주파수차법을이용한남극크릴의종식별 789.,, 2 (Miyashita et al., 1997; Kang et al., 2002; Han, 2017)., khz. 2 (EK60, 38 and ) South Shetland island (Subarea 48.1)

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1 한수지 50(6), , 2017 Original Article Korean J Fish Aquat Sci 50(6), ,2017 주파수차법을이용한남극크릴 (Euphausia superba) 의종식별에관한연구 최석관 한인우 1 * 황두진 1 김태호 1 안두해 이경훈 1 국립수산과학원원양자원과, 1 전남대학교수산과학과 Species Identification of Antarctic Krill Euphausia superba Using the 2-frequency Difference Method Seok-Gwan Choi, Inwoo HAN 1 *, Doo-Jin Hwang, Tae-Ho Kim, Doo-hae An and Kyounghoon LEE Distant Water Fisheries Resources Research Division, National Institute of Fisheries Science, Busan 46083, Korea 1 Division of Fisheries Science, Chonnam National University, Yeosu 59626, Korea Antarctic krill Euphausia superba are important components of the Antarctic marine ecosystem both economically and ecologically; to manage this species effectively, their distribution and abundance must be understood. Using the Kwang Ja-Ho (3,012 tonnage), a commercial fishing vessel, we conducted acoustic surveys during April 13-24, 2016, to estimate the distribution and population size of krill around the South Shetland Islands of the Antarctic Continent, We used acoustic techniques based on the db-difference, a method used mainly to classify of marine species. We found that Antarctic krill were present in numbers over 99% at six survey stations, with the exception of Station 3, where we only found Electrona carlsbergi. There was no difference in cell size due to frequency differences, but echo signals differed between species: db for Antarctic krill, and -4.1~0 db for Electrona carlsbergi. Key words: Antarctic krill, Euphausia superba, 2-Frequency difference method, Species identification 서론 (Euphausia superba),,, (Everson, 2000),, (Hewitt and Demer, 1993; Atkinson et al., 2009; Jarvis et al., 2010; Fielding et al., 2014).,, (Commission for the Conservation of Antarctic Marine Living Resources, CCAMLR), (Hewitt and Low, 2000; Hewitt et al., 2004). 25, CCAMLR., (Lawson et al., 2008; Cox et al., 2011; La et al., 2016).,,,,..., Korean J Fish Aquat Sci 50(6) , December 2017 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial Licens ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Received 6 September 2017; Revised 18 October 2017; Accepted 30 October 2017 *Corresponding author: Tel: Fax: address: a2anna13@naver.com Copyright 2017 The Korean Society of Fisheries and Aquatic Science 788 pissn: , eissn:

주파수차법을이용한남극크릴의종식별 789.,, 2 (Miyashita et al., 1997; Kang et al., 2002; Han, 2017)., 38 120 khz. 2 (EK60, 38 and ) South Shetland island (Subarea 48.1). 재료및방법 조사해역및표본채집 48.

2 주파수차법을이용한남극크릴의종식별 789.,, 2 (Miyashita et al., 1997; Kang et al., 2002; Han, 2017)., khz. 2 (EK60, 38 and ) South Shetland island (Subarea 48.1). 재료및방법 조사해역및표본채집 48.1 South Shetland island Elephant island, 200 m (3,012 tonnage, Insung, Korea), Fig ,, 200 CCAMLR (2011) Discovery mm. 조사시스템의구성 (EK60, Simrad, Norway), 1982 CCAMLR Table khz ES80B, ES120-7C, Table ms, ping 2, m. ( S, W), 38 khz 60 mm, 23 mm Latitude Table 1. Parameters of scientific echosounder for acoustic data collection Parameter Subarea 48.1 South Shetland Island Setting Transducer ES38B ES120-7C Power (W) Pulse duration (microsecond) Ping interval (second) 2 2 Data collection range (minimum-maximum) (m) Bottom detection range (minimum-maximum) (m) Display range (minimum-maximum) (m) Longitude ANTARTICA Elephant Island Fig. 1. Acoustic survey station for collection of Antarctic krill Euphausia superba sample. Trawl collection station were shown from T1 to T Table 2. Calibration result of frequency 38 khz and for scientific echosounder Frequency (khz) Two-way beam angle (db) Receiver bandwidth (khz) Transducer gain (db) dB Beam angel (athwart/along) (deg.) 7.08/ /5.60 Absorption coefficient (db km -1 ) Sound speed (m s -1 ) Table 2 (Foote et al., 1987)., 38 khz

