Age and Growth of White Croaker Pennahia argentata in the Southern Sea of Korea by Otolith Analysis

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한수지 54(1), 53-63, 2021

53

Original Article

서 론

보구치는민어과에속하는어류로우리나라에서는서해와남 해의내만또는연안의바닥이모래또는펄질인곳에주로서 식하며(Kim et al., 2005), 광양만, 강진만, 여자만등내만에서 계절적으로우점하는어종이다(Kim et al., 2018; Han et al., 2019; Na et al., 2019; Han et al., 2020). 또한보구치는중형저 인망, ^{대형저인망}, ^연안복합, ^{연안자망어업}^등에^의해^어획되어 상업적으로많이유통되고있는어종이다(KOSIS, 1996). 보구

치의연간어획량은 1980년대중반에약 1만톤까지증가하였

으나, 1993년에는 900여톤으로급격히감소하였고, 그후소폭 으로증가와감소를반복하다가최근다소증가하는경향을보 여 2019^년에는^약 3,000^톤^수준에^머무르고^있다(Fig. 1).

보구치의 연구동향을 살펴보면, 식성에 관한 연구(Kakuda and Matsumoto, 1978; Cha and Park, 2001; Koh et al., 2014),

재생산및산란생태에관한연구(Saishu et al., 1954; Liu and Tzeng, 1972a; Kang et al., 1999; Yamaguchi et al., 2006), 보구 치의외부형태및분류형질에관한연구(Tzeng and Liu, 1973),

보구치이석에나타나는 sulcus를이용한계군분류에관한연

구(Song et al., 2020) 등이있으며, 연령과성장에대하여는비 늘및이석을이용하여일본(Kakuda and Matsmoto 1977; Hi- guchi et al., 2003; Yamaguchi et al., 2004), 대만(Liu and Tz- eng, 1972b), ^그리고^국내에서(Kwon et al., 1999) ^다양하게^연 구되었다. 국내에서는보구치의자원생태학적특성치및자원 평가에관한연구들이이루어졌는데(Baik et al., 1999; Zhang et al., 1999a; Zhang et al., 1999b; Lee and Zhang, 2001), 특히 Zang et al. (1999a)은 20여년전연구결과에서 보구치가심각 한남획상태의징후를보인다고보고하였나, ^현재까지^특별한 어업제한조치가취해지지않아 20여년이지난현재보구치자 원의상태를재검토할필요가있다.

한국 남해안에 서식하는 보구치(Pennahia argentata)의 이석을 이용한 연령 및 성장

전복순·최정화¹·김두남·임양재²·이해원*

국립수산과학원 수산자원연구센터, ¹국립수산과학원 제주수산연구소, ²국립수산과학원 연근해자원과

Age and Growth of White Croaker Pennahia argentata in the Southern Sea of Korea by Otolith Analysis

Bok Soon Jeon, Jung Hwa Choi¹, Doo Nam Kim, Yang Jae Im² and Hae Won Lee*

Fisheries Resources Research Center, National Institute of Fisheries Science, Tongyeong 53064, Korea

1Fisheries Resources and Environment Division, Jeju Fisheries Research Institute, Jeju 63068, Korea

2Fisheries Resources Management Division, National Institute of Fisheries Science, Busan 46083, Korea

Age structure and growth of white croaker Pennahia argentata were estimated an analysis of otoliths. Fish specimens were collected from the Southern Sea of Korea from January to December 2018. A thin section method was used for age determination because otoliths of white croaker are oval in shape and large in size. Otoliths were cut vertically into 0.4-0.5 mm thick sections with an electric saw (Micracut 125). Monthly changes in the marginal index indicated that rings (opaque zone) were formed once a year in August. The estimated von Bertalanffy growth equation estimated by a non-linear regression were L_∞=34.71 (1-e0.38(t+0.80)). In the present study, the oldest female was 8 years old and the male was 7 years old.

