• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.55 no.5
• /
• pp.751-757
• /
• 2022

To develop a trap to prevent the catch of juvenile rockfish Sebastes inermis and bycatch, we compared the fishing characteristics of four traps with different mesh sizes (35 mm and 50 mm) and flapper connecting lines (FCL) (3 lines and 4 lines).The number of rockfish caught in trap 1 (35 mm, 4 FCL) was 200, and juvenile rockfish (15 cm or less) accounted for 49.0%. The number of rockfish caught in trap 2 (35 mm, 3 FCL) was 185, and juvenile rockfish accounted for 58.9%. The number of rockfish caught in trap 3 (50 mm, 4 FCL) was 82, and juvenile rockfish accounted for 4.9%. The number of rockfish caught in trap 4 (50 mm, 3 FCL) was 68, and juvenile rockfish accounted for 22.1%. The total catch (bycatch rate) in trap 1, trap 2, trap 3 and trap 4 was 565 (64.6%), 637(71.0%), 260 (68.5%) and 276 (75.4%), respectively. The catch per unit effort (CPUE) for juvenile rockfish in trap 1, trap 2, trap 3 and trap 4 was 0.8, 0.9, 0.0, and 0.1 individuals/trap, respectively. The CPUE of bycatch in trap 1, trap 2, trap 3 and trap 4 was 2.9, 3.6, 1.4 and 1.7 individuals/trap, respectively.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.40 no.4
• /
• pp.295-303
• /
• 2004

In order to estimate the effect of ceramic artificial reefs on the fisheries resources enhancement, we have studied the variation of catch and species, which were caught by trammel net on the three fishing grounds of ceramic artificial reef, natural reef, and control(non-reef)in the coast of Geomun-do, Korea from 2001 to 2003. Catch per unit effort (CPUE ; g/panel) of fishing ground with the ceramic artificial reef area was 1,621.9g, it was about 67.9% higher than the natural reef area 333.3% higher than the control area. The catch of fish with the ceramic artificial and the natural reef area was not significantly different based on statistical analysis of Tukey test, whereas the relationship between the ceramic artificial reef and the control area was significantly different (p<0.05). Monthly mean number of species caught by the artificial reef area, the natural reef area and the control area was no difference by ANOVA test. The catch of fish was highest in November and lowest in May, whish was associated with the natural reef and the control area. The dominant species were demersal fishes living around rock such as Pagrus majir, Thamnaconus modestus, Stephanolepis sirrhifer, Pleuronichthys curntus, and Ostracion cubicus in the artificial reef area, but demersal of migratory fishes in the natural reef and the control area.

• Journal of Fisheries and Marine Sciences Education
• /
• v.20 no.3
• /
• pp.400-409
• /
• 2008

The purpose of this study is to examine annual changes of coastal fisheries production in the shore of Jeonbuk Province in Korea. The catch data of an experimental vessel that used dredge nets were used to study fish species and catch per unit of fishing effort carried out from April 2002 to November 2004. The total number of fish species caught in 2002 was 23, and 15 in 2004. Total number of individuals were 6,008 and their total weight was 376.38 kg in 2002. In 2004, total number of fishes was 2,469, and their weight was 211.99 kg. The annual changes in fisheries production in the western coast of Korea were also analyzed from 1990 to 2007. The total near shore fisheries products in Korea has been relatively stable around 1,4000,000 metric tons to 1,8000,000 tons during this period. Similarly the Chungnam Province's annual fish catch had steadily risen from about 51,187 tons in 1990 to 85,637 tons in 2007. However, Jeonbuk Province's annual fish catch declined dramatically at around 133, 000 tons in 1990 to 45,000 tons in 2007. In summery, while the overall Korea's fisheries production has been stable over the past decade, that of Jeonbuk Province suffered drastic decline in the period. This decline was reflected in the decreased number of fish species, total individuals, and total catch in surverys performed with an experimental vessel.

• Journal of Environmental Science International
• /
• v.12 no.11
• /
• pp.1137-1144
• /
• 2003

To provide evidence that the changes in oceanic environmental conditions are useful indices for predicting stock structure and distribution of the Pacific saury (Cololabis saira), the body length compositions and catch per unit fishing effort were examined in relation to the sea surface temperature(SST) anomalies in the Tsushima Warm Current(TWC) region. The size of the fish became larger(smaller) than the average in the same size category during the season of higher SST(lower SST) as opposed to the normal SST. The year-to-year changes in body size caused by the changes in the environmental conditions led the stock to be homogeneous during the period of high stock level from the late 1950s to early 1970s and in the 1990s. The changes in body size manifested by higher(lower) occurrence rates of larger (smaller) sized groups in relation to temperature anomalies suggest that the changes in the environmental conditions affect the distribution and the structure of the stock in the TWC region. Therefore, if the SST anomaly derived from satellite data is large enough in the early spring months(Mar. or Apr.), it is possible to predict whether or not sea temperature will be favorable for large sized groups of saury at normal or slightly earlier time of commencement of the fishery in spring(Apr.∼June).

