• 한국수산과학회지
• /
• 제53권1호
• /
• pp.50-56
• /
• 2020

Determination of the precise size at sexual maturity is very important for science-based stock assessment and fisheries resource management. In this study, two different models, (1) a visual method and (2) a gonadosomatic index (GSI) method, were employed to estimate length at sexual maturity of the small yellow croaker Larimichthys polyactis in the Yellow Sea of Korea. The visual method is a common qualitative method using visual gonadal identification. Conversely, the GSI method is a quantitative method using the GSI, which can be easily and precisely collected. We compared results from these methods to determine the best approach, and to examine the practicality of the GSI method. Logistic regression of the maturity ogive was conducted using a general linear model (GLM) with the R statistics program. Also, the bootstrapped 95% confidence intervals of all estimates were calculated. The best-fit model was the visual method (R_Mc²=0.805, AUC=0.989, L₅₀=15.1). Among models using the GSI method, the model computing GSI_ref=0.94 was the best-fit model (R_Mc²=0.792, AUC=0.989, L₅₀=15.2). There was no significant difference between the two models, evidencing the effectiveness and accuracy of the GSI method.

• 한국수산과학회지
• /
• 제22권5호
• /
• pp.306-316
• /
• 1989

우리나라 근해에서 어획되는 병어류의 어획물에 혼재된 "병어"와 "덕대"의 혼획비를 조사하고, 그중에서 양적으로 월등히 많은 것으로 확인된 덕대를 대상으로 실측 조사된 체급별 체장조성과 어체조사자료를 기초로 하여 자원해석을 실시하고 자원관리방안을 검토하였다. 병어류의 어획물중에서 덕대의 혼획비율은 중양비로써 $60\~70\%$를 차지하는 것으로 밝혀졌으며, 어획물의 체장조성은 FL 15 cm를 중심으로 한 단일 mode로 구성되고 체장조성의 연변동은 거의 없었으며, 연령조성은 1세어가 $41\~46\%$를 차지하며 다음으로 많은 조성비를 차지하는 것은 0세어로 나타났다. 현재의 자원특성치는 다음과 같이 추정되었다. 자연사망계수(M) : 0.6 어획사망계수(F) : 0.924($1986\~1988$년 값의 평균) 어장가입년령($t_r$) : 0.19 어획개시년령($t_c$) : 0.49 0세어의 어장가입률(Q) : 0.29 가입당어획이론에 의하여 이루어진 자원진단결과 어획개시연령과 어획사망의 두 가지 기준에서 볼 때 덕대의 현재 자원상태는 적정수준이하에 있으며, 어획강도의 조절에 의한 어획량증가효과는 거의 없으므로 최선의 관리방법은 어획강도의 조절보다 어획개시년령을 현재의 0.49로 부터 1.5세 부근까지 높이는 것으로 판단되었다.

• Ocean and Polar Research
• /
• 제25권4호
• /
• pp.483-491
• /
• 2003

Since the red grouper was declared overfished, the Gulf of Mexico Fishery Management Council must prepare a rebuilding plan considering the following alternative management policies: a Total Allowable Catch (TAC), 5-month season closure, 1800-pound trip limit, and a 50-fathom longline boundary. This study was aimed at evaluating the effects of proposed policies for rebuilding the red grouper stock in a 10-year period by developing a bioeconomic model. Under the assumption that the recreation sector was held to its share of TAC (24% of the total quota), the target stock biomass goal was attained in all policies. The NPV was the largest in the 5-month season closure policy if the output price did not fall. There were distributional effects on the different components of the fleets in the 1800-pound trip limit and the 50-fathom longline boundary policy.

