Dark Chub Research Articles

Redescriptions of Illiosentis ctenorhynchus Cable & Linderoth, 1963 (Illiosentidae) and Micracanthorhynchina motomurai (Harada, 1935) (Rhadinorhynchidae: Gorgorhynchinae) (Acanthocephala: Palaeacanthocephala)

We provide redescriptions of two species of acanthocephalans in one class Palaeacanthocephala and 2 families collected from hosts in different geographical locations in Jamaica and Korea. Each species account is annotated and morphologically presented using light microscopy showing new characteristic diagnostic features. In Illiosentidae, we provide a new description of Illiosentis ctenorhynchus Cable & Linderoth, 1963 from the type host, the yellow goatfish Mulloidichthis martinicus (Cuvier) in Jamaica that completes and corrects the inadequate and incomplete original description. In Rhadinorhynchidae (Rhadinorhynchinae), we redescribe Micracanthorhynchina motomurai (Harada, 1935) from the pale chub Zacco platypus (Temminck & Schlegel) and the dark chub Zacco temmincki (Temminck & Schlegel) in Korea and complement much missing information and images. We also provide museum numbers for lectotype male, allolectope female, and paralectotypes that we have deposited as Harada did not designate type material for M. motomurai.

Resolution of cryptic species complexes within the genus Metagonimus (Trematoda: Heterophyidae) in Japan, with descriptions of four new species.

A nationwide fish survey was conducted in Japan to detect metacercariae of the genus Metagonimus (Trematoda: Heterophyidae). The metacercariae were subjected to DNA barcoding for molecular species identification. A phylogeny inferred from the sequences of mitochondrial cytochrome c oxidase subunit 1 (cox1) prompted us to recognize three cryptic species complexes (i.e., the M. miyatai complex, the M. takahashii complex, and the M. katsuradai complex). Each complex included one or two undescribed species. For morphological description, adult flukes of each species were raised through the experimental infections of immunosuppressed mice. We propose M. saitoi n. sp., M. kogai n. sp., M. shimazui n. sp., and M. kinoi n. sp., based on their phylogeny, morphology, biogeography, and ecology (host-parasite relationships). The originally described species, M. miyatai, was split into M. miyatai sensu stricto and M. saitoi n. sp. The former is distributed mainly in eastern Japan and uses the sweetfish (Plecoglossus altivelis) and daces (Pseudaspius hakonensis and Ps. sachalinensis) as principal second intermediate hosts, while the latter is in western Japan and its principal fish hosts are the dark chub (Nipponocypris temminckii) and the pale chub (Opsariichthys platypus). The present survey resolves a long-standing controversy on the microtaxonomy of Metagonimus in Japan since the first discovery of Metagonimus yokogawai in 1912, and shows that 10 species of Metagonimus are still distributed in Japan, although human metagonimiasis is almost eradicated.

Waves Out of the Korean Peninsula and Inter- and Intra-Species Replacements in Freshwater Fishes in Japan.

The Japanese archipelago is located at the periphery of the continent of Asia. Rivers in the Japanese archipelago, separated from the continent of Asia by about 17 Ma, have experienced an intermittent exchange of freshwater fish taxa through a narrow land bridge generated by lowered sea level. As the Korean Peninsula and Japanese archipelago were not covered by an ice sheet during glacial periods, phylogeographical analyses in this region can trace the history of biota that were, for a long time, beyond the last glacial maximum. In this study, we analyzed the phylogeography of four freshwater fish taxa, Hemibarbus longirostris, dark chub Nipponocypris temminckii, Tanakia ssp. and Carassius ssp., whose distributions include both the Korean Peninsula and Western Japan. We found for each taxon that a small component of diverse Korean clades of freshwater fishes migrated in waves into the Japanese archipelago to form the current phylogeographic structure of biota. The replacements of indigenous populations by succeeding migrants may have also influenced the phylogeography.

Reproduction, growth rate and dispersal of the dark chub, Candidia sieboldii, as estimated by using the mark–release–recapture method

ABSTRACTWe investigated the breeding season, growth rate and dispersal of the dark chub, Candidia sieboldii, an endangered species in Japan. A mark–release–recapture survey was performed in three branches of the Ishizu River system in Osaka Prefecture, Japan, between May 2012 and August 2013. A total of 963 individuals were marked in one river branch and 275 (29%) were recaptured at least once in the same river section. The breeding season was determined to be June–August, and the size at maturity for both males and females was estimated at about 70 mm standard length. Growth rates calculated from standard lengths of recaptured individuals were higher between April and September than between October and March. Among 963 marked individuals, only a single fish was found 500 m downstream from the release point. Moreover, although we released 409 more marked individuals in the three branches to follow inter-branch dispersal between September and December 2013, we observed none. These results indicate that this species has low dispersal and a short lifespan of 1–2 years. This short lifespan could increase the risk of breeding failure, and the low frequency of dispersal, restricted by weirs, could make population re-establishment and recovery difficult.

