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.

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 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,

How the Desert got a Past: A History of Quaternary Research in Australia’s Deserts

2014 ◽  
Vol 25 (2) ◽  
pp. 172 ◽  
Author(s):  
Mike Smith
Keyword(s):  
Climate Changes ◽  
Conceptual Space ◽  
The Past ◽  
History Of ◽  
The 1960S

This paper examines how the past of desert landscapes has been interpreted since European explorers and scientists first encountered them. It charts the research that created the conceptual space within which archaeologists and Quaternarists now work. Studies from the 1840s–1960s created the notion of a ‘Great Australian Arid Period'. The 1960s studies of Lake Mungo and the Willandra Lakes by Jim Bowler revealed the cyclical nature of palaeolakes, that changed with climate changes in the Pleistocene, and the complexity of desert pasts. SLEADS and other researchers in the 1980s used thermoluminescence techniques that showed further complexities in desert lands beyond the Willandra particularly through new studies in the Strzelecki and Simpson Dunefields, Lake Eyre, Lake Woods and Lake Gregory. Australian deserts are varied and have very different histories. Far from ‘timeless lands', they have carried detailed information about long-term climate changes on continental scales.

Who Owns the Fish in the Sea?

2017 ◽  
Author(s):  
Carla Rahn Phillips
Keyword(s):  
Sixteenth Century ◽  
Natural Resources ◽  
Bluefin Tuna ◽  
Statistical Evidence ◽  
Population Pressure ◽  
Thunnus Thynnus ◽  
History Of ◽  
Western Spain

From the fourteenth to the mid-nineteenth centuries, the ducal house of Medina Sidonia held exclusive rights to fish for Bluefin tuna (Thunnus thynnus) in south-western Spain. Framed by recent theories about the privatization of access to natural resources, this essay explores the history of successive royal grants to the house of Medina Sidonia. It then examines statistical evidence for the tuna catch over the long term, especially in the late sixteenth century, when the annual catch reached a peak and then suddenly declined. The ducal house may have contributed to that decline by overfishing. During the long term, however, ducal control may unintentionally have aided in the conservation of tuna stocks in times of population pressure, both by not fully exploiting their exclusive rights to fish, and by preventing all others from doing so.

Cities and Urban Patriciates

2010 ◽  
Author(s):  
Alexander Cowan
Keyword(s):  
Rural Areas ◽  
Academic Discipline ◽  
Urban Centers ◽  
Urban Experience ◽  
Counter Reformation ◽  
The Reformation ◽  
History Of ◽  
Urban And Rural Areas ◽  
The 1960S

Urban centers had an influence on the development of Renaissance Europe disproportionate to their overall demographic importance. Most of the population continued to live and work in the countryside, but towns and cities functioned as key centers of production, consumption and exchange, political control, ecclesiastical organization, and cultural influence. Historians still debate the relative roles of urban and rural areas in facilitating the development of capitalism in the long term. Writing on urban history has a very long pedigree dating back to the 16th century, but as an academic discipline it began to flourish in the late 19th century. Since the 1960s, the range of approaches to the field has widened considerably from concerns with political and economic organization to take in issues of governance, social structure, and, most recently, overlapping urban cultures. The role of religious belief, particularly in the context of the Reformation and the Counter-Reformation, runs as a thread throughout the history of the urban experience.

scholarly journals An Introduction to Nicos Hadjinicolaou's “Art Centers and Peripheral Art” (1982)

ARTMargins ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 112-118
Author(s):  
Terry Smith
Keyword(s):  
The United States ◽  
Political Art ◽  
Book Art ◽  
Hard Edge ◽  
War Of Independence ◽  
History Of ◽  
The 1960S ◽  
The Impact ◽  
First Time

Change in the history of art has many causes, but one often overlooked by art historical institutions is the complex, unequal set of relationships that subsist between art centers and peripheries. These take many forms, from powerful penetration of peripheral art by the subjects, styles and modes of the relevant center, through accommodation to this penetration to various degrees and kinds of resistance to it. Mapping these relationships should be a major task for art historians, especially those committed to tracing the reception of works of art and the dissemination of ideas about art. This lecture, delivered by Nicos Hadjinicolaou in 1982, outlines a “political art geography” approach to these challenges, and demonstrates it by exploring four settings: the commissioning of paintings commemorating key battles during the Greek War of Independence; the changes in Diego Rivera's style on his return to Mexico from Paris in the 1920s; the impact on certain Mexican artists in the 1960s of “hard edge” painting from the United States; and the differences between Socialist Realism in Moscow and in the Soviet Republics of Asia during the mid-twentieth century. The lecture is here translated into English for the first time and is introduced by Terry Smith, who relates it to its author's long-term art historical quest, as previously pursued in his book Art History and Class Struggle (1973).

