Kate Mansfield, Sea Turtle Biologist

Kate Mansfield
Kate Mansfield
Kate Mansfield, a Ph.D. student under Dr. Jack Musick at the Virginia Institute of Marine Science (VIMS), invites you to follow the path of a female loggerhead turtle (Caretta caretta) tagged and released as part of a Satellite Tracking Project. Kate's doctoral work focused on aspects of sea turtle migration and continues to work recovering stranded sea turtles at any time of the day or night. Her devotion to sea turtles runs deep.

green turtle pipping
Pipping (hatching) green sea turtle, Dry Tortugas, FL 1996

loggerhead turtles emerging
Emerging loggerhead sea turtles, Keewaydin Island, FL 1994

loggerhead entering water
Swimming loggerhead, Jupiter Island, FL 1997

Between the time a female baby sea turtle enters the ocean and the time she comes ashore to nest approximately 20 years later, very little is known about her life. Even less is known about the lives of male sea turtles since they never come ashore. This makes sea turtle management and conservation very difficult. The Satellite Tracking Project, headed by Dr. Musick, has been funded by the Army Corps of Engineers since 1993 as mitigation for their dredging and beach nourishment activities. Kate has been involved with the project since 1999 and works in coordination with Back Bay National Wildlife Refuge and Virginia Marine Science Museum volunteers who monitor nesting activity and call VIMS when a nesting turtle is spotted. The tracking data supplied to the Army Corps of Engineers provide information on the at-sea movements and nesting behavior of female sea turtles. This will help ensure that consideration will be given to nesting turtles while coastal work is being done.

Loggerhead sea turtles usually nest several times during a nesting season, with 12-14 days between nesting events. Along the east coast, the season runs from May to September, but in Virginia the season is generally from June to August. Interestingly, sea turtles don't usually nest every year but rather every two to three or even four years. Researchers don't know exactly why, but attribute it to the energy required to produce eggs. Although juvenile loggerheads are not rare in the Chesapeake Bay, it is unusual to find a nesting female loggerhead north of Cape Hatteras. They have been found to use the Bay as a feeding habitat between nesting events, which may occur elsewhere up or down the Atlantic Coast. Feeding changes with age, but loggerheads are mainly carnivorous. Their jaws are powerful and can handle many food types. Their diet includes jellyfish, crustaceans (lobsters, crabs, and shrimps), molluscs (clams, mussels, conch), and encrusting animals attached to reefs and rocks. For more information on the life cycle of sea turtles, species differences, threats to turtles, and another classroom activity, see our July 2000 Data Activity .

satellite tag
Telonics ST-14 tag

applying fiberglass resin
Loggerhead sea turtle, Back Bay, VA 2000

The adult female currently being tracked was found nesting on the beach at Back Bay National Wildlife Refuge near Virginia Beach on July 11, 2000. She was first observed at 10:25 PM, and she laid 119 eggs. When she was finished nesting early on the morning of July 12th, her carapace length was measured (93.1 cm), a satellite transmitter was placed on the second and third vertebral scutes of her carapace (see the roll-over turtle to identify turtle parts), and she was released on the beach the same morning. The satellite transmitter was attached with epoxy and fiberglass resin, a non-invasive procedure. In addition to recording the latitude and longitude of the turtle, the tranmsitter has five sensors that collect diving/surfacing behavior data and environmental data such as water temperature. This type of information helps researchers better understand sea turtle behavior in the wild, a feat very difficult to accomplish otherwise. The transmitter sends this information to a satellite every 45 seconds while the turtle is at the surface. If the turtle is submerged, the tag stores the information and transmits it when she surfaces. The data are then sent to an intermediary company that emails the information to Kate. The turtle is tracked until the transmitter no longer sends a signal; perhaps a year if the battery lasts and all goes well, or perhaps only a month if the turtle sheds her scutes. (Since the transmitter is glued to two scutes in the center of her top shell, if she sheds them she also sheds the transmitter.)

Click here to view a photo journal of the tagging and releasing of another loggerhead sea turtle. You can also view a movie of the turtle being released at the beach. Download RealPlayer for free to play this video.)