Keywords: Age and growth, Otolith, von Bertalanffy, White croaker

*Corresponding author: Tel: +82. 55. 650. 2240 Fax: +82. 55. 650. 2206 E-mail address: [email protected]

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial Licens (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Received 9 December 2020; Revised 7 January 2021; Accepted 4 February 2021 저자 직위: 전복순(석사 후 인턴 연구원), 최정화(연구관), 김두남(센터장), 임 양재(과장), 이해원(연구사)

https://doi.org/10.5657/KFAS.2021.0053

Korean J Fish Aquat Sci 54(1), 53-63, February 2021

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전복순ㆍ최정화ㆍ김두남ㆍ임양재ㆍ이해원 54

수산자원의동태를파악하기위해서는해당어종의연령구조 를파악하고, ^이를^통해^가입과^성숙^연령, ^수명, ^성장률, ^사망 률등을분석할수있다. 일반적으로어류의연령을알기위해 서는주로비늘, 이석, 척추골, 새개골등이유용하게사용된다

(Zhang, 2012). 특히비늘은다른어떤연령형질보다처리과정

이용이하지만어류의성장과정에서탈락되어재생되는비늘로 인해고연령어에서주의가필요할뿐만아니라성장이과소평 가되는경향이나타나므로비늘보다는이석이개체의일생동 안의생물학적, 환경적요인을더욱잘반영하며, 연령형질로적 합하다고보고하였다(Secor et al., 1992; Lowerre-Barbieri et

al., 1994). 따라서본연구에서는연령형질로이석을이용하여

연령과성장을파악함으로써보구치자원의지속적인관리및 평가를위한최근의기초자료를확보하고자한다.

재료 및 방법

시료 채집

분석에필요한보구치시료는 2018년 1월부터 12월까지남

해안의 서남구외끌이중형저안망어업과 대형외끌이저인망어 업에서어획된개체를사용하였다(Fig. 2). 확보한시료는자동 어체측정기(J&J Technology, Busan, Korea)를사용하여전장 (total length)와체중(body weight)를각각 0.1 cm, 0.01 g 단위 로측정하였다(Table 1).

이석표본 제작

연령사정을위하여매월측정한시료중에서크기별로대, 중, Table 1. Number of individuals, range and mean total length of white croaker Pennahia argentata collected from the Southern Sea of Korea in 2018

Month No. of inds. Range of TL (cm) Mean TL (cm) Range of BW (g) Mean BW (g)

Jan. 250 18.7 - 31.6 24.3 83.81 - 387.98 176.44

Feb. 264 18.6 - 35.0 24.8 87.88 - 566.60 214.22

Mar 240 17.0 - 33.6 24.1 54.74 - 497.16 184.50

Apr 257 17.0 - 33.3 23.4 60.08 - 504.32 171.47

May 221 18.2 - 34.8 24.0 77.73 - 581.21 202.63

Jun. 265 16.2 - 30.5 22.7 33.29 - 388.25 150.35

Jul. 150 19.4 - 24.6 22.2 90.24 - 172.16 122.23

Aug. 261 22.2 - 34.7 26.8 127.78 - 548.88 237.47

Sep. 113 23.2 - 35.3 26.8 173.88 - 546.50 244.90

Oct. 284 17.8 - 30.2 23.4 72.66 - 367.72 169.53

Nov. 241 17.1 - 35.7 24.8 65.97 - 548.24 203.08

Dec. 314 12.8 - 30.3 22.4 23.01 - 375.34 156.35

Total 2860

*TL, total length (cm); BW, body weight(g).

Fig. 1. Annual fluctuations in catches of the white croaker Pen- nahia argentata in Korean waters from 1980 to 2019(data from KOSIS).

0 2,000 4,000 6,000 8,000 10,000

1980

124°

38°

36°

34°

32°

126° 128° 130° 132°

1985 1990 1995 2000 2005 2010 2015 Year

Catch (mt)

Korea

Jeju Island Japan

Catch area

A Dorsal

Ventral

Anterior Posterior

B

Sulcus Proximal side

Distal side Umbo

Anterior Posterior

r₁ r₂

r₃ r₄

r6

r5

R core

0.0 0.5 1.0 1.5

Jan. Feb. Mar. Apr. May Jun. Jul. Aug. Sept. Oct. Nov. Dec.

Month

Marginal index (MI)

BW = 0.0092TL^3.092 R² = 0.9712

0 200 400 600

Combine

BW = 0.01TLx^3.0655 R² = 0.9672

0 200 400 600

Female

BW = 0.0084TL^3.1207 R² = 0.9752

0 200 400 600

0 10 20 30 40

Male

Body weight (g)

Total length (cm)

0 10 20 30 40

●Female L_t= 34.86(1-e-0.35(t+1.02))

○Male

L_t=39.03(1-e-0.23(t+1.60))

Age (year)

Total length (cm)

0 10 20 30 40

0 1 2 3 4 5 6 7 8

Combined L_t=34.71(1-e-0.38(t+0.80))

Fig. 2. Sampling area of white croaker Pennahia argentata in the Southern Sea of Korea, 2018.