FROM LONG-TERM PATTERNS OF SEASONAL HUNGER TO CHANGING EXPERIENCES OF EVERYDAY POVERTY: NORTHEASTERN GHANA C. 1930–2000

2006 ◽  
Vol 47 (2) ◽  
pp. 181-205 ◽  
Author(s):  
JÉRÔME DESTOMBES
Keyword(s):  
Statistical Evidence ◽  
West African ◽  
Anthropometric Data ◽  
Poor Diet ◽  
John Hunter ◽  
History Of ◽  
The 1960S ◽  
The Way

This article is a West African case-study of the nutritional history of everyday poverty. It draws on unusually rich statistical evidence collected in northeastern Ghana. In the 1930s, pioneer colonial surveys revealed that seasonal poor diet was pervasive, by contrast with undernourishment. They pave the way for constructing a new set of anthropometric data in Nangodi, a savanna polity where John Hunter completed a classic study of seasonal hunger in the 1960s. A re-survey of the same sections and lineages c. 2000, during a full agricultural cycle, shows a significant improvement in nutritional statuses, notably for women.

scholarly journals The Politics of Heroes’ Body: Ethnographying the Training of Foreign Astronauts in Russia

Corpus Mundi ◽  
2020 ◽  
Vol 1 (2) ◽  
pp. 14-36
Author(s):  
Julie Patarin-Jossec
Keyword(s):  
Western Europe ◽  
Historical Narrative ◽  
Global Politics ◽  
Human Spaceflight ◽  
History Of ◽  
Soviet Space ◽  
Astronaut Training ◽  
Contemporary Reality ◽  
The 1960S

If the literature in the history of the Soviet space program is extremely prolific since the 1960s, including regarding cosmonaut embodiment, a lack remains regarding the contemporary reality of human spaceflight in Russia. As this article discusses, based on interviews and a long-term ethnography of the Russian training of astronauts from Western Europe, North America, and Japan, becoming an astronaut is to develop a legitimate body fitting dominant cultural and gendered models. Three mechanisms serve the manufacture of “heroes” and masculine bodies through the astronaut training: the historical narrative of human spaceflight; the values and virility attributes embed as part of the training; and the instruments used in the daily activity of astronauts (such as spacesuits). This manufacture of a legitimate body, characterized by masculinity and discipline inherited from the past, is a heuristic field for corporality and studies of global politics as it underlines how an interweaving of gender, Soviet heritage, and cultural fantasies frames the bodies of a professional elite.

scholarly journals The transformation of Caribbean coral communities since humans

2021 ◽  
Author(s):  
Katie Cramer ◽  
Mary Donovan ◽  
Jeremy Jackson ◽  
Benjamin Greenstein ◽  
Chelsea Korpanty ◽  
...  
Keyword(s):  
Coral Species ◽  
Reef Coral ◽  
Clear Understanding ◽  
Human Disturbances ◽  
Coral Communities ◽  
History Of ◽  
The Caribbean ◽  
The 1960S ◽  
Term Data

The mass die-off of Caribbean corals has transformed many of this region’s reefs to macroalgal-dominated habitats since systematic monitoring began in the 1970s. Although attributed to a combination of local and global human stressors, the lack of long-term data on Caribbean reef coral communities has prevented a clear understanding of the causes and consequences of coral declines. We integrated paleoecological, historical, and modern survey data to track the prevalence of major coral species and life history groups throughout the Caribbean from the pre-human period to present. The regional loss of Acropora corals beginning by the 1960s from local human disturbances resulted in increases in the prevalence of formerly subdominant stress-tolerant and weedy scleractinian corals and the competitive hydrozoan Millepora beginning in the 1970s and 1980s. These transformations have resulted in the homogenization of coral communities within individual countries. However, increases in stress-tolerant and weedy corals have slowed or reversed since the 1980s and 1990s in tandem with intensified coral bleaching. These patterns reveal the long history of increasingly stressful environmental conditions on Caribbean reefs that began with widespread local human disturbances and have recently culminated in the combined effects of local and global change.

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