Tracking Exercise

NATIONAL SCIENCE EDUCATION STANDARDS CORRELATIONS

Science as Inquiry

  • Ability to do scientific inquiry (5-8, 9-12)
  • Understanding of scientific inquiry (5-8, 9-12)

    Life Science

  • Regulation and behavior (5-8)
  • The behavior of organisms (9-12)

    Science in Personal and Social Perspectives

  • Populations, resources, and environments (5-8)
  • Natural resources (9-12)
  • *PLEASE NOTE: Use of Kate's data is limited to classroom teachers for the purpose of this web activity only. Do not cite.

    Using Kate's data (Excel spreadsheet format) and a blank map, plot the points at which the turtle's location has been recorded. Number the points on the map as you plot them, and mark the date of the satellite transmission next to each point. Connect the numbers sequentially to show the route of the sea turtle. (Note: these data are approximations, the precise data are published elsewhere.)

    Compare your map to Kate's map for accuracy, and check your answers to the above questions with our answer key.

    Nesting Exercise

    Kate has observed and photographed many nesting events on various beaches and has become an expert on sea turtle nesting. In fact, using parts of her Master's thesis along with a number of other resources, she produced sea turtle monitoring manuals for the National Park Service.

    hawksbill nesting
    Nesting hawksbill sea turtle, Buck Is., US Virgin Islands 1998
    In general, all sea turtles carry out a similar sequence of events when nesting: crawling up the beach to find a suitable nesting site, brushing away the sand to create a body pit, digging out sand with the rear flippers to create an egg chamber, laying the eggs, covering the egg chamber with sand, attempting to cover the nest site, and crawling back to the ocean. However, the characteristics of the tracks and the nest site give clues about what species of turtle was present and whether or not eggs were laid. Learning to examine a site and more accurately identify the nesting turtle is a useful tool for beach monitors.

    After reading Kate's excerpt on nesting behavior, take a look at her photographs below and see if you can identify which species of turtle was present. Click on the image for the answer. Bridge TROLL Ly Williams has developed an additional list of questions regarding nesting behavior to use with your students.

    turtle crawl #1turtle crawl #2

    Final Analysis

    Unfortunately, the transmitter lasted a little less than a month, but the information gathered on any at-sea movements of sea turtles is extremely valuable. This is especially true for information from turtles utilizing Virginia beaches as their nesting habitats since Virginia is the northernmost area within which loggerhead turtles are known to nest regularly. The track of this turtle was analyzed in the context of all tracking data gathered for this project, including tracks dating back to 1993 from up to eight transmitters deployed. This turtle added pieces to the puzzle of where turtles go after nesting along Virginia's shores.

    One interesting thing about this turtle is that she entered the waters of the Albermarle and Pamlico Sounds rather than first moving up into the Chesapeake Bay or Delaware Bay. Other turtles tracked by VIMS have also entered into these Sounds, but only briefly before moving back out along the coast. This turtle is unique in that she remained so long inside the Sounds and was shown to move back and forth between the Sounds and the ocean.

    Loggerhead turtles nest multiple times within a season and are able to nest again 12-15 days after their previous nesting event. Keeping this in mind, it is possible that our turtle nested again after leaving Virginia's waters. In examining her track along North Carolina's coast, there are several positions that come very close to shore, and we can't rule out the possibility that perhaps she did nest again (and again...!). Unfortunately, no one in North Carolina saw her nesting, so we have no way of confirming this.

    Had the transmitter continued to transmit, we would have seen this turtle move south at some point in the fall--usually around the first real cold snap of the season. Some of the turtles tracked by VIMS have traveled as far south as Florida. In fact, two turtles have traveled all the way to the Florida Keys and into the Gulf of Mexico. This information is very important since sea turtles don't recognize human-made boundaries like state lines or even international boundary waters. For management purposes, it is important to know that a turtle nesting in one area may overwinter in another area thousands of miles away. These turtles don't belong to just Virginia's waters.

    Finally, the early loss of contact with this turtle has convinced us that we need to spend time re-evaluating the design of our transmitters. Hopefully, we'll have much longer tracks to analyze in the future! Thanks for following along, and stay tuned!

    We are extremely grateful to Kate for giving us firsthand insight into her research.

    All photos on this page are courtesy of Kate Mansfield.

    *Follow current Virginia Institute of Marine Science Sea Turtle Research Program satellite-tagged turtles on the seaturtle.org tracking site.

    For more resources, be sure to visit the Bridge's Sea Turtles page. If you have questions or comments about the Spotlight, contact , Bridge Webkeeper.


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