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Poster De Conférence Année : 2019

Spatio-temporal patterns of larval fish settlement in the Northwestern Mediterranean Sea

Résumé

To identify the spatial and temporal patterns of larval fish supply to coastal habitats in the NW Mediterranean Sea, 13 sites were monitored throughout the French Mediterranean coast using light-traps, from July 2012 to December 2015. A total of 27,800 coastal fish larvae belonging to 72 species were caught over 1073 sampling nights. Three species assemblages were detected in late spring-early summer, summer, and winter, with high consistency among years at each site. Catches Per Unit Effort (CPUE) were most often very low (median CPUE=0), with rare high catches events. Statistical analyses of CPUE were therefore conducted with quantile regressions, focusing on low (q25), medium (q50), high (q75), and extraordinary catches (q90). Most variations in CPUE among years, topographic basins and species were statistically significant for high and very high catches only. The year-to-year variability followed the climatic variability in the NW Mediterranean basin, while at year scale, CPUE displayed strong seasonality, with a major peak in early summer accounting for most of the larval supply and a weaker peak in autumn. An influence of the lunar cycle was detected for all catch levels, with higher CPUE around the new moon and significant temporal autocorrelations at a lag of about 28 days. Spatial patterns were also detected, with, among others: a strong influence of the Rhône river's triggering a lower and later larval supply in western sites compared to eastern sites, a lower species richness at sand-dominated sites compared to rock-dominated ones, and higher diversity and abundance at sites located within or close to a marine protected. These results confirm the high variability of larval supply at all temporal scales and the foremost influence of the moon, already observed in tropical environments, also apply to Mediterranean fish assemblages, and indicate that larval fish supply is a solid candidate for monitoring the state of the NW Mediterranean ecosystems.
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Dates et versions

hal-04018675 , version 1 (07-03-2023)

Identifiants

  • HAL Id : hal-04018675 , version 1

Citer

Robin Faillettaz, Raphaël Voué, Romain Crec'Hriou, Laure-Hélène Garsi, Gilles Lecaillon, et al.. Spatio-temporal patterns of larval fish settlement in the Northwestern Mediterranean Sea. Larval Fish Conference, 2019, Palma de Mallorca, Spain. 2019. ⟨hal-04018675⟩
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