Differences in the behavior and ecology of wild type medaka (Oryzias latipes complex) and an orange commercial variety (himedaka).

Genetic disturbance in wild populations of medaka (Oryzias latipes complex) has been mainly caused by the introduction of the orange-red commercial variety medaka (himedaka) in Japan. To examine whether survival, reproduction, and species recognition would be influenced by this difference in body coloration, we conducted three laboratory experiments (predatory pressure, mate choice, schooling behavior) using wild type medaka and himedaka. In the predation experiment using dark chub (Candidia temminckii) as a predator, himedaka were predated upon more often than wild type medaka. However, individuals did not choose mates or select schooling groups based on himedaka or wild type medaka phenotypes. The results indicate that himedaka receive higher predation pressure but are able to easily mate with wild type medaka in a natural environment. To conserve the genetic diversity of wild medaka populations, we need to control the risk of genetic disturbance caused by himedaka.

Aggressive Interactions between the Dark Chub, Zacco temmincki, and the Pale Chub, Z. platypus, in Relation to Their Feeding Behaviour

Aggressive Interactions between the Dark Chub, Zacco temmincki, and the Pale Chub, Z. platypus, in Relation to Their Feeding Behaviour

Seasonal, Sexual and Individual Variations in Gonad Weight and Secondary Sexual Characters of the Dark Chub, Zacco temmincki

Seasonal, Sexual and Individual Variations in Gonad Weight and Secondary Sexual Characters of the Dark Chub, Zacco temmincki

Aggressive behaviour and dominance relationships of the dark chub, Zacco temmincki with special reference to their individual recognition

Aggressive behaviour and dominance relationships ofZacco temmincki were observed by introducing fish into an enclosed pond. Chase (-flee), lateral display, parallel swim and butt were the principal behavioural patterns in aggressive encounters between fish, while chase, resulting in lateral display by the chased fish was the most common behavioural sequence. Initially, mutual behavioural patterns such as parallel swim and mutual lateral display were most evident among the total aggressive acts although chase became dominant three days after introduction into the pond. The dominance matrix constructed from chase-flee interactions during all observation periods contained many reverse attacks (336 out of 2,740 chases). These reverse attacks did not concentrate upon a specific period and were not site-dependent. Examination of chase-flee interactions and the subsequent behavioural pattern revealed that a chased fish reacted to the chaser either by attacking in turn, or performing lateral display etc. roughly in relation to the dominance rank of the chaser. This result implies that fish recognized each other to a great extent during aggressive encounters. It seems likely that such individual recognition was initiated during the early period when mutual behaviour was most frequent, and that some attacks against the dominance order were caused as a result of revolts rather than mistakes.

Changes of Oxygen Consumption in Rose Bitterling, Field Gudgeon, Common Minnow, Dark Chub and Common Carp under Progressive Hypoxia

Changes of Oxygen Consumption in Rose Bitterling, Field Gudgeon, Common Minnow, Dark Chub and Common Carp under Progressive Hypoxia

Study of Fish Fauna in Tamjin River on Jangheung Dam Construction

In order to perform environmental impact assessment on Jangheung Dam construction, we investigated fish fauna and community from February to November 2005. Fishes were collected seasonally in 3 sites at upstream and 5 sites at downstream of the dam using cast net and kick net. A total number of fish caught from the study area was 8,733 fish representing 15 families and 45 species, and Cyprinidae and Gobiidae Families had twenty-four (53.3%) and four (8.9%) species, respectively. However, rest of families composed of one to three species. There was the 2nd-class endangered species, Sand lamprey (Lampetra reissneri), found in the upstream (Site 3) of the dam, and fourteen Korean endemic species (31.1%) including southern king spine loach (Iksookimia hugowolfeldi). In the mean time, one foreign introduced species, Crucian carp. (Carassius cuvieri) was mostly found in upstream of the dam among the 45 species. The number of species in each site ranged 20 to 34 species, and it tended to increase toward to downstream. The species of pale chub (Zacco platypus, 43.5% relative abundance) and dark chub (Zacco temminckii, 14.7%) were dominant and subdominant species, and 14 species including eel (Anguilla japonica) comprised less than 0.1% relative abundance (rare species) of the total catch. Compared to assessments in previous years (1998~2004), the number of species found in 2005 was the maximum. Fifteen species were not confirmed at this year even if they were found in previous years, and some of them including hickory shad (Konosirus punctatus) were peripheral species of fish collected in only single year. Whereas three species (Lampetra reissneri, Carassius cuvieri, Hemiculter eigenmanni) was confirmed for the first time in 2005. Based on the results, modification of fish fauna and community in Tamjin River watershed should be monitored in detail in order to assess any negative effect due to dam construction, and additional investigation for the endangered species needs to be performed to establish conservation of their habitat and population.

