In this study, we estimated the applicability of length-weight relationship-based biomass calculations by comparison of body length of genus Polyarthra collected from different habitats. Through the comparison, we also tested availability of representative species-specific biomass value of Polyarthra which is often used without length measurement. Polyarthra samples were collected from rivers (Han River and Nakdong River) and reservoir (Paldang Reservoir), and the body length was measured for statistical comparison among habitats and biomass calculations using different equations suggested previously. According to the results, the body length of Polyarthra spp. was significantly different among sampling sites, and the necessity of body length measurement for rotifer species in each situation has been suggested rather than using the representative biomass values which is fixed without considering time and space. Comparison of suggested biomass calculations based on our measured Polyarthra body length, the equation suggested by McCauley showed more reasonable range of biomass values than that suggested by EPA. In addition, in order to calculate more accurate biomass, it is necessary to measure the body length of rotifers, at least more than 44 individuals to reduce error probability to less than 5% with 99% probability. However, since direct measurement of rotifers biomass is limited, it is considered that further analyses are required for more precise application of rotifer biomass of which has high variability due to complex morphologies and species-specific cyclomorphosis often induced by biotic and abiotic factors in the habitats.

The length frequency and weight-length relationships within the loach population of Misgurnus anguillicaudatus were investigated in environment-friendly (EFP) and conventional paddy fields (CP) in South Korea, in order to identify the influences of farming practices to the loach population living in paddy ecosystem. The size-frequency of distribution of M. anguillicaudatus populations noted to differ significantly when the loach populations of the EFP and the CP were compared. The mean weight and length of the loach population in EFP was greater than those of the loaches in CP. The equations based on weight and total length relationship in EFP and CP were W=0.000004L3.0747 and W=0.000002L3.2106, respectively. The condition factor (K) against total length of loaches at two paddy field types with different farming practices indicates that the loach population in EFP (mean K=0.95) had access to better nutritional conditions than those in CP (mean K=0.67). It therefore appears that the size and structure of loach populations in rice paddy fields might be affected by farming practices.

We measured the target strength according to the swimming tilt angle and size change for Pacific herring at the frequency of 70 kHz as the basic database in order to estimate its abundance as well as density in the survey area using the hydroacoustical method. The number of the sample used in this study was 14 individuals, and its size distribution by fork length ranged between 20.3 and 29.8 cm and wet weight was measured between 187.6 and 269.9 g. The variation of TS according to the swimming angle (-30~30°) was measured between 10.3 and 18.8 dB in frequency range, the highest value was measured at head-down of Pacific herring in the tilt angle range between 5 and 9 deg. of its swimbladder. The relationship between TS–FL of herring was the same as TS = 20log10 (FL) – 66.79 when its swimming tilt angle in the daytime (3.8 ± 6.0°) and nighttime (-3.2 ± 13.6°), respectively.

Rockfish was a commercially important fish specie in marine ranching areas in Korea. To estimate density and biomass of rockfish using acoustic method, target strength (TS) information is required on the species. This study measured TS dependence on tilt angle and size on 14 live rockfish individuals at 38, 70, and, 120 kHz by ex-situ measurement (tethered method) and acoustic scattering model (Krichhoff ray mode, KRM). The swimbladdered angle ranged from 18 to 30˚ (mean ± s.d. = 26 ± 4˚ ). The mean TS for all individuals was highest -35.9 dB of tilt angle -17˚ at 38 kHz, -35.4 dB of tilt angle -25˚ at 70 kHz, and -34.9 dB of tilt angle -22˚ at 120 kHz. The ex-situ TS-total length (TL, cm) relationships were TS38kHz = 20log10(TL) - 67.1, TS70kHz = 20log10(TL) - 68.6, and TS120kHz = 20log10(TL) - 69.9, respectively. The model TS-total length (TL, cm) relationships were TS38kHz = 20log10(TL) - 66.4, TS70kHz = 20log10(TL) - 67.0, TS120kHz = 20log10(TL) - 67.0. The two measurements between the ex-situ TS and KRM model for TS-tilt angle and fish size were found to be significantly correlated.

