You are here

Raymond Bauer

1969 B.S. (Biology) University of Missouri, Kansas City, KA

1976 Ph.D (Marine Biology) Scripps Institution of Oceanography, University of California, San Diego, CA


My areas of interest include marine biology, invertebrate zoology and the biology of crustaceans (shrimps, crayfishes, hermit crabs, stomatopods, crabs etc.). Specialized research focuses on structure and function, reproductive ecology, sexual systems, mating behavior, reproductive migrations of freshwater shrimps, and a variety of other aspects of the biology of crustaceans. Please visit my research website: A summary of research interests is given below.

One major interest is reproductive ecology, specifically, what are the environmental factors and selective pressures which explain latitudinal variation in spawning patterns in shrimps and other crustaceans? Over the years, considerable work has been done on hermaphroditism in shrimps such as Thor, Lysmata and rhynchocinetid species. The goal of this comparative work is to understand why the various forms of hermaphroditism evolve in some species but not others. Mating strategies and behavior of shrimps and other crustaceans are yet another focus of research. All of these studies involve field work, behavioral observations using time-lapse video, and experimental work to test hypotheses.

Much of my work has been on the adaptive value of structures of unknown or undocumented function. One ongoing interest is on antifouling mechanisms and behavior (how do shrimps and other crustaceans maintain their bodies free of aquatic "dirt" and of fouling organisms that find their hard exoskeletons a good place to grow?). Fouling can severely impair sensory, respiratory, and locomotory systems of crustaceans. In this work, I like to use a mix of descriptive morphology (with scanning electron microscopy to document ultrastructual details), behavioral observations (often with time-lapse video), and manipulative experiments testing hypotheses on function. Another area of study about functional morphology has been the mechanics of insemination in caridean and penaeoidean shrimps, i.e., how do the often complex genitalia function during mating?. My work in functional morphology is always undertaken with an evolutionary perspective, i.e., what is the adaptive value and evolution of these structures?

My lab has studied a diadromous life history strategy of some freshwater species, known as amphidromy, in the river shrimp Macrobrachium ohione in the Atchafalaya river system, specifically the female migration to estuaries in the Gulf of Mexico to release larvae in salt water, where planktonic larval development takes place. We have documented the subsequent mass migrations of postlarval shrimps from the sea back up into rivers and the adult freshwater habitat.

As an Emeritus Professor, I have spent the last several years in continuing research, teaching short courses on shrimp biology in Latin America, and most recently working on a book on the biology of shrimps:

Bauer, R.T. 2023. Shrimps: Their Diversity, Intriguing Adaptations and Varied Lifestyles. Springer Cham. 720 pp., 199 b/w and 19 color figures, 26 color/greyscale (SEM) plates. Available in hard cover and pdf or eBook.

Book website:

Please feel free to contact me at