scholarly journals TINGKAT EKSPLOITASI IKAN TUNA SIRIP BIRU SELATAN (Thunnus maccoyii) DI SAMUDERA HINDIA BERDASARKAN HASIL TANGKAPAN YANG DIDARATKAN DI PELABUHAN BENOA, BALI

2016 ◽  
Vol 5 (4) ◽  
pp. 345-352
Author(s):  
Damar Nusawicaksono Kurniawan ◽  
Abdul Ghofar ◽  
Suradi Wijaya Saputra ◽  
Bram Setyadji
Keyword(s):  
Growth Rate ◽  
Size Structure ◽  
Stock Assessment ◽  
Total Mortality ◽  
Bluefin Tuna ◽  
Fisheries Resources ◽  
Southern Bluefin Tuna ◽  
The Indian Ocean ◽  
Data Length ◽  
Length Frequency Data

ABSTRAK Pengkajian dan pendugaan status sumberdaya perikanan di suatu wilayah perairan dapat dilakukan dengan mengetahui laju eksploitasinya. Data frekuensi panjang merupakan salah satu data yang dapat digunakan untuk melakukan pendugaan tingkat eksploitasi tersebut. Penelitian ini bertujuan untuk menduga nilai mortalitas, laju pertumbuhan, ukuran pertama kali tertangkap dan tingkat eksploitasi. Penelitian dilakukan pada bulan April-Mei 2016 di Loka Penelitian Perikanan Tuna Pelabuhan Benoa, Denpasar, Bali. Metode yang digunakan adalah metode survei. Sementara data panjang ikan tuna sirip biru selatan tahun 2013-2014 kemudian diolah dengan perangkat lunak FISAT II. Hasil penelitian menunjukkan struktur ukuran ikan tuna sirip biru selatan 145 - 210 cmFL dengan modus di ukuran 170-174 cmFL, ukuran pertama kali tertangkap (Lc) 171 cmFL, hubungan panjang berat mendapat nilai W= 0,00006*FL2,792, faktor kondisi berada pada angka 1,86-2,00, laju pertumbuhan yang didapat yaitu Lt=220,50(1 - e 0,2(t+0,488)), dimana nilai dari L∞ yaitu 220,50 cmFL dan nilai t0 -0,49, laju mortalitas total (Z) sebesar 1,14/tahun, laju mortalitas alami (M) sebesar 0,36/tahun, dan laju mortalitas akibat penangkapan (F) sebesar 0,78/tahun, dan tingkat eksploitasi (E) 0,68/tahun, Hal ini menunjukan penangkapan  ikan tuna sirip biru selatan oleh kapal rawai tuna di Samudera Hindia dalam keadaan berlebih (overfishing) karena nilai tingkat eksploitasi yang didapat melebihi tingkat pemanfaatan optimum atau Eopt = 0,5/tahun (0,68 > 0,5). Kata Kunci : Ikan Tuna Sirip Biru Selatan, Tingkat Eksploitasi, Mortalitas, Pertumbuhan  ABSTRACT Stock assessment and prediction status of fisheries resources in the waters can be made by knowing the rate of exploitation. Length-frequency data is one can be used to suspect rate of exploitation . The aimed of this research was to suspect value of mortality, the growth rate, size at first capture and the level of exploitation. This research was conducted on April-May 2016 at the Loka Fishery Tuna's Research Benoa Port, Denpasar, Bali. This research used survey method.While data length of the southern bluefin tuna 2013-2014 was processed with FISAT II. The results showed size structure of southern bluefin tuna 145-210 cmFL with mode in sizes 170-174 cmFL, size at first capture (Lc) 171 cmFL, value of lenght and weight relationship W = 0,00006 *,792 FL2, condition factors 1,86-2.00, the growth rate Lt = 220,50 (1-e of 0.2 (t + 0,488)), where the value of L ∞ was 220.50 cmFL and value t0 -0.49 total mortality rate (Z) of 1.14/year, rate of natural mortality (M) of 0.36/year, and  rate of mortality due to the arrest of (F) amounted to 0.78/year, and the rate of exploitation (E) 0,68/year, it shows the fishing of southern bluefin tuna by the longline in the Indian Ocean was overfishing because level of exploitation value was over the optimum effort or Eopt = 0,5/year (0.68 > 0.5). Keyword: Southern Bluefin Tuna, exploitation rate, Mortality, growth,