Yield-per-recruit (YPR) analysis is used to provide management guidance for the efficient use of a fish cohort. However, the individual fish price per unit weight of small yellow croaker (Larimichthys polyactis) or hairtail (Trichiurus lepturus) increases dramatically by size in Korea. Therefore, age-based production value-per-recruit (PPR) analysis has recently been developed (Zhang et al., 2014). Since age determination requires a substantial amount of money and time and it is even impossible for some fish species, it is difficult to obtain age information to apply the age-based PPR model. Thus, we attempted to develop an alternative method, which uses length data rather than age information, called the length-based PPR analysis. The results revealed that length-based PPR analysis was much more conservative for stock management than the YPR analysis. Furthermore, the PPR analysis was more economically beneficial than the YPR analysis, which can prevent the fish stock from the economic overfishing. In conclusion, the length-based PPR analysis could be a proper approach for stock assessment in the case that the individual fish price per unit weight increases dramatically by size, and this analysis is useful to obtain vital management parameters under data-deficient situation when traditional stock assessment methods are not applicable.

옥정호로 유입되는 37km의 추령천에는 육봉화된 은어의 이동을 가로막는 많은 보가 설치되어 있었으나 2006년 12월 옥정호 추령천 하류에는 은어가 성숙하기 위해 추령천 상류로 이동하도록 어도가 설치되었다. 따라서 2007년 4월부터 10월까지 13개 지점에서 어도와 은어의 성장률을 조사하였다. 그 결과 어도의 설치 후, 치어들은 강수량이 풍부했던 시기에만 소상할 수 있는 상류를 새로 설치된 어도를 통해서 자유롭게 상류로 이동할 수 있었다. 2007년 9월 산란시기 동안 성숙된 은어는 163±21.5mm로 어도가 설치되기 전인 2006년에 비해 약 13mm, 2004년 약 20mm, 2005년 약 57mm정도 더 크게 나타났다. 따라서 하천에서 어도는 육봉형 은어집단의 평균 크기와 생존력에 중요한 역할을 하는 것으로 확인되었다.

Black porgy and fat greenling are commercially important fish species due to the continuously increasing demand in Korea. When estimating acoustically the fish length by a fish sizing echo sounder, it is of crucial importance to know the target strength (TS) to length dependence. In relation to these needs, the target strength experiments for live fishes were conducted in an acrylic salt water tank using two split-beam echo sounders operating at 70 and 120kHz. The target strength under well-controlled laboratory conditions was simultaneously measured with the swimming movement by digital video recording (DVR) system and analyzed as a function of fish length (L) and frequency (or wavelength λ). Equations of the form TS-alog (L)+blog (1)+c were derived for their TS-length dependence. The best fit regression of TS on fork length for black porgy was TS=20.62 log (L, m)-0.62 log (λ, m)-30.68 (r2=0.77). The best fit regression of TS on fork length for fat greenling was TS=12.06 log (L, m)-5.85 log (λ, m)-22.15 (r2=0.44).

 ,  , The size of infective Steinernema arenarium juveniles is variable and ranges from 724 to 1408 ㎛. Effects of harvest time and infective juvenile size on pathogenicity, development, and reproduction were examined in the last instar of the great wax moth, Galleria mellonella. Harvest time of infective juveniles (IJs) of S. arenarium affected pathogenicity. IJs harvested at the 10th day from trapping were more pathogenic than those harvested the 3rd day from trapping. Mortality of G. mellonella also depending on harvest time, i.e, 100% died within 48h when IJs were harvested at the 10th day, without relation to size. However, mortality was 40% in the small size group (SSG) compared with 18% in the large size group (LSG) within 48h when IJs were harvested at the 3rd day. Establishment of S. arenarium within the host was different depending on IJ size. The number of established IJs was 1.8 in the SSG, 3.3 in the LSG, and 3.2 in the mixed size group (MSG) when IJs were harvested at the 3rd day, and 5.3 in the SSG, 7.4 in the LSG, and 7.6 in the MSG when IJs were harvested at the 10th day. The length of the female adult was 7,070.5 ㎛ in the SSG and 7,893.9 ㎛ in the LSG and that of the male was 1,460.5 ㎛ in the SSG and 1,688.2 ㎛ in the LSG when IJs were harvested at the 3rd day. The length of the female adult was 7,573.6 ㎛ in the SSG and 8,305.4 ㎛ in the LSG and that of the male adult was 1,733.4 ㎛ in the SSG and 1,794.4 ㎛ in the LSG when IJs were harvested at the 10th day. Harvest time and size of IJs did not influence numbers of progeny or size of IJS.

