Research
- Introduction
- Emerging Pathogens and Infectious Diseases
- Aquaculture and Aquarium Health
- Cetaceans (dolphins and whales)
- Manatees
- Sea Turtles
- Trace Elements/Environmental Toxicology
- Comparative Neurological and Sensory Physiology
- Permit Applications and Research Request Forms
- Grant Opportunities
- Student Research
Introduction
There is an increasingly greater depth of information available regarding aquatic species but unfortunately it is still quite limited when compared to domestic or terrestrial animals. While many aquatic species are maintained in progressive education based collections there is actually a near void in our knowledge base of wild aquatic animals and their reliance on the complicated environments they inhabit. To advance the conservation of these species it is imperative to investigate disease processes and environmental changes that impact these unique animals and their watery home. Human development and competitive activities threaten the very existence of many animal species relying on finely balanced ecosystems that are easily tipped in the wrong direction. There is a vast range of research that directly and indirectly benefits aquatic animals, from invertebrates to marine mammals, as well as their environments. The aquatic animal health program at the University of Florida contributes to our better understanding and management of aquatic species through basic and applied research.
Emerging Pathogens and Infectious Diseases
Research in the Marine Veterinary Virology Laboratory (MMVL)
The Marine Veterinary Virology Lab consists of researchers and graduate students with interests in diseases of marine animals. The lab has facilities at both the University of Florida (Gainesville, FL) and the Hubbs-SeaWorld Research Institute (San Diego, CA). We work in close collaboration with SeaWorld Adventure Parks and the U.S. Navy Marine Mammal Program on various aspects of infectious diseases, especially viral diseases, of marine mammals.
Our lab mainly provides expertise in virus discovery and marine mammal viral disease investigation. Pathogen discovery efforts go beyond the simple cataloguing of these agents. Instead, the veterinary relevance of newly discovered pathogens is explored via extensive disease investigations. We develop the tools needed to assess the clinical signs and severity of diseases that are caused by each agent. Using these data, the impact a virus may have on individuals and populations is then determined. A complete work-up of a pathogen typically includes surveillance of multiple wild and managed marine mammal populations for evidence of and frequency of virus and/or exposure. This information is then used to provide the science needed to generate guidelines for disease outbreak management and prevention strategies. Recent pathogen assessments include, but are not limited to poxviruses of seals, sea lions and dolphins, dolphin parainfluenzavirus type 1, San Miguel sea lion virus, dolphin enterovirus, and herpesviruses of whales and dolphins.
Failure of passive antibody transfer in neonatal bottlenose dolphins makes up a distinct, second research component of our lab. Like many other species, the amount of antibodies that dolphin calves receive via the dam’s colostrum significantly influences the survival of neonate dolphins. Failure to obtain these maternal antibodies is common, especially in stranded orphan calves. Our lab has developed protocols for the purification of intravenous-grade dolphin immunoglobulins (IVIG) for therapeutic use. IVIG supplementation protocols are currently based on empirical evidence. We are working closely with veterinary clinicians of various oceanaria and zoological parks to develop effective, science-based IVIG supplementation protocols for bottlenose dolphin calves.
The MVVL does not provide routine diagnostic services. Please contact Dr. Nollens or Dr. Stacy for inquires regarding our availability for sample submissions and participation in research projects.
Further information on the Marine Veterinary Virology Lab and active research projects can be found on the individual profile pages of MVVL members and the Publications page.
Lab members:
Brian Stacy, DVM, PhD, Dipl ACVP
James Wellehan, DVM, MS, Dipl ACVM, Dipl ACZM
Linda Archer, BSc
Rebecca Rivera, PhD (San Diego)
Katy Davis, BSc (San Diego)
Research in Dr. Carlos H. Romero’s Laboratory on marine mammal viruses
Work in my laboratories aims at isolating and characterizing viruses of marine mammals, with special emphasis on those that affect cetaceans and pinnipeds and adversely impact on their health. We use conventional and molecular assays for these purposes and over the years have been accumulating a significant amount of genetic data on viral members of the Caliciviridae, Herpesviridae, Papillomaviridae, Paramyxoviridae, and Poxviridae.
