Atlantic Surfclam, Spisula solidissima
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Nina Shepherd (NS) has been working with Atlantic Surfclam since 2018; before that, the age reader was Blanche Jackson (BJ, retired). A section is taken from the hinge of the shell and viewed with reflected light.
In tests where agreement is below 90%, bias indicates either the P-value of a symmetry test or ‘n/s’ (test not significant at the α = 0.05 level). The Evans & Hoenig test was used to test bias starting 1/2022; prior to that, a Bowker's test was used.
| Sample Source | Test Type | Date Completed | Age Reader | Number Aged | Number Tested | CV (%) | Agree-ment (%) | Bias |
|---|---|---|---|---|---|---|---|---|
| 2023 Clam Survey (202360) | Precision | 4/2024 | NS | 219 | 49 | 1.24 | 87.8 | n/s |
| 2021 Clam Survey (202160) | Precision | 12/2022 | NS | 130 | 40 | 0.46 | 87.5 | n/s |
| 2018 Clam Survey (201860) | Precision | 4/2020 | NS | 659 | 94 | 0.43 | 95.7 | |
| 2015 Clam Survey (201560) | Precision | 12/2015 | BJ | 717 | 100 | 0.26 | 94.0 | |
| 2012 Clam Survey (201260) | Precision | 11/2015 | BJ | 328 | 70 | 0.09 | 97.1 | |
| 2013 Clam Survey (201360) | Precision | 8/2015 | BJ | 94 | 35 | 0.29 | 94.3 | |
| 2011 Clam Survey (201104) | Precision | 10/2012 | BJ | 444 | 95 | 2.25 | 72.6 | n/s |
| 2008 Clam Survey (200808) | Precision | 10/2008 | BJ | 840 | 100 | 3.13 | 76.0 | n/s |
| 2005 Clam Survey (200507) | Precision | 8/2005 | BJ | 889 | 141 | 3.43 | 65.2 | n/s |
| 2002 Clam Survey (200206) | Calibration | 6/2005 | BJ | — | 609 | 1.75 | 84.2 | n/s |
