Author Topic: Possible addition of new value in "Counting Method" field  (Read 2118 times)


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Possible addition of new value in "Counting Method" field
« on: January 30, 2014, 11:04:26 AM »
Potential new value for release table field 36 Counting Method. Currently it reads:

36   Counting Method
counting_method   1   No   Lookup
’F’   Method used to determine number of non-CWT fish in the given release group; If present, must match one of the following:
=Book estimates
=Actual physical counts
=Petersen estimates
=Weight derived estimates
=Volumetric Conversion
=Feed Conversion Estimates

In the past when releases using electronic counters have been reported, NIFC have been passing them as counting method “C” (actual physical counts).  We have also been using this value in instances where marking / tagging has occurred immediately prior to a release.  To me they both imply a much higher precision than the other counts offered, especially the often used “Book Estimates”.  Now with sophisticated electronic counters, managers are opting to forgo these other methods, and use electronic counters inserted into dam boards, with Mark/Tag ratios derived from population estimates.

I would like the group to consider a new value to the Counting Method field “E” = Electronic counter derived estimates.  Here is a current example of how it is being used:

Coho release numbers at xxxx in 2013 were based on hard counts made by an electronic fish counter with an arithmetic mean error rate of only -0.14% with a 95% confidence interval of 2.27%.  Applying the 95% confidence interval of ± 2.27% to the total electronic count yielded a 95% confidence interval of 1,097,697 to 1,148,689, with a point estimate of 1,123,196 ± 25,496 for the total release.  Coho smolts were wanded with hand-held metal detectors and visually inspected for the presence/absence of adipose fin clips immediately prior to the releases in 2013.   A total of 3,005 Coho smolts were inspected, of which 160 were AD+CWT (5.3%), 2,775 were Ad-Only (92.3%), 6 were CWT Only (0.2%), and 64 were Unmarked and Untagged (2.1%).  Applying these ratios to the total electronic count yielded total Coho release numbers of 59,964 AD&CWT, 1,039,995 AD-Only, 2,249 CWT-Only, and 23,985 Unmarked and Untagged for a total of 1,126,193
« Last Edit: January 30, 2014, 11:08:06 AM by kenp »