0 2,000 4,000 6,000 8,000 10,000

1980

124°

38°

36°

34°

32°

126° 128° 130° 132°

1985 1990 1995 2000 2005 2010 2015 Year

Catch (mt)

Korea

Jeju Island Japan

Catch area

A Dorsal

Ventral

Anterior Posterior

B

Distal side Umbo

Anterior Posterior

r₁ r₂

r₃ r₄

r₆ r₅

R core

0.0 0.5 1.0 1.5

Month

Marginal index (MI)

BW = 0.0092TL^3.092 R² = 0.9712

0 200 400 600

Combine

BW = 0.01TLx^3.0655 R² = 0.9672

0 200 400 600

Female

BW = 0.0084TL^3.1207 R² = 0.9752

0 200 400 600

0 10 20 30 40

Male

Body weight (g)

Total length (cm)

0 10 20 30 40

●Female L_t= 34.86(1-e-0.35(t+1.02))

○Male

L_t=39.03(1-e-0.23(t+1.60))

Age (year)

Total length (cm)

0 10 20 30 40

0 1 2 3 4 5 6 7 8

Combined L_t=34.71(1-e-0.38(t+0.80))

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보구치의 이석을 이용한 연령과 성장 55

소상자별 30^마리씩^무작위^추출하여^이석을^{채취하였고}, ^이 석낭과이물질을제거한후실온에서건조시켰다. 자료의통일 성을위해오른쪽이석으로무게와길이를측정하고절편을만 들었다.

실온에서건조시킨이석은실리콘몰딩틀에넣고, 에폭시레 진과경화제를사용하여 48^시간^정도^{응고시켰다}. ^몰딩^된^이석 은절단기(Micracut 125, meckton, Bursa, Turkey)를사용하여 200-300 rpm 회전속도로두께 0.4-0.5 mm정도의절편을만들 었다. 윤문의관찰을용이하게하기위해알루미늄파우더를사 용하여광택을낸후크리스탈본드를사용하여슬라이드글라 스에붙여서영구표본을만들었다. ^이석의^관찰은^{해부현미경} (Olympus SZX16, Olympus, Tokyo, Japan) 과영상분석프로 그램(i-solution x64, i-solution Inc., Burnaby, Canada)을이용 하여관찰하였으며, 윤경간거리는 0.001 mm까지측정하였다. 이석의 형태

보구치의이석은핵을중심으로두텁게성장하고바깥쪽으로 한개의돌기를가지고있다. 윤문이잘나타나는쪽을찾기위 해세로(A축) 방향과, 가로방향(B축)으로절단하였다(Fig. 3).

그결과세로방향(A축)으로절단했을때불투명대와투명대가 규칙적이고선명하게나타났다. 따라서보구치의이석을세로

(A^축)^방향으로^절단하여^핵을^중심으로^윤경이^규칙적인^방향

을기준선으로설정하고, 연령사정을실시하였다(Fig. 4).

윤문의 대응성 및 형성시기

이석에서관찰된윤문이연령형질로적합한가를판단하기위 해윤문의대응성을검토한후, 윤문의형성시기및형성횟수는 연역지수의(marginal index, MI) ^월별^변화를^통하여^추정하였 다. 연역지수는다음식으로구하였다.

MI=(R-r_n)/(r_n-r_n-1)

여기서 R은이석의중심부초점에서최외측가장자리까지의 거리, r_n은초점에서 n번째윤경까지의거리이다.

첫번째윤의형성에걸리는시간은산란기와윤문형성시기로 추정하였다. ^산란기는 Jeon et al. (2020)^의^연구^결과를^참고 하였다.

윤문의대응성과형성횟수를확인한후윤문을연륜으로인정 하고전장과윤경간의관계식을구하였다. 관계식을이용하여 각연령별역계산전장을구하였으며, 연령별역계산전장의평 균은다음의식으로가중평균을적용하여구하였다.

x̅_weighted= ∑_i=1ⁿ w_i x_i

∑_i=1ⁿ w_i

여기서 x_i는 i번째연령의체장, w_i는 i번째연령의개체수이 다.