Species of fish such as striped beakperch, bluefin searobin and konoshiro gizzard shad are commercially very important due to their high demand in the Korean market. When estimating acoustically the abundance of stocks for these species, it is of crucial importance to know the target strength (TS) to the length dependence. In relation to these needs, the TS experiments were conducted on three different species in an acrylic salt water tank using two split-beam echo sounders of 70 and 120 kHz. The TS for these three species under the controlled condition was simultaneously measured with the swimming movement by a DVR system and analyzed as a function of fish length (L) and frequency (or wavelength λ). The equation of the form TS=a log (L)+b log (λ)+c was derived for their TS-length dependence. The best fit regression of TS on fork length for striped beakperch was estimated as TS=35.67 log (L, m) -15.67 log (λ, m) -46.69 (r2=0.78). Furthermore, the best fit regression of TS on fork length for konoshiro gizzard shad was shown to be TS=25.85 log (L, m) -5.85 log (λ, m) -32.22 (r2=0.51). The averaged TS for 12 bluefin searobins with a mean length of 24.36cm at 70 kHz was analyzed to be -41.55dB. In addition, the averaged tilt angle obtained simultaneously by a DVR system with TS measurements for 27 konoshiro gizzard shads swimming within an acrylic salt water tank was estimated at -2.7˚.

Effect of inoculation level on pathogenicity, development, and propagation of entomopathogenic nematode, Steinernema arenarium was investigated using the last instar of great wax moth, Galleria mellonella. Pathogenicity of S. arenarium was higher with increasing inoculation level representing 82% at the rate of 5 infective juveniles (IJs) while >98% at the rate of >10 IJs. The number of IJs penetrated into the host was 2.7, 5.0, 7.4, and 12.2 at the rate of 5, 10, 20, and 40 IJs, respectively while 24.3 at the rate of 80 IJs and 40.2 at the rate of 160 IJs. Inoculation level did not affect female adult size (4,616 to 6,444 ㎛) while affected male adult size (1,600 to 1,934 ㎛). The rate of stunted female adults was 70.2% at the inoculation level of 80 IJs and 63.7% at the inoculation level of 160 IJs. The number of progenies was 20,431, 26,696, 47,943, 50,516, 58,701, and 74,235 at the rate of 5, 10, 20, 40, 80, and 160 IJs, respectively. The body lengths of IJs were different depending on inoculation level ranging from 636 to 1,496 ㎛.

Black rockfish and goldeye rockfish are commercially important fish species due to the increasing demand in Korea. When estimating the abundance of stocks for these species acoustically, it is of crucial importance to know the target strength(TS) to length dependence. In relation to these needs, TS measurement was conducted on black rockfish and goldeye rockfish in an acrylic salt water tank using 70kHz and 120kHz split beam echo sounders. The TS for these two species under the controlled condition was simultaneously measured with the swimming movement by DVR system and analyzed as a function of fish length(L). The results obtained are summarized as follows: The best fit regression of TS on fish length of black rockfish was TS=19.38 Log(L, cm)-70.46 (r2=0.71) at 70kHz and TS=22.39 Log(L, cm)-70.40 (r2=0.64) at 120kHz and in the standard form TS=20 Log(L, cm)-71.29 (r2 = 0.70) at 70kHz and TS=20 Log(L, cm)-66.88 (r2=0.57) at 120kHz. The best fit regression of TS on fish length of goldeye rockfish was TS=17.10 Log(L, cm)-68.28 (r2=0.37) at 70kHz and TS=24.39 Log(L, cm)-73.74 (r2=0.59) at 120kHz and in the standard form TS=20 Log(L, cm)-72.03 (r2=0.32) at 70kHz and TS=20 Log(L, cm)-67.68 (r2=0.64) at 120kHz. An empirical model for fish TS(dB) averaged over the dorsal aspect of 115 fishes of black rockfish and goldeye rockfish and which spans the fish length(L, m) to wavelength(λ, m) ratio between 8 and 30 was derived : TS=34.12 Log(L)-14.12 Log(λ)-23.83, (r2=0.90).

