The transmittance properties of fishing lamp of the squid jigging vessel was investigated during nighttime operations in the Northwest Pacific on 21 and 29 September 2005. The metal halide lamps of white color(2.0kW×168) in the air and metal halide lamp of white color(10.0kW×1) in the underwater were used as a fishing lamp for gathering squids. The relative irradiance of metal halide lamp in the air showed peak in 850nm of wave length. The relationship between underwater illuminance(Y) and water depth(X) of metal halide lamp light in the observation areas is represented, Y=84.137e-0.1105X, R2=0.9974. The distribution of underwater illuminance of measure points St. 1-5 showed low value of 0.11x in 80m depth.

This paper described the experimental squid jigging fishery conducted by a commercial fishing vessel in the Northwest Atlantic Ocean from August to October 2005. Author carried out experimental jiggings of 65 times during 57 days by three type of jigs which were pick jig, soft jig and soft luminous jig. The total catch, effort/day and catches/line-day of northern shortfin squid (Illex illecebrosus) were 12,726kg, 35 auto jigging machine and 3.5kg, respectively. Higher CUPE was observed in September, August and October. Catch ratio of pick jig was higher by 57-86% than those of soft jig and soft luminous jig. Higher catch was recorded at the 42˚55'N, 62˚10'W with surface temperature ranging 18-21℃. The range of the dorsal mantle length was from 13.5cm to 23.0cm with average 17.2cm for female and from 13.0cm to 20.0cm with average 17.0cm for male. Sex ratio showed 55.4% of female.

A model experiment, simulation test using personal computer and real sea trial fishing were carried out to investigate the basic efficiency of bottom trawl net which can be used in the sea mount of North West Pacific, and experimental values were analyzed as the values of full-scale bottom trawl net. Hydrodynamic resistance for the full-scale trawl net according to the Koyama equation was 2.1 times higher than that of simulation and 2.4 times higher than that of model experiment at the average towing velocity. At the 3.5kt's of towing speed, net width of the full-scale trawl net was 2.5% smaller than that of simulation and 8.2% larger than that of model experiment. On the fishing experiment of the full-scale trawl net for the 3.5kt's of average towing speed, average net height of A group(same direction with external force) was 423.5% higher than that of model experiment and 457.1% higher than that of simulation and that of B group(opposite direction with external force) were 283.8% and 306.3% higher than in case of model experiment and Simulation respectively. Net mouth of the full-scale trawl net was 338.1-504.6% higher than those of model experiment and simulation in A group, and 525.2-745.3% higher in B group.

A model experiment using circulation water channel was carried out to investigate the dynamic characteristics of bottom trawl net which can be used in sea mount of North Pacific. Hydrodynamic resistance and shape variation according to the flow velocity and angle of hand rope transformation for net were measured, and experimental value was analyzed as the value of full-scale bottom trawl net. The results summarized are as follows; At the 30˚ of angle of hand rope to net, hydrodynamic resistance varied from 0.5kgf to 2.68kgf as the flow velocity increased between 0.31m/s and 0.92m/s, and formula of hydrodynamic resistance for the model net was Fm=3.04 · r1.53. At the fixed angle of hand rope, Net height was low and Net width was high according to the increase of flow velocity, and in addition, vertical opening was low and Net width was high by the increase of angle of hand rope at the fixed flow velocity. At the 30˚ of angle of hand rope to net, net opening area was 0.214m2 as flow velocity was 0.61m/s, and formula of net opening area for the model net was Sm=-0.22r+0.35. At the 30˚ of angle of hand rope to net, catch efficiency seemed to be highest as 0.319m3/s of filtering volume at the 0.76m/s(51kt's) of flow velocity. Shape variation of net showed the gradual laminar transform for the variation of flow velocity but there needed some improvements due to the occurrence of shortening at the ahead of wing net.

