A Study to Determine Effects of Beach Sand Grain Size on Sea Turtle Nesting for Caretta caretta in Southwest Florida
Kelly Bonkowski
Florida Gulf Coast University
10/11/2015
Abstract The following is a proposal for a study that looks at sand grain effects on sea turtle nesting particularly of the species Caretta caretta (loggerhead sea turtle) in Southwest Florida. The study will observe and relate various properties in an attempt to know an ideal nesting environment. Nest sites of different sand grains will be observed to see differences in clutch survival. Caretta caretta is expected to have a high clutch survival in loosely packed, fine grained sand and a low clutch survival in compact, large grained sand.
Table of Contents …show more content…
Caretta caretta is found in the Atlantic, Pacific, and Indian Oceans, as well as the Mediterranean Sea and spends the majority of its life in saltwater habitats, only females coming onshore to lay eggs. The species we are studying has a low productive rate; with females laying an average of four egg clutches and then becoming quiescent, producing no eggs for two to three years. Florida is the most popular nesting site for Caretta caretta, with more than 67,000 nests built per year. Females exhibit basic nesting behavior, returning to the beach where they hatched to lay eggs at intervals of 12-17 days during nesting season. They exit the water, climb the beach dunes, and excavate an egg chamber to deposit their clutch. Loggerheads have an average clutch size of 112.4 …show more content…
It is hypothesized that fine sand grains that are loosely packed will have a higher clutch survivor rate.
Methods
Experimental Design
To better control the experiment, we will use nests that need to be relocated because of hazards to the original nest site selection of the sea turtle, such as too close to the shoreline or in an area traveled too frequently by humans. The eggs will be dug up and relocated to Lovers Key State Park. They will be dispersed evenly on the beach to help control differences in outside variables such as temperature.
Fig 1. Relocated turtle nest site.
The study nests will then be filled with 1 of 3 sand types: Fine, Medium, or Coarse grained. The Wentworth (1992) grain size classification will be used to define the sand grain sizes. A second factor will also be used for the sand; either firmly packed or loosely packed sand. There are 6 different treatment combinations that will be repeated a total of 5 times, so a total of 30 nests will be needed. The response variables that will be looked at will be the amount of eggs that successfully hatch and the amount of hatchlings that crawl out of the
Kelly Bonkowski
Florida Gulf Coast University
10/11/2015
Abstract The following is a proposal for a study that looks at sand grain effects on sea turtle nesting particularly of the species Caretta caretta (loggerhead sea turtle) in Southwest Florida. The study will observe and relate various properties in an attempt to know an ideal nesting environment. Nest sites of different sand grains will be observed to see differences in clutch survival. Caretta caretta is expected to have a high clutch survival in loosely packed, fine grained sand and a low clutch survival in compact, large grained sand.
Table of Contents …show more content…
Caretta caretta is found in the Atlantic, Pacific, and Indian Oceans, as well as the Mediterranean Sea and spends the majority of its life in saltwater habitats, only females coming onshore to lay eggs. The species we are studying has a low productive rate; with females laying an average of four egg clutches and then becoming quiescent, producing no eggs for two to three years. Florida is the most popular nesting site for Caretta caretta, with more than 67,000 nests built per year. Females exhibit basic nesting behavior, returning to the beach where they hatched to lay eggs at intervals of 12-17 days during nesting season. They exit the water, climb the beach dunes, and excavate an egg chamber to deposit their clutch. Loggerheads have an average clutch size of 112.4 …show more content…
It is hypothesized that fine sand grains that are loosely packed will have a higher clutch survivor rate.
Methods
Experimental Design
To better control the experiment, we will use nests that need to be relocated because of hazards to the original nest site selection of the sea turtle, such as too close to the shoreline or in an area traveled too frequently by humans. The eggs will be dug up and relocated to Lovers Key State Park. They will be dispersed evenly on the beach to help control differences in outside variables such as temperature.
Fig 1. Relocated turtle nest site.
The study nests will then be filled with 1 of 3 sand types: Fine, Medium, or Coarse grained. The Wentworth (1992) grain size classification will be used to define the sand grain sizes. A second factor will also be used for the sand; either firmly packed or loosely packed sand. There are 6 different treatment combinations that will be repeated a total of 5 times, so a total of 30 nests will be needed. The response variables that will be looked at will be the amount of eggs that successfully hatch and the amount of hatchlings that crawl out of the