• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.47 no.3
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• pp.234-240
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• 2011

In order to obtain the fundamental data about the behavior of sharks by underwater audible sound, this experiment was carried out to investigate the auditory characteristics of tiger shark Scyliorhinus torazame which was caught in the coast of Jeju Island by heart rate conditioning method using pure tones coupled with a delayed electric shock. The audible range of tiger shark extended from 80Hz to 300Hz with a peak sensitivity at 80Hz including less sensitivity at 300Hz. The mean auditory thresholds of tiger shark at the frequencies of 80Hz, 100Hz, 200Hz and 300Hz were 90dB, 103dB, 94dB and 115dB, respectively. The positive response of tiger shark was not evident after the sound projection of over 300Hz. At the results, the sensitive frequency range of tiger shark is narrower than that of fish that has swim bladder. In addition, it is assumed that the most sensitive frequency in auditory thresholds of Chondrichthyes is lower than that of Osteichthyes. Critical ratios of tiger shark measured in the presence of masking noise in the spectrum level range of about 60-70dB (0dB re $1{\mu}Pa/\sqrt{Hz}$) increased from minimum 27dB to maximum 39dB at test frequencies of 80-200Hz. The noise spectrum level at the start of masking was distributed at the range of about 65dB within 80-200Hz.

• Journal of fish pathology
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• v.14 no.2
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• pp.59-64
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• 2001

A complementary DNA encoding metallothionein(MT), a heavy metal-responsive protein was cloned from a cartilaginous shark species. Scyliorhinus torazame. An expressed sequence tag(EST)from the shark liver, which showed high similarity with a MT gene, was isolated and its full-length sequence(390bp)was determined. The putative shark MT cDNA sequence contained an open reading frame consisting 68 amino acids and 182bp of 3-untranslated region including the poly (A+) signal. The deduced amino acid sequence was 41-54% identical to those of other animals including mammals and fish species. Tiger shark MT cDNA showed high conservation in the Cys regions. however, peculiarly contained not only additional five amino acids just prior to the conserved beta-domain but also a Ser residue at C terminal, which has not been seen in other MT sequences.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 1998.06a
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• pp.346.1-347
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• 1998

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.6
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• pp.984-991
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• 1997

New tumor suppressor gene, snm23, homologous to human nm23/NDP kinase (human nucleoside diphosphate kinase) gene whose product has a tumor metastasis inhibitory activity, was first cloned from Korean tiger shark (Scyliorhinus forazame) skin cDNA library constructed by using a $\lambda$ ZAP-II cDNA synthesis kit. About $1\times10^5$ plaques were screened and several positive plaques were isolated and confirmed by second screening. The phagemid containing a positive clone from the Uni-Zap XR vector was excised in vivo and the gene containing the tumor metastasis suppressor protein was named as snm23. Cloned gene, snm23, was sequenced with ABI-PRISM 310 Genetic Analyzer. The nucleotide and deduced amino acid sequences of snm23 have shown an open reading frame consisting of 450 base pairs that correspond to a protein of 150 amino acid residues, with a calculated molecular mass of 16.8 kDa. Sequence comparison of snm23 with human nm23/NDP kinase was performed by using Blast protein data base of National Center for Biotechnology Information. In order to determine tissue specificity, reverse transcription-polymerase chain reaction (RT-PCR) was used. Good expression level of snm23/NDP kinase was detected at the tissues from skin, cartilage, and liver of Korean tiger shark.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.39 no.2
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• pp.87-91
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• 2003

Experimental fishing was carried out to investigate the survival rate of fishes discarded after hauling from the trawl and to develop the fishing gear and method for fisheries management which can improve the survival rate of young fishes escaped from the trawl codend in offshore korean southern sea and off Cheju Island of Korea. The young fishes were bred in fish cage on the board to measure the sustainable survival time for fishes escaped from grid panel and codend. The obtained results are summarized as follows' 1. Japanese flying squid(Todarodes pacjficus), mitra squid(Loligo chinesis), hair-tail( Trichiurus lepturus), john dory(Zeus japonicus), spanish mackerel(Scomberomorus niphonius), redlip croaker (Pseudosciaena polyactis) and blackthroat seaperch(Doederliinia berycoides) were dead instantly after hauling. 2. Survival rate of tiger shark(Galeocerdo cuvier), conger eel (Conger myriaster), red skate (Dasyatis akajei), black scraper(Navodon modestus) and japanese fan lobster(Ibacus ciliatus) might be high after discarding because they survived for long hours in fish cage. 3. Blotched eelpout(Zoarces gili) escaped from the escapement device(grid) was dead within 6 hours in the water tank installed on the board but 97% of tiger shark and 72% of conger eel survived over 72 hours. 4. Red skate escaped from trawl codend was dead within 60 hours in the water tank installed on the board but sustainable survival time of 25% of octopus(Paroctopus dofleini) and 100% of black scraper was over 72 hours. 5. Compared with the survival rate of rosefish(Helicolenus higendorfi) escaped from the escapement device(grid) and trawl codend, all of the rosefish escaped from the grid was dead within 7.2 hours but 8.3% of the rosefish escaped from the codend survived over 72 hours. 6. In comparison with the survival rate of japanese fan lobster survived over 72 hours, survival rate of japanese fan lobster escaped the codend was much higher as 75% than 33% of japanese fan lobster escaped from the grid.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.6
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• pp.445-454
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• 2004

A search for contraction and relaxation responses on the smooth muscles, antimicrobial and antioxidant activity in different body parts of 4 freshwater fish and 4 marine fish were conducted. The four freshwater fish studied were Sarotherodon niloticus (tilapia), Channa arus (snake head), Cyprinus carpio (Israel carp) and Siluru osotus (catfish), and the four marine fish were Scyliorhinus torazame (tiger shark), Ateiepus japonicus (tadpole fish), Mugil cephalus (gray mullet) and Thamnaconus modestus (file fish). Frozen samples were extracted with distilled water containing $1{\%}$ acetic acid. Antimicrobial activity against Bacillus subtilis and Eschrrichia coli was detected in extracts from several tissues in all species tested. Relatively high antimicrobial activity could also be detected in the bile extracts from C. carpio, M. cephalus, and T. modestus. Contraction and relaxation responses on smooth muscles could be detected in all species tested, especially in the intestine extracts. Antioxidant activity was also detected in extracts from several tissues in all species tested, while in the extracts from S. osotus, excluding livers and spleens, no antioxidant activity was detected. Results from this study suggest that fish are a potential source for the discovery of novel bioactive materials.