• Development and Reproduction
• /
• v.23 no.4
• /
• pp.323-331
• /
• 2019

In this study, an experiment was conducted to investigate the annual reproductive cycle of a Korean flat bittering, Acheilognathus rhombeus, from Ogok-myeon located in Seomjin River. The reproductive cycle was examined histologically regarding water temperature and day length of the habitat, the gonadosomatic index (GSI), and developmental characteristics of female and male gonads. The maximum GSI was found to be 3.50±0.53 and 1.36±0.14 for females and males, respectively, when the water temperature and day light was 16.9℃ and 11.3 hours, respectively in October 2018. On the other hand, the minimum GSI was found to be 0.16±0.09 and 0.69±0.15 for males and females in December 2018 and February 2019, respectively. The ovipositor of females appeared from August to November 2018. We compared and calculated the stages of germ cell developmental characteristics in the testis and ovaries to determine the reproductive cycle. According to the result, we classified the female A. rhombeus reproductive cycle into four phases, which are ripe and spawning phase (October), degenerative phase (November to December), growing phase (January to March) and mature phase (April to September). The annual reproductive cycle of male A. rhombeus was categorized into four phases: mature phase (June to October), degenerative phase (November to March), resting phase (April) and growing phase (May). The Korean flat bittering is an autumn-spawner as the main spawning season in October. In male, testicular spermatogonia appeared all year-round, and the ripe and releasing phase, which is characteristics of the spawning season in other fish, did not appear.

• Korean Journal of Environment and Ecology
• /
• v.34 no.4
• /
• pp.274-281
• /
• 2020

This study aimed to investigate the autumn spawning by bitterling (A. rhombeus) inside mussel (Unio douglasiae) and the adaptation characteristics at the Bongseocheon Stream of Mankyeonggang River. The survey was carried out between August 2015 and July 2016. The spawning season was from September to November, and 17-75 (36.2 ± 16.44) eggs were found from mature females. During the survey period, 476 mussels were collected, 129 (27.1%) of spawned A. rhombeus. Mussels that spawned eggs, embryos, and larva of A. rhombeus (46.3 ± 4.55 mm, n = 129) were larger than than those that did not spawn (42.6 ± 8.51 mm, n = 347). The appearance frequency of A. rhombeus larva before and after the formation of lens was 99.8% (n = 597) vs. 0.2% (n = 1) from October 2015 to March 2016, 25.6% (n = 23) vs. 74.4% (n = 67) in April 2016, 0% (n = 0) vs. 100% (n = 40) on May 2016. The number of eggs, embryos, and larvae of A. rhombeus inside the mussels were 1-18 (5.6 ± 3.81). The number and appearance frequency of A. rhombeus eggs, embryos, and larvae inside the mussel according to mussel gill demibranchs position were 1 (0.01 ± 0.09, n = 1) and 0.78% in the left outer demibranch, 1-18 (2.33 ± 3.31, n = 63) and 48.84% in the left inner demibranch, 1-15 (2.97 ± 3.79, n = 76) and 58.91% in the right inner demibransh, and 1-12 (0.33 ± 1.71, n = 7) and 5.43% in the right outer demibransh. The highest frequency of the developmental position of eggs, embryos, and larvae occurred 71.8% (n = 445) in lower part 3 (L3) before formation lens and 94.4% (n = 102) in L3 after formation lens, indicating that L3 was dominating position for eggs, embryos, and larvae. More eggs, embryos, and larvae of A. rhombeus were found more often in the inner demibranshs than outer demibranchs. Since A. rhombeus is a species that spawn in the autumn and thus avoids the competition with interspecific and glochidia. However, they have to spend the winter in low water temperature. Consequently, we assume that A. rhombeus have evolved toward embryonic diapause under the low water temperature before the formation of lens and spawning inside the supracranchial cavity to save the transit energy from the water space to the suprabranchial cavity after the achieving movement ability with the formation of lens.

