Age and Growth of Daggertooth Pike Conger Muraenesox cinereus in the South Sea of Korea

한수지 52(6), 650-655, 2019

650

Copyright © 2019 The Korean Society of Fisheries and Aquatic Science pISSN:0374-8111, eISSN:2287-8815 Korean J Fish Aquat Sci 52(6),650-655,2019

Original Article

서 론

갯장어

(Muraenesox cinereus)

^{는 뱀장어목}

(Order Anguil- liformes),

갯장어과

(Family Muraenesocidae)

에속하며

,

인도

양

-

서태평양해역에널리분포하고수심

100 m

이내모래진흙

바닥에서식한다

(Yamada et al., 2007; NIFS, 2017).

갯장어는우리나라

,

^중국

,

^일본

,

^{말레이시아}

,

^태국

,

^대만등에 서이용되고있으며

,

최근

10

년간세계어획량의

97%

가중국

에서어획되고있다

(FAO, 2017).

우리나라에서갯장어는주요

수산자원인멸치

,

고등어

,

오징어류와비교하여어획량대비생 산금액이높아상업적가치가높은어종이다

.

우리나라갯장어 어획량은

1970

^{년이후지속적으로증가하여}

1978

^년

9,852

^톤 으로최고치를기록한이후감소하였으며

, 2006

년

672

톤으로 최저치를나타냈다

.

최근갯장어어획량은

2018

년

981

톤이며

,

자원관리를위하여

2016

년포획금지체장이전장

40 cm

로설 정되었다

.

갯장어의국내선행연구중생식생태연구에따르면

,

^성숙체 장이

1998

년

, 2012

년

, 2018

년에각각전장

70.6 cm, 55.5 cm, 63.5 cm

로줄어드는 경향을보이고있다

(Kang et al., 1998;

Cha et al., 2012; Koh et al., 2018).

성숙체장감소는자원량감 소의징후로판단할수있으나

,

^{정확한원인을파악하기위해서} 는어획특성

,

해양환경및성장의차이등을면밀히검토해야한 다

.

갯장어의연령과성장은

Kim et al. (1998)

에의해연구되었 으나

,

약

30

년전결과이며갯장어어획량이비교적높았을때 수행된연구이다

.

연령과성장연구는우리나라갯장어계군의 질적구조를평가하여지속가능한어획한계를설정하기위한 자료를제공하지만

,

이에대한연구는매우부족한실정이다

.

따라서본연구는한국남해에분포하는갯장어의연령과성 장파라미터등을추정하여

,

갯장어자원평가와기술적자원관 리방안을마련하기위한기초자료를제공하고자한다

.

재료 및 방법

갯장어표본은

2018

년

5

월부터

2019

년

4

월까지우리나라남 해에서 대형외끌이기선저인망

,

서남구중형외끌이기선저인망 또는연안연승에 의해어획된것을구입하였다

(Fig. 1).

구입 한갯장어중갈창갯장어

(Muraenesox bagio)

^{로판별된개체는} 제외하고갯장어

(M. cinereus)

^{만을표본으로이용하였다}

.

표본

한국 남해에 분포하는 갯장어(Muraenesox cinereus)의 연령과 성장

고은혜·권대현*·김영혜

국립수산과학원 연근해자원과

Age and Growth of Daggertooth Pike Conger Muraenesox cinereus in the South Sea of Korea

Eun Hye Koh, Dae-Hyeon Kwon* and Yeonghye Kim

Fisheries Resource Management Division, National Institute of Fisheries Science, Busan 46083, Korea

The age and growth of Muraenesox cinereus collected in the South Sea of Korea by Danish seine and coastal Long- line fisheries were determined from right sagittal otoliths between May 2018 and April 2019. Otoliths of 353 fish were observed under reflected light, and the edges of the opaque zone were considered to be the otolith ring. Monthly changes in the marginal index indicated that rings (opaque zones) were formed once a year from June to July.

The estimated von Bertalanffy growth equation with growth parameters estimated from non-linear regression were L _t = 138.37 (1- e -0.18(t+0.79) ) for females and L _t = 99.00 (1- e -0.13(t+3.99) ) for males. The oldest female M. cinereus was 12 years old, and the oldest male was 8 years old.

Key words: Muraenesox cinereus , Age, Growth, Otolith, von Bertalanffy growth equation (VBGE)

*Corresponding author: Tel: +82. 51. 720. 2295 Fax: +82. 51. 720. 2277 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 22 April 2019; Revised 20 May 2019; Accepted 2 December 2019 저자 직위: 고은혜(박사후 인턴 연구원), 권대현(연구사), 김영혜(연구관) https://doi.org/10.5657/KFAS.2019.0650

Korean J Fish Aquat Sci 52(6), 650-655, December 2019

갯장어의 연령과 성장

651

353

마리는실험실로옮겨전장

(total length, TL) 0.1 cm,

항문 전장

(preanus length, PaL) 0.1 cm,

전중

(total weight, TW) 0.1 g,

^{생식소중량}

(gonad weight, GW) 0.1 g

^{까지측정하였다}

.

