The aim of this study is to analyse different models describing demographic scenarios of Atlantic Bluefin Tuna in the Mediterranean Sea using an ABC approach to model the complex dynamics of this pelagic fish. Indeed, in spite of recent progress due to genetic surveys and intensive electronic tagging experiments, its spatial dynamics are still partially unknown. These complex dynamics are difficult to explore with classical population genetics tools (likelihood-based or Bayesian methods) because of the lack of flexibility required to describe these scenarios. Moreover in a recent study (Riccioni et al. 2010 ) we could not ascertain thoroughly the presence of signals of bottleneck in the Mediterranean sea as the results are not fully coherent and each subpopulation shows its own demographic history. In reason of these difficulties we propose to determine if these results describe the real ecological and demographic history of ABFT using ABC to test different scenarios taking into account the colonization of the Mediterranean sea (~ 12000 ya, Alvarado Bremer et al. 2005). Indeed Pleistocene glaciations may have limited inter-oceanic gene flow and reproduction of Atlantic bluefin tuna. Oceanographic studies suggest that temperatures in the Mediterranean during the LGM most likely prevented bluefin tuna reproduction (sea surface temperature lower than 24°C). Therefore we can hypothesize a more recent re-colonization of the Mediterranean sea by ABFT during the Holocene. The small scale structuring detected in the Mediterranean sea suggest a possible split into several partially independent subpopulations in this basin . This kind of complex scenario can be compared to alternative ones with ABC enabling the identification of the model that better reproduces the current genetic diversity.

Modelling Bluefin tuna Mediterranean colonization through ABC.

RICCIONI, GIULIA;TINTI, FAUSTO
2010

Abstract

The aim of this study is to analyse different models describing demographic scenarios of Atlantic Bluefin Tuna in the Mediterranean Sea using an ABC approach to model the complex dynamics of this pelagic fish. Indeed, in spite of recent progress due to genetic surveys and intensive electronic tagging experiments, its spatial dynamics are still partially unknown. These complex dynamics are difficult to explore with classical population genetics tools (likelihood-based or Bayesian methods) because of the lack of flexibility required to describe these scenarios. Moreover in a recent study (Riccioni et al. 2010 ) we could not ascertain thoroughly the presence of signals of bottleneck in the Mediterranean sea as the results are not fully coherent and each subpopulation shows its own demographic history. In reason of these difficulties we propose to determine if these results describe the real ecological and demographic history of ABFT using ABC to test different scenarios taking into account the colonization of the Mediterranean sea (~ 12000 ya, Alvarado Bremer et al. 2005). Indeed Pleistocene glaciations may have limited inter-oceanic gene flow and reproduction of Atlantic bluefin tuna. Oceanographic studies suggest that temperatures in the Mediterranean during the LGM most likely prevented bluefin tuna reproduction (sea surface temperature lower than 24°C). Therefore we can hypothesize a more recent re-colonization of the Mediterranean sea by ABFT during the Holocene. The small scale structuring detected in the Mediterranean sea suggest a possible split into several partially independent subpopulations in this basin . This kind of complex scenario can be compared to alternative ones with ABC enabling the identification of the model that better reproduces the current genetic diversity.
2010
4° Congresso SIBE- Società Italiana Biologia Evoluzionistica
Giulia Riccioni; Silvia Ghirotto; Giorgia Ferrara; Ilaria Milano; Guido Barbujani; Fausto Tinti
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/393651
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