• Korean Journal of Ecology and Environment
• /
• v.38 no.2 s.112
• /
• pp.188-195
• /
• 2005

The dynamics of the fish community in the Lake Hoengseong region, Korea, were investigated from April 2000 to November 2004. During the surveyed period 39 species belonging 10 families were collected, and there were 17 Korean endemic species (43.59%) including Rhodeus pseudosericeus. Dominant species were Acheilognathus lanceolatus (20.10%), Zacco platypus (15.94%), Z. temmincki (6.92%), Carassius cuvieri (6.33%), A. rhombeus (6.18%), Pungtungia herzi (5.13%), and Pseudorasbora parva (4.93), In the comparison community of fish according to ecotype by each studied years, benthic fished are gradually decreasing and pelagic fishes creasing. Also, according to the fish distribution, the fish community of each studied years was divided into 3 groups by UPGMA. Being based on the fish community, similarity analysis results of each artificial lakes and this lake were divided 2 groups by water system, and divided again 3 groups in the same water system. Fish Community of the Lake Hoengseong was similar with that of the Lake Chuncheon and Cheongpyeong of the Bukhan-River.

• Korean Journal of Ecology and Environment
• /
• v.40 no.2
• /
• pp.303-317
• /
• 2007

The fish community of small freshwater ecosystems gets easily disturbed by direct or indirect human induced disturbances during the period of urbanization. Urbanization is one of factors that generate changes in stream and influences fish fauna in developed countries. This study was conducted in Busan Metropolitan City from 2001 to 2004. In order to investigate the fish community, the city was divided into 3 parts, eastern, central and western. A total of 3,206 individuals of 46 species from 19 families were collected from 55 sites. The dominant species was Rhynchocypris oxycephalus, whereas Zacco temminckii was the subdominant species. Cluster analysis was conducted using primary freshwater fish species collected from each stream. As a result of the analysis, study sites were well differentiated into 3 parts. Two species of Z. temminckii and R. oxycephalus represented the upper part of the stream and Carassius cuvieri, Acheilognathus rhombeus, Hemiculter eigenmanni and Micropterus salmoides represented the middle and lower parts of the stream. When compared with previous studies, fish community of the eastern part of the Busan city where urbanization is in progress, showed similar patterns to the central part. At the time of the habitat restoration of fish fauna in stream, appropriate selection of fish species should be made through analysis of stream character and biogeographic distribution of fish, and long-term monitoring is also needed for sustaining the management of fish fauna.

• Parasites, Hosts and Diseases
• /
• v.52 no.4
• /
• pp.399-412
• /
• 2014

The infection status of zoonotic trematode metacercariae was investigated in a total of 2,293 freshwater fish collected from 11 rivers or streams in 9 administrative regions of Gangwon-do, Korea for 5 years (2009-2013). All fish were collected by netting methods and examined using the artificial digestion methods. Clonorchis sinensis metacercariae were detected in 4 fish species, i.e., Pungtungia herzi, Squalidus japonicus coreanus, Acheilognathus rhombeus, and Ladislabia taczanowskii, from only Hantangang in Cheorwon-gun. Metagonimus spp. metacercariae were found in 1,154 (50.3%) fish and their average number per infected fish was 55.8. Among the positive fish species, especially Tribolodon hakonensis from Namdaecheon in Yangyang-gun and Plecoglossus altivelis from Osipcheon in Samcheok-si were most heavily infected. Centrocestus armatus metacercariae were detected in 611 (26.7%) fish and the average metacercarial burden per infected fish was 1,032. Two chub species, Zacco platypus and Zacco temminckii were highly and heavily infected with C. armatus metacercariae in almost all regions surveyed. Echinostoma spp. metacercariae were also found in 24 fish from a few localities, but their numbers per fish infected were very low. From the above results, it is confirmed that the metacercariae of intestinal flukes, especially Metagonimus spp. and C. armatus, were heavily infected, while C. sinensis metacercariae were rarely found in fish from Gangwon-do, Korea.

