• Title, Summary, Keyword: Catch per Unit Effort

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Catch per Unit Effort and Size Composition of Crayfish, Astacus leptodactylus Eschscholtz 1823, in Lake İznik

  • Balik, Ismet;Ozkok, Ergun;Ozkok, Remziye
    • Asian-Australasian Journal of Animal Sciences
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    • v.15 no.6
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    • pp.884-889
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    • 2002
  • This paper was carried out from 15 June to 24 December in 2000 in Lake İznik of Turkey, to determine catch per unit effort (CPUE) and size composition of crayfish, Astacus leptodactylus Eschscholtz 1823, captured by fyke-nets of local fishermen. The average CPUE of all size groups was found as 1.65 crayfish/fyke-net/night for fishing season in 2000, but 26.4% of which was below the legal minimum size (crayfish<90 mm). The average CPUE of legal-sized (crayfish$\geq$90 mm) crayfish was 1.10 crayfish/fykenet/night. The annual catch of crayfish was estimated as 2990 tonnes. The length and weight compositions of crayfish captured in the fyke-nets have varied between 60 and 130 mm, and 6 and 71 g, respectively. The mean length and weight were found as 95.5 mm and 28.8 g for all size groups and 100.1 mm and 33.0 g for legal-sized individuals.

Trawl Fishing of Alaska Pollack in the Northwestern Pacific (북서태평양 트로올 어장의 명태어항)

  • Sung, Byung-Oun;chang, sun-duck
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.11 no.1
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    • pp.15-20
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    • 1975
  • The catch per unit effort and the migration of Alaska pollack Theragra chalcogramma were deduced from the catch data of 1, 208 hauls of a stern trawler operated on and around the continental shelf east of the Kamchatka Peninsula and Kurile Islands from October 1974 to December 1975. Alaska pollack occupied more than ninety per cent of the total catch of approximately 17, 760 metric tons, while the cuttle and flat fishes occupied less than five percent. Beside those fishes, approximately 131 metric tons of Alaska pollack roe were produced during the voyage from February to April 1975. The mean catch per unit effort in each sub-area of fishing ground was approximately 15.5 metric tons and the peak of the CPUE occured in January and August. The CPUE in the continental shelf east of Kamchatka Peninsula ($50^{\circ}- 52^{\circ} N$ Lat) showed the maximum of 25-34 metric tons in August. The main fish school is thought to migrate southward speedily in August-September along the continental shelf from the Kamchatka Peninsula to the east of Kurile Islands. The CPUE on the continental shelf east of Kamchatka Peninsula was higher than that on the steeper continental slope. However, the CPUE on the steeper flank of the bank east of Paramushiru Island and Onekotan Island was remarkably higher than that on the relatively flat top of the bank. The small-sized fishes of less than thirty centimeter in fork length began to recruit in the fishing ground since August 1965.

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Species composition and abundance of fishery resources collected by gill net, trap net, and longline near Oenarodo, Go-heung Peninsula, Korea (고흥 외나로도 연안에서 자망, 통발, 주낙에 어획된 어족생물의 종조성 및 어획량 변동)

  • YOON, Eun-A;HWANG, Doo-Jin;MIN, Eunbi;CHO, Nam-Kyung;HAN, Yeoung-Min
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.53 no.3
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    • pp.246-255
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    • 2017
  • The species composition and variation in abundance of fishery resources near Oenarodo, Go-heung Peninsula, Korea, were investigated by gill net, trap net, and longline in May, July, and October 2015 and 2016. During the study period, the total catch included 14 species in the gill net, 11 species in the trap net, and 4 species in the longline. The dominant species were Portunus trituberculatus and Raja pulchrain the gill net, Charybdis japonicaand and Octopus vulgarisin in the trap net, and Muraenesox cinereusin in the longline. The Catch Per Unit Effort (CPUE) per individual and per weight in the gill net were similar in May and July of 2015 and 2016. In October 2015, the CPUE per individual was 2.1 ind./h and the CPUE per weight was 505 g/h higher than the results in 2016, but there was no significant difference in the total CPUE between 2015 and 2016. In the trap net, the CPUE per weight was similar in both 2015 and 2016, but the CPUE per individual was 2.7 ind./h higher in October 2015 than in October 2016 and the total CPUE was not significantly different from 2015 to 2016. The CPUE per individual and weight in the longline were significantly higher in July and October 2015 than in the same months of 2016, but the total CPUE in 2015 and 2016 did not show a significant difference.