3 790 최석관ㆍ한인우ㆍ황두진ㆍ김태호ㆍ안두해ㆍ이경훈 -20.6, -21.0, Receiver bandwidth 2.43, 3.03, Transducer gain db, db. 9.8 (db/km), 24.7 (db/km), m/ s. 남극크릴의채집어구. Fig m, 40 m, 72 m. 32 m, 1.5 m, 3 m. 15 mm, 100 mm.,.,.,.. PP Super Danline 3st. (Danlin Fig. 2. Arrangement of the Antarctic krill Euphausia superba trawl net used in this study.

Longitude 791 주파수차법을 이용한 남극 크릴의 종 식별 강도가 일반로프에 비해 1.3배정도 더 우수함)를 사용하였으 며, 그물 부분은 PE재질의 결절 그물감과 무결절 그물감으로 제작되었다 (Fig 2). PP Danline 8st은 헤드라인과(91.3m), 사 이드라인(86.1 m), 힘줄이다.

0 m)에 구성되며, 사이드라인(64.4 m)과 힘 줄의 재질은 나일론으로 구성되었다.

잡음 제거 음향조사의 자료 분석은 후처리소프트웨어(Echoview Ver. 4.7, Echoview Software Pty. Ltd, Australia)를 이용하여 분석 하였다.

4 Longitude 791 주파수차법을 이용한 남극 크릴의 종 식별 강도가 일반로프에 비해 1.3배정도 더 우수함)를 사용하였으 며, 그물 부분은 PE재질의 결절 그물감과 무결절 그물감으로 제작되었다 (Fig 2). PP Danline 8st은 헤드라인과(91.3m), 사 이드라인(86.1 m), 힘줄이다. 뜸줄의 부분은 로프 가운데에 와 이어 심이 들어가 있고, PP재질의 밧줄로 감싸진 컴파운드로 프(Compound rope)를 사용되었다. 로프부분은 나일론 재질의 Super 12st. 로프와 PP재질 로프를 사용하고 있으며, 나일론 재 질의 Eurofix br. netting을 사용하였다. Dyneema SK75 12st 로 프는 헤드라인(88.0 m)에 구성되며, 사이드라인(64.4 m)과 힘 줄의 재질은 나일론으로 구성되었다. 각 정점별로 채집하였으 며, 크릴의 트롤 어획 횟수는 4월 14일부터 4월 23일까지 약 10 일동안 7번의 채집이 이루어졌으며, 예망 시간은 평균적으로 1 시간 기준으로 하였으며, 최저 예망 수심은 30, 최고 예망 수심 은300 m으로 조사 정점의 수심에 따라 다르게 나타났다. 남극 크릴의 트롤 채집 예망속도는 약 knot로 유지하였다. 잡음 제거 음향조사의 자료 분석은 후처리소프트웨어(Echoview Ver. 4.7, Echoview Software Pty. Ltd, Australia)를 이용하여 분석 하였다. 선박에서 음향조사를 진행하면서 발생하는 배경잡음, 전기신호에 의한 잡음, 기계적인 잡음 등 다양한 잡음이 발생하 게 되는데, 음향자료의 정확한 분석을 위해서는 이러한 잡음을 NOISE SV removed noise SV raw data De Robertis and Higginbottom (2007) Data range bitmap 1 Mask 1 Wang et al. (2015) Erosion filter 3 3 Data range bitmap 3 Dilation filter 5 5 Dilation filter 7 7 Data range bitmap 2 Mask 2 Median filter 7 7 Select Fig. 3. Flow chart for the noise removal using acoustic data analysis software. 제거하는 것이 매우 중요하다. De Robertis and Higginbottom (2007)의 의해 제안된 방법으로 기본적인 잡음을 제거하고, Wang et al. (2015)의 의해 제안된 방법으로 다양하게 개발된 노이즈 필터를 이용하여 잡음을 제거하였으며 잡음처리 과정 의 흐름도를 Fig. 3과 같이 나타내었다. 또한, De Robertis and 의 제안된 방법과 Higginbottom 38 (2007) Wang et al. (2015)의 khz raw data raw data Noise 38 khz (a) raw Noise Cleaned 38 khz Cleaned 38 khz (e) Dilation filter 5 5 SV difference khz (db) Data range bitmap Mask (Krill) Resample vertically (c) Minimum SV (g) Median filter 7 7 (d) Erosion filter 3 3 (i) Select Fig. 4. Example of echogram for the noise removal based on acoustic data. Match ping times (db) db difference (db) (f) Dilation filter 7 7 Target strength (db) (b) TVT