^이

석표본은어체의통낭에서편평석

(sagitta)

을추출하여점막과

이물질을제거하였으며

, 50%

알코올에보관한후오른쪽이석 만을사용하였다

.

산란기는윤문형성까지의시간간격을파악하기위하여살펴 보았으며

,

^{산란기의 경향을살펴보기위하여국립수산과학원} 의갯장어측정자료중최근

3

년간의자료를활용하여추정하 였다

.

산란기추정에이용된표본은

2016

년

1

월부터

2018

년

12

월까지우리나라남해안에서외끌이대형기선저인망과서남해 구중형기선저인망에서어획된갯장어이며

,

표본의생식소중 량

(GW)

^과전중

(TW)

^{자료를사용하였다}

.

GSI = GW/ TW×100

연령형질로사용되는이석은길이

(otolith length)

가

1cm

이 상인경우

,

근위측

(proximal side)

과 원위측

(distal side)

을사 포

1200, 2400 grit

^{로 연마후}

, slide glass

^{에 놓고 근위측을}

blanchard wax

로고정하여영구표본으로만들었다

.

이석길이

가

1 cm

미만인개체는연마중파손의위험이있어

,

자동연마

용원형틀에근위측을

varnish

로고정후

,

에폭시레진

(epoxy resin)

과에폭시경화제

(epoxy hardner)

를사용하여몰딩하고

,

연마기

(Ecomet 4000, Buehler, USA)

^{를이용하여근위측을사} 포

800, 1200, 2400 grit

에서단계적으로연마한후

,

알루미나 파우더

(alumina powder)

로광택을내었다

.

연마된이석은입 체현미경

(SZX16, Olympus, Japan)

에연결된영상분석시스템

(TCapture software, Tucsen, China)

을이용하여원위측사진

을찍은후표면관찰법으로분석하였다

.

윤문은불투명대

(opaque zone)

에서투명대

(translucent zone)

로이행하는경계를기준으로하였으며

, mm

^{단위로측정하였}

다

(Fig. 2).

연령형질의가능성은 이석반경

(radius, R)

과전장

(total length, TL)

간의관계로부터확인하였다

(Table 1).

윤문 판독은

1

명의판독자가

2

회수행하였으며

,

판독횟수간재현 성은첫번째와두번째로판독된윤문개수의평균차를검증 하였다

(Paired t-test, α=0.05).

^{윤문형성시기는월별연역지수}

(maginal index, MI)

로추정하였다

.

MI=(R-r

_n

)/(r

_n

-r

_n-1

)

여기서

R

^{은이석중심부초점에서가장자리까지의거리}

, r

_n은 초점부터

n

^{번째윤문까지거리이다}

.

^{초륜형성기간은산란기와} 윤문형성시기로추정하였다

.

이석경

(R)

과전장

(TL),

항문장

(PaL)

과전장

(TL)

그리고전장

(TL)

과전중

(TW)

간의상대성장식은

Huxely (1932)

방법에따 라추정하였다

.

이석반경과전장간의상대성장식은평균이석 경으로부터윤문형성시기의전장의역계산에사용되었다

.

^암

·

수간성장의차이는공분산분석법

(ANCOVA)

으로추정하였 다

(P<0.05).

성장식은

von Bertalanffy growth equation (von Bertalanffy, 1938)

을이용하여추정하였다

.

L

_t

=L

∞

(1-e

^-K(t-t0)

)

여기서

L

_t는연령이

t

일때의전장

, L

_∞는이론적최대전장

, K

는성장계수

, t

₀는전장이

0

일때의이론적연령을의미한다

.

성 장식의매개변수추정은

Walford

정차도법

(Walford and Lio- nel, 1946)

^{에의해추정치}

(L

_∞

, K, t

₀

)

^를구한후

,

^{그결과를초기} Fig. 1. Sampling area of Muraenesox cinereus in the South Sea of

Korea (●).

39°N

37°

35°

33°

123° 125° 127° 129° 131°E 31°

KOREA

JAPAN

r1

R r3 r2 r5 r4 r7 r6 r8

Anterior Posterior

Dosal

Ventral F

Distal surface

0.00 0.20 0.40 0.60 0.80 1.00 1.20

May '18 Jun. Jul. Aug. Sep. Oct. Nov. Dec. Jan.

'19 Feb. Mar. Apr.

