SEMINAR: MBF602 STUDENT SEMINAR ***FRI 9/28 @ 1PM---Erica Towle & Bruce Pohlot

[Pam Harris <pharris@rsmas.miami.edu>]

 

MBF Student Seminar Series

 

Erica K. Towle

Advisor: Dr. Chris Langdon

“Variability in heterotrophic feeding capacity among Caribbean coral species: implications for resilience to climate change”

As atmospheric levels of CO2 increase, Scleractinian corals will face increased stress due to warming temperatures and declining pH.  Few studies to date have focused on physiological processes that may confer resilience to stress.  Increasing the energetic status of corals by enhanced heterotrophic feeding may mitigate the negative impacts of increased temperature (Grottoli et al 2006) and acidification (Cohen and Holcomb 2009).  Some species may be more capable of heterotrophy than others, and such species-specific differences may play a key role in determining resilience to climate change.  In  a study of nine Caribbean coral species, heterotrophy rates were quantified across four treatments: 27°C, 390 ppm CO2; 27°C, 900 ppm CO2; 30°C, 390 ppm CO2; and 30°C, 900 ppm CO2.  S. siderea, M. cavernosa, and M. faveolata had depressed feeding rates at high temperature or high CO2, while D. strigosa, S. hyades, D. stokesii, and A. agaricites showed increased feeding rates at high temperature or high CO2.  P. divaricata and S. radians showed no difference in feeding rates at elevated temperature and CO2.  If heterotrophy is a marker for resilience to climate change stress, corals with increased heterotrophy at stress may be “winners” on reefs of the future, whereas those with decreased heterotrophy may require stronger conservation efforts.                                   

 

Bruce Pohlot

Advisor: Dr. Nelson Ehrhardt

“Discovering Pacific sailfish population dynamics: a technological approach to examining behavior and habitat use”

The Pacific sailfish, Istiophorus platypterus, is a vital resource to Central American catch-and-release sportfisheries operating in the eastern tropical Pacific. This fishery contributes substantially to the regional economy in the form of tourism, but sailfish are commonly caught as bycatch in commercial fisheries targeting mahi-mahi, sharks, and tunas, thus affecting population abundance and decreasing economically important recreational catch rates. Because of these declines, there exists a need to better understand the behavior of the eastern tropical Pacific sailfish to be able to properly manage and conserve the stock. A technological approach has been implemented to extract these behavioral dynamics through: satellite tagging, video analysis, diet analysis, and prey abundance surveys. Modern satellite tags are capable of collecting large amounts of data over long periods of time. Our tags also collect new information such as: acceleration data in high-resolution, behavior following release, feeding accelerations, and spatial and temporal aspects of movement both horizontally and vertically. This information will be coupled with a video analysis endeavor to examine sailfish feeding and locomotion within schools as well as a prey examination via diet analysis and abundance surveys. Modeling these behavioral aspects in relation to environmental and oceanographic features, especially oxygen constraints, is fundamental to understanding the species habitat usage and linkage to prey.

 

FRIDAY, SEPTEMBER 28, 2012

1:00pm

RSMAS campus, S/A 103

Pamela Harris

Marine Biology and Fisheries

Rosenstiel School of Marine & Atmospheric Science

University of Miami

4600 Rickenbacker Causeway/SLAB-118

Miami, FL 33149

(305) 421-4176

fax - (305) 421-4600

pharris@rsmas.miami.edu  

 

http://www.rsmas.miami.edu/academics/divisions/marine-biology-fisheries/