5 792 최석관ㆍ한인우ㆍ황두진ㆍ김태호ㆍ안두해ㆍ이경훈 Noise 38 khz 38 khz raw data Cleaned 38 khz 38 khz SV difference khz (db) Data range bitmap Mask (Krill) Resample vertically Match ping times raw data Cleaned., raw data TVT (Time Varied Threshold). data range bitmap S v (volume backscattering strength) S v mask., data range bitmap,., Erosion filter 3 3. Erosion filter, Dilation filter 5 5, Dilation filter 7 7. Dilation filter data range bitmap S v, mask. Median filter 7 7, Select mask Median filter, data range bitmap (Fig. 4). 주파수차이를이용한남극크릴의신호추출 Noise Fig. 5. Flow chart of acoustic data processing using db difference method at 38 khz and. 38 khz. (mean volume backscattering strength, MVBS) Fig. 5.,. CCAMLR ping interval 2., resampled., data range bitmap 120 khz mask, ping. (target strength).,., distorted wave Born approximation (DWBA) stochastic distorted wave Born approximation (SDWBA). SDWBA 3 (1) (Stanton et al., 1996; McGehee et al., 1998). k 2 f bs = 1 a ( - r )e 2ik2rposJ (2 k a cos ) 1 2 tilt d rpos (1) pos 4k 2 cos tilt, k (m -1, k=2 / ), (m, =c/f ); c (m/sec), f (Hz). 1, 2. =( 2-1 )/ 1 =( 2-1 )/ 1, ( =1/ c 2 ), (kg/m 3 ), c (m/s). a (m), r pos ( ), tilt (degree), J f bs ( bs ), (2). TS=10log bs =10log f bs 2 (2)

Noise 38 khz Noise Cleaned Cleaned 38 khz (b) TVT (f) Dilation filter 7 7 38 khz 주파수차법을 이용한 남극 크릴의 종 식별 793 SV difference 120-38 khz (db) Data range bitmap 란강도의 비율과 동일하다는 것으로 Mask (Krill), 식 (3)에 의해

(Stochastic distorted-wave Born approximation) 모델로 계산된 TS-체장 관계(Fig. 6)와 크릴의 분포 사이 즈 Sv주파수 차의 범위(min-max)를 이용하였다 (Table. 3, SCCCAMLR-XXIX, Annex 5, CCAMLR 2010; Fieding et al.

산란강 도를 분석하였다(Demer and Conti, 2005; Conti and Demer, 2006; CCAMLR, 2010).

