Use of Post-Larval Otoliths to Compare Age, Growth, and Pelagic Larval Durations of Caribbean Amphidromous Gobies

Artisanal fisheries for post-larval amphidromous fishes occur on tropical islands globally and can have large economic and cultural value. Despite the importance of amphidromous fishes to marine and freshwater ecosystems, their ecology and management have received little research attention. Additionally, the life history of amphidromous fishes creates unique challenges to managing fisheries exploited at both at early life stages (e.g., larval, post-larval) during recruitment to freshwater systems and as adults. Post-larvae were sampled weekly at the Rio Grande de Arecibo in Puerto Rico June 2013–October 2014, and daily growth rings were counted from sagittal otoliths to describe temporal patterns in age and length at recruitment, and to estimate pelagic larval duration. Length and age at recruitment generally increased over the sampling period and provide insight on mechanisms responsible for recruitment. For example, River Goby Awaous banana post-larval recruits sampled from the Arecibo River exhibited greater variation in age (46-79 d, CV 11%) than total length (13.5-16.7 mm, CV 4%), suggesting recruitment timing to freshwater habitats may be size-dependent despite a wide range in ages and protracted spawning period. Overall, our findings provide crucial information for the ecological understanding and management of Caribbean amphidromous fishes.