1. A Study on the Possible Correlation between Sand Compaction and the Success of Hatchling Emergence
By Alexandra Alterman

2. Research Question
Does Beach renourishment and our relocation methods impact the compaction levels of the nests and subsequently the success of hatchling emergence?

3. Background: Renourishment
Beach renourishment to combat erosion- “Soft approach”
Occurred on a portion of South beach
Dredging from adjacent Channel
Creates more nesting area but can affect the quality of it
Soft approach means no “hard” engineering structures like groins and break waters and it is the preffered approach in NC
Nourishement affects nesting environment by altering sand compaction, color, grain size and shape, moisture content, slope, mineral content, and gas exchange
Usually sediment taken from regularly maintained navigation channels does not require sampeling b/c it is assumed the sediment originated from native beach and is therefore compatible

4. Background: Nest Relocations
Relocations frequent on BHI
Causes: too close to high tide line, near eroding structures
Automatic relocations: the point, shoals club area, sections of west beach
Specific relocation protocol- Focus on how we compact the sand
Too close to high tide line can cause excessive washover/ flooding and eroding structures can expose or excessively cover a nest; one relocation this season from a turtle nesting in a narrow private access
The point is prone to flooding, the area of beach by the shoals club is non existent during high tide and the dunes are rapidly eroding, sections of west beach are also too narrow during high tide
Take eggs out and count them with out rotating them, take sand from bottom, estimate width and depth of original egg chamber, dig new chamber with cockle shells to match original, put eggs in the same order from original, cover and pack it down to compact sand like the mother does

5. Methods
Took compaction measurements of nests using a pocket penetrometer
Marked down location of beach and if the nest was natural or relocated
Measurements taken at various times throughout incubation
Recorded straggler numbers after excavation
Statistical analysis of compaction measurements and straggler numbers
Took measurements in the center of nests before we caged them
I also went back to some of the earlier nests laid this season to gage how compaction changed over time- compaction increased with time
Ran T Test (one tailed, and unpaired except for the comparisons within south beach)

6. Data Nest # Nest Type Compaction (Kg/ cm2) Straggler # BA 1 N 0.225
R 18 (S) 2
0.131
L 11 (S) 3
0.106 11
L 42 (E) 4 R
0.234 6 7
0.088 10
0.069 14
L 13 (S)
0.231 17
L 20 (S) 15
0.056 5
R 39 (E)
0.025
L 36 (S) 37
0.05 9
-sample of some of my data points
I also calculated the success rates of nests to exclude nests that were very unsuccessful

7. Results
Sand compaction significantly different between nourished and unourshied areas
Sand compaction not significantly different between natural and relocated nests
Straggler #s not significantly different between nourished and unourished areas
Straggler #s significantly different between natural and relocated nests
compaction was higher in nourished areas of the beach
I compared the nourshied and unourished areas in 2 ways: first by comparing the nourished section of south to the unourshied area of south and east beach then just between the 2 areas on south beach-both showed a significant difference
the average compaction levels were higher for relocated nests but I did not find a signifcant difference between the two
The average number of stagglers in a nest were actually higher in the unourished areas ( where compaction is lower) but the difference was also not significant
The average number of stragglers in relocated nests was higher and this difference was significant

8. Discussion
Results support previous studies linking increased sand compaction and renourished beaches
No evidence of increased compaction resulting in increased emergence difficulty
No evidence of relocated nests having higher compaction
Other aspects of our relocation methods may make emergence more difficult
Previous studies have found that renourishment can lead increased compaction levels which can lead to increased emergence difficulty for hatchlings
I did not find a correlation between increased compaction and increased difficulty of hatchling emergence through my own research. A larger sample size might change this
the fact that relocated nests do not have significantly higher compaction levels than the natural nests suggests that our relocation methods do not play a role in increased compaction of nests
There may be other aspects of our relocation methods that are altering emergence success because there was a significant difference in the straggler numbers in the natural and relocated nest- we may deviating to far from the original egg chamber geometry, and egg placement

9. Going Forward Repeat studies More testing of sand quality
Review relocation protocol
Look into impact of renourished areas on nesting mothers
Studies similar to this should continue to be done ideally with larger sample sizes and maybe taking measurements in other areas besides the nests
If we continue to see a significant difference in compaction we should consider implementing more tests for the sand before it is placed on the beach
As of right now we are estimating the egg chamber measurements with arm lengths and hand widths, it might be beneficial to implement taking exact measurements of the original egg chamber to use on the reconstructed one to see if it helps decrease the number of stragglers in a relocated nest
I did not look at how the renourishment affects nesting mothers but this should be looked into as previous studies have found not only the machinery to deter moms but also the sand itself- determing the proportion of crawls that result in nests could also be beneficial for assessing the quality of the sand being placed on our beaches

10. Acknowledgements
Thank you to all my fellow BHIC summer interns, and Emily Hardin
Mentor: Dr. Suzanne Dorsey
Also a big thanks to the BHIC for supplying the materials necessary for this project!

11. References
Byrd, Julia I. "THE EFFECT OF BEACH NOURISHMENT ON LOGGERHEAD SEA TURTLE (Caretta Caretta) NESTING IN SOUTH CAROLINA."Dnr.sc.gov. N.p., Dec Web. July
Hernandez, Kimberly. "Protecting Beaches and Sea Turtles: An Analysis of Beach Nourishment in North Carolina, the Impacts on Nesting Loggerhead Sea Turtles, and How Sea Level Rise Will Transform the Status Quo." Dukespace.lib.duke.edu. Duke University, 25 Apr Web. July 2016.
Mcelroy, Mandi. "THE EFFECT OF SCREENING AND RELOCATION ON HATCHING AND EMERGENCE SUCCESS OF LOGGERHEAD SEA TURTLE NESTS AT SAPELO ISLAND, GEORGIA." Getd.libs.uga.edu. University of Georgia, Aug Web. July 2016
Tuttle, Jacob Anthony, "Loggerhead Sea Turtle (Caretta Caretta) Nesting on a Georgia Barrier Island: Effects of Nest Relocation" (2007). Electronic Theses & Dissertations. Paper 733.
Rush, Matthew D. "AN EVALUATION OF NEST RELOCATION AS A LOGGERHEAD SEA TURTLE (Caretta Caretta) MANAGEMENT TECHNIQUE IN NORTH CAROLINA." Dukespace.lib.duke.edu. Duke University, Web. July 2016.
Wilgis, Ted, and Frank Tursi. "The Risks of Renourishment: How Pumping Sand on North Carolina’s Beaches Can Affect Sea Turtles, Mole Crabs and Other Critters." Nccoast.org. NCCF, Apr Web. July 2016.

12. Questions?