Estimate of exploitation rates and population size of skipjack tuna off the southeastern coast of Brazil
Autor(a) principal: | |
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Data de Publicação: | 1985 |
Outros Autores: | |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Boletim do Instituto Oceanográfico |
Texto Completo: | https://www.revistas.usp.br/biocean/article/view/6597 |
Resumo: | Size compositions and total landings of skipjack tuna caught in the southeastern Brazilian waters by bait-boats are used as the basis of the assessment of the population for 1980-1983 period, employing the length cohort analysis and virtual population analysis. From monthly size frequency data it is suggested that there is constant immigration and emigration of different modal groups in the fishing area with an interval of two to three months. The exploitation rate was very low for length class between 35-45 cm FL, then increased gradually. The weighted mean exploitation rates were 0.060 and 0.448, respectively for length classes smaller and larger than 55 cmFL. The estimate of the average number of fish attaining a size of 43 cm FL (recruit) was 11.0 x 10(6) fish for assumed values of M - 0.7 and K = 0.307. Increasing the fishing mortality rate by 30% and 50%, an estimated increment in yield is 8% and 12%, respectively. From virtual population analysis, we obtained the biomass estimate of skipjack population older than two years-old to be 70.3 thousand tonnes for assumed value of M = 0.7 and the estimated MSY was 24.6 thousand tonnes. |
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Boletim do Instituto Oceanográfico |
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Estimate of exploitation rates and population size of skipjack tuna off the southeastern coast of Brazil BiomassaRecrutamentoExplotaçioEstimativa do estoqueRendimento potencialPesca comercialBorda da plataforma continentalPesca com linha^i2^sisca-vKatsuwonus pelamisScombridaeAtlântico Sul OcidentalCosta sul^i2^sBraCosta sudeste^i2^sBraBiomassRecruitmentExploitationStock assessmentPotential yieldCommercial fishingContinental shelf breakPole-line fishingKatsuwonus pelamisScombridaeSW AtlanticSouthern coast^i1^sBra Size compositions and total landings of skipjack tuna caught in the southeastern Brazilian waters by bait-boats are used as the basis of the assessment of the population for 1980-1983 period, employing the length cohort analysis and virtual population analysis. From monthly size frequency data it is suggested that there is constant immigration and emigration of different modal groups in the fishing area with an interval of two to three months. The exploitation rate was very low for length class between 35-45 cm FL, then increased gradually. The weighted mean exploitation rates were 0.060 and 0.448, respectively for length classes smaller and larger than 55 cmFL. The estimate of the average number of fish attaining a size of 43 cm FL (recruit) was 11.0 x 10(6) fish for assumed values of M - 0.7 and K = 0.307. Increasing the fishing mortality rate by 30% and 50%, an estimated increment in yield is 8% and 12%, respectively. From virtual population analysis, we obtained the biomass estimate of skipjack population older than two years-old to be 70.3 thousand tonnes for assumed value of M = 0.7 and the estimated MSY was 24.6 thousand tonnes. Universidade de São Paulo. Instituto Oceanográfico1985-01-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionapplication/pdfhttps://www.revistas.usp.br/biocean/article/view/659710.1590/S1679-87591985000100003Boletim do Instituto Oceanográfico; v. 33 n. 1 (1985); 29-38 Boletim do Instituto Oceanografico; Vol. 33 No. 1 (1985); 29-38 Boletim do Instituto Oceanográfico; Vol. 33 Núm. 1 (1985); 29-38 2316-89510373-5524reponame:Boletim do Instituto Oceanográficoinstname:Instituto Oceanográfico da Universidade de São Paulo (IOUSP)instacron:USPenghttps://www.revistas.usp.br/biocean/article/view/6597/8068Jablonski, SilvioMatsuura, Yasunobuinfo:eu-repo/semantics/openAccess2012-05-02T17:04:24Zoai:revistas.usp.br:article/6597Revistahttps://www.revistas.usp.br/bioceanPUBhttps://www.revistas.usp.br/biocean/oaiamspires@usp.br0373-55240373-5524opendoar:2012-05-02T17:04:24Boletim do Instituto Oceanográfico - Instituto Oceanográfico da Universidade de São Paulo (IOUSP)false |
dc.title.none.fl_str_mv |
Estimate of exploitation rates and population size of skipjack tuna off the southeastern coast of Brazil |
title |
Estimate of exploitation rates and population size of skipjack tuna off the southeastern coast of Brazil |
spellingShingle |