6 Noise 38 khz Noise Cleaned Cleaned 38 khz (b) TVT (f) Dilation filter khz 주파수차법을 이용한 남극 크릴의 종 식별 793 SV difference khz (db) Data range bitmap 란강도의 비율과 동일하다는 것으로 Mask (Krill), 식 (3)에 의해 설명된다. (g) Median filter 7 7 Resample vertically )-TS(38kHz, L ) MVBS = TS(120kHz, L Match ping times )-SV(38kHz, L ) (3) = SV(120kHz, L (i) 크릴을 Select 식별하기 위한 주파수차 범위는 2010년 현존량(dB) 평가에 사용한 SDWBA (Stochastic distorted-wave Born approximation) 모델로 계산된 TS-체장 관계(Fig. 6)와 크릴의 분포 사이 즈 Sv주파수 차의 범위(min-max)를 이용하였다 (Table. 3, SCCCAMLR-XXIX, Annex 5, CCAMLR 2010; Fieding et al., db difference (db) Target strength (db) 대해서 대상생물 내의 축 변형과 움직임에 의 DWBA 모델에 (c) Minimum SV 한 몸체변형을 확률적(stochastic)으로 고려한 모델이 SDWBA 모델이며, 두 주파수의 음향 산란층 내의 남극크릴의 신호를 분 리하기 위해서 먼저 SDWBA 모델로 주파수 별 크릴의 산란강 도를 분석하였다(Demer and Conti, 2005; Conti and Demer, 2006; CCAMLR, 2010). SDWBA 모델을 이용하여 채집된 남 (d) Erosion filter 3 3 극크릴의 최소, 최대길이에 대해 38과 의 산란강도 차 이를 계산하였으며, 계산시 모델의 매개변수인 크릴의 체장길 이와 기존연구를 통한 밀도비(g=1.0357), 음속비(h=1.0279) 와 평균유영각(θ)인 N (0, 40.5 )값을 적용(Conti and Demer, 2006)하여 실험에 사용된 각 주파수(38, )에 있어서의 체장 (L)에 대한 평균 TS 값을 Fig. 7에 나타내었다. 크릴을 식 별하기 위한 주파수차 범위를 나타낸 것으로, 2010년 현존량 평 가 (SC-CCAMLR-XXIX, Annex 5, CCAMLR 2010; Fielding et al., 2011)에 사용된 SDWBA 모델로 계산된 TS 체장 관 계식 회귀선이다. 실선은 38 khz의 체장 관계식이며, 점선은 이다. 파선은 와 38 khz의 평균값을 나타내 었다. 본 논문에서의 크릴의 체장은 mm으로 설정하였으 며, 그 결과 주파수차 범위는 db로 나타났다. 과학어군탐지기로부터 음향산란층 내에 존재하고 있는 남극 크릴과 다른 생물 간의 종식별을 위해, 2개의 주파수 38 khz와 에 의한 주파수 차를 계산해야 하므로, 음향이론모델에 의해 추정된 남극크릴의 TS 주파수 특성을 이용하였다. 두 주파 )에 평균 수 차에 의한 종 식별 방법은 대상 생물의 평균 체장(L TS의 주파수 차에 대한 비율이 임의의 체적에 대한 평균체적산 Length (mm) Fig. 6. Relationship between TS and body length calculated by SDWBA model (SC-CCAMLR-XXIX, Annex 5, CCAMLR 2010; Fieding et al., 2011). 38kHZ 120kHZ SV raw data De Robertis and Higginbottom (2007) Wang et al. (2015) Cumulative Distribution Function ping 2 m T1 0.8 T2 T3 T4 0.6 T5 T6 0.4 T MVBS khz (db) 10 Fig. 7. Comparison of De Robertis and Higginbottom s method and Wang s method using the noise removal of 38 khz and. 20