As very little is known about marine viruses’ genetic diversity and dissemination in their marine ecosystem, research efforts also involve developing improved diagnostic assays for virus detection in natural secretions and excretions and in lesions and tissues from affected marine mammals. Sequencing of full virus genomes or recovery of complete genes in the case of large genomes has allowed for the engineering of recombinant antigens and virus-like particles that are being used in ELISA platforms to study virus spread in the US Pacific and Atlantic coasts as well as in waters of the Gulf of Mexico.
The development of a real-time PCR assay has allowed for the identification of previously unknown gammaherpesviruses in mucosal lesions of captive and free-ranging cetaceans that affect the digestive, genital and respiratory tracts. Our group and other research groups hypothesize that the increase in clinical cases of gammaherpesviruses observed over the last decade may be a consequence of marine habitat degradation and relative immunosuppression of marine mammals. Real-time RT-PCR assays have also been developed for the rapid detection and identification of known and emerging marine vesiviruses of Steller sea lions from Alaska waters. Furthermore, real-time RT-PCR assays recently developed in our laboratories for the detection of morbilliviruses were successfully used to identify a dolphin morbillivirus associated with mass mortality of striped dolphins in waters of the Mediterranean coast of Spain in 2007. These unique real-time assays allow for the first time for the rapid differential diagnosis of dolphin and porpoise morbillivirus.
For more information please visit Dr. Romero's profile which contains publication and contact information.
Research in Dr. Sheppard's Laboratory
Discovery and investigation of the OIE- reportable shellfish pathogen, Perkinsus olseni, in ornamental reef clams, Tridacna crocea, legally imported from Vietnam into the USA (Sheppard and Phillips, 2008); cross-infection potential for domestic shellfish; implications/sentinel role for ocean health and enhanced escalation of pathogen loads in stressed aquatic ecosystems. For more about this discovery see the article in our News section.
Investigation of brevetoxin-induced DNA damage, mitogenesis, and apoptosis in human lung cancer cell lines, collaborative investigation and development of murine cancer models with UF Cancer Center, and detoxification mechanisms in aquatic molluscs and environmental/evolutionary relevance of toxin metabolism for aquatic invertebrate resistance.
Special interest in aquatic invertebrate pathology; pathologist for endangered Partula sp. snails and aquatic invertebrate TAG.
We generally do not test outside samples but will accept samples on an individual basis if contacted directly.
For more information please visit Dr. Barbara Sheppard's profile which contains publication and contact information.
Please visit Dr. Lisa Farina's profile for information on her research work.
UF Emerging Pathogens Institute
Aquaculture and Aquarium Health
Health Surveillance of cultured Florida hard clams Mercenaria mercenaria
Baseline health monitoring of cultured stocks has proven to be an important management tool. In 2003, DFAS and SAEP faculty conducted a preliminary health assessment of cultured clams by examining samples from 3 growing areas in the state during the winter and summer. No serious disease-causing agents associated with clams were detected. However, there is a growing concern regarding the health of stocks as growers report crop losses during the summer months. Stressors such as high temperatures, poor water quality, or high stocking densities are typical concerns. A more thorough examination of stocks both prior, during, and after the problematic summer months is necessary to determine if environmental diseases or disease pathogens are present. This project conducts health surveys of cultured clams from lease areas and of hybrid stocks.
Site visits to clam hatcheries and a survey of hatchery protocols may reveal practices that are limiting seed production. Increasing shellfish seed production would increase industry growth. A minimum of four commercial hatcheries will be visited and their protocols reviewed with emphasis on water treatment, algae culture practices, and larvae and post-set culture practices. Health of larvae and post-set seed will be assessed. In addition, two workshops (one on each Florida coast) given by a nationally recognized hatchery/disease expert will review hatchery protocols and health of clam seed stocks will be conducted.
Surgeon Fish Nutrition
Coming soon...
Perkinsus information
UF Tropical Aquaculture Laboratory
Cetaceans (dolphins and whales)
Gastrointestinal physiology
Coming soon...
Manatees
Research in Dr. Iske Larkin's Laboratory
A descriptive analysis of Florida manatee (Trichechus manatus latirostris) embryology
The overall goal is to help us better understand embryological and fetal development of the endangered Florida manatee. By understanding normal development, we can better understand when problems in development lead to death in a calf during pregnancy or shortly after birth (i.e. neonatal and perinatal mortality).
