Amphidromy and marine larval phase of ancestral Gobioids Rhyacichthys guilberti and Protogobius attiti (Teleostei: Rhyacichthyidae).

<p>Even if amphidromous fish species contribute most to the diversity of fish communities in the tropical insular<br />
rivers, their biological cycle remain poorly known. For the first time, the otolith elemental composition and microstructure<br />
of two ancestral gobioids, Rhyacichthys guilberti and Protogobius attiti, were investigated to describe their biological<br />
cycle and pelagic larval duration (PLD). The otolith analysis using a femtosecond laser ablation coupled to an inductively<br />
coupled plasma–mass spectrometer (fs-LA-ICP-MS) revealed an amphidromous life history for R. guilberti and it<br />
suggested a progressive habitat shift from a marine habitat to a freshwater environment for P. attiti. For the first time, an<br />
endemic species, P. attiti, showed longer and more variable PLD (55.2
13.5 days) than did a widespread one<br />
(R. guilberti: ,30 days). These results need to be confirmed by analysing more samples but suggest that factors other<br />
than the PLD control endemism and dispersal processes. In association with this first description of the biological cycle for<br />
both species, such an approach is a prerequisite for the management and conservation of both patrimonial species.</p>