Pioneers in Marine and Fisheries Research at the Gulf Coast Research Laboratory 

Robin M. (Bob) Overstreet

August 1, 2012

Dr. Robin (Bob) Overstreet, research pioneer at the Gulf Coast Research Laboratory This is the third contribution in our series of “Pioneers in Marine and Fisheries Research at the Gulf Coast Research Laboratory.”  The first article was on Tom McIlwain, longtime GCRL scientist and administrator, and the second on Jim Franks, Senior Research Scientist in the Center for Fisheries Research and Development at GCRL.

The present article deals with Robin M. (Bob) Overstreet, marine parasitologist and professor in the Department of Coastal Sciences at the Gulf Coast Research Laboratory.  The background for this narrative came mainly from discussions a group of scientists and colleagues had with Robin.  The group included Jeff Lotz (Interim GCRL Director and Professor), William Font (Professor Emeritus and Scholar in Residence, Southeastern Louisiana University), Ash Bullard (Assistant Professor, Auburn University), Ronnie Palmer (Senior Parasitology Technician), Chris Snyder (Director of the GCRL Marine Education Center) and William Hawkins (former GCRL Director and Professor Emeritus). 

By any measure Robin Overstreet is an elite scientist.  According to his curriculum vitae, he has published over 300 peer-reviewed research papers, garnered almost $20M in extramural support for his own research and collaborated on a total of about $50M in research funding. He has mentored students ranging from high school to post-graduate, including 16 who earned their graduate degrees working in Overstreet’s laboratory.   Many consider him to be the premier aquatic (both marine and freshwater) parasitologist in the world.  Certainly any serious aquatic parasitologist is familiar with Overstreet’s body of work in the field, and his travels worldwide have bolstered that reputation. 

The discipline of parasitology is not an esoteric scientific exercise.  There are more parasites on Earth than there are free-living animals. While many organisms evolve to be parasitic, parasites themselves rarely if ever ‘abandon’ the lifestyle and become free living. This makes the study of parasites a multidisciplinary and highly integrated and relevant field of biology. Parasitologists typically must be intimately familiar with a great diversity of organisms because they take them apart (literally, during a necropsy) but also because the biological attributes of the parasite's host impact the biology and occurrence of parasites infecting them.  Of course parasites also cause major human and animal diseases. 

Robin’s research in aquatic parasitology has spanned collecting, describing (“taxonomy”), and classifying (“systematics”) parasite biodiversity as well as characterizing how parasites and hosts live their lives together (“parasite ecology”), which includes solving problems associated with disease in natural and man-made settings.  Overstreet has exemplified the modern, integrated biologist, with many of his most important contributions addressing parasites and disease including the use of parasites as indicators of ecological and environmental health and the use of fish to identify cancer causing agents in the environment.

Robin’s relentless drive to describe the natural world around him and from a parasitology perspective has shaped a significant body of knowledge regarding marine ecology, biodiversity, and aquatic animal health in the Gulf of Mexico. We know a lot more about the Gulf because of him.

Early Years and Professional History

Robin grew up in Eugene, Oregon.  His father, a pediatrician, treated the family of Bill Bowerman the track coach at the University of Oregon and in trade for treatment Dr. Overstreet turned down some cheap stock in a small company that made running shoes.  The company went on to become Nike, Inc., of which Bowerman was a co-founder.  Robin hunted and fished with his dad and in high school developed interests in football, basketball and track, and in building and racing cars.  Needing time to think about his life’s direction, he joined the Navy and served on icebreakers from 1957-1959 venturing to both poles.  While in the Navy he developed a keen interest in oceanography, working with the civilian oceanographers on board and collecting biological specimens. Some of those now are archived in the Smithsonian Institution in Washington, D.C. 

After his Navy hitch was up, Robin returned to Eugene and enrolled as a business major at the University of Oregon but quickly changed his attention first to advertising then to science.   Opportunities as an undergraduate science major arose for him to spend time on the Oregon coast where he went out on shrimp boats and conducted detailed studies of parasites of cephalopods (octopuses) and his interest in parasitology was ignited.   This experience clearly demonstrated to him and others his passion for marine biology and one of his professors at Oregon suggested that he go to a marine biology institution for his graduate degree.  He applied for and was accepted into three graduate programs: Scripps Institution of Oceanography, Auburn University and the Institute of Marine Science, now named the Rosenstiel School of Marine and Atmospheric Science (RSMAS), at the University of Miami.   Although there was only one parasitologist at RSMAS, Edwin Iverson who would be Overstreet’s major professor, Overstreet chose Miami because he believed it had a stronger biology emphasis than the other schools, and perhaps because of the sage advice that his professor at Oregon had given him as an undergraduate. 

