• Korean Journal of Ecology and Environment
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• v.38 no.3 s.113
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• pp.352-360
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• 2005

Acheilognathus signifer is distributed widely in high density in the Naechon-stream. The order of this-stream was 2 ${\sim}$ 4 and the water width is wide but the depth is relatively shallow and the sinuosity is 1.83, which indicates a meandering stream. The water width/stream width ratio is 1.59, which suggests moderate entrenchment. Naechon-stream was classed as B type by Rosgen (1995). The natural habitat of A. signifer is a slow flow velocity pool, like a backwater pool, which is made up of piled up boulders that restricts the flow of water. The stream bed is made up of boulders and sands that enable the spawning host to inhabit. A. signifer selects a microhabitat where the boulders furnish hiding places. The Habitat of A. signifer is strongly affected by the existence or not there of U. douglasiae sinuolatus. After hatching from the mussel, A. signifer inhabits the surface of the water. It then moves to the low layer once it acquires swimming ability. While A. signifer inhabits the river in summer, A. signifer moves to the deeper layers in winter, where there are the refuge like rocks and boulders. In spring A. signifer moves from the deep water to the river line where the mussels reside.

• The Korean Journal of Zoology
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• v.32 no.1
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• pp.22-33
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• 1989

Comparison of morphological characters and development of eggs and larvae of two bitterlings, Acheilognathus limbata and A. signifer from Korea were observed and discussed taxonomically. A. signifer differs from A. limbata by the color pattern of dorsal and anal fin ray of male, egg form and the length of ovipositor of female. Although two species are overlapping each other in some morphometric characters, there is a great difference between the two in the multivariate analysis of 15 morphological characters of five comparative populations. These results indicate that A. limbata and A. signifer are two independent allopatric sibling species in Korea.

• The Korean Journal of Ecology
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• v.28 no.5
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• pp.281-286
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• 2005

The ripe unfertilized eggs of Acheilognathus signifer were elliptical shape and baggily swollen toward animal pole. The size of fertilized eggs were $2.19{\pm}0.01$ mm in long axis and $1.85{\pm}0.08$ mm in short axis and oil globe were not observed. The zona radiata of A. signifer had the structure of regular fibrilar net and the diameter of outer opening micropyle was about $2.5{\mu}m$ and that of inner opening micropyle was about $1.5\sim2.0{\mu}m$. Development of fertilized eggs in A. signifer was proceeded in inclining position of animal pole and hatched in 49 hours under $20{\pm}1^{\circ}C$. The yolk sac was absolutely absorbed in 21 days after hatching.

• Korean Journal of Ichthyology
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• v.25 no.4
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• pp.208-215
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• 2013

Host species preference of Acheilognathus signifer for spawning in freshwater mussels was investigated at the part of the Dalcheon Stream (site 1) and the Gaedaecheon Stream (site 2) in Chungcheongbuk-do, Korea from April to June (spawning period) 2011. The spawned mussel rate of A. signifer at the study site 1 (wild condition) was 63.6% in Lamprotula leai and 2.1% in Unio douglasiae sinuolatus. It was not found in Anodnta arcaeformis flavotincta and Lanceolaria grayana. The number of eggs, larvae, or both of A. signifer at the study site 1 (wild condition) was 1~41 ($12.0{\pm}9.21$) in L. leai and 6 in U. d. sinuolatus. As a result of experiment 1, A. signifer was only spawned in L. leai with 60% of spawned mussel rate and the number of eggs, larvae, or both was 1~19 ($6.8{\pm}5.44$). According to experiment 2, A. signifer was spawned in all mussels. Spawned mussel rate of A. signifer was 75.0% in L. leai, 42.9% in U. d. sinuolatus and 21.4% in A. a. flavotincta and the number of eggs, larvae, or both was 1~35 ($13.0{\pm}8.80$) in L. leai, 1~26 ($5.2{\pm}6.92$) in U. d. sinuolatus and 2~19 ($8.6{\pm}5.64$) in A. a. flavotincta. Experiment 3 showed A. signifer was solely spawned in L. leai and the number of egg was from 2 to 10 ($6.7{\pm}4.16$). This study confirmed A. singifer is not so much generalist as specialist. We found the most preference species for spawning in the mussels by A. signifer was L. leai.

• Korean Journal of Ichthyology
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• v.17 no.2
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• pp.105-111
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• 2005

Most of the eggs and (or) pre-larvae of Acheilognathus signifer were observed from the gills of Unio douglasiae sinuolatus, 30~45 mm in the shell length, that is the host mussel of A. signifer. There was no selectivity in proportion to mussel size at the range observed. One to seven individual eggs and (or) pre-larvae were found in the mussels, with a mean of 2.5 individuals, and the rate of possessing one egg and (or) pre-larva was 50.0%. When the prelarva of A. signifer acquired swimming ability inside the mussel, it moved into the suprabranchial chamber. It was estimated that the growth period was 4~6 weeks. The minute tubercles of the pre-larvae were observed immediately after hatching. Absorption of the minute tubercles was observed starting the 7 th day, with most of tubercles absorbed 13 days after hatching and completed 20 days after the yolk was entirely absorbed.

