Recruitment of Atlantic croaker, Micropogonias undulatus: Do postsettlement processes disrupt or reinforce initial patterns of settlement?
Levin, Phillip S.
Stunz, Gregory W.
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Understanding the relative importance of pre- and postsettlement processes is critical to understanding the population dynamics of marine fishes. Our goals in this study were 1) to examine habitat preference and habitat use of newly settled Atlantic croakers, Micropogonias undulatus, and 2) to determine is postsettlement growth or predation varied with habitat type. Field surveys showed no differences in croaker abundance among three estuarine habitats: marsh edge, seagrass, and sand. Behavioral experiments in laboratory mesocosm suggested that the pattern of similar use of habitats in the field results from a lack of preference among habitats. In a field experiment, croaker recruitment was greater to articifal seagrass than to sand habitats, but there was no differences in fish density in habitats with or without food supplementation. Moreover, growth rates were similar in both sand and articfial seagrass habitats and in habitats with or without food supplementation. In a second experiment, we were unable to detect a difference in the density of newly settled croaker between sand and articifial seagrass habitats, or betwen habitats with predator access limited by cages and cage controls. Our results demonstrate that newly settled croaker use different estuarine habitats similarly, and there does not appear to be a fitness consequence of using many habitats. We suggested that for habitat generalists, such as the Atlantic croaker, variability in larval supply will be a stronger predictor of population dynamics that will varability of habitat attributions.