Consulta: creatorFacets:"Ravier, Christelle"
Registros recuperados: 4
Data/hora: 04/06/2024 02:39:41

Eastern Atlantic bluefin tuna: what we learn from historical time-series of trap catches
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Ravier, Christelle; Fromentin, Jean-marc.
More than one hundred long-term time-series of bluefin tuna catches from the ancestral Mediterranean and Atlantic trap fisheries are used to (1) estimate historical range of BFT yields in the Mediterranean and adjacent Atlantic and (2) investigate spatial and temporal patterns of fluctuations in trap catches. Mean historical catches were around 110 000 tunas/year (± 50 000), i.e. 15 000 tons/year (∈[7 000;25 000]). Fluctuations in trap catches are of large magnitude, periods of high abundance being up to seven times higher than those of low abundance. More interesting was the occurrence of 100-year-long periodic fluctuations as well as 20-year cycles. These medium- to long-term fluctuations, representing more than 50% of the total variability in the...
Tipo: Text
Palavras-chave: Thunnus thynnus; Time series analyses; Abundance; Population dynamics; Long-term changes; Trapfishing.
Ano: 2002
URL: http://archimer.ifremer.fr/doc/00194/30497/28906.pdf

Fluctuations à long terme du thon rouge: validité, origines et conséquences
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Ravier, Christelle.
Describe and gain understanding on fluctuations in animal population over time and space is a central goal of population ecology. This is also crucial to ensure the sustainable management of exploited resources, particularly those with complex population dynamics such as the bluefin tuna. The goal of this work is to collect bluefin tuna catches from the ancestral Mediterranean and Atlantic trap fisheries to (i) characterise long-term fluctuations in bluefin tuna population migrating in the Mediterranean, (ii) analyse their causes et (iii) assess their implications for fisheries management.  The bluefin tuna main biological and ecological characteristics are first detailed. Then, the first part presents the trap fishery, and the process of collect and...
Tipo: Text
Palavras-chave: Biological reference point; V.p.a.; Management; Migration; N.a.o.; Temperature; Tunas/environment relationships; Population dynamics; Periodic fluctuations; Long term trend; Time series; East Atlantic; Mediterranean Sea; Trap fishery; Thunnus thynnus; Points biologiques de référence; V.p.a.; Modèle global; Migration; N.a.o.; Température; Relation thon/environnement; Dynamique de population; Fluctuations périodiques; Tendances à long terme; Séries temporelles; Atlantique Est; Méditerranée; Madrague; Thunnus thynnus.
Ano: 2003
URL: http://archimer.ifremer.fr/doc/2003/these-65.pdf

Retrospective analysis of the bluefin tuna Nordic fisheries data
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Pusineri, Claire; Ravier, Christelle; Fromentin, Jean-marc.
A retrospective analysis (1951-1979) was carried out on the bluefin tuna Nordic fisheries (Norway and Germany) length and weight data distributions and compared to those of Barbate trap (Gibraltar strait, Spain) to test further Tiews’ hypothesis about the disappearance of bluefin tuna in northern seas. The cohorts were identified from weight/length distributions and compared using multivariate analyses. The results showed: (i) a synchronous ageing in the 4 fisheries, (ii) similar dominant cohorts between South Norway and Barbate in the one hand (cohorts born from 1948 to 1952) and North Norway and Germany on the other hand (cohort born in 1945), (iii) a synchronous drop (or collapse) in the catches that occurred in 1963and (iv) significant correlation...
Tipo: Text
Ano: 2002
URL: http://archimer.ifremer.fr/doc/00194/30500/28910.pdf

Trends in the NE Atlantic and Mediterranean Bluefin Abundance
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Ravier, Christelle; Fromentin, Jean-marc.
Tipo: Text
Ano: 2001
URL: http://archimer.ifremer.fr/doc/00194/30569/29005.pdf