This study was conducted to survey the catches of vertical bottom longline fisheries in the sea mount of central northern Pacific(30˚-42˚N, 170˚-175˚E), during the period of July 1 to August 25,2004 by commercial fishing vessel. The number of 57 test fishing was carried out in the central northern Pacific during 43 days and the total catches were 21,092.4kg as 19 fish species, CPUE/day and catches/day were 185 baskets and 490.5kg, respectively. Main fish species caught from the experimental fishing were Squalus mitsukurii (66.3%), Coelorhyrchus asperocephaius (11.7%) and Helicolenus avius (9.8%) and, average inside diameter for fish mouth was 4.0cm over. Catch ratio according to each fishing ground was the order of F, D, J, B and C. Catch ratio fur water depth was the order of 450-500m, 350-400m, 300-350m, 400-450m, 1000-1100m and 500-550m and, main species by water depth was Squalus mitsukurii for 300-400m, Etmopterus lucifer for 300-550m, Coelorhyrchus asperocephaius far 1,000m over. Catch ratio according to the kind of hooks was higher at the hook no.6 for Squalus mitsukurii and no. 5 for Etmopterus lucifer and, catch ratio by baits was higher at squid for Squalus mitsukurii, saury and eel for Helicolemus avius and saury for Etmopterus lucifer. Accordingly, it is thought that the extension of fishing hours is needed with the reduction of damage and loss for fishing gears during fishing operation.

This study was conducted in order to the experiment of bottom trawl fisheries in the sea mount of central northern pacific(30˚-40˚N, 170˚-175˚E), during the period of July 1 to August 25, 2004 by commercial trawl ship. Fishing experiment was carried out by bottom trawl, with the codend of 110mm mesh size. The number of 101 test fishing was done in the sea mount of central northern pacific during 56 days and the total catches were 198,593kg as 18 fish species, and CPUE/day and catches/day were 8.3 hours towing time and 3,546kg. Catch ratio according to each fishing ground was higher with the order of B, C, and E, and catches for B was 7,171.0kg during the towing time of 13.2 hours. Main target species were Pseudopentaceros richardsoni and Beryx splendens, there was 14.9% of damage ratio for fishing gears on catching the target fishes inhabiting on the rough sea bottom. Catches by water depth was the order of 300m below, 301-350m, 451-500m and 351-400m. It is thought that there was no problem on the mesh size because most of fishes caught from the experimental fishing was 30cm over.

새우조망 끝자루의 망목선택성을 조사하기 위한 시험조업은 여수 거문도 주변해역에서 2002년 10월 중에 끝자루의 망목을 28, 38, 51 그리고 61mm로 구성하여 덮그물 방식으로 각각 5 회씩, 총 20회 거문도 주변해역에서 실시하였다. 주 어획대상 어종인 수염대롱새우의 끝자루 망목별 어획률과 망목선택성 곡선 S=1/(1+exp-αCL+β))의 기울기 (a)와 절편 (b) 및 선택계수 그리고 표본망목선택성곡선 S=1/(1+exp(-α(CL/M)+β)))의 기울기(a)와 절편 (b) 및 적정망목을 추정한 결과는 다음과 같다. 1. 시험조업 결과 어획미수는 끝자루 11,504마리, 덮그물 12,879마리로 총 24,374마리, 313.1kg이 어획되었고 종별구성은 새우류, 어류, 게류, 연체동물 순이었으며, 부수 어획물은 어류의 자치어가 대부분을 차지하였다. 2. 끝자루 망목 28.0, 38.0, 51.0, 61.0 mm에 어획되는 대롱수염새우의 어획률은 각각 0.72, 0.63, 0.46, 0.29로 나타났다. 3. 끝자루 망목 28.0, 38.0, 51.0, 61.0 mm에 대한 선택성곡선의 a와 b 값은 0.53 -12.65, 0.35 -9.40, 0.28 -8.97과 0.24 -8.27이었고, 선택계수는 0.85, 0.71, 0.62, 0.55이었다. 4. 표본망목선택성곡선의 기울기(α)와 절편(β) 값 은 8.44, -5.49이었고, 대롱수염새우의 최소성숙갑각장 20.6 mm에 대한 적정망목은 30.7 mm, 상품(上品) 최소갑각장 25 mm에 대한 적장망목은 38.5 mm로 나타났다.