Increase in growth rates of southern bluefin tuna (Thunnus maccoyii) over four decades: 1960 to 2000

2004 ◽  
Vol 61 (2) ◽  
pp. 307-322 ◽  
Author(s):  
Tom Polacheck ◽  
J Paige Eveson ◽  
Geoff M Laslett
Keyword(s):  
Stock Assessment ◽  
Temporal Trends ◽  
Integrated Approach ◽  
Bluefin Tuna ◽  
Fish Stocks ◽  
Southern Bluefin Tuna ◽  
History Of ◽  
The 1960S ◽  
Length Frequency Data

Estimates of long-term temporal trends and variability in growth are often not available for many commercially exploited fish stocks. An integrated estimation framework that combines growth information from tagging studies, direct age estimates from hard parts, and modal progression estimates from length–frequency data is applied to data on southern bluefin tuna (Thunnus maccoyii, SBT) collected over four decades, from 1960 to 2000. By using an integrated approach, a comprehensive set of growth estimates can be obtained for each of these four decades even though substantive deficiencies exist in the coverage of the historical data from any single source. The results confirm previous findings that cohorts from the 1980s grew substantially faster at young ages than cohorts from the 1960s. The results also suggest that the 1970s was a period of transition and that growth of fish up to about age 4 was faster in the 1990s than in the 1980s. The changes in SBT growth over these four decades are consistent with density-dependent responses given the history of exploitation and stock assessment estimates of changes in population size.

scholarly journals LAJU PERTUMBUHAN, LAJU KEMATIAN DAN EKSPLOITASI IKAN TONGKOL KOMO, Euthynnus affinis (Cantor 1849), DI PERAIRAN SAMUDERA HINDIA BARAT SUMATERA

2015 ◽  
Vol 6 (2) ◽  
pp. 69
Author(s):  
Irwan Jatmiko ◽  
Ririk Kartika Sulistyaningsih ◽  
Duto Nugroho
Keyword(s):  
Stock Assessment ◽  
Total Mortality ◽  
Assessment Tools ◽  
Instantaneous Rate ◽  
Exploitation Rate ◽  
The Indian Ocean ◽  
Euthynnus Affinis ◽  
The One ◽  
Base Data ◽  
Length Frequency Data

Tongkol komo (Euthynnus affinis Cantor, 1849)merupakan hasil tangkapan utama bagi nelayan pukat cincin di Samudera Hindia sebelah barat Sumatera. Penelitian ditujukan untukmemperoleh data dan informasi tentang estimasi laju pertumbuhan, laju kematian dan laju eksploitasi ikan tongkol komo. Analisis dilakukan berdasarkan himpunan data frekuensi panjang cagak sebanyak 1.325 ekor hasil tangkapan pukat cincin yang didaratkan di Pelabuhan Sibolga. Contoh ikan dikumpulkan secara bulanan dari bulan Juli 2012 hingga Februari 2013. Pendugaan parameter dilakukan menggunakan program FISAT II (FAO-ICLARM Stock Assessment Tools). Hasil kajian menunjukkan kisaran panjang cagak antara 30 - 60 cm, panjang asimptotik (L∞)= 63,5 cm, laju pertumbuhan(K) = 0,63/tahun dan umur teoritis pada saat panjang ke 0 ( t0 ) = -0,21 tahun. Estimasi laju kematian total tahunan (Z) sebesar 2,40/tahun, laju kematian alami (M) sebesar 1,07/tahun dan laju kematian akibat penangkapan(F) sebesar 1,33/tahun. Perkiraan Laju eksploitasi (E) = 0,55 mengindikasikan bahwa tingkat pemanfaatan berada pada tingkat yang moderat.Kawakawa (Euthynnus affinis Cantor, 1849) is the one of the major catch of fishermen in the Indian Ocean west off Sumatera. This study was aimed to investigate data and information on growth, mortality and the exploitation rates of kawakawa. Analyses were carried out based on a number of 1,325 length frequency data from purse seine fishery landed in Sibolga Fishing Port. Monthly base data were collected from July 2012 to February 2013. The specimens ranged from 30 to 60 cm FL. parameters were determined through a packageprogramof FISAT II (FAO-ICLARM StockAssessment Tools). The result showed that asymptotic length (L∞) were 63.5 cmFL, growth rates (K) 0.63/yr and estimated t0 -0.21 years. The annual instantaneous rate of total mortality (Z) was 2.40/yr, the natural mortality (M) was 1.07/yr and the fishing mortality (F) was 1.33/yr. The exploitation rate (E = 0.55) indicated that E. affinis was moderately exploited in the area.

