한수지 46(4), 445-453, 213 Original Article Kor J Fish Aquat Sci 46(4),445-453,213 197-199 년대동해에서어획된명태 (Theragra chalcogramma) 의체장에따른체급별어획마릿수추정 강수경ㆍ박정호 1 ㆍ김수암 2 * 국립수산과학원자원관리과, 1 국립수산과학원동해수산연구소, 2 부경대학교자원생물학과 Size-class Estimation of the Number of Walleye Pollock Theragra chalcogramma Caught in the Southwestern East Sea during the 197s-199s Sukyung Kang, Jung Ho Park 1 and Suam Kim 2 * National Fisheries Research and Development Institute, Busan 619-92, Korea 1 East Sea Fisheries Research Institute, National Research & Development Institute, Gangreung 21-861, Korea 2 Department of Marine Biology, Pukyong National University, Busan 68-737, Korea Walleye pollock Theragra chalcogramma fisheries in Korean waters have changed dramatically during the last three decades: the highest catches occurred in, followed by continuous decreases through the 199s, ending with a complete collapse of the population in the 2s. The major spawning ground of walleye pollock is located in North Korean waters, and some juveniles (called nogar in Korean, <3 mm) migrate to the south for feeding and growth. Since the 196s, Korean fishermen have often caught juveniles, and the weight (metric tons) of juvenile catch was recorded from. However, because the walleye pollock were not aged, the population age structure was not delineated. We developed a model to estimate the number of walleye pollock of each size class based on catch statistics of adults and juveniles, the catch proportion of each size class, and length and weight information on specimens collected by Danish-seine and drift-gill-net fisheries. The model results demonstrated that the recruitment size of walleye pollock was consistently within the 2-25mm size class, and the highest number of this size class occurred in, although values greatly fluctuated interannually. The number of juvenile pollock was 1.4 times higher than that of adult pollock during -. The total yield of juvenile pollock was.95 million tons, which was equivalent to about 68.2% of total pollock production. The number of juvenile pollock caught during the same period, however, was 16 billion, comprising about 91.2% of the total number caught. Such high fishing pressure on juvenile pollock is considered one of the main factors causing the collapse of the pollock population. Key words: Walleye Pollock, Pollock, East Sea, Korean Waters, Length-Frequency Distribution of Fish 서 론 (Theragra chalcogramma) (Family Gadidae). 1,2 m (FishBase, 213), 2-35 m (NFRDI, 21). 2-1ºC, 25 cm 2-3,. Article history; Received 12 April 213; Revised 31 July 213; Accepted 15 August 213 *Corresponding author: Tel: +82. 51. 629. 5923 Fax: +82. 51. 629. 5923 E-mail address: suamkim@pknu.ac.kr, 3-5ºC 12 3 (Park and Ok, ).,, 2 m (Kim, ; Kim, a).,., (Kendall and Kim, ). Kor J Fish Aquat Sci 46(4) 445-453, August 213 http://dx.doi.org/1.5657/kfas.213.445 pissn:374-8111, eissn:2287-8815 c The Korean Society of Fishereis and Aquatic Science. All rights reserved 445
446 강수경ㆍ박정호ㆍ김수암 Longitute ( N) 52 5 48 46 44 42 4 38 36 34 128 13 132 124 136 138 14 142 Longitude ( E) Fig. 1. Spawning areas of walleye pollock Theragra chalcogramma in the East Sea. Four major spawning stocks located in the Wonsan Bay, the Peter the Great Bay, Tartar Strait, and off the western Hokkaido, and several local stocks along the rim of the coast are indicated by dots [from Kim and Kang (1998)]., (Muigwa, ; Kim, b). (Food and Agriculture Organization, FAO) 25, (anchoveta), (FAO, 27). 198 5% (Kim, 199).,,,.,.,, (Kim and Kang, 1998, Fig. 1), 3 (Oh et al., 24)., 1932, 47,81 13,, (Gong and Zhang, ; Iwata, )., -, - (Gong and Zhang, ; Oh et al., 24)., 197 198 (Kim and Kang, 1998), -.. 2,. 197 16 6 (Fig. 2). (Kim and Kang, 1998), 198., - 1.7, 24.4 44%. 198., (catch per unit effort: CPUE) 1977 Catch (X1, ton) 16 14 12 1 8 6 4 2 Total 196 1965 197 198 199 2 25 21 Fig. 2. Annual yields of walleye pollock Theragra chalcogramma in the southern part of the Korean Peninsula. Catch statistics (dotted line) between and indicate the portion of juvenile catches.