• 수산경영론집
• /
• 제42권3호
• /
• pp.41-61
• /
• 2011

Marine protected Areas(MPAs) are specially designated zones of the sea that are designed to secure operation of ecosystem function and to restore marine ecosystem to the original state by excluding all detrimental human activities. MPAs have been proposed in many countries as means of realizing sustainable fisheries and recently MPAs are newly receiving attention as precautionary measure for global warming and climate change. The purpose of this paper is to examine the possibility of MPAs as fisheries management tools through a wide range of literature analysis and to suggest necessity of fisheries purpose of MPAs in Korea. Establishment of marine protected area can accompany various economic benefits such as restoration of marine environment, preservation of habitats, promotion of marine tourism and so on. Especially, a lot of case studies suggested that MPAs may bring out benefits to the fishing industry as a result of enhanced stocks. Fisheries benefits of MPAs on targeted species include increased abundance, increased mean individual size and age, increased reproductive output, enhanced recruitment inside and outside refuge, maintenance of genetic diversity of stocks, and enhanced fishery yields in adjacent fishing grounds, so called spill-over. MPAs for ecosystem conservation and protection of coastal wetland have been applied appropriately and effectively, however, the Korean MPAs system is still detective due to absence of fisheries purpose MPAs. Finally, suggestions for Korean MPAs can be summarized as following four recommendations; to establish number of small-scale MPAs rather than few large MPAs, to designate island and its surrounding areas as reserve, to consider MPA design with stock enhancement program, and to undertake co-management with Eochon-Gye, the traditional coastal community in Korea.

• 수산해양기술연구
• /
• 제56권1호
• /
• pp.26-36
• /
• 2020

Thousands of pelagic and demersal fishes inhabit the waters around Korea and many of them are overexploited. One of the reasons is technological development, which increases the efficiency of the vessels continuously. The analysis was conducted to identify the change of fishing power index to develop the vessel and gear technology that may have improved the fishing efficiency of the otter trawl fishery from 1960s to 2010s. Gross tonnage was decreased stably, but horse power was increased annually. The perimeter of net mouth was somewhat longer, but little changed. Color fish finder was utilized from the mid-1960s. Hydraulic net drum were introduced in the early 1990s, and supply rate was gradually increased. Surveys on the supply and upgrading of fishing equipment utilized visiting research. Therefore, the relative fishing power index in the trawl fishery increased about two to three times in the 2010s compared to the 1980s. The results are expected to contribute to reasonable fisheries stock management.

• Fisheries and Aquatic Sciences
• /
• 제23권5호
• /
• pp.13.1-13.7
• /
• 2020

Stock enhancement is considered to be a valuable approach for restoring fishery resources. Because no specific official institution in Taiwan is responsible for the production of fry, the released fry are purchased directly from the private sector. However, fishermen from the private industry have not established a genetic background, so the genetic composition for each batch of released fry is unclear. Mangrove red snapper (Lutjanus argentimaculatus), a prominent species released in Taiwan, was collected after its official release. One hundred and two field samples were compared with four batches of hatchery fry (n = 685) by using a microsatellite-based multiplex PCR assay. Four of the field samples (3.9%; 4/102) were revealed to be from a fish farm and most likely from a single batch. This study revealed that wild mangrove red snappers are genetically different from those originating from farms, and their origins can be traced through molecular markers, even without information on breeding stocks.

• 수산경영론집
• /
• 제35권2호
• /
• pp.117-137
• /
• 2004

지속적인 어업자원 이용에 대한 수산보조금의 역할을 분석한 기존 연구들은 단순히 세계 전체적이거나 국가별 총어업수입과 총어업비용만을 고려하여 잠정적으로 비용 절감형 또는 수입조장형 보조금이 어획노력량 수준을 증가시켜 어업자원의 감소를 부추기거나 남획을 초래했다고 결론짓고 있다. 또한 어업의 특성상 어업에 있어서 각종 규제수단이 사용되고 있음에도 불구하고 이들 수단들의 효과와 보조금과의 관계를 분석하지 못함으로써 어업자원에 대한 보조금의 영향을 명확하게 설명하지 못하였다. 본 연구에서는 어업에 있어서의 각종 규제수단의 사용에 따른 보조금의 영향을 국제적으로 권고되고 있는 생물경제모델을 이용하여 분석함으로써 보조금이 어업자원에 미치는 영향을 살펴보았다 분석결과에 따르면, 기존 연구들의 잠정적인 결론은 관리수단조치가 전혀 이루어지지 않거나, 이루어지더라도 불완전하게 어획노력량 등이 통제될 경우에만 타당한 것으로 나타났다. 반대로, 관리수단 하에서 어획노력량 등에 대한 감시 및 통제가 완벽하게 이루어질 경우에는 기존 연구결과와 달리 수산보조금이 어업자원에 부정적인 영향을 미치지 않는 것으로 분석되었다 오히려 일반적으로 부정적인 것으로 취급되는 보조금의 경우도 어업상황에 따라서는 어업자원에 대한 부정적인 피해 없이 어업에 긍정적인 영향을 줄 수 있는 것으로 나타났다.