The Southern Bluefin Tuna, Thunnus thynnus maccoyii (Castelnau), in Australian Waters

1956 ◽  
Vol 7 (1) ◽  
pp. 1 ◽  
Author(s):  
DL Serventy
Keyword(s):  
Growth Rate ◽  
Feeding Habits ◽  
Bluefin Tuna ◽  
Thunnus Thynnus ◽  
Younger Age ◽  
Southern Bluefin Tuna ◽  
Local Breeding ◽  
Australian Coastline ◽  
Migratory Movements ◽  
Length Frequency Data

This paper deals with the results of the investigations of the Division of Fisheries, C.S.I.R.O., into the biology of the southern bluefin tuna (Thunnus thynnus maccoyii (Castelnau)), a representative in southern Australia and New Zealand of the tunny of Europe and the bluefin tuna of California. A comparative description of the morphology of the ,Australian form is given with a detailed study of its occurrence in Australia, including a discussion of the possible presence of local breeding stocks. The growth rate is considered from a study of length frequency data.' Considerable variations have been found in the growth rate of the younger age classes, as well as fluctuations in their relative abundance and their migratory movements along the eastern Australian coastline. Reference is made to the feeding habits in various areas.

scholarly journals COMPARISON OF INDONESIAN TUNA LONGLINE FISHING PERFORMANCE WITHIN AND OUTSIDE INDONESIA EXCLUSIVE ECONOMIC ZONE (EEZ)

2017 ◽  
Vol 23 (1) ◽  
pp. 1
Author(s):  
Bram Setyadji ◽  
Irwan Jatmiko
Keyword(s):  
Indian Ocean ◽  
Bluefin Tuna ◽  
T Test ◽  
Exclusive Economic Zone ◽  
Southern Bluefin Tuna ◽  
The Indian Ocean ◽  
The Mean ◽  
Economic Zone ◽  
Tuna Longline ◽  
High Seas

Indonesian tuna longline fleets have been fishing in the Exclusive Economic Zone (EEZ) and high seas of the Indian Ocean for quite some time. However, effort has never been made to separate catch from the EEZ and the high seas as it important for fisheries management. A total of 2,430 set-by-set longline fishing data had been collected by scientific observers based in the Research Institute of Tuna Fishery in Bali since August 2005 to December 2014 on which present analysis was made. The research aims to compare between trend of tuna catch of the EEZ and of the high seas of Indian Ocean. The results show that the mean hook rate of both catches of big eye tuna (BET) and southern Bluefin tuna (SBT) caught in the high seas was significantly higher than that the EEZ (two sample t-test, p<0.05), while for yellow fin tuna (YFT) it was in the opposite direction (two sample t-test, p<0.05). As for albacore (ALB), the mean hook rate value was statistically similar in both fishing grounds (two sample t-test, p>0.05).

MULTIFAN a Likelihood-Based Method for Estimating Growth Parameters and Age Composition from Multiple Length Frequency Data Sets Illustrated using Data for Southern Bluefin Tuna (Thunnus maccoyii)

1990 ◽  
Vol 47 (2) ◽  
pp. 301-317 ◽  
Author(s):  
D. A. Fournier ◽  
John R. Sibert ◽  
Jacek Majkowski ◽  
John Hampton
Keyword(s):  
Growth Parameters ◽  
Bluefin Tuna ◽  
Parameter Estimates ◽  
Data Sets ◽  
Frequency Data ◽  
Length Frequency ◽  
Objective Criterion ◽  
Southern Bluefin Tuna ◽  
Robust Likelihood ◽  
Length Frequency Data

