebrates (Oncorhynchus mykiss and Bufo arenarum) to azinphos methyl and carbaryl

We studied the effect of two insecticides azinphos methyl and carbaryl on two resident aquatic species (Oncorhynchus mykiss and Bufo arenarum). Juvenile trout and larval stages of toad were used for exposure and recovery assays. O. mykiss was more sensitive to azinphos methyl exposure than B. arenarum larvae, with a mean 96-h LC50 of 0.007 mg/l. Carbaryl is markedly less toxic than the organophosphate and the differences in potency, expressed as LC50, for both species varies only by five-fold. The relationship between cholinesterase (ChE) inhibition and lethality is not straightforward: O. mykiss survives with an almost complete inhibition of the brain enzyme when exposed to azinphos methyl and carbaryl. Their IC50 values are one or two orders of magnitude lower than the corresponding 96-h LC50 value. In B. arenarum larvae, the IC50 values for azinphos methyl and carbaryl are one half and one third of their 96-h LC50s, respectively. The time courses of enzyme inhibition and recovery also points out differences between both types of pesticides and species. Identifying the key features conferring species selectivity can be exploited to minimize the incidence and severity of intoxication of non-target organism. The data presented here highlight the necessity of including several species and endpoint analyses in the pesticide risk evaluations of aquatic ecosystems.     

A STUDY OF CRYPTOLECHIA ZELLER (LEPIDOPTERA: OECOPHORIDAE) IN CHINA (II): SPECIES FROM GUIZHOU PROVINCE

Abstract  The present paper reports fourteen species of the genus Cryptolechia from Guizhou Province, China. Eleven species are described as new: C. proximideflecta sp. nov., C. muscosa sp. nov., C. solifasciaria sp. nov., C. spinifera sp. nov., C. denticulata sp. nov., C. furcellata sp. nov., C. latifascia sp. nov., C. acutiuscula sp. nov., C. fasciculifera sp. nov., C. hamatilis sp. nov. and C. concaviuscula sp. nov. The female of C. gei Wang is reported for the first time, and the genital structures of the new species are illustrated.     

Screening of population genetic SCAR markers for mykiss <Emphasis Type="Italic">Parasalmo</Emphasis> (<Emphasis Type="Italic">Oncorhynchus</Emphasis>) <Emphasis Type="Italic">mykiss</Emphasis> from Kamchatka

Using AP-PCR, the genome of Kamchatka mykiss (Parasalmo (O.) mykiss) was examined. Polymorphic fragments, implying geographic differences among the samples, were selected, cloned, and sequenced. Based on these sequences, longer, specific SCAR primers were selected and constructed. Using the BLAST software program, the sequences were analyzed for analogy to those from the GenBank database. It seemed likely that all sequences obtained belonged to earlier unexamined repeated sequences, variable in the populations of the species of interest. A total of seven SCAR markers, characterized by population-significant variability of the DNA products in Kamchatka geographic group of rainbow trout were constructed. These markers can be used for further investigation of the species Parasalmo (O.) mykiss. The SCAR marker sequences were deposited in GenBank under the accession numbers EU805500 to EU805506.