New Host Records for Lernaea cyprinacea (Copepoda), a Parasite of Freshwater Fishes, with a Checklist of the Lernaeidae in Japan (1915-2007)

The lernaeid copepod Lernaea cyprinacea Linnaeus, 1758, was found attached to three species of freshwater fishes, the barbell steed Hemibarbus labeo (Pallas) (Cyprinidae), the dark chub Zacco temminckii (Temminck and Schlegel) (Cyprinidae), and the Amur catfish Silurus asotus Linnaeus (Siluridae) from Hiroshima Prefecture in Japan. The findings from Hemibarbus labeo and Zacco temminckii represent new host records for L. cyprinacea, while Silurus asotus is a new host in Japan. Based on the literature published for 93 years from 1915 to 2007, a checklist of three species of lernaeid copepods (Lernaea cyprinacea, Lernaea parasiluri, Lamproglena chinensis) from Japan is given, including information on the synonym(s), host(s), site(s) of infection, and distribution. The checklist shows that in Japan L. cyprinacea has been reported from 33 or 34 species and subspecies of fishes belonging to 17 families in 10 orders and also from 2 species of amphibians from 2 families in 2 orders.

Ephemera strigata imagoes are the likely source of a parasitic nematode infection of fish

Ephemera strigata imagoes are the likely source of a parasitic nematode infection of fish

Zacco sieboldii , a species distinct from Zacco temminckii (Cyprinidae)

Two biological types of Japanese dark chub, so-called types A and B of Zacco temminckii, were taxonomically inspected. A comparison of types A and B with the lectotypes of Leuciscus sieboldii and L. temminckii in Siebold's collection revealed that type A is identical to L. sieboldii, whereas type B matches L. temminckii. Hence, Zacco sieboldii and Z. temminckii were redescribed on the basis of the lectotype and additional specimens from Japan. Zacco sieboldii is distinguishable from Z. temminckii by having a narrower band on the anterior portion of both body sides, nine branched rays of anal fin (10 in Z. temminckii), lateral line scales not less than 53 (not more than 52 in Z. temminckii), and scales above lateral line not less than 13 (not more than 11 in Z. temmincki). A key to the species of Japanese Zacco is also provided.

Possible involvement of nitric oxide in signaling pigment dispersion in teleostean melanophores.

The possible involvement of nitric oxide (NO) in regulating the motile activities of teleostean melanophores was studied in the dark chub Zacco temmincki (Cyprinidae, Cypriniformes) and in the translucent glass catfish Kryptopterus bicirrhis (Siluridae, Siluriformes). NO donors, including (+/-)-(E)-methyl-2-[(E)-hydroxyimino]-5-nitro-6-methoxy-3-hexaneamide (NOR1), molsidomine (MSD), sodium nitroprusside (SNP) and glyceryl trinitrate (GTN), had no pigment-aggregating action on melanophores, but actively dispersed melanosomes in those cells. Among those reagents, NOR 1, a spontaneous releaser of NO, was the most effective. Inhibitors for nitric oxide synthase (NOS), i.e. N omega-nitro-L-arginine methyl ester (L-NNA), N omega-nitro-L-arginine (L-NAME) and N omega-monomethyl-L-arginine (L-NMMA), showed melanosome-aggregating effects. A membrane-permeable analogue of cyclic guanosine-3',5'-monophosphate (8-Br-cGMP) was effective in dispersing melanosomes. The sum of these results suggests that NO plays an active role in the elaborate control of color changes in teleosts by dispersing pigment in melanophores via activation of soluble guanylyl cyclase to increase cytosolic levels of cGMP.

Growth of dark chub, Zacco temmincki (Cyprinidae), with a discussion of sexual size differences

Growth of dark chub, Zacco temmincki (Cyprinidae), with a discussion of sexual size differences

Herbicides in water and fish from rivers flowing into lake Biwa

Surveys of twelve herbicides were performed for water and fish samples obtained from seven rivers flowing into Lake Biwa from April in 1994 to March in 1996. Eleven herbicides were detected at high frequency for molinate, simazine, bromobutide, simetryne, benthiocarb, preti‐lachlor, oxadiazon and mefenaset but at low frequency for terbucarb, butachlor and CNP. Molinate, simetryne, benthiocarb, oxadiazon and mefenaset were detected in ayu sweetfish, pale chub and dark chub but not for simazine, butachlor, pretilachlor and CNP in spite of their detections in the river water. These are probably due to their low bioconcentration potential or temporary contamination. The bioconcentration factors (BCF) of molinate, benthiocarb, oxadiazon and simetryne in the three species of fish calculated from the field data were approximately consistent with the BCF values from the laboratory data on willow shiner or topmouth gudgeon. However, the difference of fish species should be considered for the evaluation of the field BCF data by the laboratory BCF data.

