Acheilognathus Tabira Research Articles

Phylogeography and genetic population structure of the endangered bitterling Acheilognathus tabira tabira Jordan & Thompson, 1914 (Cyprinidae) in western Honshu, Japan, inferred from mitochondrial DNA sequences

Phylogeography and genetic population structure of the endangered bitterling Acheilognathus tabira tabira Jordan & Thompson, 1914 (Cyprinidae) in western Honshu, Japan, inferred from mitochondrial DNA sequences

The complete mitochondrial genomes of two endangered bitterling Acheilognathus tabira tohokuensis and A. tabira erythropterus (Cyprinidae, Acheilognathinae)

Acheilognathus tabira (tabira bitterling) comprises of 5 subspecies, all of which are endangered. In this study, the mitochondrial genome (mitogenome) of the 2 subspecies, A. tabira tohokuensis and A. tabira erythropterus, whose mitogenomes have not been reported previously, was determined. The total lengths of A. tabira tohokuensis and A. tabira erythropterus mitogenomes were 16,774 bp and 16,770 bp, respectively, and were noted as slightly AT-rich. Phylogenetic analysis revealed that these 2 subspecies of A. tabira were the most closely related, out of the 5 subspecies. The deciphered mitogenomes would be useful for conservation and evolutionary studies.

Age-dependent changes in the growth and reproductive patterns of the southern red tabira bitterling, Acheilognathus tabira jordani

The age structure, growth pattern, and reproductive traits of the southern red tabira bitterling, Acheilognathus tabira jordani, were investigated in a small pond in Toyama Prefecture, central Honshu, Japan. Analysis of 5,720 individuals over two years revealed the existence of three or four age groups in every month, and individuals born during the study years were observed after June. Individuals of two years of age and younger increased their body size in the spring and summer and maintained them in the winter, while individuals in the 3+ age cohort did not show noticeable increases in body size throughout the year. Based on the appearance of spawning-capable individuals, the oviposition period of the A. t. jordani population was estimated to range from late April to late August. Compared with the oviposition periods of populations in other regions, the period in the study area was delayed, probably as a result of lower water temperatures, especially in the summer. During the oviposition period, the proportion of spawning-capable individuals differed between age cohorts in both males and females; in younger individuals the proportion of ovipositors was higher in the early part of the oviposition period. Taking into consideration observed differences in growth and spawning patterns due to age, younger individuals appear to invest their acquired energy into their own growth, while older individuals invest it in spawning. The present study reveals that habitat conservation strategies for A. t. jordani should be determined for specific regions.

Interspecific comparison of movement patterns among bitterling species in an agricultural ditch system

Patterns of movement are related to life history and/or species traits. Understanding movement patterns of multiple species sharing the same niche may clarify coexistence mechanisms. Therefore, the movement patterns of three bitterling species, Acheilognathus tabira erythropterus, Acheilognathus melanogaster, and Rhodeus ocellatus ocellatus, were examined between June and November 2009 in an agricultural ditch system associated with Lake Kasumigaura in central Japan. The mark–recapture method was used with a fixed releasing point in an approximately 5.5 km-long ditch. Movement distances of A. t. erythropterus and A. melanogaster were longer than that of R. o. ocellatus, but the direction of movement was similar among the three species. However, R. o. ocellatus moved to locations with a low dissolved oxygen concentration and deeper water. These results suggest that R. o. ocellatus may adapt better to environmental fluctuations, because its tolerance to hypoxia is the highest of the three species. Compared with R. o. ocellatus, A. t. erythropterus and A. melanogaster may move relatively longer distances to search for suitable habitats following an environmental fluctuation.

Site selection for habitat conservation/restoration of threatened freshwater fishes in artificial channels of northern Kyushu Island, Japan

The aim of this study was to propose a method for site selection for habitat conservation or restoration of threatened freshwater fishes inhabiting ditches or canals in the main plains of northern Kyushu Island, Japan. The environmental data of 4,084 third meshes in six regions and faunal data of 337 meshes that included 462 sites were analyzed using generalized liner mixed models, and species distribution models with high accuracies were developed for nine threatened species. Habitat conservation or restoration for each species was discriminated using gaps between actual and potential distributions. The number of species under each management was determined for each site, and the management type with a large number of species was selected (Case 1), or the target species were set for each potential faunal group based on similarities of fish fauna, and the type was selected by counting only the target species (Case 2). On the basis of the conserved sites showing actual presences, Case 2 showed higher effectiveness than Case 1. The estimated practices and successes of all habitat managements in Case 2 showed an increase of 1.3–4.6 times for actual presences, with optimal habitats reaching 78–91 % of their potential presence and conserved sites attaining 64–97 % of the actual presence of each species. In the case with special attention to the most threatened species, Acheilognathus tabira nakamurae, a small decrease in effectiveness was noted for several species.

