Graduate student, Johanna Imhoff received her B.S. and M.S. in Marine Biology from the University of North Carolina, Wilmington, where she studied the utility of an accelerometer tag for detecting feeding movements (e.g., chasing) in juvenile lemon sharks.  She then worked at the Florida Museum of Natural History for three years conducting fishery-independent surveys and tagging and tracking bull sharks and smalltooth sawfish in Florid waters. She came to the FSUCML with broad interests in feeding and movement ecology of marine fishes.

Johanna's dissertation research is focused on trophic (= feeding) ecology and mercury contamination in deepwater sharks in and near the De Soto Canyon in the northeastern Gulf of Mexico. She is studying six species of sharks that are mid-level predators, occupy a range of depths and demonstrate a range of feeding habits. She is interested in evaluating depth-mediated differences in feeding ecology of these species from a community ecology perspective. She also will investigate whether mercury contamination reflects feeding ecology along this depth gradient, and with respect to competition and niche partitioning. The Deepwater Horizon oil spill created the perfect environment for elevating methylmercury levels, in that methylation of mercury is facilitated by the microbes that degrade the oil and dispersants and the FSUCML's new vessel, the RV APALACHEE, provides the perfect platform for this work. Questions remain about the extent to which methylmercury has increased in the animals of the De Soto Canyon since the oil spill.  

In addition to this work, Johanna is investigating mercury contamination in sandbar sharks (Carcharhinus plumbeus) from Hawaii. She and Dr. Grubbs are comparing the total mercury concentrations of sandbar sharks caught in 2003-2005 to published values from sandbar sharks caught in 1971. They have muscle tissue from a wide range of shark sizes from embryos to adults, and from both stillborn and healthy embryos. 

Johanna attributes her success on these projects  to the support she has received from the FSUCML Scholarship and from Dr. Bill Landing (FSU Department of Earth Ocean and Atmospheric Sciences), in whose lab she has conducted her mercury analyses, with significant help from Dr. Vincent Perrot (postdoc in EOAS) and Ph.D. student Nish Krishnamurthy.  

This summer, undergraduate students in the Program of Marine Biology and Living Marine Resource Ecology linked up with the FSUCML graduate students and post-docs to get a taste of what it means to be a research scientist. Kali Spurgin, working with FSUCML post doc Dr. Stephen Gosnell, is working on local oyster reefs to determine how young oysters respond to the presence of predators.  Her project may offer some insight on how natural oyster reefs are structured, thus informing how we rebuild oyster reefs or grow oysters for harvest.  She is also evaluating how crown conch, a major predator in Appalachicola Bay, affect growth of oysters in aquaculture settings. 

Undergraduate Evan Courtney -- an avid fishing and boating enthusiast -- is working with grad student Zach Boudreau on stone crabs. For his project, he is conducting a tethering experiment with stone crabs to evaluate how claw loss influences rates of predation and burrow creation.  Before joining Zach, Evan had a productive summer immersed in research in the Field Marine Science class.

Ashley Dillon  is studying the behaviors exhibited by local sea anemones in the presence of their nudibranch predators.  Her  experiments are designed to characterize the interactions between these two understudied species. Thus, she is looking at the foraging behavior and prey choices of the nudibranch as well as the influence of nudibranch presence on the growth and behavior of the anemones.  

Katie Kaiser, after observing aggressive behavior of hermit crabs towards crown conchs, became interested in the relationship between these two species because hermit crabs often inhabit crown conch shells.  She has been characterizing the size and species distributions of snail shells preferred by hermit crabs both at the FSUCML and in St. Joe Bay.  Using this information, she has been conducting choice experiments to elucidate those species most vulnerable to direct aggression from hermit crabs.

Meaghan Feletti is working in the Florida Keys with graduate student Bob Ellis on the diet of invasive lionfish. Compared to lionfish in their native range (the Indo-Pacific), the lionfish invading U. S. waters are eating more, growing faster, and showing up in much higher densities.   Compared to native predators, lionfish can completely denude a reef of reef fish in just a few years.  Meaghan's study is the first to evaluate the diets of this invasive species as it invades a novel habitat, and will help us to better understand the full impact of this invasion.