Pelagic Larval Duration and Population Structure of a Widely Distributed Amphidromous Fish in the Indo‐Pacific Region

ABSTRACT Freshwater habitats in the Indo‐Pacific Islands are colonised by amphidromous fish, which undergo a marine larval phase while the rest of the life cycle takes place in the riverine habitat. These fish are mainly represented by Gobiiformes. Among these, Stenogobius genivittatus (Valenciennes, 1837) is widely distributed in the Indo‐Pacific Region, from South Africa to French Polynesia. We studied elements of the life history of S. genivittatus to better understand the processes contributing to its vast distribution: we analysed population genetic structure based on partial mitochondrial DNA sequences ( COI and ND6 ) and we used otolith microstructural analysis to estimate the duration of the marine pelagic larval phase (PLD). The analysis indicates the presence of a unique population broadly distributed across the Indo‐Pacific Ocean, from South Africa to French Polynesia, while individuals from Hawaii appear to constitute a potentially distinct population. Also, our results show a homogeneous PLD in the West Indo‐Pacific Region, except for Hawaii where it is longer and the Central Pacific Ocean (French Polynesia and the Marquesas) where it is shorter.