Divergence of ovipositor length and egg shape in a brood parasitic bitterling fish through the use of different mussel hosts

Bitterling fishes deposit their eggs on the gills of living mussels using a long ovipositor. We examined whether ovipositor length (OL) and egg shape correlated with differences in host mussel species in the family Unionidae among populations of the tabira bitterling (Acheilognathus tabira) in Japan. Bitterling populations that use mussels in the sub-family Anodontinae possessed longer ovipositors and more elongated eggs than those using mussels of Unioninae, as expected from the difference in host size between the sub-families (anodontine mussels are larger than unionine mussels). Based on a robust phylogeny of A. tabira populations, we demonstrated that the evolution of both OL and egg shape were correlated with host differences, but not with each other, suggesting that these traits have been selected for independently. Our study demonstrates how adaptive traits for brood parasitism may diverge with host shift due to different host availability and/or interspecific competition for hosts.

Predicting distributions of seven bitterling fishes in northern Kyushu, Japan

The distributions of seven bitterling species and subspecies—Tanakia lanceolata, T. limbata, Acheilognathus tabira nakamurae, A. rhombeus, Rhodeus ocellatus kurumeus, R. ocellatus ocellatus, and R. atremius atremius—in northern Kyushu were predicted using generalized linear models (GLMs) in order to provide information helpful for conserving native bitterlings and preventing the expansion of alien bitterling species. Predictions were made according to the following procedure: (1) a set of GLMs for each species was formulated using environmental data from 710 sites that were derived using digital maps and GIS software, from which the best fit model for each species was selected using the Akaike information criterion for predicting the fish occurrence, (2) model performance was evaluated based on the receiver-operating characteristics (ROC) analysis using occurrence and environmental data from 362 sites, and (3) potential distributions of the bitterling were analyzed using the best fit models and environmental data for 1,272 sites, of which 200 data points without occurrence data were prepared. The best fit models revealed that 4–6 environmental factors were important in predicting seven bitterling distributions, which was supported by the area under the ROC curve (AUC) values of these fishes ranging from 0.753 to 0.927. The AUC values in model evaluation were significantly greater than 0.5 for six fishes, suggesting the moderate accuracies of these best fit models for predicting the fish distributions. These predictive models can be used for evaluating potential native bitterling richness and the potential distribution expansion of an alien subspecies.

The reproductive ecology of the southern red tabira bitterling Acheilognathus tabira jordani in Japan

The life history, population and reproductive variables of the southern red tabira bitterling Acheilognathus tabira jordani were investigated in a lowland reach of the River Ohara in Shimane Prefecture, western Honshu, Japan. Acheilognathus t. jordani, like all other species of bitterling, lays its eggs on the gills of freshwater mussels. It was the only species of bitterling present in the study reach, and three species of bivalve mussel were available to it for spawning: Anemina arcaeformis, Anodonta lauta and Corbicula leana. Spawning by A.t. jordani was recorded between early April and early July in 2003 and began at a size of 38. 0 mm standard length (L(S)) in the 1+ age class. Ovipositor length (L(OP)) during oviposition was positively correlated with female L(S), and showed significant seasonal variation, with a mean +/-s.d.L(OP) of 27. 5 +/- 5. 3 mm ranging from 16. 8 to 42. 0 mm during the spawning period, which was shorter than that of a previously studied A. t. tabira population. Eggs of this subspecies are relatively long and elliptic in shape, with a volume of c. 2. 4 mm(3). Egg number correlated positively with female L(S) and both egg shape and volume changed significantly with season. The population size of adults was estimated to be 850 individuals, and comprised age 0+ to 3+ individuals with L(S) ranging from 12. 0 to 72. 2 mm. The population sex ratio was significantly female biased, with seven females: three males. Egg shape and size and L(OP) during oviposition in the present A. tabira population may be the result of local adaptations to the mussel species utilized and no competition with other bitterling species for spawning sites.

The reproductive ecology of two subspecies of the bitterling Rhodeus atremius (Cyprinidae, Acheilognathinae)

The reproductive ecology of two endangered subspecies of the bitterling Rhodeus atremius was investigated in two rivers in Okayama and Fukuoka Prefectures, Japan. Several other bitterling species, R. ocellatus, Tanakia limbata, T. lanceolata, Acheilognathus tabira and A. rhombeus, are also found in these rivers. Spawning of both R. atremius subspecies was recorded between late March and August 2007, peaking between April and July. Females of R. atremius began to mature at small body size (minimum 25 mm). They had small clutch sizes (maximum 16 eggs) and developed a short ovipositor (mean 13.6 mm), which was used to deposit a bulb-shaped egg of comparatively large size (3.2 mm3, major and minor axes 2.8 and 1.5 mm). Clutch size, ovipositor length and egg size appear to be a function of female body size. Both the body size and ovipositor length of R. atremius with ripe ova and the size and shape of the eggs varied seasonally. Rhodeus a. suigensis achieved maturity at a smaller body size, had a longer ovipositor and produced smaller eggs, with the minor axis being wider relative to the major axis than those of R. a. atremius. Rhodeus atremius may be adapted for depositing small numbers of eggs in a much shallower position inside the gills of smaller host mussels than other bitterling species.