The Florida Manatee, Trichechus manatus latirostris, is an aquatic mammal of the order Sirenia. Studies of manatee reproduction have thus far focused on natural history data such as gestation length, birthing interval, age at sexual maturity, and associated mating behavior. Little work has been done to focus on embryological and fetal development of the manatee. Understanding normal manatee embryological
development may provide critical information for understanding trends in early mortality, allowing us to differentiate between healthy and unhealthy states.
The long life and low reproductive rate of the Florida manatee makes it susceptible to population crashes when negative trends in reproduction occur. As pollutant levels rise in manatee habitats, the affect of toxins on growing embryos may become a factor in development. Decreases in the quality of manatee sea grass beds may impact manatee nutrition, thus affecting potential congenital defects of developing embryos and fetuses. A standard description of normal manatee development is needed to provide comparative data for healthy and unhealthy states. This data also provides a comparison among species in similar environments or which are evolutionarily related.
Behavioral and histological evaluation of the chemical senses of the Florida manatee, Trichechus manatus latirostris
This work is being conducted by Meghan Bills, a PhD student in Dr. Larkin and Dr. Samuelson's laboratory
The Florida manatee has many interesting and unexpected traits including the apparent use of taste and smell. Although one would not expect an aquatic animal to be able to smell airborne scents, the manatee possesses the ability to do this. The question is whether or not this animal uses its ability to smell and taste to find a mate. It appears that a male manatee can find a female from far away, even though he cannot see or hear her. Manatees also are frequently seen “kissing” and “smelling” each other underwater and even at the surface. This leads us to believe that the female manatee is expressing a signal, most likely in urine, feces, or vaginal secretions, to the male manatee when she is ready to mate. To determine if this is true, we will use microscopic examination of the lips, hard palate, tongue, and nasal passages to find any receptors for these signals. The samples for these analyses will come from dead animals which were brought from all over the state of Florida to the Marine Mammal Pathobiology laboratory, in St. Petersburg, FL. No animals will be harmed for the purposes of this project. We will also determine the chemical composition of the female’s urine when they are reproductively active to find out what signals are being broadcast. Through these experiments the ability of the manatee to smell and taste will be further defined. We will also be able to find out more about their reproductive behavior through future studies using those chemicals isolated from the urine. Additionally, this will be the first in depth project examining the sense of taste and smell in an aquatic mammal and therefore will help in future studies involving other marine mammals.
Comparing fecal cortisol levels among captive West Indian manatees: Are they stressed?
This work is being conducted by Kyle Donnelly, an undergraduate student in Dr. Larkin's laboratory
The effects of stress can be damaging to health, and this is of particular interest to West Indian manatees (Trichechus manatus) since the overall health of an endangered species is of the utmost concern to ensure their future. The primary stress hormone or glucocorticoid released by adrenocortical activity in all marine mammals is cortisol. We propose to non-invasively measure fecal cortisol concentrations to estimate the level of overall stress in captive manatees. In our pilot studies comparing captive and wild animals in Florida, we found captive animal fecal cortisol concentrations from a single facility were significantly higher. This trend also has been seen in studies comparing other species of captive and wild populations. We propose to determine how other manatee facilities compare with the known stressed facility, since our preliminary data cannot be generalized to other groups of captive manatees. Adrenocortical activity can be severely damaging to the health, reproduction, and welfare of animals if it is chronically elevated and not stopped or suppressed. Thus, the captive population of manatees will potentially benefit if this research reveals stressful environments that can be remedied. All captive manatees are part of a rehabilitation program and may be at differing stages of recovery, from medical treatment of injuries or disease to recuperation until the animal is either the appropriate age, weight or it is the correct time of year for release. Comparisons will be made between facilities, season, wild vs. captive manatees, and clinically healthy vs. unhealthy captive manatees. It is hoped that the results of this study will identify areas that need improvement and assist managerial decisions to enhance the condition of these captive environments to prevent or reduce any stress and suffering of future manatees housed in captive facilities.
