Graduation Year

2012

Document Type

Thesis

Degree

M.S.

Degree Granting Department

Marine Science

Major Professor

David J. Hollander

Co-Major Professor

Carole C. McIvor

Keywords

habitat use, nursery habitat, snook ecology, stable isotopes, trophics

Abstract

The common snook, Centropomus undecimalis, is an estuarine dependent sport fish that relies upon subtidal wetlands as nursery habitat. Despite the economic and recreational significance of this species, there are portions of its life history and biology that are poorly understood, particularly its early life history. Understanding juvenile snook use of wetland habitats is crucial given the rapid loss and degradation of these areas to anthropogenic impacts. Young-of-the-year snook were collected in pond and creek habitats of a single wetland system to assess early life ecology and habitat use. Proxies of habitat quality were used to determine which habitats within a small spatial scale were optimal for young-of-the-year snook recruitment. Results indicated that even on a very small spatial scale, differences in habitat use were apparent, whereby smaller snook initially recruited to pond habitats and dedicated all energy into growth. Upon reaching a size of at least 40 mm SL snook began an ontogenetic habitat shift and moved to the tidal creek habitat. There, snook began to store energy, thus becoming more robust. Stable carbon and nitrogen isotopic analyses confirmed the ontogenetic habitat shift and revealed that snook have high site fidelity within the pond and creek habitats. Stable isotopic analysis also indicated that YOY snook appear to feed at the third trophic level consuming neonatal poecilliids and shrimp, and ultimately rely on benthic microalgae and particulate organic matter as basal resources. Results of this study advance the knowledge of juvenile snook ecology and will likely have implications for resource managers who are responsible for preserving and restoring wetland habitats upon which juvenile snook rely.

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