We present a method for simultaneously analyzing multiple length frequency data sets. The method utilizes a robust likelihood-based estimation procedure that provides an objective criterion for hypothesis testing. The method is applied to length frequency data from southern bluefin tuna (Thunnus maccoyii) for which independent estimates of growth parameters based on tag return data are available. The estimates of the growth parameters from the new method were found to be in substantial agreement with the values previously obtained for these parameters. The strength of the likelihood approach is demonstrated by discriminating between alternative structural hypotheses for describing the data. The ability to simultaneously analyze multiple samples permits the method to exploit the extra information not available when analyzing samples one by one. The computer program maintains a database of fits to the data which enable the user to organize the results of the analysis. Graphical displays permit the user to view any of the fits, and an interactive graphics routine aids the user to find good initial parameter estimates.

Changes in growth of juvenile southern bluefin tuna (Thunnus maccoyii): an analysis of length-frequency data from the Australian fishery

2000 ◽  
Vol 51 (2) ◽  
pp. 143 ◽  
Author(s):  
George M. Leigh ◽  
William S. Hearn
Keyword(s):  
Modal Analysis ◽  
Growth Rates ◽  
Bluefin Tuna ◽  
Frequency Data ◽  
Length Frequency ◽  
Southern Bluefin Tuna ◽  
History Of ◽  
The Mean ◽  
Western Australian ◽  
Length Frequency Data

Modal analysis is applied to historical length–frequency records of the Australian southern bluefin tunafishery, in order to quantify the variation in mean length from year to year. In the South Australian fishery in the first half of March, the mean length has ranged between 54 cm and 64 cm for 1-year-old fish, 73 cm and 85 cm for 2-year-old fish, and 85 cm and 100 cm for 3-year-old fish. The mean lengths of 2-, 3- and 4-year-old fish, and the increment from age 1 to age 3, have increased substantially over the history of the fishery. This increase in growth is probably a response to a decline in the population due to heavy fishing. In many years in the Western Australian fishery, two or more groups of 1-year-old fish were found: the mean lengths of these groups typically differed by 10 cm. Growth rates also varied markedly according to the season of the year.

scholarly journals Stock Assessment for Seven Fish Species Using the LBB Method from the Northeastern Tip of the Bay of Bengal, Bangladesh

2021 ◽  
Vol 13 (3) ◽  
pp. 1561
Author(s):  
Md. Abdullah Al-Mamun ◽  
Qun Liu ◽  
Sayedur Rahman Chowdhury ◽  
Md. Sharif Uddin ◽  
K. M. Shahriar Nazrul ◽  
...  
Keyword(s):  
Bay Of Bengal ◽  
Stock Assessment ◽  
Fish Stock ◽  
Marine Fishery ◽  
Fishery Resources ◽  
Fisheries Resources ◽  
Pampus Argenteus ◽  
Management Measures ◽  
The Status ◽  
Length Frequency Data

Assessment of fish stock status is generally required for fisheries management, which is difficult when the data are limited. The length-based Bayesian Biomass (LBB) approach is a powerful and new method, where only the length-frequency data are used for estimating the status of fisheries resources. Here, we applied the LBB method to assess the status of seven commercially valuable marine fishes from the northern tip of the Bay of Bengal (BoB), Bangladesh. These species were Lepturacanthus savala, Pampus argenteus, Nemipterus japonicas, Nemipterus randalli, Ilisha filigera, Saurida tumbil, and Upeneus sulphurous. The current relative biomass (B/B0) ratios were smaller than the BMSY/B0 in five stocks, except for N. japonicas and N. randalli, and this indicates that, of the seven populations assessed, two are grossly overfished, three are overfished, and two are healthy stocks. Moreover, the length at first capture (Lc) was lower than the optimal length at first capture (Lc_opt) in all seven populations, which indicates growth overfishing, suggesting that increasing the mesh sizes would be beneficial. The present findings confirm that Bangladesh’s coastal water fishery resources are declining. More specific targeted management measures should be taken to recover the country’s marine fishery resources.

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