422 이형빈ㆍ윤상철ㆍ임양재ㆍ김정년ㆍ김맹진ㆍ최광호. ( ) (Simmonds and McLennan, 2002). (Von Szalay et al., 2007; Zwolinski et al., 2012; Kang et al., 2015)..,,.. 재료및방법 2016

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1 한수지 50(4), , 2017 Original Article Korean J Fish Aquat Sci 50(4), ,2017 음향기법을이용한동계독도주변해역매오징어 (Watasenia scintillans) 및기타어군의분포및현존량산정 이형빈 * 윤상철 1 임양재 2 김정년 2 김맹진 최광호 국립수산과학원서해수산연구소, 1 국립수산과학원독도연구센터, 2 국립수산과학원수산자원조사센터 Distribution and Biomass Using Acoustic Method of the Squid Watasenia scintillans Near Dok-do, East Sea of Korea Hyungbeen Lee*, Sang Chul Yoon 1, Yang Jae Lim 2, Jung Nyun Kim 2, Maeng Jin Kim and Kwang Ho Choi Fisheries Resources and Environment Division, West Sea Fisheries Research Institute, National Institute of Fisheries Science, Incheon 22383, Korea 1 Dokdo Fisheries Research Center, National Institute of Fisheries Science, Pohang 37709, Korea 2 Fisheries Resources Research Center, National Institute of Fisheries Science, Tongyeong 53064, Korea The spatial distribution and abundance of fish species was estimate near Dok-do, East Sea of Korea by conducting midwater trawl survey with hydroacoustic method. Acoustic and midwater trawl data were collected onboard the R/V Tamgu 21 during 7-8 March Acoustic data were collected at the frequencies of 38 and 120 khz and converted to nautical area scattering strength (m 2 /nmile 2 ). Species are distributed mainly over an extent of m, generally around southwest of Dok-do; the squid Watasenia scintillans was the dominant species found. The length-weight function and target strength of squid and other fishes were used to estimate the W. scintillans stock at tons and other fish at 43.8 tons during the winter season. The hydroacoustic method offers an approach for the determination of the biomass and vertical and spatial distributions of species aggregating near Dok-do, East Sea of Korea. Key words: Watasenia scintillans, Hydroacoustic survey, Mid-water trawl survey, Dok-do, Stock assessment 서론, (polar front) (MOF, 1999; Kang et al., 2002). (Myoung, 2002; Lee et al., 2010). (Kang et al., 2002), (Park et al., 2002), (Choi et al., 2009), (Kim et al., 2004), (Lee et al., 2010) EK80 (Simrad, Norway) ME70 (Simrad, Norway)., (Kim et al., 2010; Choi et al., 2012; Seo et al., 2013)., Korean J Fish Aquat Sci 50(4) , August 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 29 May 2017; Revised 3 July 2017; Accepted 31 July 2017 *Corresponding author: Tel: Fax: address: hblee7777@gmail.com Copyright 2017 The Korean Society of Fisheries and Aquatic Science 421 pissn: , eissn:

422 이형빈ㆍ윤상철ㆍ임양재ㆍ김정년ㆍ김맹진ㆍ최광호. ( ) (Simmonds and McLennan, 2002). (Von Szalay et al., 2007; Zwolinski et al., 2012; Kang et al., 2015)..,,.. 재료및방법 2016 3 7 8 21 (R/V Tamgu 21) (Fig. 1, Table 1).

2 422 이형빈ㆍ윤상철ㆍ임양재ㆍ김정년ㆍ김맹진ㆍ최광호. ( ) (Simmonds and McLennan, 2002). (Von Szalay et al., 2007; Zwolinski et al., 2012; Kang et al., 2015)..,,.. 재료및방법 (R/V Tamgu 21) (Fig. 1, Table 1). (EK80; Simrad, Norway). (split-beam) 38 khz 120 khz, (pulse length) (transmission interval) ms 0.25 pings/s (Table 2). EK80 Narrow-Band Continuous wave (NB CW) Wide-Band Frequency Modulation (WB FM). NB CW EK60, WB FM. EK80 NB CW, NB CW (calibration Korea East Sea 1 Dokdo Trawl 1 Trawl 2 2 Fig. 1. Location of the hydroacoustic and mid-water trawl survey area around Dok-do, East Sea of Korea during winter season, Study area showing the acoustic transects (black line), trawl transects (gray dot line), and CTD station (black squares). Table 1. Detail on mid-water trawl surveys Transect Trawl location Start End Fishing depth (m) Distance (nmile) N, E N, E N, E N, E

동계시기독도주변어류현존량 423 sphere). Table 2. 8,. (net height, 3.6 m; net pendant, 97 m; cod-end mesh size, 60 mm) 2 1 (Table 1). 4 30.. 1 2 100 m 207 m.. Kim et al. (2005),, (1 g), (0.1 cm).