• Parasites, Hosts and Diseases
• /
• v.62 no.1
• /
• pp.1-29
• /
• 2024

This article analyzed the infection characteristics of metacercariae of Metagonimus spp. (MsMc) in fish from 9 major water systems in Korea. A total of 19,568 fish in 87 species were examined over a period of 10 years (2011-2020). MsMc were detected in fish from all 44 survey areas in 9 water systems. Most of the surveyed sites showed very low and low infection levels (66.7%), while 33.3% of the areas, such as Tamjin-gang and Seomjin-gang, revealed moderate and high infection levels. High endemicity depends on the abundance of susceptible fish species, especially sweet smelt (Plecoglosus altivelis). The susceptibility index (SI) with MsMc in index fish, Zacco spp., was very low and low levels in 62.0%, moderate in 28.0%, and high in 10.0% regions. The SI was highest in the following order: Yeongam-cheon (283.8), Hoeng-cheon (192.3), Togyo-jeosuji (131.2), Deokcheon-gang (119.1), and Joyang-gang (106.3). The recent infection status of MsMc in P. altivelis was analyzed by the survey localities. In addition, except for P. altivelis, 9 fish species were highly infected with MsMc in some survey areas, including Zacco platypus, Z. koreanus, Z. temminckii, Opsariichthys uncirostris, Rhynchocypris oxycephalus, Carassius auratus, Acheilognathus rhombeus, Onchorhynchus masou, and Tribolodon hakonensis. In Korea, 74 fish species (15 families) are collectively listed as second intermediate hosts of Metagonimus spp. This review provides several novel characteristics of MsMc infection and clarifies the fish species of second intermediate host of Metagonimus spp. in this country.

• Korean Journal of Ichthyology
• /
• v.1 no.1_2
• /
• pp.73-82
• /
• 1989

The development of eggs and larvae, and minute scale-like tubercles on the skin surface of the larval Acanthorthodeus asmussi from Korea were observed in the laboratory. The egg was nearly ovoid-shaped. The number of egg averaged 195 per an oviposition. The morphological character of larval development was relatively similar to those of Acheilognathus tabira tabira, A. tabira subsp. (a), A. yamatsutae, A. moriokae, A. cyanostigma and A. rhombeus. The larvae of this species had many scale-like tubercles ellipsoided in a diagonal cross section on the skin surface of the body. And also this species moved like incessant wiggly movement pattern as that of fly maggot duing the larval development. As regards the tubercles and larval movement pattern, the larvae of A. asmussi shared similar characters with those of Acheilognathus rhombeus, A. longipinnis and Pseudoperilampus typos. Hence A. asmussi may be closely related to these species. The latter three species are autumn-spawning bitterlings and the larval development always retard in a certain stage, while A. asmussi is a spring-summer spawning species and the larval development never retards. Judging from these facts, it should be considered that there are close relations in evolutionary trend between the two spawning species.

• Korean Journal of Environment and Ecology
• /
• v.37 no.2
• /
• pp.151-162
• /
• 2023

This study investigated the characteristics of fish communities and inhabiting status of the endangered species, Rhodeus pseudosericeus, in the Geumdang Stream in Korea from March to October 2021. A total of 1,698 fish in 5 families and 25 species were collected from 7 survey stations during the survey period. The dominant species was Zacco platypus (relative abundance, 46.5%), and the subdominant species was Squalidus gracilis majimae (16.7%), followed by Rhynchocypris oxycephalus (12.0%), Z. koreanus (5.7%), Pungtungia herzi (3.2%), R. pseudosericeus (2.0%), R. notatus (1.9%), and Acheilognathus rhombeus (1.8%). Nine Korean endemic species (36.0%) were collected, including R. pseudosericeus, R. uyekii, Sarcocheilichthys variegatus wakiyae, Microphysogobio yaluensis, S. gracilis majimae, Z. koreanus, Cobitis nalbanti, Iksookimia koreensis, and Odontobutis interrupta. An exotic species, Micropterus salmoides, designated as an invasive alien species (IAS), was collected downstream. The investigation of the habitat patterns of the endangered species (class II), Rhodeus pseudosericeus, showed a habitat range of about 6 to 7 km in the middle of Geumdang Stream (RP-1 to RP-4), and this species inhabited the edge with water depths of 0.3 through 1.0 m with slow water flow and many aquatic plants. According to the community analysis results, the overall dominance and evenness indexes were low, while diversity and richness indexes were high, and the cluster structure was largely divided into upstream and middle-downstream areas. The river health (fish assessment index) evaluated using fish was assessed as good (3 stations), normal (3 stations), and bad (1 station), and water quality was evaluated as good both upstream and downstream. Compared to previous studies, the number of species was relatively similar, and among the species that appeared in the past, 13 species did not appear in this survey, while 6 species appeared for the first time in this survey. Disturbance factors included river construction, many weirs, and the appearance of the ecosystem-disturbing species, M. salmoides. Since Geumdang Strem has high conservation value because it is home to many species in the Acheilognathinae subfamily, including the endangered species R. pseudosericeus, continuous attention and systematic conservation measures are required.