Acoustic target strength (TS) of 12 commercially important fish species caught in the Korean waters had been investigated and their results were presented. Laboratory measurements of target strength on 12 dominant fish species were carried out at a frequencies of 75 kHz by single beam method under the controlled condition of the water tank with the 241 samples of dead and live fishes. The target strength pattern on individual fish of each species was measured as a function of tilt angle, ranging from -45˚ (head down aspect) to 45˚ (head up aspect) in 0.2˚ intervals, and the averaged target strength was estimated by assuming the tilt angle distribution as N (-5.0˚, 15.0˚). The 75 to fish length relationship for each species was independently derived by a least - squares fitting procedure. Also, a linear regression analysis for all species was performed to reduce the data to a set of empirical equations showing the variation of target strength to fish length and fish species. An empirical model for fish target strength(TS, dB) averaged over the dorsal aspect of 158 fishes of 7 species and which spans the fish length(L, m) to wavelength(λ, m) ratio between 6.2 and 21.3 was derived: TS: 27.03 Log(L)-7.7Log(λ)-17.21, (r2=0.59).

우리나라 주변해역에 서식하는 주요 어종의 체장식별에 필요한 음향반사강도의 data bank를 구축하기 위한 연구의 일환으로 대형음향수조에서 부세의 체장에 따른 음향반사강도를 측정하고, 그 반사강도의 체장 의존성 및 KRM 산란모텔에 의한 이론 반사강도와 측정치를 비교, 분석한 결과를 요약하면 다음과 같다. 1. 체장의 범위가 21.0-32.5 cm인, 총 13마리의 부세를 대상으로 구한 평균반사강도패턴에서 최대 반사강도는 tilt angle이 -13.35˚ 인 입사방향에서 나타났고, 이 때의 반사강도는 -35.13 ㏈ 이었다. 2. 부세의 체장 (fork length, cm)과 평균반사강도의 사이에는 다음의 회귀직선식이 성립하였다. TS=23. 76log(L) -73.45(r=0.47) TS=20log(L) -67.35이 결과로부터 부세의 반사강도는 체장의 2.376승에 비례하는 경향을 나타내었고, 체장변환계수는 체장의 2승에 근사시켜 구한 값 보다 6.1 ㏈ 더 낮게 나타났다. 이들의 결과는 향후 체장어군탐지기의 체장변환계수의 값으로서 활용될 것으로 판단된다. 3. 평균체장은 25.59 cm인 총 13마리의 부세에 대한 반사강도의 빈도분포로부터 구한 반사강도는 -41.23 ㏈이었고, 이 값으로부터 구한 체장변환계수는 -69.72 ㏈이었다. 4. KRM model에 의한 부세의 이론반사강도는 L/λ 비가 15보다 작은 영역에서는 파동상의 변화를 나타내면서 증가하는 경향을 나타내었고, 15보다 큰 영역에서는 매우 완만하게 증가하는 경향을 나타내었다. 5. 부세의 평균반사강도의 측정치는 KRM 산란모델에 의한 예측치보다 전반적으로 낮은 경향을 나타내었고, 보다 정량적인 분석을 위해서는 광범위한 주파수 범위에 대한 실험이 필요하다고 판단된다.리오차는 수온변화에 의한 송신주기의 변화를 측정하여 최소화하도록 하였다. 핑거 부근의 수온을 알 수 있다면 핑거 송신주기의 수온특성을 보정하여 74%정도 측정거리오차를 줄일 수 있지만, 장기간에 걸쳐 추적을 하기 위해서는 다른 보정방법의 개발이 필요함을 알 수 있었다.법이 모색되어야 한다. 앞으로 한국실정에 맞는 토착화된 사별관리를 위한 다각적인 연구가 시도되어야 하며 이를 실무에 적용시켜야 한다.ssumption, additional study is needed to examine the relationship between the levels of microbes and excessive concentrations of EA, and borate at a high pH level.부정적인 반응을 보였다. '한국음식을 더 많이 해서 전통음식과 친밀한 장소로 발전시키자', '계절식품을 이용하고 비슷한 종류의 음식은 빼서 가격을 낮추자', '연령에 따라서, 또, 성인에서는 성별에 따라 가격 차이를 두자'는 의견 등이 있었다.이용한 배반포의 체외생산에 있어서 배양액내 항산화제의 첨가는 체외성숙단계에서만 효과적이었다. 이것은 아마도 항산화제가 체외성숙 시 난포란 내에서 일어나는 여러 가지 생화학 반응의 처리시간과 관련하여 활성화시킴으로써 난포란의 생존력을 높인 것이라고 사료되기 때문에 앞으로는 돼지 난포란의 효율적인 체외성숙에 대해서 배양액내 첨가물질은 물론 나아가서 방법론적인 측면에서 더욱 연구되어져야 할 것이다.ed from Nusselt's film condensation theory on tilted plate. Using those two expressions, a correlation was formulated as a function of heat flux and tilt ang