Acheilognathus tabira from Natori Basin, Miyagi, Japan produces elliptical eggs and their juveniles do not have a dark spot on the dorsal fin

<i>Acheilognathus tabira</i> from Natori Basin, Miyagi, Japan produces elliptical eggs and their juveniles do not have a dark spot on the dorsal fin

Chromosomal location and nucleotide sequences of 5S ribosomal DNA of two cyprinid species (Osteichthyes, Pisces).

5S ribosomal DNAs (rDNAs) from two cyprinid species, Acheilognathus tabira subsp. 1 and Cyprinus carpio, were isolated and sequenced. Tandemly arranged rDNAs were 179 bp in A. tabira and 204 bp in C. carpio. The non-transcribed spacer region elucidates the size difference of 5S rDNA between the two species. Fluorescence in-situ hybridization (FISH) localized 5S rDNAs to the short arms of two pairs of chromosomes in A. tabira and two to four pairs in C. carpio. Subsequent analysis demonstrated NORs in one pair of chromosomes in both species. Both the NOR and 5S rDNA are carried by a chromosome pair in A. tabira, but they are located on different chromosomes separately in C. carpio. Karyotype evolution by tetraploidy seems complex in cyprinid species.

Factors involved in the development of and decline in photoperiodism as it relates to the gonadal activity of a spring‐spawning bitterling, Acheilognathus tabira

AbstractThe involvement of changes in photoperiodism in gonadal activity was investigated in the spring‐spawning bitterling, Acheilognathus tabira, in which photoperiodism develops during the summer and declines during the winter. In spring, gonadal development occurred without a need for photoperiodic stimulation and independently of the preceding photoperiod (9 hours or 12 hours light; 9L or 12L) during the winter. This observation indicates that the natural photoperiod during the corresponding season is not responsible for the decline in photoperiodism. Fish kept at moderate temperatures (16°C or 22°C) during the winter eventually achieved gonadal maturation, even under short daylength conditions (11L), indicating that low temperature during the winter is not necessary for the decline in photoperiodism. Both treatment with moderate temperature and long days (22°C, 15L) treatment and treatment with moderate temperature and short days (22°C, 11L) induced the development of photoperiodism during the summer, an indication that neither high temperatures during the summer nor long days during the early summer are necessary for the development of photoperiodism in this species. Since the natural photoperiod and temperature conditions during the corresponding seasons are not responsible for the changes in photoperiodism, these changes are probably caused by an internal factor such as circannual rhythm.Alteration of the photoperiodic regime from 11L to even fewer hours of daylight during the period when photoperiodism was declining did not affect subsequent gonadal development. The nature of the changes in photoperiodism in this species is, therefore, a rapid switchover of the responsiveness to daylength rather than a gradual change in the critical daylength for gonadal development. © 1993 Wiley‐Liss, Inc.

春産卵魚アカヒレタビラの成熟に関する光周性の変化

春産卵魚アカヒレタビラの成熟に関する光周性の変化

Studies on the reproductive rhythms of fishes - III. Environmental regulation of annual reproductive cycle in a spring-spawning bitterling Acheilognathus tabira.

Spring-spawning bitterling Acheilognathus tabira were kept under several combinations of photoperiod and water temperature regimes at different phases of their annual reproductive cycle. In early spring, the gonads developed rapidly under warm temperature (16°C) regardless of photo-period. In early summer, gonads intensely regressed under high temperature (26-30°C), also regardless of photoperiod. In early autumn, the first phase of gonadal recrudescence, i.e. forma-tion of spermatocytes and accumulation of yolk vesicles, proceeded under lower temperature (22°C-16L), regardless of photoperiod. In a mid autumn experiment, the second phase of gonadal recrudescencd, i.e. active spermatogenesis and accumulation of yolk globules, could be commenced only by warm temperature-long day (22°C-16L) treatment. Thus, it is concluded that the spawning period of A. tabira is initiated by the rising of water temperature in spring and is terminated by the high temperature in summer. The first phase of gonadal recrudescence is induced by the lowering temperature in autumn. In this season, how-ever, the second phase of gonadal recrudescence is prevented by the short daylength although the temperature is permissive. Seasonal changes in photoperiodism are also suggested.