Tracking Study - Studies of the Florida manatee reproductive cycle: Behavior and correlated hormones in free ranging animals
The Florida manatee is a unique herbivorous marine mammal, which can be observed in fresh and salt coastal waters throughout the state of Florida. This endangered species has captured the fascination of many people who come to Florida to watch these animals in their natural habitat. Threats to this species include collisions with boats, reduction or loss of habitat, pollution, entanglement in fishing gear and ingestion of debris leading to injury and often death. As wild populations are reduced, genetic variability may be lost and reproductive success may be compromised. In monitoring species, understanding reproductive rates is critical for modeling population numbers, and thus influences management decisions. Various factors can impact reproduction, including those with social and hormonal characteristics. Drs. Larkin and Schulte have been collaborating on studies of behavior and hormones for several years. Through our research, we have validated non-invasive fecal hormone assays, found that manatees are reproductively active throughout the warm months of the year, but are limited in the winter, and females have an estrous cycle that averages 24 ±5.4 days long. Manatees are found within our study area, Crystal River, Florida, throughout the year, and are composed primarily of mother-calf pairs and juvenile males during the warmer months. This provides an exceptional study site to focus on reproduction. In utilizing behavioral and physiological techniques in this study, a more complete and biologically relevant picture of manatee reproduction can be drawn, thus providing more accurate assessments of reproductive rates and means of saving this endangered species.
The goals of this study are to monitor the manatee reproductive cycle of three wild female manatees with second year calves. We will focus on calf weaning, the estrous cycle (mating), and early pregnancy. Behavioral and hormonal data will be collected to characterize normal baseline data of reproduction in this species. This will expand our knowledge of the real reproductive potential of female manatees and will in turn affect modeling of the population dynamics of the species. In addition, a clear understanding of the basic reproductive physiology of the manatee in a normal state will allow us to identify abnormal or unhealthy states. These critical aspects are needed to manage and help save this endangered species from extinction. We also plan to provide an educational experience for middle and high school students and teachers during field work to teach about manatee natural history, conservation and the scientific process. Students and teachers will be invited on our boat to observe manatee tracking and be asked questions about their knowledge at the beginning and again at the end of our trip, to identify the efficacy of our learning experience.
For more information please visit Dr. Larkin's profile which contains contact information and the Publications page.
Histology Research in Dr. Samuelson's Laboratory on the Florida manatee and other selected Paenungulate species
Individuals who have participated in our laboratories in ongoing research studies involving the Florida manatee and relatives over the past 12 months:
Don Samuelson, Jennifer McGee, Kimberly Goldbach, Kelly Cuthbert, Danielle Lore, Liesl Flandenmeyer, Michael Wong, Greg Reppas, Pat Lewis, Carolyn Valle, Ramiro Isaza, Esther Greenbarg, Mallorie McCormack, Nicole Helmers, Peter McGuire, Gil Ben-Shlomo, Kathleen Barrie
The Nasolacrimal System
During the course of vertebrate evolution, the nasolacrimal system is believed to be developed among the first animals to become terrestrial. In doing so, the anterior portion of the eyes of these ‘land invaders’ were kept moistened so as to maintain corneal clarity as well as provide protection against potential microbial pathogens. 
The nasolacrimal system of the Florida manatee and other members representing the three paenungulate (“near-ungulate”) orders, Hyracoidea, Proboscidea, and Sirenia, have been little understood. We have discovered that the Asian elephant (Elephas maximus), the rock hyrax (Procavia capensis), and the West Indian manatee (Trichecus manatus) do not form the
traditional nasolacrimal system as they lack lacrimal glands, lacrimal punctae, nasolacrimal ducts and the tarsal glands (Meibomian glands). Instead, these animals possess unusual nasolacrimal systems not previously encountered among mammalian species or other vertebrates for that matter.
The present study primarily involves anatomical examination of the nasolacrimal systems associated with the paenunugulate eye. The three orders that the present species represent have been ancestrally linked through both morphological and molecular evidence. To date, the evidence for the close phylogenetic relationship of the Sirenia, Proboscidea and Hyracoidea, which collectively form the clade Paenungulata, consists of a combination of similiarities across a wide breadth of characteristics, such as hemoglobin sequences, lens protein construction, mitochondrial rRNA sequences, as well as dental, taxepodial and other skeletal features. In spite of the variety of supporting findings, some of the morphological features have been questioned or refuted as being primitive or convergent. In the present study, the lack of traditional nasolacrimal systems in the Florida manatee, Asian elephant and rock hyrax strongly supports their common evolutionary origin. The absence of the lacrimal gland among terrestrial vertebrate spp is rare (snakes), especially among mammals. Its agenesis among humans is an extremely rare mutative event that involves a concomitant loss of salivary glands, but not a loss of the drainage puncta or other orbital glands. The loss of both lacrimal and tarsal glands as well as those components for tear drainage strongly suggests that the Paenungulata shared an aquatic past.