Distribution Characteristics of Fishes by a Bottom Trawl in the Jointly Controlled Waters of the East China Sea (동중국해 한일공동수역에서 저서 어획물의 분포특성)

  • Kim, Min-Seok;Kim, Dong-Su
    • Journal of Fisheries and Marine Sciences Education
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    • v.22 no.3
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    • pp.330-340
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    • 2010
  • This study was investigated the species composition of demersal fishes by a bottom trawler GAYA, in order to be used basic data for resources management of fishery in the jointly controlled waters of the East China sea. We caught 52 species, 1,167 individuals and 186.171kg in biomass in summer, and 1,924 individuals and 200.871kg in biomass in winter The first dominant species in individuals in summer was Glossanodon semifasciatus, and in biomass was Dentex tumifrons. But that in winter was Ovalipes punctatus in both individuals and biomass. It was a special phenomenon that crustacea was to be the first dominant species compared with general offshore fishery in Korea. Catch per unit effort (kg/hr) of bottom trawl in winter was higher than that in summer. There was also big difference by station in the diversity index, the evenness index and the dominant index.

Estimation on Optimum Fishing Effort of Walleye Pollock Fishery in the East Coast of Korea : Based on the Economic Analysis between Danish Seine Fishery and Trawl Fishery for Walleye Pollock (한국 동해 명태 어업의 적정어획노력량 추정 -동해구기선저인망어업과 동해구트롤어업의 경제성분석을 근거로-)

  • 이장욱
    • The Journal of Fisheries Business Administration
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    • v.22 no.2
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    • pp.75-99
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    • 1991
  • A quantitative analysis was carried out to monitor the commercial yield level of walleye pollock Theragra chalcogramma in the east coast of Korea, based on available data on catch and fishing effort, catch per unit of effort including fish prices from 1911 to 1988, using a traditional yield model. The results from the quantitative assessment were based to estimate maximum economic yield (MEY) and optimal fishing effort (E-opt) at MEY. On the other hand, interaction aspects between danish seine fishery and trawl fishery mainly targeting walleye pollock in the east coast of Korea were studied to predict optimal situation in fishing effort level from economic point of view which gives the most benefits to the two fisheries. Total production of walleye pollock in 1911 when its catch record was begun for the first time was about 12, 000 metric tons(M/T), and then the catch trend maintained nearly at the level of 50, 000 M/T per annum, showing a decreasing trend until 1930. The highest production from historical data base on walleye pollock fishery statistics was from the years in 1939 and 1940, about 270, 000 M/T and 26, 000 M/T, respectively. No production of the fish species was recorded during the years from 1943 to 1947, and from 1949 to 1951. From 1952 onwards annual production was only available from the southern part of 38$^{\circ}$N in the east coast. During two decades from 1952 to 1970, the production had sustained about less than 30, 000 M/T every year. Annual production showed an increasing trend from 1971, reaching a maximum level of approximately 162, 000 M/T in 1981. Afterwards, it has deceased sharply year after year and amounted to 180, 000 M/T in 1988. The catch composition of walleye pollock for different fishery segments during 1970~1988 showed that more than 70% of the total catch was from danish seine fishery until 1977 but from 1978 onwards, the catch proportion did not differ from one another, accounting for the nearly same proportion. Catch per unit of effort (CPUE) for both danish seine fishery and trawl fishery maintained a decline tendency after 1977 when the values of CPUE were at level of 800 kg/haul for the former fishery and 1, 300 kg/haul for the latter fishery, respectively. CPUEs of gillnet fishery during 1980~1983 increased to about 3.5 times as high value as in the years, 1970~1979 and during 1987~1988 it decreased again to the level of the years, 1970~1978. The bottom longline fishery's CPUE wa at a very low level (20 kg/basket) through the whole study years, with exception of the value (60 kg/basket) in 1980. Fishing grounds of walleye pollock in the east coast of Korea showed a very limited distribution range. Danish seine fishery concentrated fishing around the coastal areas of Sokcho and Jumunjin during January~February and October~December. Distributions of fishing grounds of trawl fishery were the areas along the coastal regions in the central part of the east coast. Gillnet and bottom longline fisheries fished walleye pollock mainly in the areas of around Sokcho and Jumunjin during January~February and December. Relationship between CPUEs' values from danish seine fishery and trawl fishery was used to standardize fishing effort to apply to surplus production model for estimating maximum sustainable yield (MSY) and optimum fish effort (F-opt) at MSY. The results suggested a MSY of 114, 000 M/T with an estimated F-opt of 173, 000 hauls per year. Based on the estimates of MSY and F-opt, MEY was estimated to be about 94, 000 M/T with a range of 81, 000 to 103, 000 M/T and E-opt 100, 000 hauls per year with a range of 80, 000 to 120, 000 hauls. The estimated values of MEY and E-opt corresponded to 82% of MSY and 58% of F-opt, respectively. An optimal situation in the fishing effort level, which can envisage either simultaneously maximum yield or maximum benefit for both danish seine fishery and trawl fishery, was determined from relationship between revenue and cost of running the fleet : the optimal fishing effort of danish seine fishery was about 52, 000 hauls per year, corresponding to 50 danish seiners and 27, 000 hauls per year which is equal nearly to 36 trawlers, respectively. It was anticipated that the net income from sustainable yield estimated from the respective optimal fishing effort of the two fisheries will be about 3, 800 million won for danish seine fishery and 1, 000 million won for trawl fishery.