-a (Chlorophyll-a). CTD 200 m, 1 m,. (Echoview ver. 7.0; Myriax software Pty Ltd, Australia). 38 khz 120 khz 69.7 nmile 250 m. Fig. 2 38 khz 1.

(Mean Volume Backscattering Strength, MVBS) (Kang (a) 38 khz Raw data (b) 38 khz TVT noise removal (c) 38 khz median filter Fig. 6 Table 2.

3 동계시기독도주변어류현존량 423 sphere). Table 2. 8,. (net height, 3.6 m; net pendant, 97 m; cod-end mesh size, 60 mm) 2 1 (Table 1) m 207 m.. Kim et al. (2005),, (1 g), (0.1 cm). CTD (conductivity-temperature-depth; Sea-Bird, SBE 911plus; Seabird electronics, Bellevue, WA, USA) 2 (St.1: N, E, St.2: N, E),, (fluorescence) (Fig. 1). -a (Chlorophyll-a). CTD 200 m, 1 m,. (Echoview ver. 7.0; Myriax software Pty Ltd, Australia). 38 khz 120 khz 69.7 nmile 250 m. Fig khz khz 120 khz (Volume backscattering strength, SV) (Fig. 2a),, CTD, 0.1 nmile 1 m. TVT (time-varied threshold) (Fig. 2b), (3 3 filter) (Fig. 2c-d). (Mean Volume Backscattering Strength, MVBS) (Kang (a) 38 khz Raw data (b) 38 khz TVT noise removal (c) 38 khz median filter Fig. 6 Table 2. System parameters calibrated for the acoustic survey System parameters Simrad EK80 Frequency (khz) Transmitted power (W) Ping duration (ms) way beam angle (db) Received bandwidth (khz) Transducer gain (db) dB beam angle ( )(along/athwart) 7.06/ /6.31 Absorption coefficient (db m -1 ) s A Correction Fig. 6 Fig. 2. Example of echograms from volume backscattering strength (SV, db) at 38 and 120 khz around Dok-do, East Sea of Korea during winter season, (a) raw data with general background noise at 38 khz, (b) echogram after removing using TVT compensation st 38 khz. Echogram after median filter at 38 khz(c) and 120 khz(d).

4 424 이형빈ㆍ윤상철ㆍ임양재ㆍ김정년ㆍ김맹진ㆍ최광호 et al., 2002). (Watasenia scintillans),., (Todarodes pacificus) (Kang et al., 2005). 38 khz (Nautical Area Scattering Coefficient, NASC, m 2 /nmile 2 ). 0.1 nmile EDSU (elementary distance sampling unit) NASC. MABLAB (R2009a, The MathWorks, Inc., USA). 결과 2. (W. scitillans) 2,299 23,456 g 90% (Table 3). (Maurolicus japonicus; 1,518, 979 g), (Arctoscopus japonicus; 71, 840 g), C, 100 m 200 m 3 C (Fig. 3a). 200 m (Fig. Table 3.Weighted ratio with dominant fish species by mid-water trawl fishing data around Dok-do, East Sea of Korea during winter season, 2016 Species Weighted ratio (%) Weight (g) Length (cm) Watasenia scintillans , (ML) Maurolicus japonicus (ML) Arctoscopus japonicus (BL) Other species Total ,302 ML, Mantle length; BL, Body length. 3b). St.1 St.2 (Fig. 3a) Fluorescence 2 (Fig. 3c) m, 2 30 m m, 40 m (Fig. 4a). 38 khz 120 khz ~ db ~ db, -75 db. (diel vertical migration). 147 m (Fig. 4a). (a) Temperature ( ) (b) Salinity (c) Flourescence (mg/m 3 ) Depth (m) Fig. 3. Vertical temperature and salinity profile of the water column measured by conductivity-temperature-depth casts.

