Estimation of year class abundance and mortality of yellowfin tuna in the Eastern Tropical Pacific
ENGLISH: Age composition of catch, and growth rate, of yellowfin tuna have been estimated by Hennemuth (1961a) and Davidoff (1963). The relative abundance and instantaneous total mortality rate of yellowfin tuna during 1954-1959 have been estimated by Hennenmuth (1961b). It is now possible to extend...
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ftoceandocs:oai:aquadocs.org:1834/20414 2023-05-15T13:53:08+02:00 Estimation of year class abundance and mortality of yellowfin tuna in the Eastern Tropical Pacific Estimación de la abundancia de las clases anuales y de la mortalidad del atún aleta amarilla en el Pacífico Oriental Tropical Davidoff, Edwin B. 1965 application/pdf 353-394 http://hdl.handle.net/1834/20414 ? unknown http://hdl.handle.net/1834/20414 http://aquaticcommons.org/id/eprint/2621 8 2011-09-29 18:48:16 2621 Inter-American Tropical Tuna Commission Fisheries abundance mortality yellowfin tuna Thunnus albacares Eastern Tropical Pacific abundancia mortalidad atún aleta amarilla Pacífico Oriental Tropical article 1965 ftoceandocs 2023-04-06T17:01:37Z ENGLISH: Age composition of catch, and growth rate, of yellowfin tuna have been estimated by Hennemuth (1961a) and Davidoff (1963). The relative abundance and instantaneous total mortality rate of yellowfin tuna during 1954-1959 have been estimated by Hennenmuth (1961b). It is now possible to extend this work, because more data are available; these include data for 1951-1954, which were previously not available, and data for 1960-1962, which were collected subsequent to Hennemuth's (1961b) publication. In that publication, Hennemuth estimated the total instantaneous mortality rate (Z) during the entire time period a year class is present in the fishery following full recruitment. However, this method may lead to biased estimates of abundance, and hence mortality rates, because of both seasonal migrations into or out of specific fishing areas and possible seasonal differences in availability or vulnerability of the fish to the fishing gear. Schaefer, Chatwin and Broadhead (1961) and Joseph etl al. (1964) have indicated that seasonal migrations of yellowfin occur. A method of estimating mortality rates which is not biased by seasonal movements would be of value in computations of population dynamics. The method of analysis outlined and used in the present paper may obviate this bias by comparing the abundance of an individual yellowfin year class, following its period of maximum abundance, in an individual area during a specific quarter of the year with its abundance in the same area one year later. The method was suggested by Gulland (1955) and used by Chapman, Holt and Allen (1963) in assessing Antarctic whale stocks. This method, and the results of its use with data for yellowfin caught in the eastern tropical Pacific from 1951-1962 are described in this paper.SPANISH: La composición de edad de la captura, y la tasa de crecimiento del atún aleta amarilla, han sido estimadas por Hennemuth (1961a) y Davidoff (1963). Hennemuth (1961b), estimó la abundancia relativa y la tasa de mortalidad total instantánea del ... Article in Journal/Newspaper Antarc* Antarctic IODE-UNESCO: OceanDocs - E-Repository of Ocean Publications Antarctic Pacific Schaefer ENVELOPE(166.383,166.383,-71.367,-71.367) |
institution |
Open Polar |
collection |
IODE-UNESCO: OceanDocs - E-Repository of Ocean Publications |
op_collection_id |
ftoceandocs |
language |
unknown |
topic |
Fisheries abundance mortality yellowfin tuna Thunnus albacares Eastern Tropical Pacific abundancia mortalidad atún aleta amarilla Pacífico Oriental Tropical |
spellingShingle |
Fisheries abundance mortality yellowfin tuna Thunnus albacares Eastern Tropical Pacific abundancia mortalidad atún aleta amarilla Pacífico Oriental Tropical Davidoff, Edwin B. Estimation of year class abundance and mortality of yellowfin tuna in the Eastern Tropical Pacific |
topic_facet |
Fisheries abundance mortality yellowfin tuna Thunnus albacares Eastern Tropical Pacific abundancia mortalidad atún aleta amarilla Pacífico Oriental Tropical |
description |
ENGLISH: Age composition of catch, and growth rate, of yellowfin tuna have been estimated by Hennemuth (1961a) and Davidoff (1963). The relative abundance and instantaneous total mortality rate of yellowfin tuna during 1954-1959 have been estimated by Hennenmuth (1961b). It is now possible to extend this work, because more data are available; these include data for 1951-1954, which were previously not available, and data for 1960-1962, which were collected subsequent to Hennemuth's (1961b) publication. In that publication, Hennemuth estimated the total instantaneous mortality rate (Z) during the entire time period a year class is present in the fishery following full recruitment. However, this method may lead to biased estimates of abundance, and hence mortality rates, because of both seasonal migrations into or out of specific fishing areas and possible seasonal differences in availability or vulnerability of the fish to the fishing gear. Schaefer, Chatwin and Broadhead (1961) and Joseph etl al. (1964) have indicated that seasonal migrations of yellowfin occur. A method of estimating mortality rates which is not biased by seasonal movements would be of value in computations of population dynamics. The method of analysis outlined and used in the present paper may obviate this bias by comparing the abundance of an individual yellowfin year class, following its period of maximum abundance, in an individual area during a specific quarter of the year with its abundance in the same area one year later. The method was suggested by Gulland (1955) and used by Chapman, Holt and Allen (1963) in assessing Antarctic whale stocks. This method, and the results of its use with data for yellowfin caught in the eastern tropical Pacific from 1951-1962 are described in this paper.SPANISH: La composición de edad de la captura, y la tasa de crecimiento del atún aleta amarilla, han sido estimadas por Hennemuth (1961a) y Davidoff (1963). Hennemuth (1961b), estimó la abundancia relativa y la tasa de mortalidad total instantánea del ... |
format |
Article in Journal/Newspaper |
author |
Davidoff, Edwin B. |
author_facet |
Davidoff, Edwin B. |
author_sort |
Davidoff, Edwin B. |
title |
Estimation of year class abundance and mortality of yellowfin tuna in the Eastern Tropical Pacific |
title_short |
Estimation of year class abundance and mortality of yellowfin tuna in the Eastern Tropical Pacific |
title_full |
Estimation of year class abundance and mortality of yellowfin tuna in the Eastern Tropical Pacific |
title_fullStr |
Estimation of year class abundance and mortality of yellowfin tuna in the Eastern Tropical Pacific |
title_full_unstemmed |
Estimation of year class abundance and mortality of yellowfin tuna in the Eastern Tropical Pacific |
title_sort |
estimation of year class abundance and mortality of yellowfin tuna in the eastern tropical pacific |
publishDate |
1965 |
url |
http://hdl.handle.net/1834/20414 |
long_lat |
ENVELOPE(166.383,166.383,-71.367,-71.367) |
geographic |
Antarctic Pacific Schaefer |
geographic_facet |
Antarctic Pacific Schaefer |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
http://aquaticcommons.org/id/eprint/2621 8 2011-09-29 18:48:16 2621 Inter-American Tropical Tuna Commission |
op_relation |
http://hdl.handle.net/1834/20414 |
_version_ |
1766258089486450688 |