• 수산해양기술연구
• /
• 제49권3호
• /
• pp.261-269
• /
• 2013

The age and growth of the Pacific cod, Gadus macrocephalus were investigated using left sagittal otoliths of 682 individuals collected in the West Sea of Korea from January to December 2007. The seasonal changes in the ratio of an opaque zone to interval between annular rings revealed that the narrow translucent parts of the otolith were annual growth rings formed between February and March once a year. The spawning period was December to January and therefore the duration from fertilization to the complete formation of the opaque zone became thirteen months. From the parameters calculated using the average length when the year ring was formed, the estimated von Bertalanffy growth equations were $L_t=100.0(1-e^{-0.1640(t+0.5247)})$ for females and $L_t=64.6(1-e^{-0.3335 (t+0.3342)})$ for males when is total length in age t.

• 한국수산과학회지
• /
• 제42권5호
• /
• pp.487-493
• /
• 2009

Available ecological and fishery data of sailfin sandfish, Arctoscopus japonicus, was examined to ascertain its population dynamic parameters in Korean waters. The instantaneous coefficient of total mortality (Z) was estimated to be 1.361/yr, and annual survival rate (S) was 0.256. The estimated instantaneous coefficient of natural mortality (M) was 0.482/yr, and the instantaneous coefficient of fishing mortality (F) for recent years was calculated to be 0.879/yr from Z and M values. Age at first capture was estimated to be 1.958 years. These parameters, in conjunction with catch landings data between 1991 and 2008, were used to estimate annual biomass using a biomass-based cohort analysis. The biomass of A. japonicus was estimated at approximately 7,600 mt in 1991, but since 1994 decreased to below 4,000 mt by 2001. After 2002 they started to increase gradually, and showed the level of more than 5,000 mt in recent years.

• 한국수산과학회지
• /
• 제42권6호
• /
• pp.633-641
• /
• 2009

Maturity and spawning of the atka mackerel, Pleurogrammus azonus, was investigated based on the samples collected by gill net and set net in the East Sea from January 2006 to March 2009. Gonadosomatic index (GSI) began to increase in October, and reached a maximum between November and December. After spawning GSI began to decrease from January. The spawning period was from October to January, and main spawning period was from November to December. Annual reproductive cycles of this species could be divided into five successive stages in females; early growing stage (June), late growing stage (July to August), mature stage (September to October), ripe and spent stage (November to January), and recovery and resting stage (January to May). Males showed four successive stages: growing stage (June to August), mature stage (September to October), ripe and spent stage (October to December), and recovery and resting stage (January to May). P. azonus could be one of polycyclic species spawning two times or more during one spawning season. Number of total and mature eggs in the fecundity were proportional to fork length. The fork length at 50% group maturity was estimated to be 26.9 cm.

• Bulletin of the Korean Chemical Society
• /
• 제34권8호
• /
• pp.2408-2412
• /
• 2013

We demonstrate herein the synthesis and modification of magnetic nanoparticles and its use in the immobilization of the lipase. Magnetic $Fe_3O_4$ nanoparticles (MNPs) were prepared by simple co-precipitation method in aqueous medium and then subsequently modified with tetraethyl orthosilicate (TEOS) and 3-aminopropyl triethylenesilane (APTES). Silanization magnetic nanoparticles (SMNP) and amino magnetic nanomicrosphere (AMNP) were synthesized successfully. The morphology, structure, magnetic property and chemical composition of the synthetic MNP and its derivatives were characterized using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) analysis, X-ray diffraction, superconducting quantum interference device (SQUID) and thermogravimetric analyses (TGA). All of these three nanoparticles exhibited good crystallization performance, apparent superparamagnetism, and the saturation magnetization of MNP, SMNP, AMNP were 47.9 emu/g, 33.0 emu/g and 19.5 emu/g, respectively. The amino content was 5.66%. The AMNP was used to immobilize lipase, and the maximum adsorption capacity of the protein was 26.3 mg/g. The maximum maintained activity (88 percent) was achieved while the amount of immobilized lipase was 23.7 mg $g^{-1}$. Immobilization of enzyme on the magnetic nanoparticles can facilitate the isolation of reaction products from reaction mixture and thus lowers the cost of enzyme application.