Estimate of exploitation rates and population size of skipjack tuna off the southeastern coast of Brazil Jablonski, Silvio Biomassa Recrutamento Explotaçio Estimativa do estoque Rendimento potencial Pesca comercial Borda da plataforma continental Pesca com linha^i2^sisca-v Katsuwonus pelamis Scombridae Atlântico Sul Ocidental Costa sul^i2^sBra Costa sudeste^i2^sBra Biomass Recruitment Exploitation Stock assessment Potential yield Commercial fishing Continental shelf break Pole-line fishing Katsuwonus pelamis Scombridae SW Atlantic Southern coast^i1^sBra |
title_short |
Estimate of exploitation rates and population size of skipjack tuna off the southeastern coast of Brazil |
title_full |
Estimate of exploitation rates and population size of skipjack tuna off the southeastern coast of Brazil |
title_fullStr |
Estimate of exploitation rates and population size of skipjack tuna off the southeastern coast of Brazil |
title_full_unstemmed |
Estimate of exploitation rates and population size of skipjack tuna off the southeastern coast of Brazil |
title_sort |
Estimate of exploitation rates and population size of skipjack tuna off the southeastern coast of Brazil |
author |
Jablonski, Silvio |
author_facet |
Jablonski, Silvio Matsuura, Yasunobu |
author_role |
author |
author2 |
Matsuura, Yasunobu |
author2_role |
author |
dc.contributor.author.fl_str_mv |
Jablonski, Silvio Matsuura, Yasunobu |
dc.subject.por.fl_str_mv |
Biomassa Recrutamento Explotaçio Estimativa do estoque Rendimento potencial Pesca comercial Borda da plataforma continental Pesca com linha^i2^sisca-v Katsuwonus pelamis Scombridae Atlântico Sul Ocidental Costa sul^i2^sBra Costa sudeste^i2^sBra Biomass Recruitment Exploitation Stock assessment Potential yield Commercial fishing Continental shelf break Pole-line fishing Katsuwonus pelamis Scombridae SW Atlantic Southern coast^i1^sBra |
topic |
Biomassa Recrutamento Explotaçio Estimativa do estoque Rendimento potencial Pesca comercial Borda da plataforma continental Pesca com linha^i2^sisca-v Katsuwonus pelamis Scombridae Atlântico Sul Ocidental Costa sul^i2^sBra Costa sudeste^i2^sBra Biomass Recruitment Exploitation Stock assessment Potential yield Commercial fishing Continental shelf break Pole-line fishing Katsuwonus pelamis Scombridae SW Atlantic Southern coast^i1^sBra |
description |
Size compositions and total landings of skipjack tuna caught in the southeastern Brazilian waters by bait-boats are used as the basis of the assessment of the population for 1980-1983 period, employing the length cohort analysis and virtual population analysis. From monthly size frequency data it is suggested that there is constant immigration and emigration of different modal groups in the fishing area with an interval of two to three months. The exploitation rate was very low for length class between 35-45 cm FL, then increased gradually. The weighted mean exploitation rates were 0.060 and 0.448, respectively for length classes smaller and larger than 55 cmFL. The estimate of the average number of fish attaining a size of 43 cm FL (recruit) was 11.0 x 10(6) fish for assumed values of M - 0.7 and K = 0.307. Increasing the fishing mortality rate by 30% and 50%, an estimated increment in yield is 8% and 12%, respectively. From virtual population analysis, we obtained the biomass estimate of skipjack population older than two years-old to be 70.3 thousand tonnes for assumed value of M = 0.7 and the estimated MSY was 24.6 thousand tonnes. |
publishDate |
1985 |
dc.date.none.fl_str_mv |
1985-01-01 |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
https://www.revistas.usp.br/biocean/article/view/6597 10.1590/S1679-87591985000100003 |
url |
https://www.revistas.usp.br/biocean/article/view/6597 |
identifier_str_mv |
10.1590/S1679-87591985000100003 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
https://www.revistas.usp.br/biocean/article/view/6597/8068 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.publisher.none.fl_str_mv |
Universidade de São Paulo. Instituto Oceanográfico |
publisher.none.fl_str_mv |
Universidade de São Paulo. Instituto Oceanográfico |
dc.source.none.fl_str_mv |
Boletim do Instituto Oceanográfico; v. 33 n. 1 (1985); 29-38 Boletim do Instituto Oceanografico; Vol. 33 No. 1 (1985); 29-38 Boletim do Instituto Oceanográfico; Vol. 33 Núm. 1 (1985); 29-38 2316-8951 0373-5524 reponame:Boletim do Instituto Oceanográfico instname:Instituto Oceanográfico da Universidade de São Paulo (IOUSP) instacron:USP |
instname_str |
Instituto Oceanográfico da Universidade de São Paulo (IOUSP) |
instacron_str |
USP |
institution |
USP |
reponame_str |
Boletim do Instituto Oceanográfico |
collection |
Boletim do Instituto Oceanográfico |
repository.name.fl_str_mv |
Boletim do Instituto Oceanográfico - Instituto Oceanográfico da Universidade de São Paulo (IOUSP) |
repository.mail.fl_str_mv |
amspires@usp.br |
_version_ |
1797049928936062976 |