자원관리형 자망.통발 어구어법 기술개발을 위한 연구의 일환으로 서해구의 자망.통발어업에 대한 현황을 파악하고, 서해구의 대표적인 어종 중의 하나인 민어를 어획대상으로 하는 민어 연안 유자망어업과 피뿔고둥을 주 어획대상으로 하는 기타 통발어업을 연구대상으로 선정하여 현장조사 등을 통하여 조업실태와 대상어종의 체장조성 등을 조사한 결과는 다음과 같다. 1. 서해구의 연안어업 총 허가건수는 12,944건(조업건수 7,558건; 2001년 12월말 현재)이며, 그 중에서 자망어업이 5,154건(조업건수 3,724건)으로 39.8%, 통발어업이 1,025건(조업건수 662건)으로 7.6%를 차지하였으며, 서해구에서의 조업율은 연안 자망어업과 연안 통발어업이 각각 72.3%와 64.6%로서 타 업종에 비해 비교적 높은 편이었다. 2. 민어 유자망어업의 주어기는 7월 중순부터 9월 초순까지이며, 주어장은 서해 남부 연안의 섬주변의 수심 약 15∼50m(주로 30m 이내)이고, 조업은 저질이 펄 또는 사니질인 해역에서 사리때를 전후하여 1일 1∼2회 1주일 정도 창조시 투망하여 1∼2시간 정도 어구가 조류에 표류하도록 한 후 양망하는 것으로 조사되었다. 3. 민어 유자망어업의 현장조사 결과 어획된 139마리의 체장 범위는 43.0∼120cm이고, 모우드(mode)는 85cm였으며, 꽃게.병어.가오리 등이 소량 혼획되었다. 4. 서해구에서의 피뿔고둥을 주대상으로 하는 기타 통발어업은 꽃게 어기(9월 초순∼10월 중순)를 제외한 시기에 연중 조업하며, 서해 연안의 수심이 10∼20m이고 저질이 사니질인 해역에서 보통 전날 투망하여 다음 날 양망하는 것으로 조사되었다. 5. 기타 통발어업의 현장조사 결과 조사기간 중 어획된 피뿔고둥 5,372마리의 갑장 범위는 4.5∼8.5cm이고, 모우드(mode)는 7.5cm였으며, 피뿔고등 91.7%, 배꼽고등 4.8%, 민꽃게.쥐노래미.조피볼락 등이 3.5% 정도 혼획되었다.