전장(TL)-체중(BW) 관계

전장과체중의관계는어체의비만상태를나타내고, ^산란기 를추정하는 정보를제공해줄 뿐만아니라연령별전장추정 치로부터체중추정치로환산하는데사용될수있다. 체장-체 중간의관계식은다음과같이나타낼수있다(Huxley, 1932).

W=αL^β

전장(L)과체중(W) 간의함수관계가비선형이므로, 다음과 같이자연대수를취하여선형화하여최소자승법으로 α^와 β^를 추정하였다.

lnW=lnα+βln L

성장식 추정

연령에따른성장식은역계산된연령별평균전장으로 von

Bertalaffy 성장식을이용하여추정하였다. L_t=L_∞(1-e^-k(t-to))

여기서, L_t^는^연령이 t^일^때의^전장, L_∞^는^이론적^최대^전장, k는성장계수, t_o는전장이 0일때의이론적연령을의미한다. Fig. 3. External morphology and cutting dimension (A, vertical; B, transvers) of right otolith of the white Croaker Pennahia argentata.

0 2,000 4,000 6,000 8,000 10,000

1980

124°

38°

36°

34°

32°

126° 128° 130° 132°

1985 1990 1995 2000 2005 2010 2015 Year

Catch (mt)

Korea

Jeju Island Japan

Catch area

A Dorsal

Ventral

Anterior Posterior

B

Distal side Umbo

Anterior Posterior

r₁ r₂

r₃ r₄

r₆ r₅

R core

0.0 0.5 1.0 1.5

Month

Marginal index (MI)

BW = 0.0092TL^3.092 R² = 0.9712

0 200 400 600

Combine

BW = 0.01TLx^3.0655 R² = 0.9672

0 200 400 600

Female

BW = 0.0084TL^3.1207 R² = 0.9752

0 200 400 600

0 10 20 30 40

Male

Body weight (g)

Total length (cm)

0 10 20 30 40

●Female L_t= 34.86(1-e-0.35(t+1.02))

○Male

L_t=39.03(1-e-0.23(t+1.60))

Age (year)

Total length (cm)

0 10 20 30 40

0 1 2 3 4 5 6 7 8

Combined L_t=34.71(1-e-0.38(t+0.80))

Fig. 4. Vertical otolith section of the white croaker Pennahia argentata. R, otolith radius; r1- r6, annual ring radii.

0 2,000 4,000 6,000 8,000 10,000

1980

124°

38°

36°

34°

32°

126° 128° 130° 132°

1985 1990 1995 2000 2005 2010 2015 Year

Catch (mt)

Korea

Jeju Island Japan

Catch area

A Dorsal

Ventral

Anterior Posterior

B

Distal side Umbo

Anterior Posterior

r₁ r2

r₃ r₄

r6

r5

R core

0.0 0.5 1.0 1.5

Month

Marginal index (MI)

BW = 0.0092TL^3.092 R² = 0.9712

0 200 400 600

Combine

BW = 0.01TLx^3.0655 R² = 0.9672

0 200 400 600

Female

BW = 0.0084TL^3.1207 R² = 0.9752

0 200 400 600

0 10 20 30 40

Male

Body weight (g)

Total length (cm)

0 10 20 30 40

●Female L_t= 34.86(1-e-0.35(t+1.02))

○Male

L_t=39.03(1-e-0.23(t+1.60))

Age (year)

Total length (cm)

0 10 20 30 40

0 1 2 3 4 5 6 7 8

Combined L_t=34.71(1-e-0.38(t+0.80))

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Walford 정차도법으로 L_∞, k, t_o를구하여, 이결과를초기값으 로비선형회귀분석방법으로성장매개변수를추정하였다. ^추 정된성장계수들을선행된연구결과들과비교를위해 Munro and Pauly (1983)의 Growth performance index (Φ)를사용하 였다

Φ=logK+2logL_∞

여기서 K는성장계수, L_∞는이론적최대전장이다. 연령구조

연령구조를알아보기위하여연령-전장상관표를작성하였 다. 연령별전장분포는정규분포한다고할수있으므로연령별 평균전장과표준편차의정규분포함수로부터연령-전장상관 표를구하였다.

