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 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.

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 Feeding habits of the Atlantic bluefin tuna, Thunnus thynnus (L. 1758), in the central Mediterranean Sea (Strait of Messina)

2012 ◽  
Vol 67 (1) ◽  
pp. 97-107 ◽  
Author(s):  
Pietro Battaglia ◽  
Franco Andaloro ◽  
Pierpaolo Consoli ◽  
Valentina Esposito ◽  
Danilo Malara ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Feeding Habits ◽  
Bluefin Tuna ◽  
Thunnus Thynnus ◽  
Central Mediterranean ◽  
Atlantic Bluefin Tuna ◽  
Central Mediterranean Sea

Southern bluefin tuna populations in south-west Australia

1965 ◽  
Vol 16 (1) ◽  
pp. 25 ◽  
Author(s):  
JS Hynd
Keyword(s):  
Growth Rate ◽  
Age Groups ◽  
Bluefin Tuna ◽  
Length Frequency ◽  
South West ◽  
Size Groups ◽  
Southern Bluefin Tuna ◽  
The Times

Length-frequency histograms of southern bluefin tuna caught for tagging and other purposes by F.V. Estelle Star in the course of survey operations showed heterogeneity in that the catches contained size groups, the differences between which could not be regarded as simply those to be expected between the age groups of a single stock. The times at which these groups appeared in the catches showed that the groups were characterized by distinct distributional behaviour, and this was confirmed by the results of the tagging operations. However, the groups are indistinguishable in their growth rate, so far as this has been shown by the present work, and no evidence is yet available as to the origins or status of these groups.

Density Dependence of Larval Growth of a Marine Fish, the Southern Bluefin Tuna, Thunnus maccoyii

1991 ◽  
Vol 48 (8) ◽  
pp. 1358-1363 ◽  
Author(s):  
Greg P. Jenkins ◽  
Jock W. Young ◽  
Tim L. O. Davis
Keyword(s):  
Growth Rate ◽  
Marine Fish ◽  
Food Limitation ◽  
Larval Growth ◽  
Bluefin Tuna ◽  
Density Dependent ◽  
East Indian ◽  
Southern Bluefin Tuna ◽  
Slow Growing ◽  
East Indian Ocean

Competition for food among larvae and subsequent reduction in growth rates has been proposed as a mechanism to explain the apparent density-dependent control of some exploited marine fish populations, but has received little support from field data. Growth of larvae of southern bluefin tuna, Thunnus maccoyii, in the East Indian Ocean was significantly different among stations sampled randomly within a 20-km radius. Growth rate was positively correlated with feeding rate but not with temperature, indicating that larvae were food limited to a varying degree. A negative correlation between growth rate and abundance suggested that food limitation was density dependent. Regression analysis indicated that in areas of highest larval densities there was an approximate 25% reduction in growth rate. We suggest that in areas of high abundance, larvae were competing for food, leading to a density-dependent reduction of growth rate. Because the larval stage of high mortality is prolonged, cumulative mortality of slow-growing larvae over this period may be greater, even if the mortality rate is constant.

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