The aim of this study is to investigate influence of moon light to the fishing of squid jigging fishery in the southwest Atlantic Ocean based on analyses of date taken from 127 vessels in Falkland fishing ground by squid jigging fishery from 2010 to 2015. Catch and CPUE were analyzed between the new moon and full moon phases. Catches of the new moon phase were higher than those of the full moon phase by 7.6% and CPUE expressed in mt/day-vessels and mt/line-day were also higher by 18.2%, 18.2% respectively. However, as a result of statistical analysis at a significance level of p ＞ 0.05, no significant statistical differences in catch, mt/day-vessels and mt/line-day were found between the new moon and the full moon as a result of statistical analysis at a significance level of p ＞ 0.05.

This study aims to suggest the methodology to improve to estimate back-calculated fish growth parameters using weighted average. It is to contribute to correct errors in the calculation of back-calculated growth equation with unequal numbers of sample by age. If the numbers of sample were evenly collected by age, each back-calculated length at age was equal between arithmetic and weighted averages. However, most samples cannot be evenly collected by age in reality because of different catchability by fishing gear and limitation of environment condition. Therefore, the estimation of back-calculated length by weighted average method is essential to calculate growth parameters. There were some published growth equations from back-calculated length using a simple arithmetic average with different numbers of samples by age when searching for back-calculated growth equations from 91 relevant papers. In this study, the process of deriving growth equation was investigated and two different average calculations were applied to a fish growth equation, for example of Acheilognathus signifer. Growth parameters, such as L∞, k and t0, were estimated from two different back-calculated averages and the growth equations were compared with growth performance index. Based on the correction of back-calculated length using weighted average by age, the changes by female and male were -14.19% and -5.23% for L∞, and 59.28% and 18.91% for k, respectively. The corrected growth performance index by weighted average improved at 7.05% and 2.46% by female and male, respectively, compared to the arithmetic averages.

Commercial split beam echosounder (ES70) installed on a krill fishing vessel was calibrated in order to utilize it in estimating biomass of Antarctic krill (Euphausia superba). The method of calibration was to analyze the difference between the bottom backscattering strength of the commercial split beam echosounder (i.e. ES70) and the scientific echosounder (i.e. EK60) at one of transects near South Shetland Islands designated by CCAMLR. 38 kHz and 120 kHz were used for the calibration, and krill swarm signal levels obtained from multi frequencies, was examined to verify the calibration result. The analysis result indicated possibility of calibration by bottom backscattering strength, since the proportion of krill swarm signals within 2 dB < SV 120 kHz-38 kHz < 12 dB (i.e. a common SV 120 kHz-38 kHz range of 38 kHz and 120 kHz to be an indicator of Antarctic krill) over the total acoustic signals were 26.95% and 92.04%, respectively before and after the calibration.

The Commission for Conservation of Antarctic Marine Living Resources (CCAMLR) is utilized to manage krill resources using acoustic data collection and a scientific observer program operating on the fishing boats. However, the acoustic data were contained seriously noise, example of background, spike, and intermittent noise, due to purpose of fish boats. In this study, the noise removal techniques were confirmed the potential of the acoustic data analysis. Acoustic system and frequency used in the survey were commercial echosounder (ES70, SIMRAD) and 200 kHz split beam transducer. Acoustic data were analyzed using Echoview software (Myriax), and general data analysis and new noise removal method was used. Although a variety of noise, most of the noises have been removed using the noise removal processing. We confirmed the possibility of analyzing the acoustic data obtained from fish boats. The results will be useful for analysis of the acoustic data acquired from krill fishing boats.

Morphological and positional characteristics of anchovy aggregations, confirmed by trawling, were examined in two locations of the southern part of theWest Sea (T1) and the western side of South Sea (T11) of South Korea. Morphological characteristics (mean length, height and area) of the anchovy aggregations at T1 were smaller than those at T11, however the positional characteristics (distributional depth and bottom depth) of the aggregations at T1 were larger than those at T11. Diverse dataset such as the ship’s cruise track, the cruse map, and interpolated three-dimensional-like water temperature were visualized in multiple dimensions. For a comprehensive understanding of the anchovy aggregations within their surrounding circumstances, the interpolated water temperature transferred to the location of anchovy aggregations at both stations were visualized based on geospatial information. Using quantitative investigation, the overall range of change in water temperature and salinity of anchovy aggregations at stations was considerably small. However, the water temperature and salinity of anchovy aggregations at T11 were somewhat higher than those at T1.

2007년 4월부터 5월까지 시험조사선을 이용하여 동해의 해양성 조류 분포조사를 실시하였다. 조사 기간 동안 동해 연안에서 총 10과 23종 1,379개체의 조류가 관찰되었으며, 이 중 6과 14종 1,324개체는 해양성 조류였다. 해양성 조류의 발견율은 2.5 birds km-2였다. 가장 높은 발견율을 보인 종은 슴새(Calonectris leucomelas)로 전체 관찰개체수의 74.5%를 차지하였다. 이밖에 발견된 조류 중 1% 이상을 차지한 주요종은 바다쇠오리(Synthliboramphus antiquus)(8.3%), 아비(Gavia stellata)(5.0%), 제비갈매기(Sterna hirundo)(2.1%), 회색머리아비(Gavia pacifica) (2.0%), 괭이갈매기 (Larus crassirostris)(1.1%) 순으로 나타났다. 해양성 조류의 개체수는 동해 중남부 해역인 36˚N~37˚N 사이에서 가장 많았으나 종다양도 지수(H')는 동해 남부 해역인 35˚N~36˚N에서 가장 높은 값을 보였다. 발견된 대부분의 종은 해안선에서부터 멀어질수록 발견율이 줄어들었다. 발견된 주요종 이외에도 뿔쇠오리(Synthliboramphus wumizusume), 흰부리아비(Gavia adamsii), 쇠부리슴새(Puffinus tenuirostris), 붉은발슴새(Puffinus carneipes)와 같은 희귀종을 관찰하였다. 본 조사와 동시에 행해진 밍크고래(Balaenoptera acutorostrata) 목시조사의 자료를 통해 볼 때 슴새의 분포 패턴과 밍크고래의 분포 패턴 사이에서 높은 상관관계를 나타냈다. 아비류(Gavia spp.)의 분포는 공간적으로 분리되는 양상을 보였다.

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.

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.