결 과

윤문의 대응성 및 형성시기

보구치의이석은핵을중심으로두텁고크기때문에연마보다 는절단하는방법이적절하였으며, 수직방향으로절단했을때 핵과윤문이선명하게관찰되었다. 이석의윤형성은성장이빠 르고느림에따라불투명대와투명대가나타나는데, 보구치는 불투명대에서투명대로이행하는경계가비교적명확하여윤문 으로간주하고윤경을측정하였다.

보구치이석에서확인된윤문에위륜또는잘못판독된윤이 있는지가려내기위하여각윤군별이석경과윤경간의관계를 검토한결과각연륜군별이석에서보이는각각의 윤은인접한 윤문과분리되어있었고, ^또^각^윤군별로^이석경이^커지면^윤경

역시크게나타났다(Fig. 5). 따라서보구치의이석에나타나는

Fig. 5. Relationship between otolith radius and ring radius at each ring of the white croaker Pennahia argentata in the Southern Sea of Korea, 2018.

6-ring group

Otolith radius (mm)

Ring radius (mm)

0.0 1.0 2.0 3.0

1.0 2.0

1-ring group

1.4 2.4

2-ring group

1.5 2.5

3-ring group

1.8 2.8

4-ring group

0.0 1.0 2.0 3.0

2.5 3.0

5-ring group

2.5 3.5 3.1 3.2 3.3

7-ring group

2.7 2.9

8-ring group

(5)

윤경은이석경과대응성이있는것으로판단된다.

윤문형성시기와형성횟수를알기위하여연역지수의월별 변화를살펴본결과(Fig. 6), 연역지수가 1월부터 7월까지상승 하는경향을보이다가 8월에감소하여낮은수준에머무른다. 따라서윤문형성시기는 8월로추정되며연 1회형성됨을알수

있었다. ^보구치의^산란기는 Jeon et al. (2020)^의^{연구결과로부} 터 6월부터 7월까지로확인되었으며, 윤문이형성되는시기는

8월이므로초륜형성기간은약 1.1년으로추정된다.

보구치의 이석에나타나는 윤문은연 1회 주기성을가지고 형성되는연륜으로이석의중심에서각윤문까지의평균윤경

Table 2. Mean ring radius on the otolith of the white croaker Pennahia argentata collected from the Southern Sea of Korea, 2018 Female

Estimated

age No of

samples Mean otolith ring radius (mm)

R r₁ r₂ r₃ r₄ r₅ r₆ r₇ r₈

1 203 1.449 0.877

2 194 1.833 0.898 1.534

3 104 2.192 0.899 1.539 1.938

4 17 2.416 0.885 1.499 1.899 2.226

5 18 2.790 0.943 1.508 1.923 2.238 2.546

6 3 3.137 0.956 1.634 2.031 2.378 2.704 2.988

8 1 2.900 0.671 1.008 1.342 1.624 1.792 2.091 2.554 2.769

Total 540 weighted mean 0.891 1.532 1.929 2.227 2.533 2.764 2.254 2.769

weighted S.D. 0.111 0.106 0.111 0.153 0.214 0.474 Male

Estimated

age No of

R r₁ r₂ r₃ r₄ r₅ r₆ r₇ r₈

1 165 1.436 0.874

2 166 1.840 0.884 1.505

3 85 2.170 0.902 1.536 1.924

4 19 2.453 0.893 1.475 1.893 2.237

5 16 2.910 0.948 1.533 1.961 2.322 2.648

6 10 2.900 0.907 1.465 1.868 2.190 2.498 2.754

7 2 3.176 0.920 1.548 1.937 2.253 2.519 2.777 3.000

Total 463 weighted mean 0.887 1.512 1.920 2.257 2.585 2.758 3.000

weighted S.D. 0.108 0.100 0.103 0.107 0.116 0.090 0.018 Combined

Estimated

age No of

R r₁ r₂ r₃ r₄ r₅ r₆ r₇ r₈

1 368 1.443 0.875

2 360 1.836 0.892 1.521

3 189 2.182 0.900 1.538 1.931

4 36 2.436 0.889 1.487 1.896 2.232

5 34 2.846 0.945 1.520 1.941 2.277 2.594

6 13 2.955 0.919 1.504 1.905 2.233 2.545 2.808

7 2 3.176 0.920 1.548 1.937 2.253 2.519 2.777 3.000

8 1 2.900 0.671 1.008 1.342 1.624 1.792 2.091 2.554 2.769

Total 1003 weighted mean 0.889 1.523 1.925 2.243 2.562 2.759 2.851 2.769

weighted S.D. 0.110 0.103 0.107 0.130 0.166 0.226 0.258

(6)

