Migratory Behavior of Hatchling Sea Turtles: Evidence for Population-Specific Divergence in the Loggerhead Caretta caretta L..Reportar como inadecuado

 Migratory Behavior of Hatchling Sea Turtles: Evidence for Population-Specific Divergence in the Loggerhead Caretta caretta L..

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Type of Resource: text

Genre: Electronic Thesis or Dissertation

Date Created: 2007

Date Issued: 2007

Publisher: Florida Atlantic University

Place of Publication: Boca Raton, Fla.

Physical Form: application/pdf

Extent: 44 p.

Language(s): English

Abstract/Description: Migratory bird and insect populations show differences in orientation direction, timing,and distances moved depending upon where they reside in relation to their migratorygoals. These differences presumably occur because of selection for behavioral responsesthat promote the most efficient migratory strategies among members of each population.The purpose of this study was to determine whether migratory behavior in loggerheadhatchlings differs between populations that exit nesting beaches on the East and Westcoast of Florida. When the turtles emerge from the nests, they initially show a swimmingfrenzy that serves to distance individuals from shallow coastal waters, displacing themtoward oceanic currents that are used to transport the turtles to the North Atlantic Gyre.On the East coast of Florida, turtles swim eastward toward the Florida Current (westernportion of the Gulf Stream) located relatively close to the shoreline (on average, 2 kmoffshore at Miami to 33 km offshore at Melbourne Beach). On the West coast of Florida,turtles swim westward toward the Loop Current in the Gulf of Mexico, which is locatedfarther offshore (150 km offshore at St. Petersburg to over 200 km offshore at the Everglades National Park). In a previous study, we demonstrated that for East coastloggerheads, the frenzy consists of continuous swimming for - 24 h, followed over thenext 5 days by postfrenzy (diurnal, with little nocturnal) swimming activity. Nocomparable data exist that characterize the frenzy period of loggerheads from the Westcoast ofFlorida.We used identical methods to quantify the migratory activity of hatchlings from the Westcoast of Florida. Hatchlings were captured as they emerged from nests located betweenVenice and Sarasota, Florida. They were then tethered in water-filled pools underlaboratory conditions, where temperature and photoperiod could be controlled toduplicate conditions used when studying the East coast turtles. Activity was continuouslyrecorded over the next six days. The data were analyzed to determine the proportion oftime the turtles spent swimming every day, and the proportion of that swimming activitythat occurred during the light and dark period of each day. Turtl~s from each coastshowed no statistical difference in the proportion oftime spent swimming each day.However, after day 1, West coast hatchlings showed statistically lower levels ofswimming activity during the day and statistically higher levels of swimming activity atnight than did turtles from the East coast. We hypothesize that these differences mayreflect a more diffuse period of active searching for appropriate oceanic currents by theWest coast turtles, under conditions where greater predation pressures might select formore movement under conditions of darkness. Such a response may be appropriate whenmigratory goals are located at greater distances, and when turtles must migrate fartherfrom the coast to reach deeper, and presumably less predator-rich, waters.

Identifier: FA00000792 (IID)

Degree granted: Thesis (M.S.)--Florida Atlantic University, 2007.

Collection: FAU Electronic Theses and Dissertations Collection

Note(s): Includes bibliography.

Held by: Florida Atlantic University Libraries

Sublocation: Digital Library

Links: http://purl.flvc.org/fau/fd/FA00000792

Use and Reproduction: Copyright © is held by the author with permission granted to Florida Atlantic University to digitize, archive and distribute this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder.

Owner Institution: FAU

Is Part of Series: Florida Atlantic University Digital Library Collections.

Autor: Madrak, Sheila Veronica, author Salmon, Michael Dr., Thesis advisor Charles E. Schmidt College of Science, Degree grantor

Fuente: http://fau.digital.flvc.org/islandora/object/fau%3A34619


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