• Korean Journal of Ichthyology
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• v.18 no.2
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• pp.141-147
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• 2006

The matured female and male of A. signifer differed in external morphology and body color. There were significant differences in PAD, PAB, PMP and PQR between matured female and male. Green color was very widely distributed in whole as nuptial color, that is similar to green and cyan color in the body part, yellow color in the ventral part and red and yellow color in the tail part. The nuptial organ of A. signifer was formed in a cluster on the horny substance of both sides above the mouth. There were 25~30 nuptial organs in a side. The nuptial organs disappeared with crumbling down from middle part of nuptial organ after spawning period. The nuptial organs disappeared mostly in September as non spawning period and a part of the nuptial organs remained as a vestige in the edges of both sides.

• Korean Journal of Ichthyology
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• v.22 no.4
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• pp.225-229
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• 2010

A intergeneric hybrid between Rhodeus uyekii and Acheilognathus signifer was collected in the Jojongcheon Bukhan River. The hybrid showed intermediate characteristics of two parental types in some key characters, such as color pattern of body, pigmentation of dorsal, anal, and caudal fins, and body spot and stripe. In addition, the hybrid had a fairly large number of lateral line scales, while it lacked a barbel, which is known as a key intergeneric character. The probable occurrence of a natural hybrid is supported by a viable $F_1$ hybrid produced with the parental species.

• Korean Journal of Ichthyology
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• v.26 no.2
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• pp.83-88
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• 2014

An endemic Korean bitterling, Acheilognathus signifer, known as using freshwater mussels for its spawning activity, much prefers Lamprotula leai in Dalcheon stream (Goesan population) and Unio douglasiae sinuolatus in Gadaecheon (Danyang population) stream, Korea. The spawning pattern between two mussels and one bitterling was carried out in two populations from April to June, 2011 and 2013. L. leai in the Goesan population was bigger shell length and have more eggs, larvae or both with A. signifer than those of U. d. sinuolatus in the Danyang population. Also, A. signifer in the Goesan population appeared to have a longer ovipositor and lay ripen eggs more than those of A. signifer in the Danyang population. Glochidium, a larval stage, of some L. leai in the Goesan population was incubated in all the demibranch, whereas for all of U. d. sinuolatus in the Danyang population was found in the outer demibranch only. For L. leai in the Goesan population, the eggs, larvae or both of A. signifer were much more in the non-breeding mussels (giving no glochidium) than the breeding mussels having the glochidium. For U. d. sinuolatus in the Danyang population, in contrast, the non-breeding mussels have fewer eggs, larvae or both less than the breeding one.

• Korean Journal of Ichthyology
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• v.27 no.3
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• pp.199-204
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• 2015

A natural hybrid between Acheilognathus signifer and A. lanceolatus was collected in their sympatric area, the Gimhwanamdaecheon of Hangang (River), Korea. Morphological characters, mitochondrial cytochrome b gene (cyt b), and recombination-activating gene 1 (RAG-1) were investigated to confirm the natural hybrid origin. As a result of morphological characters, the natural hybrid was appeared to have intermediate characters between two parental species in three characters; the band of dorsal fin, the color patterns of anal fin membrane, and the body color. In analysis of cyt b, it was revealed that the maternal species of the natural hybrid was appeared to be A. signifer due to their 99.9% sequence identity. Also, in analysis of RAG-1, an electropherogram of the hybrid individual displayed double peaks, strongly indicating its hybrid state.

• Korean Journal of Ichthyology
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• v.26 no.3
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• pp.153-158
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• 2014

A natural intergeneric hybrid between Rhodeus pseudosericeus and Acheilognathus signifer was collected in their sympatric area, the Jucheongang (stream), the Namhangang (river), Korea. Morphological characters as well as mitochondrial cytochrome b (mt-cyb) gene were investigated to confirm the natural hybrid origin. In the comparison of morphological characters, the natural hybrid appeared to have intermediate characters between two parental species in several key characters such as the band of dorsal fins, the color pattern of body, and the body spot and stripe. Also, the collected specimen had an incomplete lateral line with a large number of pored scales. In analysis of mt-cyb gene, it revealed that the maternal species of the natural hybrid appeared to be R. pseudosericeus due to their 100% sequence identity. Thus, such results gave convincing evidence for the occurrence of a natural intergeneric hybrid between Rhodeus pseudosericeus and Acheilognathus signifer.