은 Table 2^와^같다. ^본^연구에서^연령^사정을^실시한^총 1,037 마리 중에서 1세가 368마리, 2세가 360마리로 1세와 2세가 가장많이관찰되었으며, 4세이후로는개체수가급격히줄어 들었다. ^{최대연령은}^암컷에서 8^세까지^{관찰되었다}. ^암컷의^윤 문별평균윤경은각각 r₁=0.891 mm, r₂=1.532 mm, r₃=1.929 mm, r₄=2.227 mm, r₅=2.533 mm, r₆=2.764 mm, r₇=2.554 mm, r₈=2.769 mm였으며, 수컷은 r₁=0.887 mm, r₂=1.512 mm, r₃=1.920 mm, r₄=2.257 mm, r₅=2.585 mm, r₆=2.758 mm, r₇=3.000 mm^로^나타났다. ^다음^{윤문형성시의}^역계산^전장을 구하기위해이석반경(R)과전장간(TL)의관계식을추정한결 과암컷은 TL=8.468R+10.018, ^수컷은 TL=7.828R+10.418^로 나타났다. 이석반경(R)과전장간(TL)의관계식을사용하여역 계산전장을추정한결과암컷은 L₁=17.5 cm에서 L₈=33.5 cm 로나타났으며, ^수컷은 L₁=17.4 cm^에서 L₇= 33.9 cm^로^나타났 다(Table 3).

전장-체중 관계

보구치의전장-체중간의상대성장식을구하기위해전장과체

중간의관계를그래프로나타낸결과(Fig. 7) 비선형의관계임

을알수있었다. 따라서전장과체중을대수선형화하여최소자 승법으로관계식을구하였으며그식은다음과같다

Fig. 6. Monthly change in the marginal index (MI) of the white croaker Pennahia argentata in the Southern Sea of Korea, 2018.

0 2,000 4,000 6,000 8,000 10,000

1980

124°

38°

36°

34°

32°

126° 128° 130° 132°

1985 1990 1995 2000 2005 2010 2015 Year

Catch (mt)

Korea

Jeju Island Japan

Catch area

A Dorsal

Ventral

Anterior Posterior

B

Distal side Umbo

Anterior Posterior

r₁ r2

r₃ r4

r6

r5

R core

0.0 0.5 1.0 1.5

Month

Marginal index (MI)

BW = 0.0092TL^3.092 R² = 0.9712

0 200 400 600

Combine

BW = 0.01TLx^3.0655 R² = 0.9672

0 200 400 600

Female

BW = 0.0084TL^3.1207 R² = 0.9752

0 200 400 600

0 10 20 30 40

Male

Body weight (g)

Total length (cm)

0 10 20 30 40

●Female L_t= 34.86(1-e-0.35(t+1.02))

○Male

L_t=39.03(1-e-0.23(t+1.60))

Age (year)

Total length (cm)

0 10 20 30 40

0 1 2 3 4 5 6 7 8

Combined L_t=34.71(1-e-0.38(t+0.80))

Fig. 7. Relationship between total length (cm) and body weight (g) of the white croaker Pennahia argentata in the Southern Sea of Korea, 2018.

0 2,000 4,000 6,000 8,000 10,000

1980

124°

38°

36°

34°

32°

126° 128° 130° 132°

1985 1990 1995 2000 2005 2010 2015 Year

Catch (mt)

Korea

Jeju Island Japan

Catch area

A Dorsal

Ventral

Anterior Posterior

B

Distal side Umbo

Anterior Posterior

r₁ r₂

r₃ r₄

r₆ r₅

R core

0.0 0.5 1.0 1.5

Month

Marginal index (MI)

BW = 0.0092TL^3.092 R² = 0.9712

0 200 400 600

Combine

BW = 0.01TLx^3.0655 R² = 0.9672

0 200 400 600

Female

BW = 0.0084TL^3.1207 R² = 0.9752

0 200 400 600

0 10 20 30 40

Male

Body weight (g)

Total length (cm)

0 10 20 30 40

●Female L_t= 34.86(1-e-0.35(t+1.02))

○Male

L_t=39.03(1-e-0.23(t+1.60))

Age (year)

Total length (cm)

0 10 20 30 40

0 1 2 3 4 5 6 7 8

Combined L_t=34.71(1-e-0.38(t+0.80))

Fig. 8. The von Bertalanffy growth curve estimated from the non liner regression method of the white croaker Pennahia argentata in the Southern Sea of Korea, 2018.