• Journal of Marine Bioscience and Biotechnology
• /
• v.3 no.1
• /
• pp.31-37
• /
• 2008

Off the 1,572 km long coastline of Namibia lies known as the Benguela upwelling system, a very rich source of marine life supporting traditional and modern forms of fishery. Commercial fishing and fish processing is one of the fastest-growing sectors of the Namibian economy in terms of employment, export earnings, and contribution to GDP. The fishing industry has grown to the extent that it is currently Namibia's second biggest export earner of foreign currency after mining (90% of national output is marketed for export). In 2005, Namibia harvested about 552,164 tonnes of fish. The final value of processed products (export value) that year was around US$ 376.0 million. Besides the marine captured fisheries, Namibia also has a small but vibrant aquaculture sector. Inland captured fisheries exist in the north-east and north-west of Namibia where as commercial freshwater aquaculture of tilapia and catfish is also undertaken. The inland fisheries are mainly subsistence based and typically labour intensive, with low catch per unit effort. However the subsistence fisheries from these regions play a significant role in the lives of rural community. The domestic market for marine fish products is extremely limited due to the small size of the population (2 million). The fishing industry is a source of considerable employment for many Namibians. Huge potential to increase production exists in Namibia, unpolluted high quality marine waters, high natural primary productivity of the seawater, availability of inexpensive fish by-products from established fish processing sector for inclusion in wet aqua-feeds and well-established processing, packaging and marketing systems due to the marine capture fisheries that can be adopted for aquaculture purpose.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.54 no.5
• /
• pp.769-781
• /
• 2021

Given data about the annual fishery yield of the common squid Todarodes pacificus, and the catch-per-unit-effort (CPUE) data from multiple fisheries from 2000-2018, we applied a Bayesian state - space assessment model for the squid population. One of our objectives was to do a stock assessment, simultaneously incorporating CPUE data from the following three fisheries, (i) large trawl, (ii) jigger, and (iii) large purse seine, which comprised on average a year about 65% of all fisheries, allowing possible correlations to be reflected. Other objectives were to consider both observation and process errors and to apply objective priors of parameters. The estimated annual exploitable biomass was in the range of 3.50×10⁵ to 1.22×10⁶ MT, the estimated intrinsic growth rate was 1.02, and the estimated carrying capacity was 1,151,259 MT. Comparison with available results from stock assessment of independently analyzed single fisheries revealed a large difference from the estimated values, suggesting that stock assessment based on multiple fisheries should be performed.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.53 no.6
• /
• pp.954-959
• /
• 2020

This study aimed to verify the effectiveness of rescue apparatus, that can capture crabs using external stimuli such as food and electricity, without relying on divers. In this study, a microcomputer-based controller and an IC-device-based controller were developed, and spot inspection was conducted using 20 modules and 30 sea urchin removal modules. Accordingly, 58, 18, 17, and 74 sea urchins were introduced in the first, second, third and fourth experiments, respectively. The result of evaluating the lure of each removal mechanism, based on the catch per unit effort, with an electrical stimulus was 1.1 (32/10), with a feeding stimulus was 3.4 (100/29), and with electrical and feeding stimuli was 3.5 (35/10).

• Fisheries and Aquatic Sciences
• /
• v.24 no.4
• /
• pp.139-152
• /
• 2021

The main purpose of this study is to fit catch-per-unit-effort (CPUE) data about Korea chub mackerel (Scomber japonicus) stock with a state-space production (SSP) model, and to provide stock assessment results. We chose a surplus production model for the chub mackerel data, namely annual yield and CPUE. Then we employed a state-space layer for a production model to consider two sources of variability arising from unmodelled factors (process error) and noise in the data (observation error). We implemented the model via script software ADMB-RE because it reduces the computational cost of high-dimensional integration and provides Markov Chain Monte Carlo sampling, which is required for Bayesian approaches. To stabilize the numerical optimization, we considered prior distributions for model parameters. Applying the SSP model to data collected from commercial fisheries from 1999 to 2017, we estimated model parameters and management references, as well as uncertainties for the estimates. We also applied various production models and showed parameter estimates and goodness of fit statistics to compare the model performance. This study presents two significant findings. First, we concluded that the stock has been overexploited in terms of harvest rate from 1999 to 2017. Second, we suggest a SSP model for the smallest goodness of fit statistics among several production models, especially for fitting CPUE data with fluctuations.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.48 no.3
• /
• pp.242-255
• /
• 2012

The Nemopilema nomurai a very large jellyfish that has been found in the East China Sea and is now are migrating to Korea and Japan. To investigate the occurrence of N. nomurai based on the changing marine environment of the East China Sea, we conducted field survey in the early summer from 2006-2008. We observed the marine environment using CTD and the occurrence of N. nomurai using FMT and bottom trawling. We caught the most N. nomurai in 2007 and the fewest in 2008 and environment factors influencing its are more sensitive temperature than salinity. Large quantities of N. nomurai with a small bell diameter were caught in 2007 and large individuals with a significant bell diameter were caught in 2008. This appeared which between the catch and bell diameter of N. nomurai had (-) correlation (R=-0.988, p=0.098). Meanwhile, the spatial distribution of N. nomurai concentrations in lower salinity mixed seawater inflow in Changjiang Diluted Water.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.48 no.4
• /
• 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.