魚類の生殖リズムに関する研究 ＩＩ 春産卵魚アカヒレタビラの生殖年周期

Adult bitterling, Acheilognathus tabira, were sampled at intervals ranging from one to three months with a set net in Lake Kasumigaura for two years. Maturity of fish was estimated from gonadosomatic index (GSI) and gonadal histology. In females ovipositor length and egg diameter were also examined. Gonads stayed regressed during high summer months, when most oocytes were at perinucleolus stage, and all of male germ cells were spermatogonia, From this state, maturation progressed in two phases. In the first phase that began in September, accummulation of yolk vesicles and formation of spermatocytes occurred accompanying slow increase of GSI and egg diameter. In the second phase that began in March or early April, accummulation of yolk globules and active spermatogenesis occurred accompanyig rapid increase of GSI and egg diameter. Judging from elongation of the ovipositor and appearance of the ovulated eggs, the spawning period of this species extends from late April to late June, though it may somewhat fluctuate by years. After the period gonads regressed rapidly. Different environmental factors may effect the initiation of each phase of maturation and the termination of the spawning season. Activity of gonadotrophs corresponded to each maturation phase, which suggests that both phases are controlled by gonadotropin.

UNUSUAL OVIPOSITOR DEVELOPMENT IN A FEMALE HYBRID BETWEEN FEMALE ACHEILOGNATHUS TABIRA AND MALE ACHEILOGNATHUS LIMBATA (CYPRINIDAE, TELEOSTEI)

An abnormal female hybrid between female Acheilognathus tabira and male Acheilognathus limbata is described which showed an elongated ovipositor, although most of its eggs were in a state of degeneration. Unusual round follicles also were present in the ovary, Histomorphological data on the pituitary, thyroid, and adrenal glands are presented, and an attempt is made to relate them to ovipositor growth.

HYBRIDIZATION EXPERIMENTS IN ACHEILOGNATHINE FISHES (CYPRINIDAE, TELEOSTEI): THE INTERSPECIFIC HYBRIDS BETWEEN ACHEILOGNATHUS LANCEOLATUS AND ACHEILOGNATHUS TABIRA

In order to establish the presence of gametic compatibility and the degree of genomic compatibility between the sympatric Japanese species of bitterling, Acheilognathus lanceolatus and Acheilognathus tabira, both species were artificially crossed.From both possible cross combinations, hybrid offspring were obtained. All hybrids showed a sexually neutral phenotype. Nuptial colors and tubercles on top of the snout were absent during the spawning season of both parental species. Stripping produced no observable milt.In their body shape, both kinds of F1 hybrids were fairly Intermediate between both parental species.In their body size, they showed, however, a gradual transition from large to small. Abnormal tail development was present in a number of fishes.Although gametic compatibility was practically complete, genomic compatibility appeared to be greatly impaired.

タナゴ亜属魚類の種および雑種にみられた奇形-II

This paper deals with a morphological and histological description of the following teratic abnormities found in Acheilognathine species and hybrids. 1. Tetrophthalmia in a larval hybrid between Rhodeus spinalis ?? from Taiwan and Rhodeus ocellatus ?? from Japan. It represents a case of duplicitas anterior. 2. Duplication of dorsal fin in a hybrid between Acheilognathus rhombea ?? and Acheilognathus tabira ??, both from Japan, representing a case of duplicitas media asymmetrica. 3. Lordosis in a hybrid between A. rhombea ?? and A. tabira ??, accompanied by edema in the hind brain region. 4. Scoliosis in a larval hybrid between A. rhombea ?? and A. tabira ?? . 5. Suppression of organ differentiation and larval development as a result of an excessive bulk of yolk in a larval hybrid between A. rhombea ?? from Japan and R. ocellatus ?? from Korea.

タナゴ類属間雑種の性と不妊性

1) Almost all hybrids produced artificially from Rhodeus ocellatus ?? × Acheilognathus tabira ??, Rhodeus ocellatus ?? × Acheilognathus limbata ??, Rhodeus ocellatus ?? × Acheilognathus cyanostigma ??, Rhodeus ocellatus ?? × Acheilognathus lanceolata ?? and Acheilognathus lanceolata ?? × Rhodeus ocellatus ?? are male. Only few hybrid females from Rhodeus ocellatus ?? × Acheilognathus lanceolata ?? and Rhodeus ocellatus ?? × Acheilognathus cyanostigma ?? can be reared to adult size, while their ovaries are not developed. 2) Hybrid males display the spawning behavior to the control female or hybrid female, though the behavior is not intensive as in the case of the control and the oviposition does not occur. 3) The testes of many hybrids are nearly normal in external form, but in some hybrids they are shrunken or entirely absent. None of the spermatozoa is observed in hybrid testes.