Changes in population structure and growth of skipjack tuna, Katsuwonus pelamis during 30 years of exploitation in the southwestern Atlantic

The skipjack tuna is the main tuna species caught in Brazil with pole and live-bait. Samples taken during 1984-1986 and the 2004-2009 periods provided length, weight and age data. A comparison of the population structure was made showing a decrease in the median and means of fork length in the 80�...

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Autores principales:	Garbin,Thais, P. Castello,Jorge
Lenguaje:	English
Publicado:	Pontificia Universidad Católica de Valparaíso. Facultad de Recursos Naturales. Escuela de Ciencias del Mar 2014
Materias:	Katsuwonus pelamis skipjack population structure weight-length relationship condition factor growth CPUE southwestern Atlantic
Acceso en línea:	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2014000300013
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spelling	oai:scielo:S0718-560X20140003000132014-10-10Changes in population structure and growth of skipjack tuna, Katsuwonus pelamis during 30 years of exploitation in the southwestern AtlanticGarbin,ThaisP. Castello,Jorge Katsuwonus pelamis skipjack population structure weight-length relationship condition factor growth CPUE southwestern Atlantic The skipjack tuna is the main tuna species caught in Brazil with pole and live-bait. Samples taken during 1984-1986 and the 2004-2009 periods provided length, weight and age data. A comparison of the population structure was made showing a decrease in the median and means of fork length in the 80's (median: 55 cm) and recent years (median: 51 cm), an increased participation of smaller individuals (40 cm) in recent catches, a high variability of lengths in each year class and a decrease of the condition factor K. These results indicate alterations in the population structure and dynamics. The von Bertalanffy growth parameters calculated for the recent years were L∞= 669 mm; k = 0.24 yr-1; t o = -3.8. CPUE data for the studied period seems to be stable (mean annual catch of 20,000 ton). However, the unit of effort used in Brazil (fishing days) does not reflect changes in fishing power and technology properly as occurred during 30 years of exploitation. It is concluded that the present situation requires a close monitoring of the fishery.info:eu-repo/semantics/openAccessPontificia Universidad Católica de Valparaíso. Facultad de Recursos Naturales. Escuela de Ciencias del MarLatin american journal of aquatic research v.42 n.3 20142014-07-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2014000300013en
institution	Scielo Chile
collection	Scielo Chile
language	English
topic	Katsuwonus pelamis skipjack population structure weight-length relationship condition factor growth CPUE southwestern Atlantic
spellingShingle	Katsuwonus pelamis skipjack population structure weight-length relationship condition factor growth CPUE southwestern Atlantic Garbin,Thais P. Castello,Jorge Changes in population structure and growth of skipjack tuna, Katsuwonus pelamis during 30 years of exploitation in the southwestern Atlantic
description	The skipjack tuna is the main tuna species caught in Brazil with pole and live-bait. Samples taken during 1984-1986 and the 2004-2009 periods provided length, weight and age data. A comparison of the population structure was made showing a decrease in the median and means of fork length in the 80's (median: 55 cm) and recent years (median: 51 cm), an increased participation of smaller individuals (40 cm) in recent catches, a high variability of lengths in each year class and a decrease of the condition factor K. These results indicate alterations in the population structure and dynamics. The von Bertalanffy growth parameters calculated for the recent years were L∞= 669 mm; k = 0.24 yr-1; t o = -3.8. CPUE data for the studied period seems to be stable (mean annual catch of 20,000 ton). However, the unit of effort used in Brazil (fishing days) does not reflect changes in fishing power and technology properly as occurred during 30 years of exploitation. It is concluded that the present situation requires a close monitoring of the fishery.
author	Garbin,Thais P. Castello,Jorge
author_facet	Garbin,Thais P. Castello,Jorge
author_sort	Garbin,Thais
title	Changes in population structure and growth of skipjack tuna, Katsuwonus pelamis during 30 years of exploitation in the southwestern Atlantic
title_short	Changes in population structure and growth of skipjack tuna, Katsuwonus pelamis during 30 years of exploitation in the southwestern Atlantic
title_full	Changes in population structure and growth of skipjack tuna, Katsuwonus pelamis during 30 years of exploitation in the southwestern Atlantic
title_fullStr	Changes in population structure and growth of skipjack tuna, Katsuwonus pelamis during 30 years of exploitation in the southwestern Atlantic
title_full_unstemmed	Changes in population structure and growth of skipjack tuna, Katsuwonus pelamis during 30 years of exploitation in the southwestern Atlantic
title_sort	changes in population structure and growth of skipjack tuna, katsuwonus pelamis during 30 years of exploitation in the southwestern atlantic
publisher	Pontificia Universidad Católica de Valparaíso. Facultad de Recursos Naturales. Escuela de Ciencias del Mar
publishDate	2014
url	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2014000300013
work_keys_str_mv	AT garbinthais changesinpopulationstructureandgrowthofskipjacktunakatsuwonuspelamisduring30yearsofexploitationinthesouthwesternatlantic AT pcastellojorge changesinpopulationstructureandgrowthofskipjacktunakatsuwonuspelamisduring30yearsofexploitationinthesouthwesternatlantic
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Changes in population structure and growth of skipjack tuna, Katsuwonus pelamis during 30 years of exploitation in the southwestern Atlantic

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