동해명태어획머릿수추정 447, 197 (Lee, ). 199 2. 199. 1971 (Kim, ), (, )., 197 85-94%. (climate regime shift) (Seo et al., 26; Kim et al., 27)., (foodweb).,,,,.,,, (Park and Ok, ; Lee and Kim, 21).,,,..,, 197, -.,. Table 1. Biological parameters measured for walleye pollock Theragra chalcogramma collected from Danish seine and drift gill net fisheries during the mid 196s through the early 198s. Note that Danish seine targets only on small-size pollock, while drift gill net on large one. TL=total length, FL=fork length, BL=standard length, and BW=body weight Sampling date (month/day/year) Fishery Sample number TL FL BL BW Sex Remark 11/21/1965 Danish seine 3 O O O O 11/28/1965 Danish seine 3 O O O O 12/11/1965 Danish seine 29 O O O O 11/12/1965 Danish seine 29 O O O O 1/3/1966 Danish seine 3 O O O O 3/21/1966 Danish seine 3 O O O O 3/6/1977 Danish seine 1 O O O O 18 pollock > 3 mm 3/22/1977 Danish seine 1 O O O O 35 pollock > 3 mm 2/24/ Danish seine 6 O O O O O Sampling date (month/day/year) Fishery Sample number TL FL BL BW Sex Remark 1/27/ Drift gill net 1 O O O O O 2/18/ Drift gill net 1 O O O O O 1 pollock < 3 mm 1/7/ Drift gill net 1 O O O O O 11/16/ Drift gill net 1 O O O O O 12/15/ Drift gill net 1 O O O O O 1/28/ Drift gill net 1 O O O O O 2/1/ Drift gill net 1 O O O O O 2/25/ Drift gill net 1 O O O O O 1/7/ Drift gill net 1 O O O O O 1 pollock < 3 mm 2/1/ Drift gill net 9 O O O O O 1/3/ Drift gill net 1 O O O O O 11/23/ Drift gill net 1 O O O O O 12/4/ Drift gill net 1 O O O O O
448 강수경ㆍ박정호ㆍ김수암 생물학적시료 재료및방법. 196 2,, (Danish seine,, ), (longline), (drift gill net) 1-17,., 196 197 (Fig. 3a), 197 (Fig. 3b). 196 197 198 (Table 1).,, (total length TL), (fork length, FL), (standard length). - (, 1 (a) Frequency (%) (b) 2 Frequency (%) 15 1 25 2 15 1 5 5 1 15 2 25 3 35 4 45 5 55 Fork length (mm) 1 15 2 25 3 35 4 45 5 55 Fork length (mm) n=385 mean=216mm n=1,198 mean=367mm Fig. 3. Length-frequency of walleye pollock Theragra chalcogramma caught from (a) Danish seine in 196s and 197s and (b) drift gill net fisheries in the early 198s. 3 ) 196 197 438 3 mm 385, 198 1,2 3 mm 1,198. 모델의개발 1-55 mm 5 mm. (1) TL, FL, BL,. (2) (random sampling) (Park et al.,),. - -. (3),.. 1 단계 : FL 자료의생산 TL, FL, BL, 2 6. - FL,., 6 TL, FL, BL (regression analysis) FL =.623 +.9367 TL (r 2 =.99) FL =.2677 + 1.623 BL (r 2 =.986) FL TL BL FL 2. 198. -, 1198 FL. 2 단계 : 체장 - 체중관계식 385 1,198, 1,583 1 body length(bl).