• 수산해양교육연구
• /
• 제10권2호
• /
• pp.162-183
• /
• 1998

The fisheries resources control system in the Fisheries Act of Korea is introducing technical management method and input control method that controls fishing effort. Fishing effort control system of Korea aiming at realizing the maximum sustainable yield does not regulating the limitation of fishing quota and the limitation of fisheries object target fish. Therefore fishing operators who have fishing permit can use fishery resources without any restriction of fishing quota. But there are no rules that can controlling capacity of productivity of fishing by developing of fishing technic and fishing gear. For those reasons, productivity of fishing is superior to reproductivity of fisheries resources. Therefore, the Fisheries Act of Korea rearranges a legal basis for an introduction of fisheries resources management system by TAC, but the contents to be possible for a legal guarantee is not included and it is exceedingly defective as abstract and institutional devices. And that the affairs to be required for an enforcement of the said regime was placed in an administrative mandatory legislation and the danger to be degenerated is high in accordance with the bureaucratic self-righteous and/or the coercion of group's interest concerned and accordingly its substitute legislation system is keenly required. TAC system that is going to be introduced in our country is expected to enforce the Olympic fishing method and the individual quota method in parallel. This method is not certainly proper, because it occurs to overcapitalize and to compete fishing amounts between fishery operators. So as to prevent overcapitalization and fishing competition between fishery operators, and the exhaustion of coastal fisheries resources, individual transferable quota system should be introduced in Korean sea. Accordingly this thesis has attempted to constitute a view to improving problems of the traditional fisheries resources control system and introducing TAC fisheries resources control system.

• 수산해양기술연구
• /
• 제48권4호
• /
• pp.401-414
• /
• 2012

Distribution pattern and fishing conditions of sandfish, Arctoscopus japonicus in the East Sae were explored using catch and catch per unit effort (CPUE) by eastern sea Danish seine and coastal gill net fisheries from 2004 to 2008. A. japonicus was one of major target species for the eastern sea Danish seine and coastal gill net fisheries in the East Sea, which were caught from April to October for the eastern Danish seine, and from October to December for the coastal gill net, respectively. In recent, the distribution and centroid of fishing ground moved northward, as seawater temperature increased. The species spawned in the coastal areas of Gangwon, northern East Sea, during winter, started to move to deeper water after spawning from spring, extended widely from Gangwon to Ulsan, southern East Sea, during summer, and migrated back to the spawning ground off Gangwon during autumn.

• 한국수산과학회지
• /
• 제53권1호
• /
• pp.9-18
• /
• 2020

We investigated the maturity and spawning dynamics of chub mackerel Scomber japonicus in Korean waters using samples collected by a large purse seine fishery from January 2013 to December 2017. We analyzed sex ratio, monthly maturity stage, gonadosomatic index (GSI), Fulton's condition factor (K), and fork length at 50% group maturity. Spawning occurred from March to June, with a peak in May. We detected a significant difference in sex ratio (χ² test, P<0.05). The relationship between fork length and body weight was expressed as BW=0.0025FL^3.4693. We estimated 50% group maturity at a female fork length of 29.3 cm.

• 한국수산과학회지
• /
• 제54권1호
• /
• pp.53-63
• /
• 2021

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.

• Fisheries and Aquatic Sciences
• /
• 제12권3호
• /
• pp.236-239
• /
• 2009

We describe Ophichthus asakusae from Korea based on a single specimen (426.0 mm TL) collected from the southern sea off Jeju Island. The species is characterized by a pointed, hard, sponge-like tail tip without a caudal fin and 126-132 total vertebrae. We propose a new Korean name, "Je-ju-ba-da-baem" for the species.

• 한국수산과학회지
• /
• 제53권1호
• /
• pp.103-106
• /
• 2020

We investigated the biological maturation of blackthroat seaperch Doederleinia berycoides in southern Korea waters, based on samples collected from March 2018 to February 2019. We analyzed monthly changes in maturity stage, gonadosomatic index (GSI) and total length (TL) at 50%, 75% and 97.5% group maturity. The spawning period was May to October in 2018. We estimated the TL at 50% group maturity as 27.0 cm for females in 2018. We estimated the TL of females at 75% and 97.5% group maturity as 28.7 cm and 32.7 cm, respectively, in 2018.