Show simple item record

dc.contributor.advisor Read, Andrew J en_US
dc.contributor.author Torres, Leigh Gabriela en_US
dc.date.accessioned 2008-01-02T16:33:38Z
dc.date.available 2008-01-02T16:33:38Z
dc.date.issued 2007-11-14 en_US
dc.identifier.uri http://hdl.handle.net/10161/449
dc.description Dissertation en_US
dc.description.abstract The heterogeneous landscape of Florida Bay provides habitats for a variety of predators and prey. This dissertation examined the bottom-up transfer of affects from environmental variability through prey composition up to competition and predation affects on top predator distribution and foraging ecology in Florida Bay. Line transect surveys for bottlenose dolphins and seabirds were conducted in Florida Bay during the summer months of 2002 - 2005. Photo-identification techniques were implemented to identify individual dolphins. Synoptic with this survey effort, habitat characteristics (temperature, salinity, dissolved oxygen, turbidity, chlorophyll a, depth and bottom type) and prey composition (bottom trawl or gillnet) were sampled. Comparison of envelope maps from generalized additive models determined that predictive capacity of dolphin habitat did not improve by incorporating fish distribution data. However, models of dolphin distribution based solely on environmental proxies of fish distribution resulted in high predictive capacity. During the 2005 summer, shark distribution was sampled using a longline. The abundance of sharks was only correlated to fish catch from trawls on a regional scale. Larger sharks, of species that may threaten dolphins, were only caught in the Gulf zone of the Bay. Analysis of dolphin distribution revealed high individual site and foraging tactic fidelity. Dolphins were spatially coincident with habitat characteristics that encouraged the use of each individual's preferred foraging tactic. Depth was identified as the primary variable determining dolphin foraging tactic choice. Depth plays a significant role in the benthic composition of Florida Bay, which subsequently impacts prey communities and affects dolphin distribution, foraging and social ecology. Ordinations determined that fish distribution was also principally affected by depth and bottom type. Shallow environments frequently corresponded with mudbank habitat (depth < 1m) where the sighting rates of seabirds (cormorants, osprey, pelicans, terns) and foraging dolphins peaked. In conclusion, subtle relief in South Florida's bedrock topography dramatically affect benthic composition within Florida Bay, providing patchy habitats for prey and predators. The Florida Bay ecosystem will change with expected sea level rise, including spatial shifts of mudbank habitats. Top predator populations in Florida Bay will be forced to modify their distribution and foraging ecology accordingly. en_US
dc.format.extent 4905562 bytes
dc.format.mimetype application/pdf
dc.language.iso en_US
dc.subject Environmental Sciences en_US
dc.subject predator en_US
dc.subject prey interactions en_US
dc.subject Bottlenose dolphins (Tursiops truncatus) en_US
dc.subject Florida Bay en_US
dc.subject seabirds en_US
dc.subject sharks en_US
dc.subject habitat use en_US
dc.title Top Predator Distribution and Foraging Ecology in Florida Bay, Florida en_US
dc.type Dissertation en_US
dc.department Environment en_US

Files in this item

This item appears in the following Collection(s)

Show simple item record