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The following information and charts were taken from the 2001 Delray Beach Sea Turtle Monitoring Report.
Written by: John R. Fletemeyer.
INTRODUCTION
The Delray Beach Sea Turtle Monitoring and Conservation Program began in 1984 in response to a beach sand nourishment project. This program has three primary objectives:
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To determine the long term impact of beach sand nourishment on the local sea turtle nesting population consisting of the loggerhead, leatherback and green sea turtle.
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To conserve and protect from natural and human disturbances the population of sea turtles that select nesting sites on Delray's beach.
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To conduct a daily nesting monitoring program that permits mechanical beach cleaning and various types of recreational activities to occur on the beach concurrently with nesting.
Regarding the first objective, this program has managed to accumulate an impressive amount of scientific data that has helped biologists understand some of the short term and long term effects that beach nourishment has on nesting behavior. It is important to note that although this study reveals that some of these effects are negative, ultimately sand nourishment must be regarded as being beneficial to sea turtles because it is responsible for creating new nesting habitat that would otherwise not exist.
THE STUDY AREA
The Delray Beach monitoring program is approximately 3.1 miles in length extending between the north city limit and the municipality of Gulf Stream and the south city limit and the municipality of Highland Beach.
To make valid, long term comparisons about sea turtle nesting behavior from one area of the beach with another, the Delray Beach monitoring area is divided into seventeen, 1,000' nesting zones. These zones were established 18 years ago and their locations have remained the same over time.
RESULTS
During the 2001 season, sea turtle nesting activity lasted 145 days beginning with a leatherback nest on March 30th and ending with a loggerhead nest of August 22nd. Most nesting activity was from loggerhead turtles, however leatherback turtles and green turtles accounted for some of the nests. During this period, a total of 497 sea turtle crawls were observed. From this total, 221 resulted in viable nests containing eggs. This represents a nesting success of 44% and means that less than half of the turtles that crawled onto the beach successfully nested.
When nesting is compared to the previous seasons beginning in 1984, the 2001 season ranks 8th in regards to overall nesting and was slightly greater than the mean of 207 nests. When the number of nests for each season is plotted to identify a nesting "trend" line, nesting on Delray Beach has shown an increase in nesting over the past 18 years, albeit ever so slightly.
From this total of 221 nests, 10 (= 4.5%) belonged to leatherback turtles, 4 (= 1.8%) to green turtles and 207 (= 93.7%) to loggerhead turtles.
Summary of Nesting Activity by Species of Turtle on Delray Beach During the 2001 Season
Species of Turtles First Nest Last Nest # of Nests # of False Crawls
Loggerhead 4/28/01 8/22/01 207 273
Leatherback 3/30/01 5/20/01 10 0
Green 6/17/01 8/14/01 4 3
Totals: 221 276
Conclusion
The most encouraging finding made is the fact that Delray's sea turtle population is increasing. This finding suggests that sea turtles are able to cop with the many disturbances that are associated with the highly developed coastal zone found along Delray's 3.1 miles of beach. Another encouraging finding also related to a trend is that fewer and fewer lighting violations are being observed. This is undoubtedly due to a heightened public awareness and to the diligent work of members from Delray's Code Enforcement, Police and Planning and Zoning Departments. |