Ma rgi nal in dex (MI)

Month

0 5 10 15

'16 J M M J S N J

'17 M M J S N J

'18 M M J S N

Gonad osomatic index ( G SI)

Month

Female Male

0 50 100 150 200

0 2 4 6 8

To tal len gt h (c m )

Radius (mm)

● Female TW=0.0002TL

^3.5382

(R

²

=0.98)

○ Male TW=0.0001TL

^3.5714

(R

²

=0.95)

● Female TL=20.891R-2.4551 (R

²

=0.91)

○ Male TL=14.812R-13.329 (R

²

=0.68)

0 1,000 2,000 3,000 4,000 5,000 6,000

0 20 40 60 80 100 120 140 160

To tal w eig ht (g )

Total length (cm)

● Combined TW=2.1109Pal+10.469 (R

²

=0.99)

0 50 100 150 200

0 20 40 60 80

To tal len gt h (c m )

Preanus length (cm)

0 20 40 60 80 100 120 140 160

0 2 4 6 8 10 12 14

Tota l l en gth (c m)

Age Female

Male ● Female L

_t

=138.37(1−e

−0.18(t+0.79)

)

○ Male L

_t

=99.00(1−e

−0.13(t+3.99)

)

0 10 20 30 40 50

30 40 50 60 70 80 90 100 110 120 130 140 150

Frequenc y (% )

Total length (cm)

■ Female (n=224)

□ Male (n=129)

0 10 20 30 40

0 1 2 3 4 5 6 7 8 9 10 11 12 13

Frequenc y (% )

Age

Fig. 2. Otolith of Muraenesox cinereus female, 109.4 cm TL, 45.0 PaL. F, r₁-r₈, and R are focus, annual ring radii and otolith radius, respectively.

39°N

37°

35°

33°

123° 125° 127° 129° 131°E 31°

KOREA

JAPAN

r1

R r3 r2 r5 r4 r7 r6 r8

Anterior Posterior

Dosal

Ventral F

Distal surface

0.00 0.20 0.40 0.60 0.80 1.00 1.20

May '18 Jun. Jul. Aug. Sep. Oct. Nov. Dec. Jan.

'19 Feb. Mar. Apr.

Ma rgi nal in dex (MI)

Month

0 5 10 15

'16 J M M J S N J

'17 M M J S N J

'18 M M J S N

Gonad osomatic index ( G SI)

Month

Female Male

0 50 100 150 200

0 2 4 6 8

To tal len gt h (c m )

Radius (mm)

● Female TW=0.0002TL

^3.5382

(R

²

=0.98)

○ Male TW=0.0001TL

^3.5714

(R

²

=0.95)

● Female TL=20.891R-2.4551 (R

²

=0.91)

○ Male TL=14.812R-13.329 (R

²

=0.68)

0 1,000 2,000 3,000 4,000 5,000 6,000

0 20 40 60 80 100 120 140 160

To tal w eig ht (g )

Total length (cm)

● Combined TW=2.1109Pal+10.469 (R

²

=0.99)

0 50 100 150 200

0 20 40 60 80

To tal len gt h (c m )

Preanus length (cm)

0 20 40 60 80 100 120 140 160

0 2 4 6 8 10 12 14

Tota l l en gth (c m)

Age Female

Male ● Female L

_t

=138.37(1−e

−0.18(t+0.79)

)

○ Male L

_t

=99.00(1−e

−0.13(t+3.99)

)

0 10 20 30 40 50

30 40 50 60 70 80 90 100 110 120 130 140 150

Frequenc y (% )

Total length (cm)

■ Female (n=224)

□ Male (n=129)

0 10 20 30 40

0 1 2 3 4 5 6 7 8 9 10 11 12 13

Frequenc y (% )

Age

고은혜

ㆍ

권대현

ㆍ

김영혜

652

값으로

excel

^의

solver

^{를이용하여비선형회귀분석방법으로구}

하였다

(Zhang, 2010).

추정된성장식의성장계수들을기존의

연구결과와비교하기위하여

growth performance index (Φ)

를사용하였다

(Munro and Pauly, 1983).

Φ=logK+2log L

∞

결과 및 고찰

윤문 판독

본연구에서윤문은불투명대에서투명대로이행하는경계를 기준으로하였으며

,

선행연구에서도같은방법을사용하였다

(Kim et al., 1998; Yanagawa and Moriyama, 2010; Watari et al., 2013).

윤문판독의재현성을살펴본결과

,

전체

353

개표 본중

304

개

(

전체의

86.12%)

의측정값이일치하였으며

(Table

1),

판독간윤문개수의평균은유의한차이를보이지않았다

(P>0.05).

그러나윤문판독의정도를높이기위해서는고연령 군표본을추가해야할것으로판단된다

.

윤문 형성시기 및 산란기

윤문형성시기는연역지수

(MI)

의월별변화로추정되었다

.

연 역지수중앙값은

5

월에가장높은값을보이다가감소하여

6

월에가장낮은값을보였다

.

연역지수가최소값을보이는개 체

(MI<0.1)

^는

6

^월부터

7

^{월까지출현하였다}

.

^{따라서윤문형성} 시기는

6-7

월

,

연

1

회형성됨을알수있었다

(Fig. 3).

