Abstract

The gray snapper, Lutjanus griseus, is an ecologically and commercially important fish throughout the Caribbean. Despite its significant role in the marine ecosystem and its economic value, relatively little is known about the early life history of this species. Length of larval life may influence the geographic boundaries of local populations and linked to this is larval growth rate. Faster growth during larval life may result in shorter pelagic larval durations (PLD) and may give fish a survival advantage. Elucidating latitudinal differences in early life history traits and the environmental conditions leading to faster growth of larval and juvenile snapper should shed insight into the dynamics of larval life and the potential for population connectivity. As part of a larger study of population connectivity, young of the year L. griseus were collected from five sites in the southeastern United States during Fall 2000 and 2001: Florida Bay, Biscayne Bay, Sebastian Inlet, and Jupiter, Florida, and Core Sound, North Carolina. Fish were measured, weighed and the sagittal otoliths removed for aging. Standard otolith aging techniques were used to enumerate daily growth increments. Results demonstrated significant differences in growth rates among sites and between years, which may be correlated with environmental factors, such as temperature. There were also significant differences in the PLD of juveniles between years and sites. Despite this, the larval trajectories across sites and years were similar. The similarities among larval growth trajectories suggest that all of the snapper within a given year were either in similar water masses or the same water massduringtheir larvallife. The disconnection between larval growth and PLD may imply that habitat availability during transport, not growth, is determining settlement.

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