• 한국수산과학회지
• /
• 제46권4호
• /
• pp.445-453
• /
• 2013

Walleye pollock Theragra chalcogramma fisheries in Korean waters have changed dramatically during the last three decades: the highest catches occurred in 1981, followed by continuous decreases through the 1990s, ending with a complete collapse of the population in the 2000s. The major spawning ground of walleye pollock is located in North Korean waters, and some juveniles (called nogari in Korean, <300 mm) migrate to the south for feeding and growth. Since the 1960s, Korean fishermen have often caught juveniles, and the weight (metric tons) of juvenile catch was recorded from 1975-1997. 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 200-250mm size class, and the highest number of this size class occurred in 1981, although values greatly fluctuated interannually. The number of juvenile pollock was 10.4 times higher than that of adult pollock during 1975-1997. The total yield of juvenile pollock was 0.95 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.

• 한국수산과학회지
• /
• 제38권4호
• /
• pp.232-238
• /
• 2005

This paper describes reproduction, population structure, growth and size at sexual maturity of a deep-water mud shrimp (Solenocera melantho) in the adjacent waters of Geomun Island, Korea. The shrimp was caught by a beam trawl from November 1998 to December 1999. Spawning period was estimated by gonadosomatic index to be from August to early November with a peak in October to early November. Female shrimps were $12\%$ matured at 16 mm in carapace length, $33\%$ matured at 18 mm and $75\%$ matured at 22 mm. The size at $50\%$ maturity for female was estimated to be 20.65 mm in carapace length. Breeding season was estimated to be from August to early November with a peak in October to early November. The size at $50\%$ inseminated was 19.81 mm CL. The fecundity was 87,500-405,200 and related exponentially to carapace length and total weight. This species survived between 25 and 26 months. The maximum carapace length of females and males were 48 mm and 34 mm respectively. Sex ratio was $51.3\%$, and the females were preponderant. Growth was estimated by modified von Bertalanffy growth function incorporating seasonal variation in growth in both years females (K=1.019/yr and $L_{\infty}$=51.731 mm CL) grew faster, reaching a larger size at a given age than males (K=1.848/yr, and $L_{\infty}$=27.499 mm CL). This is indicated by differences in growth performance indices $(\varphi')$ between females (3.291) and males (3.145).

• 한국패류학회지
• /
• 제14권2호
• /
• pp.121-130
• /
• 1998

Studies on the distribution and growth of the mud mussel, Musculista senhousia, were carried out in the mud-tidal flat near Mokpo from August 1996 to July 1997. The patch distribution of the mussel was observed in the middle part of the tidalflat during the study period. Annual mean density was 8,215${\pm}$1,394 ind./m2 and annual mean biomass was 1,966.43${\pm}$668.49 g TWwt/m2 in total wet weight, 760.04${\pm}$279.13 gMWwt/m2 in meat wet weight, 209.93 ${\pm}$ 49.41 gMDwt/m2 in meat dry weight, and 109.66${\pm}$58.78 gAFDW/m2 in ash-free dry weight. The monthly mean size of shell length varied from 11.00 mm to 16.97 mm. Relationship between shell length (SL) and shell height (SH) showed a positively significant regression (SH=0.482SL+0.791, R2=0.940, P<0.001). Regressions of total wet weight (TWwt) (TWwt=7.601${\times}$10-5SL3.052, R2=0.905, P<0.001), and meat wet weight (MWwt) (MWwt=1.127${\times}$10-5${\times}$SL3.404, R2=0.784, P<0.001) on shell length were positively allometric, with highly significant correlation coefficient. The relationships between SL and meat dry weight (MDwt), and AFDW were MDwt=9.813${\times}$10-6${\times}$SL2.928 (R2=0.421), and AFDW=1.015${\times}$10-5${\times}$SL2.922(R2=0.810), respectively. The condition factor of the mussel has been increased from March and formed a peak in July and August. It was sharply dropped in September. These results suggest that the gonadal development of the species commenced to be occurred in spring and that main spawning occurred between August and September.