산란기는 생식소숙도지수의월별변화로추정하였다

.

암컷생식소숙도 지수는

2016

년에는

7

월

, 2017

년

, 2018

년에는

6

월에높았으며

, 2016

년

10

월

, 2017

년

9

월

, 2018

년

10

월에낮게나타났다

.

수

컷의생식소숙도지수의변화는암컷과유사한경향을나타냈 다

(Fig. 4).

따라서갯장어의산란기는

6

월

-10

월

(

주산란기

6-7

월

)

로추정되었다

.

Kim et al. (1998)

은제주서남부해역에출현하는갯장어의산 란기는

6-7

월

,

윤문형성시기는

6

월로보고하였다

. Watari et al.

(2013)

^{은일본세토내해서부해역출현하는갯장어의산란기}

는

7-9

월

,

윤문형성시기는

7-8

월로보고하였다

.

그리고본연구 에서갯장어이석의윤문은연

1

회형성되며

,

산란기는

6-7

월

,

윤문형성시기는이듬해

6-7

월로추정되므로

,

초륜형성까지의 소요기간은약

1

년으로추정되었다

.

이상의결과들을종합해보 면

,

^{갯장어이석의윤문형성시기는해역에따라다소차이가있} 지만모두산란시기인여름철에형성되는것으로확인되었다

. 상대성장

이석경

(R)

과 전장

(TL)

간의 상대성장식은암컷

TL=20.891

Table 1. Number of ring marks on the otolith of Muraenesox cinereus assigned by first and second measurement Ring marks

by second measurement

Ring marks by first measurement

2 3 4 5 6 7 8 9 10 11 12 Total

2 72 6 78

3 2 84 9 95

4 51 6 57

5 2 31 3 36

6 1 24 5 30

7 2 9 2 13

8 13 1 14

9 3 5 2 10

10 1 6 7

11 1 1 6 1 9

12 1 3 4

Total 74 90 62 38 29 14 18 8 9 7 4 353

Fig. 3. Monthly changes in the maginal index (MI) of Muraenesox cinereus in the south Sea of Korea from May 2018 to April 2019.

Vertical bars are minimum and maximum values.

39°N

37°

35°

33°

123° 125° 127° 129° 131°E 31°

KOREA

JAPAN

r1

R r3 r2 r5 r4 r7 r6 r8

Anterior Posterior

Dosal

Ventral F

Distal surface

0.00 0.20 0.40 0.60 0.80 1.00 1.20

May '18 Jun. Jul. Aug. Sep. Oct. Nov. Dec. Jan.

'19 Feb. Mar. Apr.

Ma rgi nal in dex (MI)

Month

0 5 10 15

'16 J M M J S N J

'17 M M J S N J

'18 M M J S N

Gonad osomatic index ( G SI)

Month

Female Male

0 50 100 150 200

0 2 4 6 8

To tal len gt h (c m )

Radius (mm)

● Female TW=0.0002TL

^3.5382

(R

²

=0.98)

○ Male TW=0.0001TL

^3.5714

(R

²

=0.95)

● Female TL=20.891R-2.4551 (R

²

=0.91)

○ Male TL=14.812R-13.329 (R

²

=0.68)

0 1,000 2,000 3,000 4,000 5,000 6,000

0 20 40 60 80 100 120 140 160

To tal w eig ht (g )

Total length (cm)

● Combined TW=2.1109Pal+10.469 (R

²

=0.99)

0 50 100 150 200

0 20 40 60 80

To tal len gt h (c m )

Preanus length (cm)

0 20 40 60 80 100 120 140 160

0 2 4 6 8 10 12 14

Tota l l en gth (c m)

Age Female

Male ● Female L

_t

=138.37(1−e

−0.18(t+0.79)

)

○ Male L

_t

=99.00(1−e

−0.13(t+3.99)

)

0 10 20 30 40 50

30 40 50 60 70 80 90 100 110 120 130 140 150

Frequenc y (% )

Total length (cm)

■ Female (n=224)

□ Male (n=129)

0 10 20 30 40

0 1 2 3 4 5 6 7 8 9 10 11 12 13

Frequenc y (% )

Age

갯장어의 연령과 성장

653

×R-2.4551 (R

²

=0.91),

수컷

TL=14.812×R-13.329 (R

²

=0.68)

로 추정되었으며

,

암

·

수 간 유의한 차이를 보였다

(P<0.05).

전장

(TL)

과 항문장

(PaL)

간의 상대성장식은 암

·

수 간 유의

한 차이를 보이지 않아

(P>0.05)

^{합하여 계산하였으며}

, TL=

2.111PaL+10.469 (R

²

=0.99)

로 추정되었다

.

전장

(TL)

과 전 중

(TW)

간의 상대성장식은 암컷

TW=0.0002×TL

^3.5382

(R

²

= 0.98),

수컷

TW=0.0001×TL

^3.5714

(R

²

= 0.95)

로추정되었으며

,

암

·

수간유의한차이를보였다

(P<0.05) (Fig. 5).

