From California to Sarasota, Florida: A community college student and marine mammal research

 

The concave space seen beneath the black line is what is known as a post-nuchal depression. In a robust animal, this area is filled in.
The concave space seen beneath the black line is what is known as a post-nuchal depression. In a robust animal, this area is filled in.

I am a Marine Biology major and come from a non-research based community college in Southern California. Under mentorship of my former marine biology professor, I was fortunate to have the opportunity to conduct environmental research at California State University, Long Beach. This prepared me both physically and mentally to participate in this intellectually challenging 10-week National Science Foundation-sponsored Research Experience for Undergraduates with the SDRP for summer 2015.

My research project was focused on the area of fat behind the skull of the dolphin that helps to provide a dolphin with positive buoyancy and metabolic energy and nutritional storage. When in poor health, this sensitive post-nuchal fat pad reduces to form a post-nuchal depression (PND). I compared PND prevalence in a year with poor resources and scarce prey with a year of excellent resources and excellent prey. I hypothesized that PND prevalence would be higher in the year of poor resources and scarce prey and tested the replicability and accuracy of this method applied to live, free-ranging dolphins. To test this hypothesis, I analyzed over 4,000 photographs with a method developed by Mary Gryzbek that involved drawing a line across the dolphin’s dorsal surface to see if a space existed between the line and body. Individuals were coded: 0 (no PND), 1 (PND), BL (borderline PND). In addition, I compared individuals with a PND from field photographs with measurements from their health assessment to determine the accuracy of a PND as an indicator of health condition. The results of this photographic method proved to be statistically significant when applied to the overall population, but inconsistent when applied to individuals who had a health assessment. Therefore, additional testing with a larger data set should be considered; and if successful, could replace the need for direct handling and increase population studies in all parts of the world.

Lynnette with mentor Katie McHugh during the 2015 Mote National Science Foundation REU poster session.
Lynnette with mentor Katie McHugh during the 2015 Mote National Science Foundation REU poster session.

My experience with the SDRP was enriching, educational, and intellectually challenging. I learned how to take photographs of dorsal fins in the field during dolphin population monitoring surveys and ID them into a catalogue database in the lab. I assisted with dolphin prey abundance surveys where I identified, weighed, and measured various species of fish. I was introduced to ArcView GIS software for the first time and frequently entered data from dolphin population monitoring and synoptic surveys. Under the guidance of Dr. Katie McHugh, I constructed a research proposal, poster presentation, and manuscript of my research project, all for the first time. I even learned how to drive a research vessel for the first time thanks to the SDRP staff! My REU experience involved weekly seminars with distinguished researchers who shared their expertise to aspiring researchers like myself. Not to mention, the exciting field trips and marine-related activities such as visiting the U.S. Geological Survey, Florida Fish and Wildlife Commission, kayaking through the mangroves, and touring Mote’s Bone Lab and Sea Turtle Hospital! This experience has truly defined life as a researcher for me and I am honored to have acquired new skills and refined existing ones at this world-renowned research program. With a special thank you to the SDRP, my research was selected to be presented at the 2015 SACNAS National Conference in Washington, D.C. targeted towards the advancement of Hispanics and Native Americans in Science. As a minority myself, I plan to inspire and educate those of similar backgrounds by presenting my research entitled: “Post-Nuchal Depression as an Indicator of Health in Bottlenose Dolphins (Tursiops truncatus)” to a diverse scientific community.

I would like to thank Katie McHugh for selecting me to work with the SDRP for summer 2015 and the following staff and graduate students: Randall Wells, Jason Allen, Aaron Barleycorn, Sunnie Brenneman, Shauna McBride, and Rachel Cassoff for an exciting and enriching experience.

This article appeared on page 33 in the December 2015 issue of Nicks n Notches.

Understanding the effects of harmful algal blooms

 

Spencer Fire using a small plankton net to collect water samples for analyses during health assessments.
Spencer Fire using a small plankton net to collect water samples for analyses during health assessments.

I joined SDRP in 2003 as a University of California Santa Cruz PhD student with interests in the effects of harmful algal blooms (HABs) on marine wildlife. My research experience prior to joining SDRP was primarily focused on fisheries and human health, and as a true lab nerd, I had never seen a dolphin or spent much time on a boat. During my time with SDRP, I learned a variety of valuable field research skills that allowed me to successfully complete a dissertation investigating the effects of HAB toxins on the Sarasota bottlenose dolphin population. I also became conversant with important issues in marine mammal conservation biology that have served me well and shaped my research interests ever since.

