본 연구는 경상남도 내 유통되는 양식 어류 116건을 대 상으로 PLS 도입 이후 동물용의약품 128종 142항목의 잔 류 실태를 분석하고, PLS 도입 전후의 변화를 평가하였다. 경상남도 양식 어류 116건 중 54건(46.6%)에서 잔류동물용 의약품이 검출되었으며, 이 중 넙치 1건에서 옥시테트라사 이클린이 기준치를 초과하였다. PLS 도입 전인 2023년의 검출률(49.6%)과 2024년의 검출률(46.6%)은 유의미한 차이 가 없었으나, 부적합률은 2023년 2.4%에서 2024년 0.9%로 감소했다. 어종별 잔류동물용의약품 검출 빈도는 미꾸라지 (81.8%), 조피볼락(78.6%), 넙치(68.4%) 순으로 높았다. PLS 도입 전후 모두 조피볼락이 해수어 중 검출률이 가장 높았 으며, PLS 도입 이후 넙치와 강도다리의 검출률이 증가한 반면, 농어와 숭어의 검출률은 감소했다. 물질별 검출 빈도 는 옥시테트라사이클린(22.4%), 엔로플록사신(19.8%), 트리 메토프림(8.6%) 순으로 높았으며, 2023년 연구에서도 유사 한 경향을 보였다. 2024년에는 미꾸라지에서 엔로플록사신 이 81.8%의 높은 검출률을 보였다. 넙치에서 옥시테트라사 이클린의 검출률은 2023년 45.5%에서 2024년 6 3 .2%로 증 가했으며, 조피볼락에서 트리메토프림의 검출률은 40.7%에 서 57.1%로 증가하였다. MRL 대비 검출 농도의 평균은 2023년 14.1%에서 2024년 14.2%로 유사한 수준이었고, 트 리메토프림, 플루메퀸, 아목시실린을 제외한 대부분의 항목 에서 MRL 대비 평균 검출농도가 증가했다. 위해성 평가 결과, 검출된 9항목에 대한 위해도는 0.0335% 이내로 매우 안전한 수준으로 평가되었다. 그러나 일부 어종에서 특정 한 약물의 잔류성이 강하다고 추정되므로, 각 어종의 특성 에 맞는 휴약기간 등의 명확한 관리 지침이 마련되어야 할 것이다. 또한 PLS 도입의 효과를 정확하게 평가하기 위해 서는 지속적인 모니터링이 필요할 것으로 보인다.

Since April 2012, doctor fish in the breeding tank and in the quarantine tank in Hanwha Aquaplanet Yeosu Aquarium have been dying, accompanied by diffuse bleeding around the mouth, in the chin, and at the bottom of the abdomen. In this study, the cause of death would be examined through the bacteriological study of doctor fish and the rearing water quality in the aquarium. The water quality and the bacterial counts of the rearing water in the exhibit tank and in the quarantine tank were analyzed once a week, starting from August to November 2014. Water quality was measured based on the following data: temperature was in the range of 24.5~26.8℃, pH at 6.77~7.94, DO at 6.15~8.61 ppm, ammonia at 0~0.93 ppm, nitrite at 0.009~0.075 ppm, and nitrate at 1.1~40.9 ppm. Studies revealed that the differences in these water quality factors were not related to the death of doctor fish. Bacterial counts in the rearing waters of Garra rufa slightly increased to 103~104 CFU/ml, just before the death of the doctor fish. Twelve strains of bacteria were isolated from the dead fish and rearing waters. The isolates were identified as Aeromonas veronii, Citrobacter freundii, Pseudorhodoferax aquiterrae, Shewanella putrefaciens, and Vibrio anguillarum on the basis of 16S rRNA gene sequences. The most dominant species was C. freundii, which showed medium sensitivity to florfenicol and norfloxacin, and was resistant to amoxacillin, doxycycline, oxytetracycline, tetracycline, and trimethoprim. Ten isolates were confirmed to be pathogenic to the doctor fish. Doctor fish infected with C. freundii and S. putrefaciens showed high mortality in the experimental groups. These results indicate that the variation in bacterial numbers in the rearing water was related to the death of doctor fish. C. freundii and S. putrefaciens were directly implicated in causing the death of doctor fish in the aquarium.

Garlic (Allium sativum) is known to have antimicrobial effects but there are few data on its effects against fish pathogenic bacteria. This study was conducted for possible development of natural food antimicrobials from garlic extracts, particularly allicin. The filter sterilized, aqueous extract of garlic was tested for its ability to inhibit the growth of 7 fish pathogenic bacteria (E. tarda, V. ichthyoenteri, V. harveyi, P. damselae, S. iniae, S. parauberis, L. garviae) using the disc diffusion test, minimum inhibitory concentration test, and minimum bacteriocidal concentration test. The garlic extract inhibited growth and killed most of the organisms tested. The disc diffusion test was performed using garlic extracts (100%, 50%, 25%, 10%, each 20㎍), and MIC test was also performed using a diluted concentration of garlic extracts (488 - 250,000 ㎍/㎖). According to the results, garlic extracts exhibited antimicrobial activity against all of seven bacteria, and these results suggest that this garlic extract can be used as an antimicrobial substance against fish bacterial diseases in the fish industry.

This paper introduces an auto-feeding system to exactly control the feeding time and the amount to cultured fishes in aquaculture industrial field. To reduce expensive costs or labors in this field, it was designed by the concept of controlling feed quantity exactly on the basis of fish's feeding behavior pattern in water tank. A feed control method of this system was developed for controlling feed amount by rotor capacity and motor rotated number. Moreover, a scattering section was selected by rotate way of propeller wing to scatter dried feed to designated site, and then, the diameter of its wing was 250mm and maximum scattering distance was 7.6m for 600rpm. Furthermore, the scattering ways were embodied 2 types such as a simplified way and a multistage shift way looks like a manual scattering. As a results, the multistage shift way is more effective to discharge the dried feed widely than the simple way in the water tank.