동해명태어획머릿수추정 449 (L)- (W) (W=aL b, a b ). 3 단계 : 체급별체중추정치와출현비율 -, (, 385 1,198 ) 5 mm (1-3 mm) (3-55 mm). W 1,j, W 2,j P 1,j, P 2,j. 4 단계 : 어획미수계산 (N) (B) (N 1 ), (N 2 ), (B 1 ), (B 2 ).. N = N 1 + N 2 B = B 1 + B 2, (j)., (B 1 ) B 1 = (W 1,j (N 1 P 1,j ) = (W 1,j P 1,j ) N 1 = k N 1 [ k= (W 1,j P 1,j )]. N 1 = B 1 / k N 1. B 1 gram., (N 1 ) (N 1,j ), (N 1 ) (P 1,j ) (N 1,j )., N 1 = N 1,j = (N 1 P 1,j ), (1-3 mm, 5 mm ) (N 1,j ). (N 2 ) (N 2,j ), (3-55 mm, 5 mm ). 결 과 385, 1,198 1,583. -, W=.55 L 3.11 (r 2 =.972, n=1583) (Fig. 4). Body weight (g) 9 8 y=.55x 3.11 7 r 2 =.9715 6 5 4 3 2 1 1 2 3 4 5 6 Fork length (mm) Fig. 4. Length-weight relationship on walleye pollock Theragra chalcogramma subsampled from Danish seine and drift gill net fisheries in Korean waters during the mid 196 through the early 198s. (FL) 124-515 mm 1.9-672. g. 1 mm, 3 mm. 35-4 mm,, 55 mm., 1 g, 2-4 g. 8 g. 5 mm. 3 mm. 1-15 mm 1.1% (Table 2a). 2-25 mm, 75.8%. 15-2 mm, 25-3 mm 8.6% 5.5%. 25-3 mm 5-6%, 2-25 mm (recruitment)., 515 mm, 5. 3-35 mm 28.8%, 35-4 mm 59.8% (Table 2b)., 5-55 mm.1%. -,. 1-15 mm 11. g, 2-25 mm 64.8 g. 25-3 mm 118.6 g. 2 g, 35-4 mm
45 강수경ㆍ박정호ㆍ김수암 Table 2. Estimated individual weight of walleye pollock Theragra chalcogramma at mid-length of each size-class, and the proportion of pollock at each size-class caught by (a) Danish seine and (b) drift gill net fisheries. Size-class (Fork length, mm) Mid-length (mm) Estimated weight (g) Proportion in sample Danish seine 1-15 125 11..11 15-2 175 3.4.86 2-25 225 64.8.758 25-3 275 118.6.55 Drift gill net fisheries 3-35 325 196.2.288 35-4 375 31.8.598 4-45 425 44..19 45-5 475 615..4 5-55 525 831.3.1 5-55 mm 31.8 g 831.3 g (Table 2).. 21.2, 3,7 (Table 3). 2-25 mm 198 7-15, 1,2. 197 198, 198 35-4 mm., 19.5, 1.7 21.2., 35-4 mm 2-25 mm, 1-15 mm 3-35 mm. 199-, 2-25 mm 6% (Table 3). 197 198.., - 85-94% (Fig. 5a), 97% (Fig. 5b). - 95.4 139.9 68.2% (Fig. 5c). 176 91.2% (Table 3)., 1.4. 199. 198 199 5%, 8%., 15% (Fig. 5c).,, 7, 37 (Fig. 5a-d). 토 의., 1945., Figure 2, -. -2,.,, 3 mm, 196-197.. 34 mm (Park et al., ; NFRDI, 21),. 197 (Huh, ),,. 197-199 (recruitment overfishing). 199..,. 2 mm, 2-25 mm, 35 mm
동해명태어획머릿수추정 451 (a) 1% 8% Adult (b) 1% 8% Adult Ratio (%) 6% 4% Ratio (%) 6% 4% 2% 2% (c) Catch (x1, ton) % 18 16 14 12 1 8 6 4 2 198 199 Total 198 199 Fig. 5. Catch variability of walleye pollock Theragra chalcogramma adult and juvenile in Korean waters. (a) Relative catches in ton, (b) Relative catches in number, (c) Absolute catches in ton, and (d) Absolute catches in number. (d) Number (million) 25 2 15 1 5 % 198 199 Total 198 199 (Fig. 6a).,, 95.6, 1-18 (Ianelli et al., 212),, 13.8, 18..,. (stable age distribution),.,,,... A Number (million) Number (million) 1,6 1,4 1,2 1, 8 6 4 2 - B 1,6 1,4 1,2 1, 8 6 4 2-1-15 15-2 2-25 25-3 3-35 35-4 4-45 45-5 5-55 Fork length (mm) 198 199 Fig. 6. Walleye pollock Theragra chalcogramma numbers estimated in size class and at recruitment size. (a) Length-frequency distribution of walleye pollock estimated in, and (b) recruitment variability of walleye pollock in the southwestern East Sea assuming the recruitment size at 2-25 mm.