After completing my graduate studies and leaving SDRP in 2006, I was fortunate to land a position with the National Oceanic and Atmospheric Administration (NOAA) due to my experience combining the study of HAB toxins and marine mammals. At the NOAA lab in Charleston, South Carolina, I led a team of scientists who responded to, and provided analytical services for, HAB-related events, most of which involved marine mammal strandings. During this time I continued my fruitful collaboration with my SDRP friends and colleagues, who allowed me back every year for health assessments despite my supernatural ability to disable boat electronics simply by being near them. One highlight of this collaboration was when we jointly published the first case of multiple HAB toxin exposure in live dolphins sampled during the SDRP health assessments.

In 2014, I moved from my role as a federal research scientist into a faculty position at Florida Institute of Technology in Melbourne, Florida. During this past year, I have been able to start my own research program and advise graduate students as we continue to investigate the role of natural toxins in marine mammal food webs. The research we are beginning through FIT focuses on the nearby Indian River Lagoon Estuarine System, a critical habitat along Florida’s Atlantic coast, where HABs and bottlenose dolphins also overlap. Fortunately, our fledgling research program continues to benefit from support, training and collaboration with SDRP staff. With time, we hope our research makes as positive an impact on the Indian River Lagoon dolphins as SDRP has had on their Sarasota Bay counterparts.

This article appeared on page 31 in the December 2015 issue of Nicks n Notches.

Use of overhead imaging for body condition assessment

pole cam, obtaining aerial photos
R/V Challenger, outfitted with the pole cam, obtaining aerial photos of Riptorn. In addition to revealing insights in body condition, this imaging technique also uniquely documented the severity of Riptorn’s scoliosis.

The body or nutritional condition of dolphins can significantly affect individual survival and reproductive success. In addition, it can be a sensitive indicator of prey abundance, feeding success, and the general health of an individual. Thus, assessing the body condition of animals is critical for monitoring the health of dolphin populations. However, current methods of measuring body condition in free-ranging dolphins require capturing, restraining and sampling individuals directly through capture-release health assessments, which are expensive, logistically complex, and are not feasible in many situations.

With a grant from the Association of Zoos & Aquariums Conservation Endowment Fund (through funding from the Disney Worldwide Conservation Fund), and a fellowship grant from the Morris Animal Foundation, we designed and built a low-cost remote controlled unmanned aerial vehicle (UAV) to remotely measure the body condition of dolphins at sea. The six-rotor UAV, which has a digital camera mounted below it, is designed to be launched from a small boat and to hover precisely over individual animals to collect photographs for detailed measurements of body size and shape (a technique called aerial photogrammetry). Initial field testing of the UAV system was conducted in 2014 over dolphins being temporarily held in large net corrals during capture-release health assessments in Sarasota Bay.

Riptorn, his severe case of scoliosis evident
Riptorn, his severe case of scoliosis evident in his peduncle.

More recently, in response to FAA restrictions and uncertainties regarding deployment of UAVs, we have been using a pole-mounted camera system to collect overhead images of Sarasota Bay dolphins. The pole camera was constructed by engineers at Woods Hole Oceanographic Institution under the guidance of Michael Moore. It makes use of a long carbon fiber pole that was previously used to deploy tags on large whales. With the pole camera mounted on the SDRP’s pontoon boat R/V Challenger, we collected overhead images of more than 60 dolphins this summer both during capture-release health assessments and during boat-based surveys while animals were free-swimming in the bay.

Lizzie, Fringes, and calf
Lizzie, Fringes, and calf FRN4, less than a month old.

The images will enable us to compare body size and shape measurements (such as total body length and girth) obtained from the aerial photographs with those obtained directly from the animals being temporarily restrained during capture-release events, to assess the accuracy of our technique. The images will also allow us to compare measurements based on the animals’ sex, age, and reproductive class, as well as between healthy and unhealthy individuals. Our novel health assessment technique could be used to help determine whether capture-release health evaluations of bottlenose dolphins are warranted in areas of concern, and it could be applied in the future to a wide variety of marine mammal species that have yet to be studied in this manner. This system was used to provide body condition data for treatment of a stranded bottlenose dolphin undergoing treatment at Mote’s dolphin hospital.

This article appeared on page 21 in the December 2015 issue of Nicks n Notches.