Metagonimus miyatai sp. nov. (Digenea: Heterophyidae), a new intestinal trematode transmitted by freshwater fishes in Japan and Korea.

Metagonimus miyatai n. sp. (Digenea: Heterophyidae) is described based on adult flukes collected from experimental dogs and hamsters fed with metacercariae encysted in the sweetfish, Plecoglossus altivelis, dace, tribolodon hakonensis and T. taczanowskii, common fat-minnow, Morocco steindachneri, pale chub, Zacco platypus, and dark chub, Zacco temmincki, and on those collected from naturally infected humans. The new species was morphologically compared with M. yokogawai and M. takahashii obtained from experimental animals fed with the sweetfish and the crucian carp, Carassius carassius, respectively. The uterine loops of M. miyatai reached near the posterior end of the body through the space between the two testes, whereas those of M. yokogawai, occupied only the space between the acetabulum and anterior border of two testes. This uterine tubule distribution was similar to that of another closely related species, M. takahashii. However, vitellaria of M. miyatai ended in front of the posterior end of the left testis, while those of M. takahashii reached the posterior end of the left testis and ran it over. By raising M. miyatai as a new species, differentiation of M. yokogawai and M. takahashii became very clear. A key to the species of the genus Metagonimus in the Far East has been proposed.

Middle- and Large-sized Aquatic Animal Assemblages Associated with Submerged Riparian Plants in the Kamo River, Kyoto.

Middle- and large-sized aquatic animal assemblages associated with the submersed leaves, stems and roots of the reed Phragmites japonica and other riparian plants were studied in the Kamo River, Kyoto, with a focus on the faunal differences in both longitudinal and seasonal distribution. At the upper and middle sites, mayfly larvae inhabiting slow riffles and shallow pools were dominant in winter and spring.Several lentic hemipteran insect species such as water scorpions and back swimmers associated chiefly with hydrophytes in ponds and marshes were also found in summer or autumn within the stands of monocotyledonous plants on the wide gravel bar of the middle site. At the lower site, within the Kyoto city limits, water slaters, leeches and snails were abundant from spring through autumn. In addition, many larvae of calopterygid and coenagrionid dragonflies were collected in spring and summer, respectively. Juvenile fishes of dark chub and lizard goby were abundant in summer and autumn at all three sites. Riparian plants were thus suggested to increase species diversity of lotic fauna, providing habitats not only for lotic invertebrates but also for lentic insects and juvenile fishes.

Pesticides in water and fish from rivers flowing into Lake Biwa.

Surveys of twelve herbicides were performed for water and fish samples obtained from seven rivers flowing into Lake Biwa from April in 1994 to March in 1996. Eleven herbicides were detected at high frequency for molinate, simazine, bromobutide, simetryne, benthiocarb, preti‐lachlor, oxadiazon and mefenaset but at low frequency for terbucarb, butachlor and CNP. Molinate, simetryne, benthiocarb, oxadiazon and mefenaset were detected in ayu sweetfish, pale chub and dark chub but not for simazine, butachlor, pretilachlor and CNP in spite of their detections in the river water. These are probably due to their low bioconcentration potential or temporary contamination. The bioconcentration factors (BCF) of molinate, benthiocarb, oxadiazon and simetryne in the three species of fish calculated from the field data were approximately consistent with the BCF values from the laboratory data on willow shiner or topmouth gudgeon. However, the difference of fish species should be considered for the evaluation of the fiel...

The endothelin receptors that mediate aggregation of pigment in fish melanophores

A study was made of effects on the melanophores of several teleosts of three isopeptides of mammalian endothelin (ET), namely, ET-1, ET-2, and ET-3. In all the species examined, these peptides induced the aggregation of pigment within the melanophores. Chemically denervated melanophores also responded to ETs quite normally. Thus, ETs may act directly on the cells. Quantitative studies on the dark chub and zebrafish indicated that the response was concentration-dependent, and that the three peptides were almost equipotent. Sarafotoxin S6c, a specific agonist of the mammalian ET A receptor, also effectively induced the aggregation of pigment in a concentration-dependent manner. IRL 1620, another specific agonist of the ET B receptor, also induced the aggregation of pigment, but only at higher doses. BQ- 123 and TTA-386, potent selective antagonists that bind to mammalian receptor of the ET B type, did not interfere with the pigment-aggregating actions of ETs, whereas BQ-788, an ET B receptor-selective antagonist, strongly inhibited the action of ETs. It appears, therefore, that the receptors for ET that mediate the aggregation of pigment in fish melanophores resemble those of the mammalian ET B type.