향어, Cyprinus carpio [Linnaeus]의 체장에 따른 심전도를 구명하기 위하여, 어체내에 전극을 삽입하여 3가지 체장 범위 (10~15, 15~20, 20~25cm)에서의 심전도를 주간과 야간으로 구분하여, 16~18℃ 수온에서 30분간 조사한 심박수와 생체전위를 마취상태와 안정상태로 구분비교 분석한 결과는 다음과 같다. 1 체장이 10~15 cm인 경우, 마비상태 (0~9분)에서의 평균심박수는 주간에 43.4 beat/min, 야간에 45.9 beat/min였고, 평균생체전위는 주간에 4.38 μ V, 야간에 3.64 μ V로 나타났으며, 안정상태 (9~30분)에서의 평균심박수는 주간에 69.4 beat/min, 야간에 67.4 beat/min였고, 평균생체전위는 주간에 3.82 μ V, 야간에 3.50 μ V로 나타났다. 2 체장이 15~20cm인 경우, 마비상태 (0~5분)에서의 평균심박수는 주간에 42.2 beat/min, 야간에 45.4 beat/min였고, 평균생체전위는 주간에 4.13 μ V, 야간에 3.95 μ V로 나타났으며, 안정상태(5~30분)에서의 평균심박수는 주간에 67.6 beat/min, 야간에 65.3 beat/min였고, 평균생체전위는 주간에 4.58 μ V, 야간에 4.61 μ V로 나타났다. 3. 체장이 20~25 cm인 경우, 마비상태(0~4분)에서의 평균심박수는 주간에 47.5 beat/min, 야간에 47.5 beat/min였고, 평균생체전위는 주간에 4.81 μ V, 야간에 4.20 μ V로 나타났으며, 안정상태(4~30분)에서의 평균심박수는 주간에 67.5 beat/min, 야간에 64.8 beat/min였고, 평균생체전위는 주간에 5.31 μ V, 야간에 4.90 μ V로 나타났다.

본 연구에서는 이스라엘잉어 Cyprinus carpio를 체장과 체중별로 분류하여 방위별 표적강도를 측정한 후, 체장 및 체중의 변화에 따른 표적강도와의 관계를 고찰하였으며, 그 결과는 다음과 같다. 1. 이스라엘잉어를 대상으로 하여 측정된 방위별 표적강도는 부레의 위치변화에 따라 심한 변화폭을 보였으나, 대체적으로 최대표적강도의 방위별 분포는 dorsal aspect인 경우 등쪽을 기준하여 10˚ 정도의 방위변화에서 최대였으며, side aspect인 경우 음원의 수직 측면상의 5˚~10˚에서 최대였다. 2. 이스라엘잉어에 대한 체장, 체중별 표적강도는 체장과 체중에 비례하여 지수함수적으로 증가하였으며, 체장(L) 및 체중(W)의 변화에 따른 표적강도의 관계식은 다음과 같다. TS sub(L)=20 LogL-65.4. TS sub(W)=6.7 Log W-53.7. TS sub(L): 체장에 대한 표적강도(dB). TS sub(W): 체중에 대한 표적강도(dB).

The author tried to clarify the distribution of the total length and body weight of the file h, Navodos modcstus, caught by trawl net during July, 1984 in the southern sea korea. Among the catches of five times fishing operation, 1540 individuals were randomly sampled for the measurement. The results are summarized as follows; " The distribution of total length showed bimodal type, wbich was able to analyzed into two normal distributions N(17.46, 1. 022) and N(22.09, 1. 772). And smaller group was much than older one. The age of the sample estimated from the total length distribution of. smaller group was 1. 5 to 2, and the larger group 2. 5 to 4. The relationship between the total length and the body weight can be presented as following equation: W=0.01726 L2.8507 ' or W= 0.01109 L3.0 or W= 0.01109 L3.0