• Korean Journal of Ichthyology
• /
• v.2 no.2
• /
• pp.169-181
• /
• 1990

The development of eggs and larvae, and minute scale-like tubercles on the skin surface of larval Acantlaorhodeus gracilis from Korea were observed. They spawned from late March through the middle of June. A fish spawned at least 5 times and the number of eggs averaged 304 per oviposition. Unfertilized eggs are nearly ovoid-shaped(mean$\pm$SD=$2.09{\pm}0.04\;mm$ in length with range of 2.05 to 2.13 mm and mean$\pm$SD=$1.26{\pm}0.02\;mm$ in breadth with range of 1.24 to 1.30 mm measured for the 50 eggs) and opaque yellow color. The tip of egg membrane at the animal pole side swelled and formed a few hilly projections. The shape of the eggs was just like a loquat. Most of embryos began to hatch out in thirty-eight hours after insemination at $22{\pm}1^{\circ}C$ in water temperature. As regards the morphological characters of the eggs and larval development, Acan. gracilis was similar to Acan. asmussi, Acheilognathus rhombeus, A. longipinnis and Pseudoperilampus typus. The larvae of this species is unique particularly in the following two characters, i.e., 1) scale-like tubercles ellipsoided in a diagonal cross section on the whole body and 2) incessant wiggly movement pattern as that of fly maggot, with the larvae of the above mentioned species. These characters seem to reflect the phylogenetic relationships among acheilognathine fishes. On the other hand, this species and Acan. asmussi are spring-summer spawning bitterlings. And also these species never retard the larval growth in such larval stage as the duration from Stage B to Stage D.

• Korean Journal of Ecology and Environment
• /
• v.56 no.4
• /
• pp.348-362
• /
• 2023

This study analyzed the monitoring results of fishways at 16 weirs constructed on four large Rivers to provide data helpful for the operation and management of fishways. The average utilization rate of the fishways at the weirs was confirmed to be 64.9%. When comparing the dominant species in the mainstream and fishway monitoring results, differences were observed in 9 weirs (56.3%). This indicated that the species prevalent in the mainstream were not necessarily the ones most frequently using the fishways. The average number of individuals using the fishways per day was 336. When classifying the fish species using the fishway by life type, 92.3% were primary freshwater fish, and migratory species accounted for only 5.6%. Analysis based on the season of fishway usage revealed that an average or higher number of fish species used the fishways from May to October, with the highest number of individual users occurring from June to August. Between May and July, 80% of the fish species using the fishways were in their spawning period, while during other season, less than 40% were species that move during the spawning period. The fishways that showed a significant alignment between the spawning period and the fishway passage period were Rhinogobius brunneus, Leiocassis nitidus, Squalidus chankaensis tsuchigae, Pseudogobio esocinus, Acheilognathus rhombeus, and Pungtungia herzi, in that order. When comparing the fishway monitoring results of the Gangjeong-Goryeong Weir and the Dalseong Weir with the upper part water level of the weir, both the number of fish species and individuals using the fishway showed positive correlations with the upper part water level of the weir. This suggests that a higher water level of the weir increases the inflow discharge within the fishway, leading to increased use by fish (number of individuals in Gangjeong-Goryeong Weir, P<0.001; number of species in Dalseong Weir, P<0.05). This study summarized and analyzed the results of fishway monitoring at 16 weirs built on four large Rivers, considering fishway efficiency, operation and management, monitoring period, and regulation of water level in the upper part of the weir. It is thought that this will help understand the status of fish use in fishways on large River and aid the construction, operation, and management of fishways in the future.