Populations of Western Atlantic loggerheads (Caretta caretta) and Florida green turtles (Chelonia mydas) have been in historical decline. The identification and protection of beaches that are major producers of loggerhead and green turtle hatchlings are vital to the preservation of these species.
A study assessing loggerhead and green turtle hatchling production was initiated at a 21 km stretch of beach in south Brevard County, Florida (Melbourne Beach) during the 1985 nesting season. Nesting densities were assessed from a season-long (10 May – 12 September) census in which every nest was counted and identified to species. An analysis of average reproductive success was made from 100 loggerhead and 27 green turtle sample nests. Daily tallies of specific disturbances to nests aided in formulating dimensional descriptions of factors which caused clutch and hatchling mortality.
An unprecedented 10,240 loggerhead and 281 green turtle nests were counted within the Melbourne Beach study area in 1985. Approximately 48 and 51 percent of the constituent eggs of loggerhead and green turtle nests resulted in hatchlings that successfully entered the surf. These values are very high compared to data from other nesting beaches.
A severe September northeaster storm was the major cause of mortality for clutches of both species. Raccoon predation and the disorientation of hatchlings by beachfront lighting were also significant in limiting reproductive success. Beachfront lighting was also found to significantly deter green turtles from nesting. Predation of nests by raccoons was limited to a small portion of the study area. The rate of hatchling disorientation was found to decrease following the enforcement of a regional ordinance restricting beachfront lights.
Management recommendations include: bestowing a special protective status for the Melbourne Beach area; providing efforts to monitor and regulate beach and nearshore activities; initiating specific management practices to mitigate mortality; and enhancing research and public education efforts regarding Melbourne Beach’s marine turtles.
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Ehrhart, Llewellyn M.
Master of Science (M.S.)
College of Arts and Sciences
Length of Campus-only Access
Masters Thesis (Open Access)
Witherington, Blair E., "Human and Natural Causes of Marine Turtle Clutch and Hatchling Mortality and Their Relationship to Hatchling Production on an Important Florida Nesting Beach" (1986). Retrospective Theses and Dissertations. 4922.
Contributor (Linked data)