동계시기독도주변어류현존량 425 NASC 30-55 m (Fig. 4b). 1 2, (Fig. 5). 4-8. NASC,, (L, cm)- (w, g)- (w=al b ),, (Target strength, TS; TS=20 log 10 (L)-b 20 ; =4 10 TS/10 ), (conversion factor, CF) ( ),.

5 동계시기독도주변어류현존량 425 NASC m (Fig. 4b). 1 2, (Fig. 5) NASC,, (L, cm)- (w, g)- (w=al b ),, (Target strength, TS; TS=20 log 10 (L)-b 20 ; =4 10 TS/10 ), (conversion factor, CF) ( ),., (a) (b) SV (db) NASC (m 2 /nmi 2 ) Depth (m) Fig. 4. Vertical distribution of acoustic backscatter into different frequencies from mean of all transects. Black line show average 38 khz, and black dot lines are average 120 khz. Vertical axis is depth in meters, x-axis are acoustic backscatter measured as SV (db) (a) and nautical area scattering coefficient (NASC) per 1 m depth channel (m 2 /nmile 2 ) (b), respectively. Latitude ( N) Longitude ( N) Fig. 5. Spatial variation of trawl catch per unit area (kg 2 /km 2 ) and nautical area scattering coefficient (NASC, m 2 /nmile 2 ) of demersal fish around Dok-do, East Sea of Korea during winter season, 2016.

6 426 이형빈ㆍ윤상철ㆍ임양재ㆍ김정년ㆍ김맹진ㆍ최광호 Table 4. Value of conversion factor (CF) and nautical area scattering coefficient (NASC) partitioning by fish species around Dok-do, East Sea of Korea during winter season, 2016 Species w i 1 <σ i > 2 Conversion Factor (CF) NASC partitioning Watasenia scintillans π10 ( 7.54) L Maurolicus japonicus π10 ( 7.14) L Arctoscopus japonicus π10 ( 7.40) L w i, Weighted proportion of species i in fish samples; 2 <σ i >, Mean backscattering cross-section of specie i. 0.94, 0.03 (Table 4; Yoon et al., 1999; Saito, 2004; Kang et al., 2005) g/m 2, g/m 2. 40,742.3 ha , , (Table 5). Table 5. Standing stock estimation of squid Watasenia scintillans using acoustic survey around Dok-do, Korea in March, The n i is the number of 0.1 EDSU (elementary distance sampling unit) and NASC is mean value of the nautical area scattering coefficient (m 2 /nmile 2 ) along i-th trensects Transect No. n i 1) 7-8 Mar m NASC 2) per 0.1 EDSU Transect Transect Transect Transect Transect Transect Transect Transect n i 536 Weighted mean NASC Survey Area (ha) Species ρ 3) (g/m 2 ) Biomass (ton) Watasenia scintillans Maurolicus japonicus Arctoscopus japonicus Total ) n i, Number of 0.1 nmile averaging intervals on i-th transact; 2) NASC, Nautical area scattering coefficient per 0.1 EDSU (0.1 nmile); 3) ρ, Mean biomass density. 고찰 (Watasenia scintillans) 92.7% (Table 3)., m, m (Watanabe et al., 2006). 3-6 C, 5-15 C. 40 m (Fig. 2c)., (Deep scattering layer, DSL).,,, khz 120 khz. -1 db < SV 120kHz 38 khz < 3 db (Goss et al., 1996). EK m m (Fig. 6). -1~3 db 90.94%, 38 khz 120 khz SV db (standard deviation, (SD)=5.07) db (SD=4.42) (Fig. 6a). SV 38 khz 120 khz db (SD=2.70) db (SD=2.12) db 7.57 db, 43.44% (Fig. 6b). -1~3 db 120 khz 38 khz,