Fairly recently, embryological development of the renal, respiratory and male reproductive systems indicated that the elephant evolved originally from an aquatic or semi-aquatic ancestor. Comparable ontogenetic findings have yet to be made in the hyrax. Among nonmammals, the presence of sebaceous glands within the nictitating membrane is common. However, among mammals the Harderian gland becomes much more lacrimal in function, losing its sebaceous nature largely due to the formation of Meibomian glands. The different ways that sebum-forming glands were reformed so that an oily layer is able to cover the seromucous portion of tears of the Asian elephant and the rock hyrax most likely are the result of the different ecological pressures encountered during their subsequent evolution. A series of articles are presently being submitted to a variety of journals that detail the unique features of the re-evolved nasolacrimal systems of the three distantly related species and their shared past.
Associated publications:
Samuelson, D.A., Reppas, G., Lewis, P.A., Valle, C., and Isaza, R. The loss of the classic nasolacrimal system in the Florida manatee and other selected paenungulate species. Intern. Assoc. Aquat. Anim. Med. 38th Ann. Conf. 71-72, 2007.
Samuelson, D.A., Reppas, G., Wong, M., Lewis, P.A., Barrie, K.P. and Graham, A.R. Re-invented nasolacrimal system among selected subungulate species. Invest. Ophthalmol. Vis Sci. (ARVO Suppl.) 47:S1214, 2007.
Elephant 3rd eyelid gland H&E x20
The Conjunctival-Associated Lymphoid Tissue (CALT)
We have begun investigating in the Florida manatee the association of tears with their health. In addition to examining those structures involved in the production of tears, we have started to investigate the composition of tears, especially antimicrobial components and the cells that produce them. These components consist primarily of enzymes and antibodies that are formed by conjunctival-associated lymphatic tissue (CALT). Jennifer McGee, a PhD student who joined the Graduate Studies program at the College of Veterinary Medicine at the beginning of the Fall semester of 2007, has presented some of her findings on the CALT of the Florida manatee at the FMMH conference at St. Augustine, Florida. She presented a poster at that conference entitled “Morphological description of conjunctiva-associated lymphoid tissue (CALT) in the Florida manatee, Trichechus manatus latirostris.” She also attended the International Association for Aquatic Animal Medicine (IAAAM) conference, which was held from May 10-14th. To that end, two undergraduate students, Esther Greenbarg, and Danielle Lore, have begun to analyze histologically CALT and other portions of the accessory lymphatic system throughout the body known collectively as the mucous-associated lymphatic tissue (MALT) as well as lymph nodes and spleen, respectively.
Manatee eyelid accessory gland H&E x20
Manatee eyelid accesory gland duct surrounded by adenoid tissue H&E x100
Associated publications:
McGee, J.L., Samuelson, D.A., Lewis, P.A., Farina, L., and deWit, M. Morphological description of conjunctiva-associated lymphoid tissue (CALT) in the Florida manatee, Trichechus manatus latirostris. Fl. Mar. Mam. Health Conf. 3rd Conf. 34, 2008.
McGee, J.L., Samuelson, D.A., Lewis, P.A., Lore, D., Schwarz, E., Greenbarg, E. and Goldbach, K. Morphological and histochemical description of conjunctiva-associated lymphoid tissue (CALT) in the Florida manatee, Trichechus manatus latirostris. Intern. Assoc. Aquat. Anim. Med. 39th Ann. Conf. 19-20, 2008.
The Immune System
Over the last 12 months, we have had another graduate student join our study, Kimberly Goldbach, who is pursuing her M.S. degree. Kimberly is working with the undergraduate students, Esther Greenbarg, and Danielle Lore, who have been analyzing histologically, and immunohistochemically the lymph nodes and spleen, respectively. Kimberly is also presently working with another graduate student, Mallorie McCormack, on the thymus of the Florida manatee and associated changes during development and aging, especially with regard to involution. Selected specimens from normal appearing samples and those from individuals who had died from asepticemia, cold stress and red tide exposure continue to be viewed by light microscopy. Serial sections of the spleen and lymph nodes are being made in order to appreciate the architectural design of these structures. Special stains, including immunohistochemistry, will be employed in order to identify specific cell types.