7 794 최석관ㆍ한인우ㆍ황두진ㆍ김태호ㆍ안두해ㆍ이경훈 Table 3. The recommended ranges (min-max) of S V values (in db) used to classify different size distributions of Antarctic krill Euphausia superba during the 2010 B0 assessment (CCAMLR 2010 (SC-CCAMLR-XXIX, Annex5), Fielding et al, 2011). The values shown on the upper and lower lines of each cell represent the S V ranges for khz and 200-, respectively Minumum krill length (mm) ).. 결과 Maximum krill length (mm) 잡음제거결과.. De Robertis and Higginbottom (2007) Wang et al. (2015) (Fig. 7). S V raw data 38,. De Robertis and Higginbottom (2007)., Wang et al. (2015) erosion filter dilation filter. erosion filter,, dilation filter.,. 주파수특성 (a) 5 ping x 2 m (b) 10 ping x 2 m (c) 20 ping x 2 m (d) 30 ping x 2 m (e) 40 ping x 2 m (f) 50 ping x 2 m (db) Fig. 8. Example of echogram as to the volume of cell according to the characteristics of the frequency of Antarctic krill Euphausia superba.

8 주파수차법을이용한남극크릴의종식별 ping 2 m 1200 Cumulative Distribution Function T1 T2 T3 T4 T5 T6 T7 NASC (m 2 /nmi 2 ) y = x R² = MVBS khz (db) Fig. 9. A difference and comparison in frequency between 7 trawl stations. T3 only detected Electrona carlsbergi, the rest was Antarctic krill Euphausia superba Catch (kg) Fig. 10. Relationship between NASC values and catch data.. Fig. 8 5 ping 2 m, 10 ping 2 m, 20 ping 2 m, 30 ping 2 m, 40 ping 2 m, 50 ping 2 m ping 2 m. 5 ping 2 m. 10 ping 2 m. 20 ping 30 ping, 40 ping, 50 ping db,., 10 ping 2 m 5-95% db. 2 (Hewitt et al., 2002; Conti and Demer, 2006), mm, 38 khz (TS 120kHz-38kHz ) db. MVBS Fig ping 2 m 4.7 db 12.0 db db 3 6,. 99.9% db,. 남극크릴의채집결과 7 Table (Euphausia superba) 10,149 kg, (Chaenodraco wilsoni) 0.52 kg, (Crydraco antarcticus) 0.03 kg, kg, 0.42 kg, (Psychroteuthis glacialis) 0.01 kg, 3 (Electrona carlsbergi) 0.01 kg kg, 0.1 kg, 0.54 kg, 5 7,925 kg, (Chionodraco rastrospinosus) 0.64 kg, 6 10,308 kg, 0.44 kg, 0.01 kg, 7 2,514 kg, 0.03 kg, 0.04 kg 3 99%, 3. (catch per unit effort, kg/hour) 1 11,489 kg/h, kg/h, kg/h, kg/h, 5 19,813 kg/h, 6 14,383 kg/h, 7 4,077 kg/h.,

9 796 최석관ㆍ한인우ㆍ황두진ㆍ김태호ㆍ안두해ㆍ이경훈 (nautical area scattering coefficient, NASC) Fig. 10., NASC (R = 0.66). 고찰,.,,, (Kang et al., 2003).,,..,. CCAMLR. De Robertis and Higginbottom (2007) Wang et al. (2015).. S V. 7 ( ) db, db, db, db, db, db, db. 3 S V -4.1 db 0 db S V 4.7 db-12.0 db. S V (Hewitt et al., 2002; Conti and Demer, 2006; Fielding et al., 2011), S V, S V, S V..,, Table 4. Stations and time of trawl, area, hauling time, depth, amounts of fish caught and rate of Antarctic krill Euphausia superba Station (date) T01 (2016/4/14) T02 (2016/4/16) T03 (2016/4/17) T04 (2016/4/20) T05 (2016/4/22) T06 (2016/4/23) Latitude(S) Longitude(W) S W S W S W S W S W S W Towing time (min.) Towing depth (m) Depth (m) <3,000 - ELC: Catch (kg) - KRI: 10,149 - WIC: 0.52, FIC: KRI: WIC: 0.42, PSG: KRI: FIC: 0.1, ELC: KRI: 7,925 - KIF: KRI: 10,308 - WIC: 0.44, KIF: 0.01 T S - KRI: 2, (2016/4/23) W - WIC: 0.03, KIF: 0.04 KRI, Antarctic krill Euphausia superba; WIC, Spiny icefish Chaenodraco wilsoni; FIC, Long-fingered icefish Crydraco antarcticus; PSG, Glacial squid Psychroteuthis glacialis; ELC, Lanternfish Electrona carlsbergi; KIF, Ocellated icefish. Chionodracorastrospinosus.