본연구의암

·

수간전장과전중간의상대성장차이는약

60 cm

^{이후암컷이}

수컷에비해월등히커지는것으로나타났다

.

이는기존의연 구에서연령이높아질수록암컷이수컷에비해월등히커지는 결과와일치하였다

(Ueta, 2008; Watari et al., 2013). Andrew and Donald (2005)

에 따르면

,

뱀장어과

(Anguillidae)

어류는 암컷이수컷보다성장이빠르며

,

^{이는산란을위한성장전략의} 차이로판단하였다

.

즉

,

암컷은생식전사망률을최소화하는 크기

-

최대화

,

수컷은작은크기에서산란회유를가능하게하는 시간

-

최소화전략을채택한것으로보고하였다

.

그러나

Zhang and Zhang (1999)

에따르면

,

갯장어정소는같은소엽에서도 세포의발달과정이다르며

,

^{산란기에여러번사정한다고보고} 하였다

.

따라서갯장어의암

·

수간생식과성장의차이를면밀 히파악하기위해서는수컷의생식과관련된연구가필요할것 으로판단된다

.

성장식 추정

윤문형성시의평균 전장을이용하여 추정한

VBGF

^{는 암컷}

L

_t

=138.37 (1-e

-0.18(t+0.79)

),

수컷

L

_t

=99.00 (1-e

-0.13(t+3.99)

)

이었다

(Fig. 6).

선행연구와비교하기위해사용된성장률지수

(Φ)

는 같은종의다른계군간에는유사한값을나타내게되며

,

성장계 수와이론적최대체장이높을수록증가한다

(Munro and Pauly,

1983).

^{갯장어의성장률지수는본연구와선행연구에서전체}

2.61-3.65,

암컷

2.90-3.64,

수컷

2.61-3.65

의범위로나타났다

(Table 2).

그러나

Yanagawa and Moriyama (2010)

의경우항 문장을기준으로추정하여직접적인비교는어려웠으나

,

암컷

성장률이수컷보다높은본연구의결과는

Watari et al. (2013)

와

Yanagawa and Moriyama (2010)

의결과와일치하였다

.

일 반적으로어류의성장률차이는성별

,

해역별서식수온과먹이 공급등의차이로알려져있다

.

갯장어성장률의지역적차이 를비교한결과

,

상대적으로위도가낮은제주남부

-

동중국해

(Kim et al., 1998)

^{갯장어가비교적위도가높은우리나라남} 해안

(present study)

과세토내해

(Watari et al., 2013)

갯장어보 Fig. 4. Monthly change of gonadosomatic index of Muraenesox

cinereus in the South Sea of Korea from January 2016 to Decem- ber 2018.

39°N

37°

35°

33°

123° 125° 127° 129° 131°E 31°

KOREA

JAPAN

r1

R r3 r2 r5 r4 r7 r6 r8

Anterior Posterior

Dosal

Ventral F

Distal surface

0.00 0.20 0.40 0.60 0.80 1.00 1.20

May '18 Jun. Jul. Aug. Sep. Oct. Nov. Dec. Jan.

'19 Feb. Mar. Apr.

Ma rgi nal in dex (MI)

Month

0 5 10 15

'16 J M M J S N J

'17 M M J S N J

'18 M M J S N

Gonad osomatic index ( G SI)

Month

Female Male

0 50 100 150 200

0 2 4 6 8

To tal len gt h (c m )

Radius (mm)

● Female TW=0.0002TL

^3.5382

(R

²

=0.98)

○ Male TW=0.0001TL

^3.5714

(R

²

=0.95)

● Female TL=20.891R-2.4551 (R

²

=0.91)

○ Male TL=14.812R-13.329 (R

²

=0.68)

0 1,000 2,000 3,000 4,000 5,000 6,000

0 20 40 60 80 100 120 140 160

To tal w eig ht (g )

Total length (cm)

● Combined TW=2.1109Pal+10.469 (R

²

=0.99)

0 50 100 150 200

0 20 40 60 80

To tal len gt h (c m )

Preanus length (cm)

0 20 40 60 80 100 120 140 160

0 2 4 6 8 10 12 14

Tota l l en gth (c m)

Age Female

Male ● Female L

_t

=138.37(1−e

−0.18(t+0.79)

)

○ Male L

_t

=99.00(1−e

−0.13(t+3.99)

)

0 10 20 30 40 50

30 40 50 60 70 80 90 100 110 120 130 140 150

Frequenc y (% )

Total length (cm)

■ Female (n=224)

□ Male (n=129)

0 10 20 30 40

0 1 2 3 4 5 6 7 8 9 10 11 12 13

Frequenc y (% )

Age

Fig. 5. Relationship of female (black circles) and male (white circles) between (A) otolith radius and total length, (B) preanus length and total length, (C) total length and total weight of Mu- raenesox cinereus in the South Sea of Korea from May 2018 to April 2019.