0 2,000 4,000 6,000 8,000 10,000

1980

124°

38°

36°

34°

32°

126° 128° 130° 132°

1985 1990 1995 2000 2005 2010 2015 Year

Catch (mt)

Korea

Jeju Island Japan

Catch area

A Dorsal

Ventral

Anterior Posterior

B

Distal side Umbo

Anterior Posterior

r₁ r₂

r₃ r₄

r₆ r₅

R core

0.0 0.5 1.0 1.5

Month

Marginal index (MI)

BW = 0.0092TL^3.092 R² = 0.9712

0 200 400 600

Combine

BW = 0.01TLx^3.0655 R² = 0.9672

0 200 400 600

Female

BW = 0.0084TL^3.1207 R² = 0.9752

0 200 400 600

0 10 20 30 40

Male

Body weight (g)

Total length (cm)

0 10 20 30 40

●Female L_t= 34.86(1-e-0.35(t+1.02))

○Male

L_t=39.03(1-e-0.23(t+1.60))

Age (year)

Total length (cm)

0 10 20 30 40

0 1 2 3 4 5 6 7 8

Combined L_t=34.71(1-e-0.38(t+0.80))

(7)

BW=0.0092TL^3.092(R²=0.9712)

암수간의성장차가있는지를확인하기위하여 암수분리하 여상대성장식을구하고, 공분산분석한결과, 기울기및위치 모두유의한차이가없는것으로나타났다(P>0.01).

성장식 추정

역계산전장으로부터 von Bertalanffy ^성장식을^{추정하였다} (Fig. 8). 성장식의매개변수는 Walford의정차도법에의해구 한결과를초기치로하여비선형회귀분석에의해추정하였다.

Table 3. Back-calculated total length at the formation annuli in otolith of the white croaker Pennahia argentata collected from the Southern Sea of Korea, 2018

Female Estimated

age No of

samples Mean total length (cm)

L₁ L₂ L₃ L₄ L₅ L₆ L₇ L₈

1 203 17.4

2 194 17.6 23.0

3 104 17.6 23.1 26.4

4 17 17.5 22.7 26.1 28.9

5 18 18.0 22.8 26.3 29.0 31.6

6 3 18.1 23.9 27.2 30.2 32.9 35.3

8 1 15.7 18.6 21.4 23.8 25.2 27.7 31.6 33.5

weighted mean 17.5 22.9 26.2 28.3 30.3 33.4 31.6 33.5

weighted S.D. 0.74 1.73 2.09 2.46 3.37 3.80

Male Estimated

age No of

L₁ L₂ L₃ L₄ L₅ L₆ L₇ L₈

1 165 17.3

2 166 17.3 22.2

3 85 17.5 22.4 25.5

4 19 17.4 22.0 25.2 27.9

5 16 17.8 22.4 25.8 28.6 31.1

6 10 17.5 21.9 25.0 27.6 30.0 32.0

7 2 17.6 22.5 25.6 28.1 30.1 32.2 33.9

weighted mean 17.4 22.3 25.4 28.1 30.7 32.0 33.9

weighted S.D. 0.17 0.24 0.26 0.37 0.52 0.09

Combined Estimated

age No of

L₁ L₂ L₃ L₄ L₅ L₆ L₇ L₈

1 368 17.4

2 360 17.5 22.6

3 189 17.6 22.8 26.0

4 36 17.5 22.4 25.7 28.4

5 34 18.0 22.6 26.1 28.8 31.4

6 13 17.8 22.5 25.8 28.4 31.0 33.1

7 2 17.8 22.9 26.0 28.6 30.7 32.8 34.7

8 1 15.7 18.5 21.2 23.5 24.8 27.3 31.0 32.8

weighted mean 17.5 22.7 25.9 28.5 31.1 32.7 33.4 32.8

weighted S.D. 0.65 1.46 1.76 2.03 2.68 2.69 1.81