452 강수경ㆍ박정호ㆍ김수암 Table 3. Estimates of walleye pollock Theragra chalcogramma numbers caught at each size class, - 1-15 mm 15-2 mm 2-25 mm 25-3 mm 3-35 mm 35-4 mm 4-45 mm 45-5 mm 5-55 mm Total 94,395,694 79,873,28 76,757,56 5,828,451 4,535,533 9,412,875 1,722,188 65,732 13,146 947,64,46 14,864,953 119,193,422 1,54,681,188 75,85,359 5,54,543 11,498,635 2,13,81 8,298 16,6 1,49,829,259 1977 177,91,341 15,539,519 1,332,46,652 95,797,876 18,565,716 38,53,587 7,49,591 269,68 53,814 1,82,763,162 158,724,751 134,35,558 1,188,4,699 85,467,174 11,283,887 23,418,154 4,284,66 163,535 32,77 1,66,81,72 116,294,294 98,42,864 87,716,254 62,62,5 11,74,473 24,291,22 4,444,37 169,63 33,926 1,188,676,775 198 116,492,224 98,57,344 872,198,193 62,726,582 28,84,341 58,285,184 1,663,99 47,19 81,44 1,247,59,22 197,169,31 166,835,562 1,476,241,945 16,168,85 5,233,528 14,252,771 19,74,18 728,22 145,64 2,12,848,999 169,337,911 143,285,924 1,267,863,331 91,181,952 38,375,27 79,642,458 14,571,455 556,162 111,232 1,84,925,632 96,8,144 81,237,66 718,83,25 51,696,693 29,612,836 61,457,364 11,244,294 429,172 85,834 1,5,62,22 113,932,781 96,44,661 853,35,179 61,348,42 39,866,738 82,737,925 15,137,85 577,779 115,556 1,263,156,844 64,922,848 54,934,717 486,89,12 34,958,456 46,452,252 96,45,253 17,638,391 673,221 134,644 82,28,796 55,425,65 46,898,589 414,981,455 29,844,557 46,843,866 97,217,995 17,787,91 678,897 135,779 79,813,835 23,132,252 19,573,444 173,195,32 12,455,828 2,142,163 41,82,287 7,648,184 291,915 58,383 298,299,776 4,934,67 4,175,437 36,946,291 2,657,96 13,334,867 27,674,681 5,63,384 193,259 38,652 95,18,275 14,385,78 12,172,583 17,78,914 7,746,189 15,77,469 32,729,436 5,988,27 228,558 45,712 196,775,846 199 28,199,95 23,861,496 211,138,88 15,184,589 9,788,36 2,314,394 3,716,74 141,86 28,372 312,373,848 17,26,888 14,65,367 129,235,366 9,294,324 1,94,59 2,948,83 3,832,817 146,291 29,258 25,447,199 8,61,437 7,278,139 64,4,52 4,631,543 9,494,649 19,74,837 3,65,215 137,64 27,521 117,881,447 12,911,54 1,925,149 96,671,18 6,952,368 9,34,13 18,749,37 3,43,341 13,929 26,186 158,83,67 5,362,888 4,537,828 4,152,92 2,887,79 7,597,518 15,767,62 2,884,855 11,19 22,22 79,323,431 3,859,641 3,265,85 28,897,825 2,78,268 6,896,28 14,312,131 2,618,56 99,945 19,989 62,48,418 6,526,581 5,522,492 48,865,686 3,514,313,44,627 9,215,99 1,686,151 64,357 12,871 79,848,987 1,552,729 1,313,848 11,625,562 836,85 6,366,73 13,213,271 2,417,512 92,271 18,454 37,436,462 Total 1,628,27,139 1,377,713,733 12,19,679,93 876,726,921 444,58,674 921,582,639 168,613,583 6,435,633 1,287,127 17,615,34,542 (Bailey, 2; Hollowed et al., 21; Hunt et al., 22), AIC (Akaike Information Criteria) (Park and Yoon, ).. (variability) (Fig. 6b),. 2-25cm 197 198., 198 8.7 7% 14.8, (interannual variability),.. Park et al.() FL-TL FL =.457 +.956 TL, (FL =.623 +.9367 TL), W=.655 L 2.988 W=.55 L 3.11.,. 3 mm,.,,. 사 사.. (213 ). 참고문헌 Bailey KM. 2. Shifting control of recruitment of walleye pollock Theragra chalcogramma after a major climatic and ecosystem change. Mar Ecol Prog Ser 198, 215-224. FAO. 27. FAO yearbook, Fishery statistics: Capture production, 25. FAO Fisheries Series No. 75, FAO Statistics Series No. 194, Food and Agriculture Organization of the United Nations, Rome, Italy. 539. FishBase. 213. Theragra chalcogramma (Pallas, 1814) Alaska pollock. Retrived from http://www.fishbase.org/summary/ Theragra-chalcogramma.html on July 4.
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