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Research Staff

Kristen Delano Walter

Graduate Students

Evan D'Alessandro
Klaus Huebert
Tauna Rankin
Kathryn Shulzitski
Sean Bignami

Undergraduate Assistants

Jennie Boulay
Jared Robbins
Jack Silverman
Caitlin Hill

Volunteers

Lindsay Glade
Susan Edwards

Alumni

In 2004 I received my Master's in Marine Science from the School of Marine Science at the College of William & Mary. My previous work spanned a wide range of taxa (including corals, clams, crabs, lobsters, American shad, and Atlantic sturgeon) in a variety of ecosystems in the Chesapeake Bay, Bahamas, and Florida Keys. My interest's tend towards population and landscape ecology, integrating biological, physical, and environmental approaches. I have extensive field experience piloting small boats in the Chesapeake Bay and the open ocean and a diverse diving resume that includes the zero visibility, tidally driven conditions in Chesapeake Bay as well as saturation diving in the Florida Keys at the Aquarius Underwater Habitat. I came to RSMAS in 2007 as a Senior Research Associate and currently am involved in a National Science Foundation project assessing linkages in recruitment of Florida Keys reef fishes. My main role in the lab is to organize, coordinate, and execute the NSF project field and labwork, but I also manage the day-to-day group and laboratory needs, oversee undergraduate interns and volunteers, maintain the databases, and collaborate on research projects, permit/grant writing, and manuscript publication.

My research interests involve the early life stages of coral reef fishes and how physical environmental factors interact with them to produce observed patterns of larval fish growth, delivery, settlement, and survival. In particular, I am interested in the effects that stochastic oceanographic features, such as internal tidal bores and large scale gyres, may have on the delivery of fish larvae to reefs. My master's thesis research was centered on an extensive time series of near-reef ichthyoplankton samples collected off Key Largo, Florida. By comparing this data to concurrently collected oceanographic and atmospheric data, we (Dr. Sponaugle and myself) were able to describe the pattern of larval fish supply to this area in terms of both cyclic and stochastic environmental factors. This research helps to improve the predictability of recruitment, a key piece of information required for effective reef management.

More recently, I have focused my research on a single species of reef fish that utilizes multiple nearshore environments during its life cycle, the great barracuda ( Sphyraena barracuda ). This species is found worldwide in tropical and subtropical waters where it is often an important food source, yet little is known of its general ecology, especially early life stages. Goals of my dissertation are to describe the early life history (distribution, growth, diet etc.) of this species and compare its bioenergetics and growth rates in different coastal habitats and geographic locations.

The distribution and community structure of fishes on coral reefs are largely determined by the transport and settlement of larvae and juveniles to reefs from the open ocean. Studying these early life history stages is therefore vital to understanding coral reef (fish) ecology. Due to their small size and fragile nature it is difficult to work with pelagic fish larvae and particularly little is known about their behavioral ecology. The goals of my dissertation research are first to describe the ability of coral reef fish larvae to orient and navigate in the ocean and second to predict the impacts of active swimming behavior on larval transport. I am taking three different approaches to work towards these goals: the analysis of larval fish distributions from plankton net samples, behavioral laboratory experiments with wild-caught larvae and direct observations of larvae swimming in their natural environment.

My research focuses on the early stages of life of coral reef fishes and their influence on population dynamics. The early life stages of many species of coral reef fishes are characterized by considerable and highly variable rates of mortality and these stages (i.e. egg and/or larval) may be the only part of the life cycle where significant dispersal occurs. Therefore processes occurring during early life may dramatically impact the overall condition of surviving individuals, year class strength, and genetic make-up of future populations. The overall goal of my dissertation research is to identify sources of variation and mechanisms important to recruitment and early juvenile life for coral reef fishes in a highly dynamic oceanographic system. Some of my individual objectives are: 1) to d etermine the temporal composition of cohorts of late-stage larvae and early juveniles using genetics and early life history traits, 2) identify traits important to survival during early juvenile life and test for carry-over effects from larval history, and 3) identify the causal mechanisms for trends in early life history traits, such as early juvenile growth.

The extent of interpopulation exchange, or connectivity, is a fundamental element in understanding ecological and evolutionary processes in the marine environment and in determining the utility of management and conservation strategies. My master's research at the University of North Carolina Wilmington examined genetic connectivity between populations of mutton snapper, Lutjanus analis , distributed across the Caribbean Sea using microsatellite markers. As genetic markers are highly sensitive to the exchange of very few individuals, they provide information on an evolutionary rather than ecological time scale. For example, populations can be genetically well-connected with a rate of interpopulation exchange that is demographically insignificant. Since demographic patterns and processes are crucial to the management of marine populations, this work led to my interest in alternative methods for approaching questions of population structure and dynamics on an ecological rather than evolutionary time scale. Population connectivity is not only determined by dispersal, but also by settlement and post-settlement processes that affect survival of late-stage larvae and juveniles as they transition from a pelagic to a benthic environment. In my dissertation research, I hope to make linkages between planktonic larvae and benthic juveniles in order to better understand factors affecting growth and mortality across early life history stages and their subsequent impact on recruitment dynamics.

Senior Honors Thesis: Larval growth and size-selective mortality in a common reef fish in the Straits of Florida .

My undergraduate research focuses on the early life history traits of a common Western Atlantic reef fish. I am evaluating traits such as size and growth at a specific age by comparing otolith size and growth rate of larval Thalassoma bifasciatum collected monthly from 17 stations along a transect across the Straits of Florida. I am interested in how these otolith-based traits influence the mortality of fish returning to the reef. The goal of my research is to determine if there is size and/or growth-selective mortality acting on the early life stages of T. bifasciatum .

Lisa Havel -- Graduate Student, Marine Science Institute, The University of Texas, Port Aransas, Texas ( lisie530@netscape.net )

Kelly Denit -- Program Coordinator Office, National Marine Fisheries Service/NOAA, Washington, DC (Kelly.Denit@mail.nems.noaa.gov)

Kirsten Grorud-Colvert -- PISCO/COMPASS Marine Reserve Science Coordinator, Oregon State University, Corvallis, Oregon (grorudck@science.oregonstate.edu)

Michelle Paddack -- PostDoc, Department of Biological Sciences, Simon Frasier University, B.C. Canada (michelle_paddack@sfu.ca)

Paige Roberts -- Smithsonian Environmental Research Center, Edgewater, Maryland (robertssp@si.edu)