7 동계시기독도주변어류현존량 427 (a) (b) S V38 khz (db) S V120 khz (db) S V120 khz (db) Fig. 6. Compare acoustic signals of squid Watasenia scintillans and other scatterer identified on a 38 khz (Fig. 2c) and 120 khz (Fig. 2d) echogram in the acoustic transects (T1). Scatter plot of volume backscattering strength (SV) at 120 khz against 38 khz from 30 to 50 m (a) and from 51 m to 95 m. The gray and red dots indicate the wholes SV and SV classified with db difference windows of 1~3 db for squid Watasenia scintillans.. MVBS., m 207 m..., %, cm., m,,,., , 사사 2017 (R ). References Choi CG, Lee HW and Hong BK Marine algal flora and community structure in Dokdo, East sea, Korea. Korea J Fish Aquat Sci 42, Choi KH, Han MH, Kang CK,Park JM, Choi JH, Park JH, Sohn MH, Baeck GW, Choi EJ and Lee CI Seasonal variations in species composition of fish assemblage collected by trammel net in coastal waters of the East Sea. J Kor Soc Fish Tech 48, / KSFT Goss C, Rodhouse P, Watkins JL and Brierley AS Attribution of acoustic echoes to squid in the South Atlantic.

8 428 이형빈ㆍ윤상철ㆍ임양재ㆍ김정년ㆍ김맹진ㆍ최광호 CCAMLR Sci 5, Kang JH, Kim WS and Shim JH Species composition and abundance of zooplankton zommunity in spring and autumn around Dokdo. Ocean Polar Res 24, Kang D, Mukai T, Iida K, Hwang D and Myoung JG The influence of tilt angle on the acoustic target strength of the Japanese common squid (Todarodes pacificus). ICES J Mar Sci: J du Conseil 62, icesjms 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: Journal du Conseil 59, Kang MH, Seo YI, Oh TY, Lee KH and Jang CS Estimating the biomass of anchovy species off the coast of Tongyeong and Yeosu in South Korea in the spring and winter of 2013 and J Kor Soc Fish Tech 51, dx.doi.org/ /ksft Kim IS, Choi Y, Lee CL, Lee YJ, Kim BJ and Kim JH Illustrated book of Korean fishes. Kyo-hak Pub. Ltd., Seoul, Korea, Kim MK, Shin JK and Cha JH Veriation of species composition of benthic algae and whitening in the coast of Dokdo island suring summer. Algae 19, Kim YS, Choi JH, Kim JN, Oh TY, Choi KH, Lee DW and Cha HK Seasonal variation of fish assemblage in Sacheon marine ranching, the southern coast of Korea. J Kor Soc Fish Tech 46, KSFT Lee HW, Hong BK, Shon MH, Chun YY, Lee DW, Choi YM and Hwamg GS Seasonal Variation in Species Composition of fish. MOF Basic study for systainment of marine environment and fihsery resources of the Dokdo area. Ministry of Oceans and Fishreies, Sejong, Korea, Myoung JG The Fish Fauna around Dokdo in the East Sea, Korea. Ocean Polar Res, 24, Park HS, Kang RS and Myoung JG Vertical distribution of mega-invertebrate and calculation ot the stock assessment of commercial species inhibiting shallow hard-boottom in Dokdo, Korea. Ocean Polar Res 24, Saito I Development of fishery resources assessment technology using a scientific echosounder, 2002 Annual report of Fisheries Promotion Center, Akita Prefecture Public Relations Division, sanno, Akita City, Japan, Seo YI, Lee JH, Oh TY, Lee JB, Choi YM and Lee DW Distribution and seasonal variations of fisheries resources captured by the beam trawl in Namhae island, Korea. J Kor Soc Fish Tech 49, KSFT Simmonds J and MacLennan D Fisheries acoustics: Theory and practice, second edition. Blackwell, Oxford, UK, Watanabe H and Kubodera T, Moku M and Kawaguchi K Diel vertical migration of squid in the warm core ring and cold water masses in the transition region of the western North Pacific. Marine Ecology Progress Series 315, Yoon G, Shin H and Hwang K Target strength of fishes for estimating biomass - Distribution characteristics and target strength measurement of micronektonic fish, Maurolicus muelleri in the East Sea. J Kor Soc Fish Tech 35, Von Szalay PG, Somerton DA and Kotwicki S Correlating trawl and acoustic data in the eastern Bering Sea: A first step toward improving biomass estimates of walleye pollock (Theragra chalcogramma) and Pacific cod (Gadus macrocephalus). Fish Res 86, fishres Zwolinski JP, Demer DA, Byers KA, Cutter GR, Renfree JS, Sessions TS and Macewicz BJ Distributions and abundances of Pacific sardine (Sardinops sagax) and other pelagic fishes in the California Current Ecosystem during spring 2006, 2008, and 2010, estimated from acoustic trawl surveys. Fish Bull 110,

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