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Size of first year [Archived]


Nikki Paige
(@npaige)
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Joined: 5 years ago
Posts: 5
Topic starter  

Posted by kwmcneel 3/17/16:

Hi All,

ADF&G-ADU uses an expected diameter range to verify the first annual band in many of the species we read. We were evaluating our criteria and noticed a discrepancy between one of our ranges and another agency's. This resulted in proposing to discuss first year criteria for the CARE 2017 agenda. 

Given this, I wanted to see what documented sizes, one-year-old/young-of-the-year otoliths, and early-life research other programs might have to help correct or corroborate our individual species criteria. I plan on summarizing our year one criteria and collections of estimated one/zero-year-old, and posting it on this thread to help get further resolution. 

The image below is an example of dorso-ventral otolith measurements, but let me know if you have any questions.

 

Thanks,
Kevin McNeel
ADF&G-ADU

~Nikki


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Nikki Paige
(@npaige)
Moderator Admin
Joined: 5 years ago
Posts: 5
Topic starter  

Posted by chrisg:

Please see above image.

This rougheye rockfish break and burn image provided by Betty Goetz from the AFSC Age and Growth Program is an example how we would measure or interpret the size of the first year. The white bar is 20 microunits, measured with a micrometer, at 2.0x magnification with 10x eyepieces. The conversion is approximately 0.92 mm for the first year.

Thanks Kevin for providing your rougheye image to compare. Looking forward to discussing early growth criteria among the age labs at the 2017 CARE Meeting rougheye rf workshop.

Chris Gburski
AFSC Age and Growth program

~Nikki


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