Measuring bone density in live, free-ranging bottlenose dolphins

James Powell measures bone density in a dolphin flipper.
James Powell measures bone density in a dolphin flipper.

Bone density is an indicator of health in many mammals, including humans. During the 2014 and 2015 Sarasota Bay health assessments, the first-ever measurements of bone density in live, free-ranging bottlenose dolphins were performed. Measurements of bone density in dead, beachcast dolphins are straightforward, as skeletal specimens can be collected and analyzed through traditional laboratory methods; however, novel technology and protocols had to be developed in order to include bone density assessments in the overall health evaluation of live dolphins. To date, bone density profiles have been established for 17 dolphins in Sarasota Bay.

In addition to these measurements, bone density values from archived skeletal specimens for nearly 300 dolphins from both Sarasota Bay and coastal South Carolina were recorded to develop the first ever reference dataset for bottlenose dolphin bone density. This reference dataset is being used as a baseline by which to compare bone density values for dolphins in areas where human impacts, such as high levels of contamination, are of great concern. In September 2015, bone density measurements were incorporated as part of the health diagnostics performed in a NOAA bottlenose dolphin capture-release health assessment in the estuarine and coastal waters near Brunswick, GA, where some of the highest PCB concentrations ever recorded for dolphins have been documented. Bone density values for individual dolphins assessed during this project will be compared to Sarasota Bay resident dolphins and the bottlenose dolphin reference dataset to determine whether coastal bottlenose dolphins differ in bone density from estuarine resident dolphins and to examine whether estuarine bottlenose dolphins exposed to high levels of environmental contamination exhibit lower bone density than dolphins from Sarasota Bay.

This article appeared on pages 19-20 in the December 2015 issue of Nicks n Notches.

 

Dental exams and radiology for dolphins

 dental x-rays on a dolphin
A digital film plate and a handheld radiograph machine enable Jean Herrman to obtain dental x-rays on dolphins while aboard the R/V Flip.

As your dentist will tell you, the mouth is an indicator of overall health. Poor oral health is linked to heart disease and other chronic health conditions in humans and our companion animals. The finding that a portion of a wild dolphin population in Louisiana was missing most of their teeth prompted the desire to investigate the oral health of wild dolphin populations in general.

It is common practice and standard care to not only examine the mouth, but also to take radiographs (x-rays) of the majority portion of the teeth that anchor them into the jawbone and are out of view to the eye. Radiographs may help understand the reasons underlying tooth loss, determining if it was just broken off, or if it is really completely missing. For dolphin mouth x-rays, a digital film plate is inserted within a holder and placed gently into a dolphin’s mouth. A very low dose of x-rays is used with dolphins because the digital plate is very sensitive; the plate is then put through a small digital laser scanner to produce the image.

Dolphins have 76-108 teeth. They are all the same shape and they are born with their adult set of teeth. They are used to grab food only, not for chewing. Typically observed wearing down of teeth in bottlenose dolphins has even led to their name Tursiops truncatus, because their teeth seemed short or truncated compared to other toothed cetaceans. With radiography we have discovered that this typical wear does not affect the supporting bone and even teeth worn down to the gum-line remain vital and healthy. Also it is common for teeth to be broken, sometimes with the gum tissue growing over the roots of the teeth. Most of these roots stay vital and sometimes they remain dead and mildly diseased in the bone. Our radiographic findings also include pocketing around worn teeth especially in the front of the mouth. This is known as periodontal disease and is usually mild, mostly in older dolphins with less than 25% of the supporting bone affected. Occasionally the jawbone loss around teeth throughout the mouth is more severe, affecting a greater number of teeth and loss of greater than 75% of the supporting bone. It is diseased bone or a severe form of periodontal disease that is suspected to be the reason for extensive tooth loss, not normal wear and tear. This has only been confirmed by radiographs in one Sarasota Bay dolphin over the past 3 years, compared to multiple dolphins in other populations.

It will be interesting to be able to link oral disease to other health information being collected by projects on the same dolphins in order to provide a more complete health assessment of our wild dolphin populations. Another potential use for dental radiology will be to provide age information. Dental radiography is used for age determination in human forensics and archeology and I would like to extend this technique to wild dolphins. It would provide a non-invasive tool to age dolphins in health assessments, stranding events, and rehabilitation efforts. The Sarasota Bay population is an important contributor to health and age assessments since most of their life histories and ages are well-known.

This article appeared on page 19 in the December 2015 issue of Nicks n Notches.