South Florida proved to be a rich area to study marine parasites with its abundant and diverse fishes and, at that time, healthy marine environment.  The Rosenstiel School similarly was an intellectually rich environment for energetic students like Robin, and while there he met most of the important, practicing ichthyologists from that period who came from all over the world to collaborate, teach, and collect specimens in the waters of South Florida. “I was very lucky,” Overstreet said about his experiences in Miami.  With advice from his committee members Ed Iverson, Richard Robins, Frederick Bayer, Henry Leigh, and Carl Sindermann, Robin’s research interests eventually centered on the ecological aspects of trematode and other parasites that infected the inshore lizardfish, Synodus foetens.  Trematodes, or “flukes,” develop partly in snails and bivalves before maturing in the gut of the fish, birds, and mammals, the “definitive hosts” that eat or come near them.  There are an estimated 50,000 species of flukes (For perspective, there are fewer than 27,000 fish species.), including the blood-dwelling flukes that cause schistosomiasis and continue to affect millions of people each year in developing countries. 

Robin has now been recognized as a scientific authority on this particular group of parasites for several decades. This deep, foundational knowledge of parasites and diseases has spilled over to other fields and society. In fact, it may have even helped to save an industry.  Early in the ‘00s, the channel catfish industry of the southeastern United States had a big problem with ‘worms’ affecting their product.   Responding to the call for help, Robin identified and described the new species of trematode as the etiological agent of the infection, determined its life cycle, and developed a control plan by instructing the catfish farmers to eliminate the snail that served as the host for a fluke that infected pelicans that would fly over, aggregate around, and hunt in the catfish ponds and transmit the parasite to the catfish.  The best management practices he recommended to the industry remain in place today and have been very important to the catfish industry, the largest aquaculture producer in the United States and a multi-million-dollar-per-year industry. Although just one example, it also serves to demonstrate Robin’s attraction to and effectiveness at solving problems that matter to a lot of people.

Solving the catfish problem is only one example of Robin’s service to the people of Mississippi, commercial and recreational fishermen, wildlife biologists and the seafood industry.  He has also provided free consultation and diagnoses to various entities on blind alligators, endangered gopher frogs, and birds that were being electrocuted in Ocean Springs Harbor as they flew into power lines.  A professor who did a sabbatical in Overstreet’s lab several years ago said that one of his strongest memories was of someone coming or calling in with a critter with a problem and that Robin never turned anyone away, no matter how busy he was. 

Back to his professional history, Robin’s development as a doctoral student would be unrecognizable to many present-day doctoral students of the sciences.  He was largely self-directed and aggressively sought expertise wherever he could find it whether at his home university or elsewhere. While enrolled in Miami in 1966, he ventured to Tulane University and participated in a summer parasitology course, taught by Paul Beaver (School of Public Health and Tropical Medicine).  Beaver at that time was one of the world’s leaders in tropical medicine and hygiene- belonging to a generation of scientists who experienced first-hand a world reality wherein parasites were killing millions of people each year and many vaccines and other anti-parasitic drugs were unavailable. Suddenly, Overstreet was in the midst of a powerhouse in Beaver, who at that time had 15 post-doctoral and associate researchers (a typical laboratory today might have 1 or 2) and was the editor of the American Journal for Tropical Medicine and Hygiene, the principal journal of its time for human parasitology.

“Once again, I was really lucky,” Overstreet said about this period of his career. It was in this bustling academic environment that Overstreet’s confidence and knowledge of the field of parasitology began to surge. This experience would later result in Ph.D. student Overstreet searching for expertise (although by this time he was quickly being an expert himself) from Raymond Cable (Purdue University, West Lafayette, Indiana) and Harold W. Manter and Mary Lou Pritchard (University of Nebraska, Lincoln), other iconic figures of North American parasitology. When Overstreet corresponded with Manter, Manter said he should visit their laboratory and discuss matters face-to-face. This ultimately resulted in  his Ph.D. thesis, which comprised a survey of the parasites that infect fishes of Biscayne Bay; the work, published as a ‘Tulane Monograph’ that would, for the first time, identify Overstreet as a heavy hitter of Parasitology.  His prior experience at Tulane led him to a postdoctoral fellowship with Beaver to learn how two species of Baylisascaris (parasites with human health implications) debilitated rodent hosts so that the raccoon and skunk final hosts could eat them and become infected.  

