음향집어기의 집어 효과

장선덕 한국어업기술학회 1986 수산해양기술연구 Vol.22 No.4

음향집어에 관한 기초자료를 제공하기 위하여 정치망내의 수중환경소음과 방성음의 분포 및 집어효과를 실험, 분석하였고, 그 결과를 요약하면 다음과 같다. 1. 수중환경 소음 및 방성음의 중심주파수대는 각각 150Hz~400Hz, 400Hz~1000Hz이고, 음압준위는 원통, 헛통, 장등, 비탈그물의 순으로 , 비탈그물, 원통, 헛통, 장등의 순으로 각각 높았다. 양망작업중의 수중소음은 양망개시후 시간의 경과에 따라 음압준위가 높아지나 양망의 마무리 단계에서는 오히려 낮아졌다. 2. 본 실험에서 제작한 방성장치로서 정치망어포부내에 방성한 결과, 초기에는 어군이 방성기주변으로 모여드는 반응을 나타내었으나, 약 30분이 경과하면서 이러한 반응은 약화되었다. 그리고 방성시간과 휴지시간의 간격보다는 방성음압에 군락이 더 민감하였다. 3. 일본에서 제작된 음향집어기(Dainy 0-8)로 해상에서 방성시험을 하여 본 결과, 대체로 방성개시후 약 20분에 어군이 모여들고 방성을 멈추면 곧 흩어졌다. 유집된 어군은 선박교통소음의 환경을 많이 받는 것으로 나타났다. 정치망입구 근처의 장등에 음향집어기를 설치하여 방성하였을 경우와 방성하지 않았을 경우에 대한 어획량이 방성하지 않았을 때에 비하여 약 3~5배 많은 것으로 나타났다. A field experiment was carried out to clarify the effect of underwater sound on the luring of fish school. The effects of. the acoustic emission on the luring of fish school were checked actually at a set net fishing site in Namhae using a commercial acoustic equipment, Dairyo-8. An emitting system of sound was designed by the authors, and the ambient noise, the sound pressure level and the reaction of fish school were measured in the set net. 1. The predominent frequency band of ambient noise was 150Hz-400Hz,.and the sound emitted was 400Hz-100Hz. The sound pressure level of ambient noise in set net was higher at the landing part, and lower at the playgrond, the gate of court and "the enterance of inclined "passage. The ambient noise was increased with the time elapse-d at the stage of hauling net, but :it was decreased suddenly at the final stage due probably to the decrease of the swimming speed of the fish school. 2. The results of the observation and the recording paper of echo sounder indicate that the effect of emitting sound in the bag net of set net was remarkable for the luring of fish school in the early stage, but decreased after 30 minutes. The reaction of fish school is more sensitiv2 to the sound pressure level than the time intervals between the emission and the pause. For the purpos~ of practical use, it is nesessary to confirm what kind of sound pressure level is the best for the luring of fish school. 3. In response to the acoustic equipment(Dairyo-8), fish school started to swarm 20 minutes after the sound emission and scattered when the sound paused. As the emitting pattern of the acoustic equiment, the three seconds of emission after one second of pause was more effective than the continuous emission at the set net fishing ground. Catch of the fish(s during th~ sound ernissio:l at the gate of court was three to five times more than that of no emission.