• 한국어류학회지
• /
• 제18권4호
• /
• pp.355-362
• /
• 2006

본 연구에서는 2003년 4월부터 2004년 3월까지 우리나라 동해안 강원도 양양군 현남면 남애리 연안에서 어획된 참가자미의 연령과 성장에 관하여 조사하였다. 연령형질로서는 이석을 사용하였고, 윤문형성시기는 3~5월로 산란시기와 일치하였으며, 연간 1회 형성되어 윤문을 연륜으로 간주하였다. 비선형 회귀방법으로부터 추정한 참가자미의 von Bertalanffy 성장식은 암컷이 $L_t=37.2$ ($1-e^{-0.131\;(t+2.008)}$)이었고, 수컷은 $L_t=28.3$ ($1-e^{-0.177\;(t+2.135)}$)으로, 암수간에 성장의 차이가 있었다.

• 한국어류학회지
• /
• 제17권2호
• /
• pp.105-111
• /
• 2005

A. signifer의 숙주 조개인 U. douglasiae sinuolatus 각 장이 30~45 mm에서 대부분의 알과 자어가 발견되었으며, 각장이 30 mm 이상에서는 크기에 따른 선택성의 차이는 없었다. 조개 내에서 발견된 난 및 전기자어의 수는 1~7개(마리)이었으며, 난 또는 자어의 보유율은 1개(마리)가 50.0%로 가장 높았고, 조개 1개체 당 평균 보유수는 2.5개 (마리)였다. A. signifer의 전기자어는 조개내에서 유영능력을 갖추면 상새방으로 이동하였으며, 상새방에서 성장기간은 4~6주 정도로 추정되었다. 전기자어의 표피상 돌기는 부화 직후부터 관찰되었다. 부화 7일째부터 표피상돌기의 흡수가 진행되기 시작하였으며, 부화 13일째부터 대부분의 표피상돌기는 흡수되었고, 난황이 완전히 흡수된 직후인 부화 20일 후에는 표피상돌기가 완전히 흡수되었다.

• 한국수산과학회지
• /
• 제45권3호
• /
• pp.246-252
• /
• 2012

The age and growth of the blackthroat seaperch Doederleinia berycoides was investigated based on samples captured in the southern seas of Korea from January to December, 2006. Age was estimated by analyzing otolith growth rings. The spawning period was extrapolated from August to November based on monthly changes in the gonad somatic index. The relationship between total length and otolith radius was analyzed separately for each sex with TL=-15.6174+10.3274R for females and TL=-4.4083+7.0749R for males. From the parameters calculated using average total length and weight when the year ring was formed, the growth of D. berycoides was expressed by von Bertalanffy growth equations as $L_t=34.71(1-e^{-0.2557(t+0.2078)})$, $W_t=713.85(1-e^{-0.2557(t+0.2078)})^{3.1972}$ for females, $L_t=27.37(1-e^{-0.3388(t+0.7362)})$, $W_t=353.91(1-e^{-0.3388(t+0.7362)})^{3.1647}$ for males, and $L_t=34.20(1-e^{-0.2530(t+0.2871)})$, $W_t=674.10(1-e^{-0.2530(t+0.2871)})^{3.1171}$ for pooled sexes, where L is total length at age t.

• 한국어류학회지
• /
• 제29권1호
• /
• pp.80-86
• /
• 2017

본 연구는 남해 중부 연안역에서 2016년 4~8월까지 자어군집구조의 월 변화를 조사하였다. 조사기간 동안 총 42종의 자어가 출현하였다. 우점종 중 멸치(E. japonicus)는 여름보다는 봄철에 우점하였고, 용서대(C. abbreviates)는 봄철에만 출현하였으며 수조기(N. albiflora)는 여름철에만 출현하였다. 자어 군집은 계절별로 4~5월 (봄)과 6~8월 (여름)의 그룹으로 유의하게 나눌 수 있었고, 여름철은 또다시 6~7월과 8월의 두개의 유의한 그룹으로 나눌 수 있었다. 2016년 8월 조사해역에서는 이상 고수온 현상이 발생하여 표면수온이 $28^{\circ}C$까지 상승하였고, 멸치와 수조기 자어의 출현량은 산란 적정수온을 넘은 수온으로 인해 급감하였다.

