• 한국수산과학회지
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• 제49권2호
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• pp.184-189
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• 2016

We investigated physiological changes in the freshwater cichlid, fish Maylandia lombardoi in response to different calcium concentrations in rearing water. Four different calcium concentrations (0, 2, 4 and 8 mM) were prepared in rearing water by the addition of ionized calcium (CaO) to examine the effect of various calcium concentrations in rearing water on physiological changes in the cichlid fish, M. lombardoi. Total calcium concentrations in plasma and body increased in a calcium concentration-dependent manner and reached the maximum at 8-mM calcium concentration. Stress-related cortisol was significantly decreased in the 8-mM group compared to the control group (0 mM). Lysozyme activity also significantly decreased in the 8-mM group. These results suggest that CaO in rearing water increases calcium uptake in fish and affects the body by decreasing stress and improving immunity in fish.

• 한국어병학회지
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• 제37권1호
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• pp.155-158
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• 2024

A blood parrot (Amphilophus citrinellus × Vieja melanurus) cichlid showing a flared left operculum was sent to the Fish Disease Clinic. The fish showed intermittently irregular ventilation and reddish soft swellings located at the ventral part of the left branchial cavity for one month. Other abnormal symptoms were not observed, and the appetite was normal. Only a putative diagnosis was conducted based on the history taking and external symptoms because the owner did not want an invasive biopsy or other potentially stressful examination of the fish. Therefore, considering the information available and the treatability, goiter (thyroid hyperplasia) was suspected as the top differential diagnosis, and the empirical treatment of administering iodide (0.03~0.015ppm) in environmental water was conducted. The treatment was discontinued for six months because the swelling was noticeably reduced. Body color became pale, but other abnormal signs were not observed.

• 한국발생생물학회지:발생과생식
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• 제20권3호
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• pp.267-274
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• 2016

Cichlid fish species exhibit characteristic sexual behaviors according to not only reproductive stages but also social status. In a reproductive season, Astatotilapia burtoni males compete for females and a small number of dominant winners finally obtain the chance of spermiation. In addition to the characteristic behaviors, the dominant males have relatively bigger gonadotropin-releasing hormone 1 (GnRH1) neurons in the preoptic area (POA) of brain compared to those of subordinate males. Although the stimulatory effect of GnRH1 in vertebrate reproduction is well established, little is known about the triggering signal pathway to control GnRH1 neurons and GnRH1-mediated sexual behavior. In the present study, we evaluated the potential effect of TOR inhibitor rapamycin in relation to the cichlid male behaviors and GnRH1 neuron. After 14 h and 26 h of intraventricular injection of rapamycin, behavior patterns of chasing and courtship display did not show significant changes between rapamycin- and DMSO-injected males. Behaviors of spawning site entry increased in rapamycin-injected fish at 26 h post-injection than at 14 h post-injection significantly (P<0.05). Meanwhile, there was a tendency that GnRH1 neurons' soma size in the POA shrank by rapamycin injection, whereas the testes did not show notable changes. Taken together, these results suggest the possible role of TOR signal on GnRH1-mediated sexual behavior in cichlid dominant males, although further biological characterization of the TOR signaling pathway will be required to clarify this matter.

• Applied Microscopy
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• 제27권4호
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• pp.417-432
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• 1997

The structures of the fertilized egg envelope in three species of cichlidae, golden severum (Cichlasoma severum var.), convic cichlid (Cichlasoma nigrofasciatum) and discus (Symphysodon aequifasciatus) were investigated by routine light and electron microscopies. The fertilized eggs of all three species were of the non-transparent, ellipsoidal, adhesive and non-floted type. The egg envelopes have a single micropyle, which is thought to the pathway of sperm in the area of the animal pole. In golden severum, an outer surface of egg envelope was covered by a reticular layer, that of convic cichlid was covered by an amorphous reticular layer and that of discus was covered by a branched reticular layer. The fertilized egg envelopes consisted of two distinct layers, an adhesive outer layer and an inner layer, consisted of lamellae alternating with interlamellae of lower electron density, in all three species; an inner layer of golden severum was $15\sim17$ layers, that of convic cichlid was $14\sim16$ layers, and that of discus was $18\sim19$ layers.

• Fisheries and Aquatic Sciences
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• 제26권9호
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• pp.548-557
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• 2023

The purposes of this research were to identify fish species using DNA barcodes or partial sequences of cytochrome b (Cytb) and to assess the diversity of fish in the Mae Tam reservoir, Phayao province, Thailand. Fish samples were collected 3 times, during the winter, summer, and rainy seasons, from 2 sampling sites using gillnets with 3 mesh sizes (30, 50, and 70 mm). A total of 34 representative samples were classified into 12 species, 7 families and 6 orders by morphological- and DNA barcoding-based identifications. However, one cichlid species, Cichlasoma trimaculatum, could only be identified using DNA barcoding. Family Cyprinidae had the greatest diversity, 50.00%. The diversity, richness and evenness indices ranged from 0.43-0.65, 0.64-1.46, and 0.27-0.40, respectively, indicating that fish diversity at both sampling sites was relatively low. A comparison of the catch per unit effort (CPUE) with 3 different mesh sizes found that the 50 mm mesh size was the best (474.80 ± 171.56 g/100 m²/night), followed by the 70 mm (417.41 ± 176.24 g/100 m²/night) and 30 mm mesh sizes (327.88 ± 115.60 g/100 m²/night). These results indicate that DNA barcoding is a powerful tool for species identification. Our data can be used for planning the sustainable management of fisheries resources in the Mae Tam reservoir.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• 제3권2호
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• pp.67-72
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• 2022

Ecological research relies on the interpretation of large amounts of visual data obtained from extensive wildlife surveys, but such large-scale image interpretation is costly and time-consuming. Using an artificial intelligence (AI) machine learning model, especially convolution neural networks (CNN), it is possible to streamline these manual tasks on image information and to protect wildlife and record and predict behavior. Ecological research using deep-learning-based object recognition technology includes various research purposes such as identifying, detecting, and identifying species of wild animals, and identification of the location of poachers in real-time. These advances in the application of AI technology can enable efficient management of endangered wildlife, animal detection in various environments, and real-time analysis of image information collected by unmanned aerial vehicles. Furthermore, the need for school education and social use on biodiversity and environmental issues using AI is raised. School education and citizen science related to ecological activities using AI technology can enhance environmental awareness, and strengthen more knowledge and problem-solving skills in science and research processes. Under these prospects, in this paper, we compare the results of our early 2013 study, which automatically identified African cichlid fish species using photographic data of them, with the results of reanalysis by CNN deep learning method. By using PyTorch and PyTorch Lightning frameworks, we achieve an accuracy of 82.54% and an F1-score of 0.77 with minimal programming and data preprocessing effort. This is a significant improvement over the previous our machine learning methods, which required heavy feature engineering costs and had 78% accuracy.

• 한국임상수의학회지
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• 제27권2호
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• pp.202-204
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• 2010

아가미 덮개 아래에 종괴를 가진 플라워혼이 서울의 사설 수족관에서 사육되다가 폐사 전 진단의뢰 되었다. 이 플라워혼은 무기력, 식욕부진, 침울 및 호흡곤란의 증상을 보인 후 폐사하였다. 종괴와 내장기관을 조직병리학적으로 조사한 결과, 갑상선에서 많은 양의 교질을 가진 다양한 크기의 낭포가 관찰되었고 간에서는 지방변성을 확인할 수 있었다. 본 증례는 플라워혼에서의 갑상선종 발생과 그것이 간에 미치는 영향을 보고하고자 한다.