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Title

The Influence of Sea Surface Temperature, Chlorophyll Concentration, and Upwelling Index on Kogia Strandings in Florida

Author

Vincent U. Cordero, Nova Southeastern University

Defense Date

11-2011

Document Type

Thesis - NSU Access Only

Degree Name

M.S. Marine Biology

Department

Oceanographic Center

First Advisor

Edward O. Keith

Second Advisor

Jose V. Lopez

Third Advisor

Daniel K. Odell

Abstract

It has been demonstrated that certain environmental fluctuations correlate with cetacean strandings in many parts of the world. I examined the correlations between three environmental variables (upwelling coefficient, temperature, and chlorophyll a concentration) and Kogia strandings in Florida from 1998 – 2007. In addition I examined the correlations between El Niño Southern Oscillation (ENSO) events and Kogia strandings in Florida and the southeastern United States (SEUS) from 1977-2007. Florida was divided into four regions and strandings were segregated by region with 76% of the strandings occurring on the east coast of Florida. AVHRR Pathfinder satellite temperature data, and MODIS Aqua and SeaWiFS satellite chlorophyll a data were downloaded from NASA websites; NOAA Fisheries Southwest Fisheries Science Center upwelling data were downloaded from the ERD Live Access Server, and ENSO data were also downloaded from a NOAA website. Upwelling was examined on a per stranding basis.

For each stranding, a square region (16 km x 16 km) of ocean adjacent to the stranding was examined for upwelling index values for the two weeks prior to the stranding (in increments of six hours). Each region was divided into 16 sub-regions (4 km x 4 km). For each increment of time the data were averaged over all 16 sub-regions. A significant change in upwelling index was defined as a change of absolute value greater than or equal to 200 m3/s/100 m of coastline. Of the 174 strandings, 91 (52%) were correlated to at least one significant upwelling event within 14 days prior to stranding.

I examined upwelling, temperature, and chlorophyll a concentration on a seasonal basis. The Florida coastline was divided into 16 regions. Each region was examined, for all three variables, out to approximately 32 km from shore. For each region the data were averaged for each month over the entire ten year study and compared to the number of strandings in each region each month. Data covering the regions of Florida were merged into four large regions (the east coast, the Keys, the west coast, and the Panhandle). I found an inverse correlation between chlorophyll concentration and strandings in Florida. In addition I found an inverse correlation between upwelling and strandings on the west coast of Florida. I examined the ENSO record from 1977 to 2007. I found a direct correlation between ENSO events and strandings in Florida (R2 = 0.1626) and the SEUS (R2 = 0.2236).

NSUWorks Citation

Vincent U. Cordero. 2011. The Influence of Sea Surface Temperature, Chlorophyll Concentration, and Upwelling Index on Kogia Strandings in Florida. Master's thesis. Nova Southeastern University. Retrieved from NSUWorks, Oceanographic Center. (206)
https://nsuworks.nova.edu/occ_stuetd/206.