39°N

37°

35°

33°

123° 125° 127° 129° 131°E 31°

KOREA

JAPAN

r1

R r3 r2 r5 r4 r7 r6 r8

Anterior Posterior

Dosal

Ventral F

Distal surface

0.00 0.20 0.40 0.60 0.80 1.00 1.20

May '18 Jun. Jul. Aug. Sep. Oct. Nov. Dec. Jan.

'19 Feb. Mar. Apr.

Ma rgi nal in dex (MI)

Month

0 5 10 15

'16 J M M J S N J

'17 M M J S N J

'18 M M J S N

Gonad osomatic index ( G SI)

Month

Female Male

0 50 100 150 200

0 2 4 6 8

To tal len gt h (c m )

Radius (mm)

● Female TW=0.0002TL

^3.5382

(R

²

=0.98)

○ Male TW=0.0001TL

^3.5714

(R

²

=0.95)

● Female TL=20.891R-2.4551 (R

²

=0.91)

○ Male TL=14.812R-13.329 (R

²

=0.68)

0 1,000 2,000 3,000 4,000 5,000 6,000

0 20 40 60 80 100 120 140 160

To tal w eig ht (g )

Total length (cm)

● Combined TW=2.1109Pal+10.469 (R

²

=0.99)

0 50 100 150 200

0 20 40 60 80

To tal len gt h (c m )

Preanus length (cm)

0 20 40 60 80 100 120 140 160

0 2 4 6 8 10 12 14

Tota l l en gth (c m)

Age Female

Male ● Female L

_t

=138.37(1−e

−0.18(t+0.79)

)

○ Male L

_t

=99.00(1−e

−0.13(t+3.99)

)

0 10 20 30 40 50

30 40 50 60 70 80 90 100 110 120 130 140 150

Frequenc y (% )

Total length (cm)

■ Female (n=224)

□ Male (n=129)

0 10 20 30 40

0 1 2 3 4 5 6 7 8 9 10 11 12 13

Frequenc y (% )

Age

고은혜

ㆍ

권대현

ㆍ

김영혜

654

다성장률지수가높게나타났다

(Table 2).

즉

,

위도가낮을수록 성장이빠른것으로판단되며

,

^{상대적으로고수온해역인저위} 도가난류성저어류인갯장어의성장에유리한환경인것으로 볼수있다

.

그러나갯장어의경우

Leptocephalus

형태로비교 적긴부유시기를가지므로지역적

·

환경적특성만을고려하기 는어려움이많으므로

,

성장과관련된차이를보다명확히파악 하기위해서는해역별계군구조에대한추가적인연구가필요 할것으로판단된다

.

전장 및 연령 조성

갯장어전장조성은암컷

41.8-133.8 cm,

수컷

40.3-96.1 cm

범위로나타났으며

,

연령조성은암컷

2-12

세

,

수컷

2-8

세로나 타났다

(Fig. 6).

^특히

9

^{세이상의갯장어는모두암컷으로나타} 났으며

,

갯장어의분포가성장또는성별에따라차이를보이 는선행연구결과와일치하였다

(Ueta, 2008; Okazaki et al., 2012).

또한본연구에서는암

·

수모두

1

세어가출현하지않은 반면

, Kim et al. (1998)

과

Watari et al. (2013)

는

1

세어의출현 을보고하였으며각각

27.2 cm

^와

25.4 cm

^를

1

^세어

(

^암컷

)

^로추 정하였다

.

본연구에서

1

세어출현이없는이유는연구기간동

안포획금지체장전장

40 cm

미만인갯장어어획이금지되었기 때문인것으로판단된다

.

본연구의갯장어최고연령은암컷

12

세

,

수컷

8

세로나타났 으나

, Kim et al. (1998)

^는암컷

14

^세

,

^수컷

11

^{세로보고하여본} 연구결과가

2-3

세낮게나타났다

.

본연구의표본채집과정중 갯장어와외형적으로매우유사한갈창갯장어가모두갯장어로 유통

·

판매되는것을확인하였으며그혼획비율이

10%

로나타 났으나

,

이전까지 우리나라에서갈창갯장어의공식적인출현 보고와생태연구는전무하다

.

^{특히본연구에서}

137.0-205.5

cm TL

범위의대형개체가모두갈창갯장어로확인되었으나

,

Kim et al., (1998)

은

130 cm

이상의대형개체를

12

세이상인 고연령어로추정하였다

.

따라서이러한차이는연령사정의방 법차이인지또는갈창갯장어의혼획유무에따른차이인지는 재검토될필요가있다고판단된다

.