우리나라의 서해와 남해 연안에 분포하는 민새우는 서해 북쪽으로는 영광에서 남쪽으로 거제도까지 널리 분포한다. 거문도 인근해역에서 채집된 민새우의 암 · 수 성비는 암컷이 48.6% 로 나타났고, 이 개체군은 7월과 8월에 성숙하고, 년 1 회 신생 가입군이 발생되었다. 교미한 개체는 7월과 8월에 출현하기 시작하였고, 갑각정 13mm 이상의 전 출현 암컷의 50% 이상이 교미한 것으로 나타났고, 성숙도지수는 7-8월에 최고치를 나타내었다. 암컷의 최소 성숙개체는 갑각장 11mm이고, 성 성숙과 교미율에 의한 군성숙도 (CL50) 는 각각 갑각장 12.53mm와 12.28mm로 나타났다. 체장 빈도 자료에 의해 추정된 민새우의 수명은 암컷이 14-15개월로 나타났다. 변형된 von Bertalanffy 성장식에 의해 추정된 성장계수(K)는 암 · 수 각각 1.22/년과 2.00/년이고, 최대 갑각장 (L∞)은 암 · 수 각각 21.99mm와 15.00mm이였으며, 암컷이 수컷보다 성장이 빠르고, 큰 것으로 나타났다.

우리 나라의 서해와 남해 연안을 분포하는 꽃새우는 북쪽으로는 강화도에서 남쪽으로 사랑도까지 널리 분포한다. 본 연구에서 대상으로 한 거문도 인근해역 꽃새우의 암ㆍ수 성비는 암컷이 48.6%로 나타났고, 이 개체군은 7월과 8월에 성숙하고, 년 1회 신생 개체군이 발생되었다. 교미한 개체는 7월과 8월에 출현하기 시작하고, 갑각장 19 ㎜ 이상의 암컷에서는 반 이상이 교미한 것으로 나타났으며, 숙도지수는 7-8월에 최고치를 나타내었다. 암컷의 최소 성숙개체는 갑각장 18 ㎜이고, CL<SUB>50</SUB> 성 성숙체장과 교미체장은 각각 갑각장 18.89 ㎜와 19.19 ㎜로 나타났다. 체장 빈도 변화에 의해 추정된 거문도 개체군의 수명은 암컷 14-15개월이고, 수컷은 13-147개월 나났다. 변형된 von Bertalanffy 성장식에 추정된 성장계수(K)는 암ㆍ수 각각 1.40/년과 2.00/년이고, 최대 갑각장(L<SUB>∞</SUB>)은 암ㆍ수 각각 29.54 ㎜와 18.95 ㎜이었으며, 암컷이 수컷 보다 성장이 빠르고, 큰 것으로 나타났다.

전라남도 여수시의 거문도, 초도, 손죽도 주변해역에서 1998년 11월부터 1999년 10월까지 12회 걸쳐 새우조망에 어획된 새우류의 종조성과 계절변동을 조사하였다. 조사해역의 수심은 20∼80m이고, 이 해역의 저층 수온의 연중범위는 8.3∼21.3℃이며, 저질은 니질대 또는 사니질이었다. 조사기간 동안 채집된 새우류는 총 11과 26속 37종 702,681개체가 출현하고 우점종은 그라비새우 48.52%, 긴줄꼬마도화새우 21.83%, 민새우 11.25%, 대롱수염새우 7.24%로 나타났다. 꽃새우, 민새우, 그라비새우는 15개 전 정점에서 골고루 출현하였으며, 대롱수염새우, 산모양깔깔새우, 긴줄꼬마도화새우는 거문도 주변해역(C구역)에서 출현하였으며, 중하, 긴발딱총새우는 초도, 손죽도 주변해역(A, B구역)에서만 출현하였다. 군집구조를 나타내는 종다양도 지수, 균등도 지수, 우점도지수는 정점 13에서 0.73과 0.61로 다양성 지수와 균등도 지수 가장 높게 나타내었고, 정점 4에서 0.14, 0.11로 가장 낮은 다양성 지수와 균등도 지수를 나타내었다. 정점별 군집의 유사도에 의하면 같은 수역인 정점 1, 7에서 0.673으로 가장 유사하고, 유사도 0.25 수준에서 거문도수역 집단(정점 10, 11)과 초도, 손죽도수역집단(정점 1∼9)으로 구분되는 것으로 나타났다.