• 한국양식학회지
• /
• 제9권1호
• /
• pp.3-10
• /
• 1996

인간의 태반성 성선자극호르몬(HCG) 또는 성선자극호르몬-방출호르몬 유도체(GnRH-A)와 pimozide를 이용하여 산란시기의 암컷황복에서 인공 산란을 유도하였다. 호르몬 또는 호르몬유도체의 효과는 배란 후 인공수정시켜 수정율과 배체형성율 및 면역방사측정법으로 혈액의 plasma 내 성선자극호르몬(GTH) 양을 측정하여 결정하였다. 수정율과 배체형성율이 가장 좋은 HCG 농도는 어체중 kg 당 1,000 IU이었다. 또한 GnRH-A ($10\;{\mu}g/kg$)와 pimozide를 동시에 처리했을 때 수정율과 배체형성율이 좋은 pimozide의 농도는 5 mg/kg이었다. Pimozide(1, 5 mg/kg)를 단독으로 처리한 어류에서는 plasma 내 GTH양에 영향을 줄 수 없었지만, GnRH-A와 동시에 처리했을 때 GTH양은 현저히 증가되었다. GnRH-A와 pimozide 및 dopamine을 동시에 처리했을 때 혈액의 plasma 내 GTH양은 크게 감소되었다. 이상의 결과는 산란시기 또는 이시기이외에 황복의 뇌로부터 여러 가지 성선자극호르몬과 성선자극억제호르몬을 분비됨을 시사해 준다.

• 한국수산과학회지
• /
• 제3권2호
• /
• pp.117-119
• /
• 1970

1967년 11월부터 1968년 12월까지 사이에 부산부근의 낙동강 유역인 선암, 가락, 성산, 하단에서 채집된 체장 7cm부터 33cm까지 사이의 풀망둑 Synechogobius hasta (TEMMINCK et SCHLEGEL) 1,050개체를 재료로 체장$\cdot$체중의 상관 관계를 조사하였다. 1) 전 개체에서 체장의 신장에 따른 체중의 회귀를 식으로 표시하면 $Y=0.09863X^{2.17926}$이였다. 2) 체장 20.5cm부터 27.5cm까지 사이에서는 성숙자 산란의 영향으로 정상적인 상대 성장을 보이지 않는다 (Fig. 1). 3) 체장 7.5cm부터 19.5cm까지의 상대 성장은 $Y=0.04995X^{2.472l6}$, 체장 28.5cm부터 32.5cm까지의 상대 성장은 $Y=0.0004127X^{3.67265}$으로 표시되었다.

• 한국수산과학회지
• /
• 제48권6호
• /
• pp.929-939
• /
• 2015

We studied the characteristics of age and growth of the Goldeyes rockfish Sebasetes thompsoni in the Ulleungdo and Dokdo areas by using 730 otoliths from February 2013 to February 2014. The lowest value of the marginal index was found in June once a year. The spawning period was estimated as April. Therefore, the duration from fertilization to the complete formation of the first annual growth ring is fourteen months. From the parameters calculated using the weighted average length of the year ring formation, the growth of S. thompsoni was demonstrated by the von Bertalanffy growth equation as $L_t=34.68(1-e^{-0.2113(t+0.7683)})$ for females and $L_t=29.79(1-e^{-0.2163(t+1.7964)})$ for males, $L_t=32.84(1-e^{-0.25(t+0.57)})$ for combined sex. Comparing with growth performance index(${\Phi}$) from these 4 offshore areas, parameter of S. thompsoni in Ulleungdo area was 2.4087, that of in Tong-yeong was 2.2835, that of in Aomori was 2.4077 and in Niigata was 2.3927. As a result, the value of Dokdo and Ulleungdo areas showed the highest.