또한과거

1990

년대후반갯장어의성숙체장은전장

70.6 cm,

Table 2. Comparison in growth parameters and growth performance index of Muraenesox cinereus among different studies estimated by von Bertalanffy growth equation

Study area L_∞ (cm) K (/year) t_o (year) Φ Material References

Southern Waters, Korea F 138.37 TL

M 99.00 TL F 0.18

M 0.13 F -0.79

M -3.99 F 3.53

M 3.11 Otolith Present study West-southern Sea of Jeju, Korea

& East China Sea F 166.00 TL

M 159.00 TL F 0.16

M 0.18 F -0.14

M -0.18 F 3.64

M 3.65 Otolith Kim et al. (1998) West Seto Inland Sea, Japan F 126.40 TL

M 80.70 TL F 0.19

M 0.33 F -0.15

M -0.06 F 3.48

M 3.33 Otolith Watari et al. (2013)

Tosa bay, Japan F 54.98 PaL

M 34.97 PaL F 0.26

M 0.33 F 1.06

M 0.75 F 2.90

M 2.61 Otolith Yanagawa and Moriyama (2010) Fig. 6. Von Bertalanffy growth curves of female (black circles) and

male (white circlue) Muraenesox cinereus in the South Sea of Ko- rea from May 2018 to April 2019.

39°N

37°

35°

33°

123° 125° 127° 129° 131°E 31°

KOREA

JAPAN

r1

R r3 r2 r5 r4 r7 r6 r8

Anterior Posterior

Dosal

Ventral F

Distal surface

0.00 0.20 0.40 0.60 0.80 1.00 1.20

May '18 Jun. Jul. Aug. Sep. Oct. Nov. Dec. Jan.

'19 Feb. Mar. Apr.

Ma rgi nal in dex (MI)

Month

0 5 10 15

'16 J M M J S N J

'17 M M J S N J

'18 M M J S N

Gonad osomatic index ( G SI)

Month

Female Male

0 50 100 150 200

0 2 4 6 8

To tal len gt h (c m )

Radius (mm)

● Female TW=0.0002TL

^3.5382

(R

²

=0.98)

○ Male TW=0.0001TL

^3.5714

(R

²

=0.95)

● Female TL=20.891R-2.4551 (R

²

=0.91)

○ Male TL=14.812R-13.329 (R

²

=0.68)

0 1,000 2,000 3,000 4,000 5,000 6,000

0 20 40 60 80 100 120 140 160

To tal w eig ht (g )

Total length (cm)

● Combined TW=2.1109Pal+10.469 (R

²

=0.99)

0 50 100 150 200

0 20 40 60 80

To tal len gt h (c m )

Preanus length (cm)

0 20 40 60 80 100 120 140 160

0 2 4 6 8 10 12 14

Tota l l en gth (c m)

Age Female

Male ● Female L

_t

=138.37(1−e

−0.18(t+0.79)

)

○ Male L

_t

=99.00(1−e

−0.13(t+3.99)

)

0 10 20 30 40 50

30 40 50 60 70 80 90 100 110 120 130 140 150

Frequenc y (% )

Total length (cm)

■ Female (n=224)

□ Male (n=129)

0 10 20 30 40

0 1 2 3 4 5 6 7 8 9 10 11 12 13

Frequenc y (% )

Age

Fig. 7. Age and length frequency distribution of female (black bars) and male (White bars) Muraenesox cinereus in the South Sea of Korea from May 2018 to April 2019.

39°N

37°

35°

33°

123° 125° 127° 129° 131°E 31°

KOREA

JAPAN

r1

R r3 r2 r5 r4 r7 r6 r8

Anterior Posterior

Dosal

Ventral F

Distal surface

0.00 0.20 0.40 0.60 0.80 1.00 1.20

May '18 Jun. Jul. Aug. Sep. Oct. Nov. Dec. Jan.

'19 Feb. Mar. Apr.

Ma rgi nal in dex (MI)

Month

0 5 10 15

'16 J M M J S N J

'17 M M J S N J

'18 M M J S N

Gonad osomatic index ( G SI)

Month

Female Male

0 50 100 150 200

0 2 4 6 8

To tal len gt h (c m )

Radius (mm)

● Female TW=0.0002TL

^3.5382

(R

²

=0.98)

○ Male TW=0.0001TL

^3.5714

(R

²

=0.95)

● Female TL=20.891R-2.4551 (R

²

=0.91)

○ Male TL=14.812R-13.329 (R

²

=0.68)

0 1,000 2,000 3,000 4,000 5,000 6,000

0 20 40 60 80 100 120 140 160

To tal w eig ht (g )

Total length (cm)

● Combined TW=2.1109Pal+10.469 (R

²

=0.99)

0 50 100 150 200

0 20 40 60 80

To tal len gt h (c m )

Preanus length (cm)

0 20 40 60 80 100 120 140 160

0 2 4 6 8 10 12 14

Tota l l en gth (c m)

Age Female

Male ● Female L

_t

=138.37(1−e

−0.18(t+0.79)

)

○ Male L

_t

=99.00(1−e

−0.13(t+3.99)

)

0 10 20 30 40 50

30 40 50 60 70 80 90 100 110 120 130 140 150

Frequenc y (% )

Total length (cm)

■ Female (n=224)

□ Male (n=129)

0 10 20 30 40

0 1 2 3 4 5 6 7 8 9 10 11 12 13

Frequenc y (% )

Age

갯장어의 연령과 성장

655

성숙연령은

3.4

^{세로보고되었으나}

(Kang et al., 1998; Kim et al., 1998), 2010

년대후반갯장어의성숙체장은전장

63.5 cm

로보고되었으며

(Koh et al., 2018),

이를본연구의성장식으로 환산하여추정한성숙연령은

2.7

세로나타났다

.