• 한국어병학회지
• /
• 제26권2호
• /
• pp.99-110
• /
• 2013

수산종묘는 인류에게 중요한 동물성 단백질을 제공할 뿐만 아니라, 방류를 통한 수산자원 관리의 측면에서도 매우 중요하다. 수산자원의 증강을 목적으로 2009년에는 33품종, 2010년에는 44품종, 2011년에는 43품종, 2012년에는 46품종에 대해 수산생물전염병에 대한 감염 여부를 조사하였다. 검사품종 중에서 해면품종으로는 전복이 가장 많았으며, 그 다음 해삼, 넙치, 조피볼락, 꽃게 순으로 나타났다. 내수면품종 중에서는 붕어가 가장 많았으며, 그 다음으로 쏘가리, 대농갱이, 다슬기, 참게의 순으로 나타났다. 감성돔, 돌돔, 붉은쏨뱅이, 뱀장어는 4년 동안 지속적으로 검사 횟수가 감소하였다. 숭어에 대해서는 2009년에만 전염병 검사가 수행되었다. 8개의 검사 항목에 대해 총 8,476건의 검사가 실시되었으며, 56건 (0.67%)에서 koi herpesvirus, white spot syndrome virus, red sea bream iridovirus 또는 viral haemorrhagic septicemia virus와 같은 병원체가 검출되어 불합격 처리되었다.

• Animal cells and systems
• /
• 제14권4호
• /
• pp.305-313
• /
• 2010

Pacific abalone Haliotis discus discus is an important fisheries resource in Jeju, Korea. For basic information about its current genetic status in relation to stock enhancement, the level and distribution of genetic variation between wild and released stocks of Pacific abalone in Jeju were examined at nine cross-species microsatellite markers including the use of two novel primers. High levels of polymorphism were observed between the two populations. A total of 146 different alleles were found at all loci, with some alleles being unique. The allelic variability ranged from five to 27 in the wild population and from four to 16 in the released sample. The average observed and expected heterozygosities were estimated to be 0.74 and 0.84 in the wild sample and 0.70 and 0.78 in the released sample, respectively. Although a considerable loss of rare alleles was observed in the released sample, no statistically significant reductions were found in heterozygosity or allelic diversity in the released sample compared to the wild population. Low but significant genetic differentiation was found between the wild and released populations. These results suggest that the intensive breeding practices for stock enhancement may have resulted in a further decrease in genetic diversity, and that the cross-species microsatellite markers used in this study represent a potentially efficient means for further genetic studies, providing beneficial information for the protection and management of H. discus discus.

• Fisheries and Aquatic Sciences
• /
• 제27권4호
• /
• pp.256-264
• /
• 2024

Small pelagic fish populations have long been exploited by various fishing gears in the Natuna Sea, and since the 1970s, purse seine exploitation has expanded to offshore fishing grounds. Various small pelagic fish species are exploited from these waters including spotted sardinella (Amblygaster sirm). This research was conducted for 22 months, from March 2019 to December 2020. The fish sample was taken from the purse seine fleet's catch in the fisheries management area (FMA) 711 Natuna Sea and Karimata Strait, which was brought to Pemangkat fishing port in the West Kalimantan Province, Indonesia. This paper aims to determine the exploitation status of spotted sardinella in the Natuna Sea as a recommendation material for management policies. The methods used in this analysis are estimated age, cohort, population parameters, and spawning potential ratio of spotted sardinella. The results show three primary cohorts of spotted sardinella in the Natuna Sea, with ages ranging from 9 months to 3.1 years and a maximum attainable age (longevity) of 4.3 years. The asymptotic value (L_∞) is 21.79 cmFL in length, with a growth rate (K) of 0.65 per year. The natural mortality rate (M) was 1.19, the total mortality rate (Z) was 2.19, and the fishing mortality rate (F) was 0.99. The exploitation rate (E) was 0.45 and the stock status was still in a sustainable condition. Therefore, the sardinella fisheries can be developed using a precautionary approach and focus on the ecosystem sustainability of FMA 711.