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Standardization of Catch per Unit Effort (CPUE) for Yellow Croaker (Larimichthys polyactis) in the East China Sea (동중국해 참조기자원에 대한 단위노력당어획량(CPUE)의 표준화)

  • Lee, Dong-Woo;Lee, Jae-Bong;Kim, Yeong-Hye;Jung, Suk-Geun
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.41 no.5
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    • pp.346-352
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    • 2008
  • Yellow croaker (Larimichthys polyactis) is a major target species of large pair trawl fishery in the East China Sea. To standardize catch per unit effort (CPUE) of yellow croaker for the large pair trawl fishery, generalized linear model (GLM) was applied to evaluate and eliminate the influence of the explanatory factors (year, month, horse power and gross tonnage of vessel) on daily catches per boat collected and compiled by National Fisheries Research and Development Institute (NFRDI) from 1990 to 2007 at the fishery auction places of Busan, Masan and Incheon in Korea. Results of GLM showed that all of the factors significantly influenced on CPUE, explaining 36% of the total deviance. The standardized CPUE indicated that the abundance of yellow croaker in 2000's was 1.7 times higher than the CPUE in 1990's.

Distribution Characteristics Composition of Fishes by a Bottom Trawl in the Jointly Controlled Waters of the East China Sea (한·중 공동수역에서 저층트롤 어획물의 조성)

  • Kim, Min-Seok;Kim, Dong-Su;Kim, Min-Son;Lee, Jong-Gun;Kim, Jong-Hwa;Kang, Il-Kwon
    • Journal of Fisheries and Marine Sciences Education
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    • v.23 no.2
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    • pp.141-152
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    • 2011
  • This study was investigated the species composition of demersal fishes by a bottom trawler GAYA, in order to be used basic data for resources management of fishery in the jointly controlled waters of the West sea. We caught 39 species, 5,532 individuals and 322.518kg in biomass. The number of species was the fewest of the jointly controlled waters of the East china sea and boundary zone between Busan and Tsushima. The first dominant species in individuals in summer was Oregonia gracilis, and in biomass was angler. But angler was the first dominant species in 7 stations of 12 stations. It was a peculiar phenomenon that cod which lives in a cold current was caught in the northern part of the West sea. In this connection it seems to be needs for oceanographic research. Catch per unit effort (kg/hr) of bottom trawl was the higher in northern part and in right line of all surveyed area respectively.