By this time, Overstreet had reached out and interacted with many of the most influential parasitologists in North America; he had published one of the most comprehensive taxonomic treatments of fish trematodes in existence, and he was now looking to put roots down and establish his own laboratory of aquatic parasitology.  During this time his wife Kim earned a Master's degree in English at LSU-NO (now the University of New Orleans), taught in the Upward Bound program, and took up quilting. Both she and Bob developed a lifelong infatuation with the city of New Orleans and especially Mardi Gras. Working in Beaver’s lab was perhaps the defining experience in Robin’s parasitology education.

In 1969 Robin reached the Gulf Coast Research Laboratory where he has spent his entire career by a somewhat circuitous route.  In the mid-1960s during his travels to Miami to start graduate school and Kim's first teaching gig, they were waylaid by car trouble for nearly a week on the Mississippi Gulf Coast.  At that time, the Gulf Coast had an anything-goes, wild-west aura with illegal gambling, prostitution and alcohol abundant.  For the Overstreets, whatever could go wrong did and they vowed that Mississippi was one place they did not intend to seek employment.  But in New Orleans, Robin learned of a job opening at the GCRL in the quaint seaside village of Ocean Springs.  In 1968, Robin visited GCRL and he saw an outstanding opportunity to set up a world class marine parasitology research lab. Both he and Kim immediately fell in love with Ocean Springs, which would become their home and the birthplace of their two sons.

Robin promptly set about equipping a laboratory, hiring support staff, and recruiting graduate students. His  first hire, Ronnie Palmer, remains with Overstreet today as a part-time, retired, Senior Parasitology Technician.  It has been stated that Ronnie has very likely collected and prepared more parasite specimens than any other living person, having conducted literally thousands of fish necropsies over his 40+year partnership with Robin. Robin’s first doctoral graduate student, Richard Heard, is a professor alongside Robin in the Department of Coastal Sciences and is a recognized authority on marine and, especially, salt marsh ecology.  

One of Robin’s most significant projects was to establish a course on marine parasitology in the GCRL Summer Field Program.   The course attracted undergraduate and post graduate students from all over the U.S. and Robin used it to recruit and evaluate potential graduate students.  Overstreet has been the recipient of numerous professional awards both domestic and international including the Czechoslovakian Fish Farmer Award, Mississippi Academy of Sciences Award for Outstanding Contributions to Science, Fellow of the American Academy of Microbiology, The University of Southern Mississippi, University Research Council’s Research Award for Applied Research and the American Fisheries Society S.F. Snieszko Distinguished Service Award.  He was the first recipient of The University of Southern Mississippi Innovation Lifetime Achievement Award.  Due to his gender neutral given name he has been offered several ‘women in science’ awards, all of which he has declined.

Robin’s impact on marine biology and parasitology, in particular, has been substantial.  He has identified and described many parasite species previously unknown to science and characterized specifics of the life cycles of many others.  Overstreet’s commitment to his research is without question even once infecting himself on purpose with a fish tapeworm to study its biology. 

Graduate Students

Most of Robin’s 20 former graduate students have gone on to have productive careers in science and biology, including several of his Ph.D. students that remain active as professors conducting parasitological research (see partial list below).

We will explore three areas of Overstreet’s research that have had special or broad impact.  They are (1) parasites and disease in shrimp aquaculture, (2) the use of fish in cancer research and (3) parasites and diseases as indicators of aquatic ecosystem health.  

Parasites and Disease in Shrimp Aquaculture

The United States now imports more than 90% of the marine shrimp it consumes, with the bulk coming from Southeast Asia (Thailand, Indonesia, China and India) and South America (Ecuador and Brazil).  By far the predominant shrimp species being cultured is the Pacific whiteleg shrimp.  None of this was the case in the early 1980s when the majority of the shrimp consumed in the U.S. was wild caught.  At that time, shrimp aquaculture was just getting started, was being conducted mainly abroad and with several species being farmed. Generally the industry was without a clear biosecurity plan for managing disease outbreaks.  

Aiming to jump start a U.S. marine shrimp farming industry researchers from the Oceanic Institute in Hawaii and GCRL conceptualized a multi-institutional consortium that would address issues related to the development of a U.S. industry. The group formed the United States Marine Shrimp Farming Program. The program soon grew to include Tufts University, Texas A&M, the University of Arizona and the South Carolina Department of Wildlife and Fisheries.  Later Nicholls State University (Louisiana) was added.  The program was funded from 1984 until 2011 when cutbacks in federal funding resulted in its demise.  The consortium developed a very innovative two-level management scheme that served it well and which has been a model for other multi-institutional consortia.  The first level was an ‘executive committee’ and consisted of administrators representing each member institution. The executive committee was responsible for raising and distributing funds and setting overall objectives for the program.  The second level, the ‘technical committee’ comprised a principal investigator from each institution and was responsible for setting and executing the specific research agendas.  Overstreet served as the first principal investigator representing GCRL on the technical committee. 

