Spatial variability in post-larval traits of Sicyopterus lagocephalus Pallas 1770 around Reunion Island

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The spatial variability of S. lagocephalus post-larval traits, in February 2015, was investigated through comparison of pelagic larval duration (PLD), standard length (SL), body mass (BM) and condition factor among 6 rivers around Reunion Island. The variability of the same traits was also investigated within a recruitment event in another river, in January 2015. Our results showed homogeneity of the PLD both between sites during the recruitment of February 2015, and during the recruitment event of January 2015 at a given site. The other traits were different between the eastern and the western rivers. The post-larvae from the East were characterised by higher BM and condition factor whereas on the West they were longer. These differences can be explained by different environmental conditions experienced by larvae in the coastal oceanic water before they entered the river, but also by different migration routes during their marine dispersal. The coastal water on the eastern side, more turbid and probably trophically richer, could have induced a better growth of the post-larvae compared to those at the same age on the western side. A singularity was highlighted concerning the Marsouins River, located East of the island, where post-larvae were at a more advanced stage of their metamorphosis, characterised by both a smaller size and a lighter weight. This particularity was related to the location of the fishermen trapnet, positioned farther up river compared to all the other rivers, either West or East of the island.