Can Spatial Structure of Juvenile Relatedness Inform Larval-Delivery Models: A Case Study with Cynoscion Nebulosus

Landscape genetic analysis of population connectivity has revealed that spotted seatrout (Cynoscion nebulosus) typically complete their life cycles within geographically-restricted ranges.  For members of spotted seatrout populations along the eastern Gulf of Mexico, the mean estimate of individual (lifetime) dispersal distance does not exceed 100 km.  To investigate localized spawning and recruitment dynamics for this species, we developed and applied novel analytical and statistical methods to ascertain first-order (parent-offspring, full-sibling and half-sibling) relationships among pairs of specimens.  The overall approach relies on genotype profiles from 34 highly variable microsatellite DNA loci.  In 2010, approximately 600 adult specimens from a large spawning aggregate in the Tampa Bay estuary were collected during the course of a spawning season and genotyped.  Approximately 600 young-of-the-year specimens from the 2010 year-class were collected throughout the estuary.  More than 450 first-order relationships were inferred among the specimen pairs.  As expected, the vast majority of first-order relationships were that of half-sibling; however, several full-sibling and parent-offspring relationships were also identified.  Using these data, analyses are currently underway to test the null hypothesis that familial spatial distributions are consistent with simulated spatial larval-delivery projections of hydrological models.