Red Tide
In the past year, we have been investigating the presence of red tide in the Florida manatee. Red tides occur almost annually along the west coast of Florida, usually in the late summer and autumn. One of the main causes of the decline in the population is the exposure of the manatees to Florida “red tide” brevetoxins. Red tide is caused by periodic blooms of Karenia brevis, which is a single-celled dinoflagellate organism normally restricted to the Gulf of Mexico and the Caribbean, and is often referred to as an algae or phytoplankton. Each cell of these small organisms produces up to nine toxins, including a neurotoxin called brevetoxin, which can be fatal to fish, birds, and mammals. The most severe events occurred in 1971, 1973 to 1974, 1996, and 2005. Until recently, blooms had only been reported on the west coast of Florida, but harmful blooms were reported on the east coast in September of 2007 (FWRI 2007). Even though these red tide explosions have been observed since the sixteenth century, it is suspected that in recent years an increase in frequency and duration of blooms has been promoted by nutrients from coastal pollution.
Our initial goal was to demonstrate exposure of red tide in the Florida manatee by revealing the presence of the dinoflagellate within portions of the different organ systems of the Florida manatee by IHC. From this study we will examine specimens of all manatees that have been determined histopathologically to have died from red tide exposure. Specimens from other manatees collected from the same regions but determined to have died from other causes will be similarly analyzed. We hope to reveal possible associations that red tide exposure may have had with regard to increased mortality of the Florida manatee. To date, we have found localization of the organism in both the respiratory and gastrointestinal systems of the same animal. We have also been able to demonstrate the presence of K. brevis by IHC localization in all five individuals that died from red tide exposure. The localization was found, in part, to be similar to that previously observed for brevetoxin. It is hoped that an intensity distribution of the organism within these immune components can be established in order to shed light further on the impact of red tide on the Florida manatee.
IHC localization of K. brevis in the mandibular lymph node.
IHC localization of K. brevis in a Peyer's patch of the small intestine.
Associated publications:
Samuelson, D., Flandenmeyer, L., Lewis, P., Helmers, N., McGee, J., and McGuire, P. Presence of red tide in the Florida manatee by immunohistochemical localization of Karenia brevis. Intern. Assoc. Aquat. Anim. Med. 39th Ann. Conf. 69-71, 2008.
For more information please visit Dr. Samuelson's profile which contains publication and contact information.
Manatee Sensory Sytems Research in Dr. Roger Reep's Laboratory is located under Comparitive Neurological and Sensory Physiology.
Population Genetics
Coming soon...
Sea Turtles
Nutrition
Coming soon...
Trace Elements/Environmental Toxicology
Coming soon...
Comparative Neurological and Sensory Physiology
Manatee Sensory Sytems Research in Dr. Roger Reep's Laboratory
Present Graduate Students: Alex Costidis, Joseph Gaspard
Former Graduate Students: Kari Clifton, Iske Larkin, Chris Marshall
Collaborators:
- Gordon Bauer, New College of Florida
- David Mann, University of South Florida
Understanding the sensory capacities of manatees is important for two main reasons. First, it is essential if we are to effectively devise ways to avoid destructive human-manatee interactions. By gaining insight into manatee sensory capacities we can design warning devices that are tuned to those capacities. Of specific interest here is the system of tactile hairs (vibrissae) on the body, which may function as a mammalian lateral line to detect water movements and low frequency vibrations associated with boats, other animals, and water currents. This system is also hypothesized to aid navigation by helping to detect landmarks in the environment. A second reason to investigate manatee sensory systems is their importance in a comparative evolutionary context. Manatees (and sirenians generally) represent a novel branch of mammalian evolution, and the brains and behaviors of these animals likewise exhibit unusual and often unique traits. Thus, by elucidating the patterns of brain organization subserving these capacities we gain direct insight into the range of evolutionary potential in the mammalian lineage.
The current goals of this project are to investigate the role of vibrissae in Florida manatee perception and behavior, and in the organization of the nervous system.
A) Side view of cranial body; small arrowheads indicate hair follicle papillae.
B) Longitudinal section of facial bristle-like hair follicle. BS=blood sinus, CAP=capsule, CT=connective tissue, EPI=epidermis, HS=hair shaft. C) Postfacial follicle from ventral body, with extended cavernous sinus. Arrowhead indicates blood vessel. Scale bar=1mm. D) Postfacial hair from dorsal body. Arrowheads indicate nerves, S is a blood sinus. Scale bar=1mm.