Early on strong philosophical disagreements occurred among the management committees as to whether the consortium agenda was an exercise in economic development or a research dominated consortium that would address specific scientific issues constraining or likely to constrain U.S. shrimp industry development.  In his insistence on having shrimp diseases be a thrust of the consortium, Robin was very persistent.  As the industry developed, devastating diseases, mainly viral ones, decimated shrimp aquaculture culture industries of entire countries.  Consortium scientists have been instrumental in identifying and recommending controls for diseases in shrimp aquaculture operations. A spinoff of the disease studies has been the development of the ability to conduct controlled laboratory experiments on shrimp diseases. This helped lead to the development of specific pathogen-free stocks of shrimp that now dominate the world shrimp production industry. 

The Use of Fish in Cancer Research

Cancer experts believe that the percentage of cancer cases due to exposure to environmental cancer causing agents (carcinogens), including smoking and diet, is certainly more than 50%.  Identifying those carcinogens has been dependent traditionally on the use of rodents (rats and mice) in controlled laboratory studies that are lengthy, expensive and sometimes difficult to interpret in the context of human risk.  Although it was known that fish could develop cancer, in the 1980s epizootics (epidemics in animals) of liver cancer began to show up in wild fishes in the Puget Sound, Great Lakes region and Boston Harbor among other locales.  Scientists at the National Cancer Institute (NCI) thought that fish might be good models for the study of environmental carcinogens including those that are sometimes found as by-products of disinfection in drinking water, the trihalomethanes.  NCI put out a contract to study the feasibility of using fish to test drinking water carcinogens. Overstreet recognized that GCRL with a state-of-the art toxicology facility and available expertise in analytical chemistry, fish culture, and fish pathology had the capacity to conduct the studies and set about developing a proposal. 

Competing against the likes of Stanford Research Institute, Battelle and Michigan State University, GCRL was awarded the contract that began a program of studies on fish and environmental cancer that lasted more than ten years and was continuously funded through competitive grants and contracts from the NCI as well as the U.S. Army, the American Petroleum Institute, American Cyanamid and the National Institutes of Environmental Health Sciences.   The studies produced many publications and supported several graduate students who went on to outstanding careers in aquatic toxicology and pathobiology.  The studies also established GCRL as a leader in the use of fish to study environmental carcinogenesis.  Overstreet’s greatest contribution might have been in developing procedures to insure that the fish used in the studies were as uniform as possible as far as genetics, diet and health were concerned.  Approaches that he and colleagues at GCRL developed are now widely employed in fish cancer studies.

Parasites and Diseases as Indicators of Ecosystem Health

Overstreet has long championed the use of parasite abundance and distribution as well as the prevalence of other diseases as indicators of the health of aquatic environments.  Concerning the parasites, it might be counter intuitive to some but because many parasites have multiple hosts, the lack of parasites within an ecosystem might indicate the absence of some host organism and a weakened ecological status rather than the contrary.  Furthermore, the role parasitic and infectious diseases play in modulating populations of aquatic organisms, as diseases do for almost every other type of organism studied, is poorly understood especially for the Gulf of Mexico.  Robin is perhaps the leading authority in this scientific arena and has collected and maintained many long-term data sets on parasites and diseases of the aquatic organisms of the Gulf. 

Recently it has been particularly vexing to Overstreet to hear reports of incidental lesions or parasites in fishes that are immediately attributed to the Deepwater Horizon oil spill of 2010.  Without comprehensive and long term studies on the prevalence of diseases and parasites in ecosystems as well as in individuals, it is impossible to attribute a specific cause to a particular lesion in an open and dynamic system like the Gulf of Mexico.  He contends that pronouncements that lesions in fishes and invertebrates being caused by the spill are needlessly harmful to the economy and esthetics of the region.   Only through the mining of existing data, seeking consensus among aquatic disease experts on the diagnosis of specific lesions and initiating long term observational studies on the prevalence of parasites and diseases in the Gulf of Mexico can accurate scientific judgments be reached.

Publications

These Overstreet's publications have cited more than 20 times, according to ISI Web of Knowledge.

Compiled by:
William E. Hawkins
Director and Professor (Retired)
Gulf Coast Research Laboratory
william.hawkins@usm.edu