10 주파수차법을이용한남극크릴의종식별 797. SDWBA S V Fielding et al., (2011) 0.36 db TS kHz db, db difference 4.7 db-12.0 db. 100%, db difference,,. (Hewitt et al., 2003), 4-5 (Feilding et al., 2014) m 200 m, 320 m, (Gaten et al., 2008; Zhou and Dorland, 2004).. 사사 (R ),. References Atkinson A, Siegel V, Pakhomov EA, Jessopp MJ and Loeb V A re-appraisal of the total biomass and annual production of Antarctic krill. Deep Sea Research Part I: Oceanogr Res Papers 56, dsr CCAMLR (Convention for the Conservation of Antarctic Marine Living Resources) Report of the twenty-ninth meeting of the Scientific Committee. Hobart, Australia, Commission for the Conservation of Antarctic Marine Living Resources. SC-CAMLR-XXIX: CCAMLR (Convention for the Conservation of Antarctic Marine Living Resources) Scientific Observers Manual Observation guidelines and reference material. CCAMLR, Hobart, Conti SG and Demer DA Improved parameterization of the SDWBA for estimating krill target strength. ICES J Mar Sci 63, Cox MJ, Watkins JL, Reid K and Brierley AS Spatial and temporal variability in the structure of aggregations of Antarctic krill (Euphausia superba) around South Georgia, ICES J Mar Sci 68, org/ /icesjms/fsq202. Demer DA and Conti SG New target-strength model indicates more krill in the Southern Ocean. ICES J Mar Sci 62, De Robertis A and Higginbottom I A post-processing technique to estimate the signal-to noise ratio and remove echosounder background noise. ICES J Mar Sci 64, fsm112. Everson I Distribution and standing, The Southern Ocean. Krill Biology, Ecology and Fisheries. by I. Everson Blackwell Science, Fielding S, Watkins JL, Trathan PN, Enderlein P, Waluda CM, Stowasser G, Tarling GA and Murphy EJ Interannual variability in Antarctic krill (Euphausia superba) density at South Georgia, Southern Ocean: ICES J Mar Sci 71, Fielding S, Watkins J, Cossio A, Reiss C, Watters G, Calise L, Skaret G, Takao Y, Zhao X, Agnew D, Ramm D and Reid K The ASAM 2010 assessment of krill biomass for area 48 from the Scotia Sea. CCAMLR 2000 synoptic survey. CCAMLR WG-EMM-11/20. Foote KG Calibration of acoustic instruments for fish density estimation: a practical guide. International Council for the Exploration of the Sea. Gaten E, Tarling G, Dowse H, Kyriacou C and Rosato E Is vertical migration in Antarctic krill (Euphausia superba) influenced by an underlying circadian rhythm?. J Genet 87, Han I A study on the density estimation of Antarctic krill using 2-frequency difference method. Master Dissertation, Chonnam National University, Yeosu, Korea. Hewitt RP and Low EHL The fishery on Antarctic krill: defining an ecosystem approach to management. Rev Fish Sci 8, Hewitt RP, Demer DA and Emery JH An 8-year cycle in krill biomass density inferred from acoustic surveys conducted in the vicinity of the South Shetland Islands during the austral summers of through Aqua Living Resour 16, S (03) Hewitt RP, Watkins JL, Naganobu M, Tshernyshkov P, Brierley AS, Demer DA, Kasatkina S and Brandon M A Setting a precautionary catch limit for Antarctic krill. Oceanogr 15, Hewitt RP, Watkins JL, Naganobu M, Tshernyshkov P, Brierley AS, Demer DA, Kasatkina S and Brandon M Biomass of Antarctic krill in the Scotia Sea in January/February 2000 and its use in revising an estimate of precautionary