즉

,

갯장어의 성숙체장과성숙연령의감소는자원량감소징후로판단되므로 갯장어의자원관리를위해서는지속적인모니터링을통한관리 방안마련이필요할것으로판단된다

.

사 사

본연구는국립수산과학원수산과학연구사업

(R2019021)

의 지원에의해수행되었습니다

.

References

Andrew D and Donald J. 2005. Sex determination in freshwa- ter eels and management options for manipulation of sex.

Rev Fish Biol Fisher 15, 37-52. http://dx.doi.org/10.1007/

s11160-005-7431-x.

Cha HK, Seo YI, Oh TY, Kim HY, Lee SG and Choi MS. 2012.

Reproductive ecology of the sharp toothed eel in the south- ern Korean waters. J Korean Soc Fish Technol 48, 217-226.

http://dx.doi.org/10.3796/KSFT.2012.48.3.217.

FAO (Food and Agriculture Organization of the United Na- tions). 2017. Global fishery and aquaculture production sta- tistics. Retrieved from http://www.fao.org/fishery/statistics/

software/fishstatj/en. on Mar 26, 2019.

Huxely JS. 1932. Problems of relative growth. 2^nd et. Dover publishing, New York, NY, U.S.A., 312.

Kang YJ, Jeon BS and Zhang CI. 1998. A study on the stock management of the sharp-toothed eel, Muraenesox cinereus (FORSKAL) in Korean Waters III. Maturation and Spawn- ing. J Korean Soc Fish Technol 1, 18-24.

Kim MJ, Kang YJ and Park CS. 1998. A study on the stock man- agement of Sharp-toothed eel, Muraenesox cinereus (FOR- SKAL) in Korean Waters II. Age and Growth. J Korean Soc Fish Res 1, 11-17.

Koh EH, Kwon DH and Jang CS. 2018. Basic reproductive biol- ogy of Muraenesox cinereus in Korean waters. J Korean Soc Fish Ocean Technol 54, 353-359. http://dx.doi.org/10.3796/

KSFOT.2018.54.4.353.

Munro JL and Pauly D. 1983. A simple method for comparing the growth of fishes and invertebrates. Fishbyte 1, 5-6.

NIFS (National Institute of Fisheries Science). 2017. Ecology and fishing ground of fisheries resources in the Korean wa- ters. National Institute of Fisheries Science, Yemoon Pub- lishing, Busan, Korea, 19-30.

Okazaki T, Ueta Y and Hamano T. 2012. Distribution and mi- gration of daggertooth pike-conger Muraenesox cinereus in the eastern Seto Inland Sea, Japan estimated by mark and recapture experiments. Nipp Suis Gak 78, 913-921.

Ueta Y. 2008. Fishery biological informations on daggertooth pike-conger eels, Muraenesox cinereus around Tokushima prefecture. Bull Tokushima Fish Res Ins 6, 85-90.

von Bertalanffy L. 1938. A quantitative theory of organic growth (inquiries on growth laws. II). Human Biol 10, 181-213.

Walford and Lionel A. 1946. A new graphic method of describ- ing the growth of animals. Biolog Bull 90, 141-147.

Watari S, Murata M, Hinoshita Y, Mishiro K, Oda S and Ishitani M. 2013. Re-examination of age and growth of daggertooth pike conger Muraenesox cinereus in the western Seto Inland Sea, Japan. Fish Sci 79, 367-373. http://dx.doi.org/10.1007/

s12562-013-0605-x.

Yanagawa S and Moriyama T. 2010. On the age and growth of

Muraenesox cinereus in Tosa Bay. In: Report of 2008 Ko-

chi Prefecture Fisheries Experimental station Project Report 106, 64-70.

Yamada U, Tokimura M, Horikawa H and Nakabo T. 2007.

Fishes and fisheries of the East China and Yellow Seas. To- kai University Press, Tokyo, Japan, 165-170.

Zhang CI. 2010. Marine fisheries resources ecology. Pukyong National University, Busan, Korea, 228-230.

Zhang KJ and Zhang YJ. 1999. Studies on the gonadal morphol- ogy and development of pike conger Muraenesox cinereus.

J Fish China 23, 13-19.