Behavioral use of tactile hairs (vibrissae) by manatees
All sirenian hairs are vibrissae, distributed over the entire face and postcranial body, in contrast to the restricted distribution seen in other mammals. This suggests an expanded functional role for vibrissae in sirenians. We hypothesize that the perioral bristles and bristle-like hairs of the face are used most often in direct tactile contact, whereas hairs of the postcranial body serve primarily as receptors of hydrodynamic stimuli associated with movement of other animals, water currents, tidal flows and changes in topographic contours of the shallow water environment.
Our behavioral experiments utilizing two captive manatees at Mote Marine Laboratory are testing this hypothesis by comparing the sensitivity of the facial vibrissae with that of postcranial vibrissae. An underwater vibrating sphere generates vibratory stimuli of known frequency and amplitude. Subjects are trained to respond in order to indicate whether they did or did not perceive the stimulus. By varying the location of the stimuli relative to the body, and the frequency and amplitude of stimuli across many trials, we are constructing a ‘tactogram’ for the use of vibrissae by manatees. We also intend to determine the ability of manatees to identify the direction from which a stimulus originates.
Schematic diagrams of innervation patterns for large U2 perioral vibrissae, bristle-like hairs of the oral disk, and postfacial vibrissae. From Sarko et al. (2007a).
Mapping somatosensory connections in the brain
We hypothesize that peripheral neuroanatomical specializations associated with the vibrissae play a major role in shaping the configuration of the central somatosensory system. The proposed anatomical studies will utilize lipophilic axon tracing to investigate patterns of connections in previously defined somatosensory regions of the brainstem, thalamus, and cerebral cortex. Fresh postmortem manatee brains will be obtained from the Marine Mammal Pathobiology Laboratory in St. Petersburg, Florida.
A: Putative primary somatosensory areas (red), based upon cytochrome oxidase staining patterns and cytoarchitecture. Inset shows hypothesized topography of the body map within SI. Putative AI in green, VI in yellow. B: Dense cytochrome oxidase staining in layer IV of SI in a coronal section. Courtesy of Diana Sarko.
Due to the manatee’s status as an endangered species, traditional electrophysiological methods of ascertaining the location of somatosensory regions within the CNS are not feasible. Fortunately, experimental findings in an array of species have shown that anatomical staining patterns correlate well with electrophysiological localization of sensory regions of the brainstem, thalamus and cerebral cortex. Based on a study from our lab involving manatee brain sections stained for cytochrome oxidase, acetylcholinesterase, myelin and Nissl bodies, manatees exhibit CNS somatosensory specializations including large, lobulated brainstem nuclei for processing information from oral disk vibrissae and perioral bristles (trigeminal nuclei), and from the vibrissae on the forelimb flipper and trunk (cuneate-gracile complex). A large Bischoff's nucleus in the caudal brainstem represents input from the fluke. Bischoff’s nucleus is present in many tailed animals. In raccoons it represents the tail and projects heavily to the somatosensory thalamus. In manatees, large, subdivided ventral posterior thalamic nuclei that receive input from the brainstem somatosensory nuclei constitute a disproportionately large volume of the thalamus. The trigeminal-recipient ventral posteromedial thalamic nucleus (VPM) and the ventral posterolateral nucleus (VPL), which receives afferents associated with the fluke, body and flipper regions, are comparable in size.
Within cerebral cortex, the large presumptive somatosensory cortex contains multiple areas distinguished by cytoarchitecture, cytochrome oxidase staining patterns, and the presence of neuron aggregates (Rindenkerne) in layer VI that may correspond to barrels in other taxa and thus represent individual vibrissae. We also found that the putative SI of the manatee is disproportionately large (based on quantitative analysis of cytochrome oxidase-stained flattened sections), comparable to SI in other somatosensory specialists like the naked mole-rat. Our experiments using lipophilic tracers will build upon this foundation and expand our understanding of the patterns of connections among these somatosensory regions of the manatee brain.
For more information please visit Dr. Reep's profile which contains contact information and the Publications page.
