Higher Trophic Levels

Marine Turtles in Florida Bay

Florida Bay Project Profile - 63

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Questions: Which species of sea turtles live in Florida Bay and how common are they? Do sea turtles spend their entire lives in Florida Bay or are they temporary residents during portions of their lives? Are sea turtles in the bay healthy and to what extent are bay turtles afflicted with fibropapilloma disease?

Background/Project: Relatively little was known about sea turtles in Florida Bay prior to the initiation of this project in 1990. Four of the five species of sea turtles that occur in Florida waters have been found in Florida Bay: the loggerhead, the green turtle, the Kemp's ridley, and the hawksbill. The leatherback turtle is absent from the bay. These threatened and endangered marine reptiles are an important component of Florida Bay's living resources.

Sea turtles have complex life cycles and most species undertake extensive migrations as they mature. Once mature, migrations are made between feeding and nesting areas. To study marine turtles in Florida Bay, turtles are captured by hand and brought aboard a research boat where they are identified, measured, tagged, and carefully examined for signs of disease (e.g., fibropapilloma tumors). A small blood sample is taken to determine the sex of the turtle, to further evaluate its' health and to associate each turtle with a nesting beach population through genetic analysis. Some turtles are fitted with radio and sonic tags to study short-range movements while others are fitted with satellite tags for studying long-range movements.

Findings to Date: Several hundred sea turtles have been captured for study since 1990. Most of the work has focused on the western part of Florida Bay (primarily the area bounded by Man O'War Key, Rabbit Keys, Arsnicker Keys, and Twin Keys). Loggerheads and green turtles are, by far, the most commonly encountered sea turtles. Loggerheads have been represented by a mix of immature and adult animals while all the captured green turtles have been immature. One of the most interesting aspects of the loggerhead population in Florida Bay is the large number of adult males. The bay offers researchers a rare opportunity to learn more about adult male loggerheads. Males, in general, have not been studied as extensively as females because they do not come to land to nest. Tagging and recapture studies, and tracking studies have shown that some turtles may be resident in Florida Bay for several months to several years. Recaptures of turtles originally tagged in Florida Bay have been reported as far away as Cuba and Nicaragua.

Of great concern has been the prevalence of a disease called fibropapillomatosis among the green turtles and loggerheads in Florida Bay. Turtles that are noticeably afflicted with this disease may have very large tumors around the base of the flippers and on the neck and eyes. About seventy percent of the green turtles and ten percent of the loggerheads captured to date had tumors.

Status: This study is ongoing. A long term approach is necessary to understand these long-lived endangered and threatened species.

Restoration Impacts: Baseline information on Florida Bay's sea turtle populations is important to guide and evaluate the restoration programs being implemented by federal and state agencies.

Funding Sources: NOAA National Marine Fisheries Services; Florida Marine Research Institute

Related Profiles: 

FBP FBPP 52 

FBP FBPP 55