	from:	 Madalyn Newman - NOAA Affiliate <madalyn.newman@noaa.gov>
	to:	     David Huddleston - NOAA Affiliate <david.huddleston@noaa.gov>
	date:	 Fri, Feb 10, 2017 at 2:10 PM
	subject: PH652U

Hey David:

The package I am working on now is PH652U, and it would be helpful to have PI  submit clarification on the background of the data set. The data are growth rate and size measurements for dead sea turtles.  Example: Explaining that the number of measurements for each individual turtle correlates to the age of that turtle when found dead, and how the growth rates were measured. Also, there are two spreadsheet with the same turtle_ID number assigned to what seems to be two different individuals. Please let me know if you have questions. Feel free to call me if this is confusing...

Thanks,
Madalyn

Madalyn Newman  
Project Scientist
Riverside Contractor
NOAA National Centers for Environmental Information
Phone: (228) 688-3313
1021 Balch Boulevard, Suite 1003
Stennis Space Center, MS 39529


	from:	 David Huddleston - NOAA Affiliate <david.huddleston@noaa.gov>
	to:	     Madalyn Newman - NOAA Affiliate <madalyn.newman@noaa.gov>
	date:	 Fri, Feb 10, 2017 at 2:28 PM
	subject: Re: PH652U

Hi Madalyn,

I will send your request on to the PI.

Thanks,
David Huddleston


	from:	 David Huddleston - NOAA Affiliate <david.huddleston@noaa.gov>
	to:	     Madalyn Newman - NOAA Affiliate <madalyn.newman@noaa.gov>
	date:	 Wed, Feb 15, 2017 at 12:37 PM
	subject: PH652U
	
Hi Madalyn,

Please add this Dataset_Metadata file to PH652U.  It explains the relationship of the two files and how to read the data.
"These data were generated through analysis of annually-deposited skeletal growth marks in humerus bones obtained from dead, stranded Kemp's ridley sea turtles in the Gulf of Mexico. Each skeletal growth mark is assigned an age estimate and calendar year. The strong relationship between skeletal growth mark diameters and body size (carapace length) allows estimation of carapace length for each measurable skeletal growth mark. Taking the difference between sequential carapace length estimates yields annual growth rates.  Because data are available to determine the timing of growth mark deposition, the size at age relationship pairs age estimates with the carapace length estimated from the skeletal growth mark associated with that age estimate.  Recommendations from the published literature are to analyze growth rates relative to the mean carapace length for the growth increment. As a result, the growth dataset pairs annual growth rate estimates with estimates of mean carapace length for the growth increment."

"The IDs refer to the same turtles in both files. For example, turtle ID 1 has 3 size at age records:
age 0 = estimated size 4.2 cm 
age 0.75 (at the time the first growth mark was deposited) = estimated size 15.8 cm
age 1.5 (the turtle died before it could complete another full year of growth and so no second growth mark was deposited) = measured size at death 23 cm

However, turtle ID 1 only has 1 growth record because it was only possible to calculate growth over 1 yearly interval: 15.8 cm - 4.2 cm = 11.6 cm
According to analytical protocol established for this field of study, that growth rate was attributed to the mean size for turtle ID 1 for that yearly growth interval: 
(4.2 + 15.8) / 2 = 10 cm"


Thanks,
David