11 798 최석관ㆍ한인우ㆍ황두진ㆍ김태호ㆍ안두해ㆍ이경훈 yield. Deep Sea Res II: Topical Studies in Oceanography 51, Hewitt R and Demer DA Dispersion and abundance of Antarctic krill in the vicinity of Elephant Island in the 1992 austral summer. Mar Eco Progr ser 99, Jarvis T, Kelly N, Kawaguchi S, Wijk E and Nicol S Acoustic characterisation of the broad-scale distribution and abundance of Antarctic krill (Euphausia superba) off East Antarctica (30-80 E) in January-March Deep Sea Res II: Topical Studies in Oceanography 57, doi.org/ /j.dsr Kang D, Shin HC, Kim S, Lee Y and Hwang D Species identification and noise cancellation using volume backscattering strength difference of multi-frequency. Korean J Fish Aqua Sci 36, kfas Kang, MH, Furusawa M and Miyashita K Effective and accurate use of difference in mean volume backscattering strength to identify fish and plankton. ICES J Mar Sci 59, La HS, Lee H, Kang D, Lee S and Shin HC Volume backscattering strength of ice krill (Euphausia crystallorophias) in the Amundsen Sea coastal polynya. Deep Sea Res II: Topical Studies in Oceanography 123, org/ /j.dsr Lawson GL, Wiebe PH, Stanton TK and Ashjian CJ Euphausiid distribution along the western Antarctic Peninsula. A. Development of robust multi-frequency acoustic techniques to identify euphausiid aggregations and quantify euphausiid size, abundance, and biomass. Deep Sea Res II 55, McGehee DE, O Driscoll RL and Traykovski LM Effects of orientation on acoustic scattering from Antarctic krill at 120 khz. Deep Sea Res II: Topical Studies in Oceanography 45, Miyashita K, Aoki I, Seno K, Taki K and Ogishima T Acoustic identification of isada krill, Euphausia pacifica Hansen, off the Sanriku coast, north-eastern Japan. Fish Oceanogr 6, x. Stanton TK, Chu D and Wiebe PH Sound scattering by several zooplankton groups. II. Scattering models. J Acoust Soc Am 103, Wang X, Zhao X and Zhang J A noise removal algorithm for acoustic data with strong interference based on postprocessing techniques. CCAMLR SG-ASAM-15/02: Zhou M and Dorland RD Aggregation and vertical migration behavior of Euphausia superba. Deep Sea Res II: Topical Studies in Oceanography 51, org/ /j.dsr

한수지 49(6), , 2016 Original Article Korean J Fish Aquat Sci 49(6), ,2016 음향산란층의식별을위한에코그램분석방법의비교 최석관 윤은아 1 * 한인우 1 오우석 1 국립수산과학원원양자원과, 1 전남

한수지 49(6), , 2016 Original Article Korean J Fish Aquat Sci 49(6), ,2016 음향산란층의식별을위한에코그램분석방법의비교 최석관 윤은아 1 * 한인우 1 오우석 1 국립수산과학원원양자원과, 1 전남 한수지 49(6), 856-861, 2016 Original Article Korean J Fish Aquat Sci 49(6),856-861,2016 음향산란층의식별을위한에코그램분석방법의비교 최석관 윤은아 1 * 한인우 1 오우석 1 국립수산과학원원양자원과, 1 전남대학교수산과학과 Comparison of Echogram Analysis Methods for