Permit Applications and Research Request Forms
Permit Applications
National Marine Fisheries Service Permits (for whales, dolphins, porpoises, seals and sea lions only. Not walrus, polar bear, sea otter, dugong and manatees)
US Fish and Wildlife Service Permits (for walrus, polar bear, sea otter, dugong and manatees only. Not cetaceans or pinnipeds)
SeaWorld Research Proposal Form (this form is only available from within the University of Florida College of Veterinary Medicine). Contact the Education Coordinator for help with this form.
Grant Opportunities
Recurring Calls for Proposals
Morris Animal Foundation - November 1st: Pre-proposal due
- Grants range from $2,500 to $180,000 annually. Duration of project (one to five years).
John H. Prescott Marine Mammal Rescue Assistance Grant Program - Proposals
accepted in the Spring and Fall
Earth Watch - Proposals accepted year round
- Focus on field work, provide funding & volunteers per capita ave $800, total grants ave $16,000 - 48,000 for one full season.
Sea World/Busch Gardens Conservation Fund - Applications due December 1st
- $5,000 - $25,000 for one year.
National Fish & Wildlife Foundation - Multiple grant programs
Census of Marine Life - Proposals accepted year round
- Sponsor: Alfred P. Sloan Foundation.; Science and Technology. Direct Support of Research
- Sponsor Type: Private foundation
- Deadline: Continuous. Grants are made by the trustees, who meet four times a year. In addition to grants made by the trustees, officer grants are made at any time throughout the year. Letters of inquiry are the recommended initial step.
- Citizenship or Residency: Unrestricted
- Activity Location: United States
- Requirements: PhD, MD, Other Professional, Nonprofit
- Abstract: The goal of the Census of Marine Life project is to advance a major new international observational program to be completed by 2010 to assess and explain the diversity, distribution, and abundance of marine life. During 1997-1998 the goal of the Alfred P. Sloan Foundation was to understand the technical and institutional feasibility of a marine census. Favorable technical and institutional signals led during 1999 to adopting the ambitious goal of trying to make the Census happen. An international Scientific Steering Committee and Secretariat based at the Consortium for Oceanographic Research and Education in Washington, District of Columbia, now guide the program. Most grant-making occurs in conjunction with the National Ocean Partnership Program. The first round of grants has focused on creation of the Ocean Biogeographical Information System (OBIS), the framework for assimilation of data for the Census. In addition, support has been provided to initiate planning for possible pilot field projects and to develop information on the history of marine animal populations.
During 2002 the foundation plans to continue to develop the institutional framework for the census. Consideration will also be given to efforts to address particular, indispensable early scientific needs, on which the success of the census will rest. Thirdly, the foundation seeks opportunities to work with the institutions and media that can build public interest and with commercial fishers and environmentalists to assure their meaningful participation.
- Contact Name: Jesse H. Ausubel, Program Director
Address: Alfred P. Sloan Foundation
630 Fifth Avenue
New York, NY 10111-0242
USA
Phone Number: (212) 649-1649
Fax Number: (212) 757-5117
One Time Requests for Proposals
None listed at this time
Student Research
Current Graduate and Veterinary Student Research
Please see the individual student profiles on the Contact Us page.
Previous Student Dissertations and Theses
Bracht, Alexa J. 2005.
Detection and molecular characterization of cetacean and pinniped poxviruses associated with cutaneous lesions. M.S. Thesis, University of Florida.
Clifton, Kari. B. 2005.
Skeletal biomechanics of the Florida manatee (Trichechus manatus latirostris). Ph.D Dissertation, University of Florida.
Graham, Anne-Renee. 2005.
Histologic examination of the Florida manatee (Trichechus manatus latirostris) integument. M.S. Thesis, University of Florida.
Keller, Martha. 2005.
Development of a competitive inhibition enzyme-linked immunosorbent assay (CI ELISA) for serosurvey of marine mammals for West Nile virus. M.S. Thesis (UF access only), University of Florida.
Nollens, Hendrik H. 2005.
Poxvirus infections in North American pinnipeds. Ph.D Dissertation, University of Florida.
Smolarek Benson, Kara. 2005.
Molecular Identification and Genetic Characterization of Cetacean Herpesviruses and Porpoise Morbillivirus. M.S. Thesis, University of Florida.
Woodruff, Rebecca A. 2005.
Detection and Molecular Characterization of Manatee Papillomavirus Associated with Cutaneous Lesions in Florida Manatees (Trichechus manatus latirostris). M.S. Thesis, University of Florida.