연안해역 중력분류의 혼합과정

장선덕 부산수산대학교 산업기술연구소 1991 産業技術硏究所 硏究報告 Vol.2 No.1

이매패류의 폐사에 미치는 현탁부니(縣濁浮泥)의 영향

장선덕,진평 한국수산학회 1978 한국수산과학회지 Vol.11 No.4

Effects of suspended silt and clay on the survival of the rearing bivalves, Meretrix lusoria, Cyckina sinensis and Mactra veneriformis were studied. During sixty-five days of experimental cultures in different concentrations of suspended silt and clay and in different time of immersions, mortalities of the bivalves were checked every day, and the rates of shell movement and oxygen consumption were measured. In general, the higher the concentration of silt and clay and the longer the immersion time, the earlier the occurence, and the higher the rate of the mortalities of the experimental bivalves. M. veneriformis was subjected to earlier mortality than the others, and the period of 50% mortality was the shortest of the three species (37 days in 1,000 ppm), and longer was that of C. sinensis (42 days). Mortality of M. lusoria occured latest and 50% mortality was seen at the immersion time of 50-51 days. Particularly, M. lusoria showed no mortality in the sea water with 100 ppm of suspended silt and clay, and even in the concentrations of 500 or 1,000 ppm they were able to survive without mortality only if the immersion time was short (12-18 hours per day). M. veneriformis and C. sinensis were also able to survive without mortality when the immersion time was short (12 hours per day) in low concentration (100 ppm). Shell movements of experimental bivalves varied depending upon species. In the case of M. veneriformis the shell was opened continuously and C. sinensis opened their shells frequently, while M. lusoria maintained their shells closed in any experimental concentrations of sea water with sus pended silt and clay. Total metabolic activity of M. veneriformis was found to be highest while that of M. lusoria showed the lowest. Little difference of oxygen consumption in excised gill tissue was shown between the control group and the experimental groups. Consequently, it may be stated that the mortality results from a immersion in sea water with high concentration of suspended silt and clay for long-time although the survival rates of the experimental bivalves depend also upon the species, physiological conditions, concentration of suspended silt and clay and immersion time. The survival percentage of bivalve y in relation to the time (day) of immersion × in sea water of suspended silt and clay was found to be: M. lusoria (1,000 ppm): y=7.7×10^9χ^-4.77 (500ppm): y=259χ^-0.26 C. sinensis (1,000 ppm): y=-21χ+936(χ<44), y=-0.65χ+35 (χ>44) (500ppm): y=4.4×10^5χ^-2.27 M. veneriformis (1,000 ppm): y=-18χ+716(χ<39), y=-0.89χ+39 (χ>39)

태양광선이 Nylon어망계의 항장력에 미치는 영항

장선덕 부산수산대학교 1962 부산수산대학교 연구보고(자연과학편) Vol.4 No.1-2

한국 남해안의 태풍에 의한 해일

장선덕 부산수산대학교 산업기술연구소 1991 産業技術硏究所 硏究報告 Vol.2 No.2

진주만의 해저유동에 관하여 -1

장선덕 부산수산대학교 1969 부산수산대학교 연구보고(자연과학편) Vol.9 No.2

진해만 조류의 현장관측 및 수리모형 실험

장선덕 부산수산대학교 산업기술연구소 1993 産業技術硏究所 硏究報告 Vol.4 No.2

동해 연안역 해수순환에 대한 바람응력 효과

장선덕,김종규 한국수산학회 1993 한국수산과학회지 Vol.26 No.6

韓國 東海 治岸域 海水循環 및 水溫分布에 대한 바람응력의 效果에 관하여 檢討하였다. 東海上의 바람응력은 國立水産振興院 停船觀測 바람자료 및 日本氣象廳 Buoy No. 6에서의 10년간(1978∼1987)의 약 5,100개의 바람 觀測資料를 사용하여 계산하였다. 여름과 겨울의 季節風의 轉換에 따른 에크만 輸送의 變化가 大韓海峽에서의 대마난류 輸送量에 미치는 影響을 定量的으로 評價하였다. 특히 東海에서의 平均的인 바람응력의 回轉性(wind stress curl) 값이 陰이 되는 사실에서 鬱陵島 近海의 暖水層의 形成에 部分的으로 도움이 됨을 알았다. 한편, 東海 暖水層의 分布를 單純化된 3層 境界面모델을 適用하여 說明하였다. In order to estimate the influence of wind stress in the southwestern coastal waters of the Japan Sea, the wind stress was estimated from the shipboard wind data of the Fisheries Research and Development Agency along the serial observation lines and Buoy No. 6 of the Japan Meteorological Agency. 5,100 wind data are used to construct a data set of monthly mean wind stress during 10 years from 1978 to 1987. The negative values of the mean zonal wind stress curl at Ulleung Basin in the study area seem to be responsible for the formation of the warm core. The volume transport of the East Korea Warm Current are estimated quantitatively by the variations of the Ekman transport associated with the reversing direction of the monsoon. And the distribution of the warm core is explained by the simple three layer model.

측류판 표류실험에 의한 하계 울릉도·독도 근해의 해수류동 특성

장선덕,김종규 한국수산학회 1994 한국수산과학회지 Vol.27 No.5

The East Korean Warm Current is known as an anticyclonic circulation in the Ulreung Basin in the southwestern East Sea of Korea. This circulation was approximately estimated by dynamic methods based on the oceanographic observation and remote sensing data. In this study, the existence of circulation in the anticyclonic region of East Korean Warm Current(Tsushima current) in early summer was directly measured by drogue tracking using a global positioning system. At the same time, the velocity was calculated by dynamic method and compared using data collected by remote sensing. As results, these values are shown to be nearly the same, and an anticyclonic circulation was found around Ulreungdo-Tokto. The maximum northward and southward flow speed was deduced to be around 0.6 and one knot, respectively.

진주만의 해양학적 연구

장선덕 부산수산대학교 1971 부산수산대학교 연구보고(자연과학편) Vol.11 No.1