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Characterization of fish
assemblages associated with high diversity and low diversity coral reefs
in the northwestern Gulf of Mexico |
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The majority of benthic habitat in the
northwestern Gulf of Mexico (GOM) consists of soft-bottom sand, silt,
and clay substrate, and it is likely that natural banks in the region
represent a critical habitat for corals, as well as reef fishes
requiring hard-bottom structure. Despite this, the resident fish
assemblages associated with many of these features have not been
thoroughly studied, and the relative importance of different bank types
(i.e. high diversity coral reefs vs. low diversity coral reefs) as
essential habitat for reef fish has never been quantified. Efforts to
characterize reef fish communities at high diversity coral reefs (East
and West Flower Garden Banks) and artificial production platforms in the
northwestern GOM began in 1997 with visual surveys on SCUBA, and these
were expanded in 2005-2006 to include two low diversity coral reef sites
(McGrail Bank and Sonnier Bank) as well as ROV surveys of deeper reef
habitats. More recent research has focused on comparing the community
and trophic structure of reef fish assemblages associated with low
diversity and high diversity coral reef habitats, as well as
characterizing seasonal and cross-shelf patterns of recruitment to both
reef types in an effort to improve our understanding of metapopulation
dynamics within the GOM continental shelf reef system. To directly
assess the relative nursery value of high diversity coral reefs, low
diversity coral reefs, and artificial structures (i.e. production
platforms) in the region, we are also in the process of analyzing
dietary composition (stomach content analysis and tissue stable
isotopes), growth rates (otolith microstructure analysis), and
nutritional condition (RNA:DNA) for two model species of juvenile
grouper collected from each habitat type in 2009 and 2010.

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Habitat connectivity of parrotfish at
Hawaiian coral reefs |
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We are collaborating with researchers at the University of Hawaii-Hilo
to examine habitat use and connectivity for two species of parrotfish at
both healthy and degraded coral reefs off the northwest coast of Hawaii
(Puako, HI) using acoustic telemetry. A VR2W positioning system (VPS) is
being used in conjunction with detailed habitat maps to investigate
fine-scale (spatial resolution <3 meters) movement patterns of palenose
(Scarus psittacus) and red lip (Scarus rubroviolaceus)
parrotfish across coral reef seascapes. The goal of this study is to
characterize species-specific patterns of habitat use across temporal
cycles (e.g. tidal, diel) at both degraded and healthy reefs to
determine how reef health affects habitat connectivity in Hawaiian
parrotfish.
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Dr. Jay R. Rooker Department of Marine Biology
Texas A&M University @ Galveston
1001 Texas Clipper Rd, Galveston, Texas 77554
rookerj@tamug.edu 409-740-4744
Site by Third Coast
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