A Variation of Fishes Catched by the Bottom Trawl in the Boundary Zone between Busan and Tsushima (부산-대마도 경계수역에서 저층트롤 어획물의 변동)

  • Kim, Min-Seok;Kim, Dong-Su;Kim, Min-Son;Lee, Jong-Gun
    • Journal of Fisheries and Marine Sciences Education
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    • v.22 no.3
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    • pp.341-353
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    • 2010
  • Authors investigated the species composition of fishes for about 13months in the boundary sea water between Busan and Tsushima. We caught 81 species, 1,603 individuals and 437.7kg in biomass. The first dominant species by seasons were common squid, angler, angler and Psenopsis anomala respectively. Angler was also the first dominant species in biomass for four seasons. Catch per unit effort (kg/hr) was the highest in winter and the lowest in summer. But there was a little difference in accordance with station compared with season. There was big difference by season in the diversity index, the evenness index and the dominant index. But there was little difference between above indexes. The total length of common squid was the tallest in autumn and winter, that of blackthroat seaperch was the tallest in autumn and the lowest in winter. But angler's total length was almost same all through the year.

Standardization of Catch per Unit Effort (CPUE) for Bigeye Tuna (Thunnus obesus) by the Korean Longline Fishery in the Pacific Ocean (한국 다랑어 연승어업에 의한 태평양해역 눈다랑어 자원의 단위노력당어획량 (CPUE)의 표준화)

  • Yoo, Joon-Taek;Hwang, Seon-Jae;An, Doo-Hae;Kim, Jong-Bin;Kim, Zang-Geun
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.43 no.6
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    • pp.740-746
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    • 2010
  • This study standardized the catch per unit effort (CPUE) of bigeye tuna (Thunnus obesus) caught by the Korean longline fishery in the Pacific Ocean. The study used a general linear model (GLM) to standardize the CPUE using catch and effort data aggregated by year, month, and $5{\times}5$ degrees of latitude and longitude in the tropical Pacific Ocean from 1982 to 2008 (except for 1988 and 1989). Explanatory variables in the GLM analysis included year, month, subtropical area, and number of hooks between floats (HBF). The study area and HBF were subdivided into three subtropical areas and six classes, respectively. During the study period, the standardized CPUE was significantly related to the nominal CPUE. The standardized CPUE declined sharply, as compared to the nominal CPUE, after the mid 1990s. In particular, the decline in the standardized CPUE in all subtropical areas in the 2000s was clearer than that of the nominal CPUE.

A Life Stage-based Model for Assessing the Walleye Pollock Gadus chalcogrammus Population in the East Sea (생활사 기반 모델을 이용한 동해 명태(Gadus chalcogrammus)의 개체군 평가)

  • Kim, Kyuhan;Sohn, Myoung Ho;Hyun, Saang-Yoon
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.50 no.1
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    • pp.65-76
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    • 2017
  • Since the late 1990s, walleye pollock Gadus chalcogrammus fisheries in Korean waters have been considered collapsed. Although many fisheries scientists suspect that the collapse might have been triggered by overexploitation of juvenile pollock or environmental changes, such conjectures have been neither tested nor investigated, partially because of limited data on the population. There has been no survey of the population, and the ages of fish in fishery catch have rarely been identified. Instead, fishery catch data from 1975-1997 included information about two life stages, 'juveniles and adults,' and data on catch-per-unit-effort (CPUE) during 1963-2007 and those on fish length and weight during 1965-2003 had been sporadically collected from commercial fisheries. To test hypotheses about the collapse of the pollock fisheries, we used a statistical linear model with juvenile CPUE as the response variable, and abiotic (e.g., water temperatures) and biotic factors [e.g., adult pollock, flatfishes (Pleuronectidae sp.), and sandfish (Arctoscopus japonicus) CPUEs] as the explanatory variables. The model results indicated that depletion of the pollock population was associated with both biotic (adult pollock and flatfishes abundance) and abiotic factors (mid-water temperatures in February and October). We further interpreted the results from ecological and biological perspectives, suggesting possible mechanisms.