Note on the stock structure of Pacific bigeye tuna to be used in stock assessments. Fonteneau, A. & Ariz, J. In volume BI-WP-3, Port Moresby, Papua New Guinea, August, 2008. WCPFC. ACTI
abstract   bibtex   
This paper reviews and discusses the stock structure of Pacific bigeye tuna in relation with the prospects of stock assessment analysis of this population. The analysis of fishery data, mainly the spatio temporal bigeye catches by gear and by sizes, indicates that the present 150°W frontier based on historical and administrative results does not appear to be a convenient biological frontier. Our conclusion is that the present lack of significant tag recoveries across the 150°W frontier should not be considered as being significant, due to the limited numbers of bigeye presently tagged and to the great distances between present tagging locations. North South movements of adult bigeye are also a potential source of mixing between eastern and western bigeye populations. It is hypothetized that there could be an increased net flow of juvenile bigeye towards the WCPO due to the increased number of FADs in the western EPO. Our conclusion is that all the bigeye stock assessments by WCPFC and the IATTC should preferably be conducted in a unified best model and at a Pacific wide scale. A large scale tagging programme covering the distribution area of the entire bigeye population and fully coordinated between WCPFC and IATTC would be necessary to obtain realistic and age specific movement patterns at a Pacific wide level. Management actions of the bigeye stocks should also be fully coordinated between the Western and Eastern stocks, because of the probably weak biological frontier and also because of the bigeye long life span. The long term management benefits or failures will probably be shared by WCPFC and IATTC.
@inproceedings{ fonteneau_note_2008,
  address = {Port Moresby, Papua New Guinea},
  title = {Note on the stock structure of Pacific bigeye tuna to be used in stock assessments},
  volume = {{BI}-{WP}-3},
  abstract = {This paper reviews and discusses the stock structure of Pacific bigeye tuna in relation with the prospects of stock assessment analysis of this population. The analysis of fishery data, mainly the spatio temporal bigeye catches by gear and by sizes, indicates that the present 150°W frontier based on historical and administrative results does not appear to be a convenient biological frontier. Our conclusion is that the present lack of significant tag recoveries across the 150°W frontier should not be considered as being significant, due to the limited numbers of bigeye presently tagged and to the great distances between present tagging locations. North South movements of adult bigeye are also a potential source of mixing between eastern and western bigeye populations. It is hypothetized that there could be an increased net flow of juvenile bigeye towards the {WCPO} due to the increased number of {FADs} in the western {EPO}. Our conclusion is that all the bigeye stock assessments by {WCPFC} and the {IATTC} should preferably be conducted in a unified best model and at a Pacific wide scale. A large scale tagging programme covering the distribution area of the entire bigeye population and fully coordinated between {WCPFC} and {IATTC} would be necessary to obtain realistic and age specific movement patterns at a Pacific wide level. Management actions of the bigeye stocks should also be fully coordinated between the Western and Eastern stocks, because of the probably weak biological frontier and also because of the bigeye long life span. The long term management benefits or failures will probably be shared by {WCPFC} and {IATTC}.},
  publisher = {{WCPFC}},
  author = {Fonteneau, Alain and Ariz, Javier},
  month = {August},
  year = {2008},
  note = {{ACTI}}
}
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