Atlantic Cod, Gadus morhua
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Eric Robillard (ER) has been working with Atlantic Cod since 2025; before that, the age reader was Nina Shepherd (NS, 2003-2025). Baked and sectioned otoliths are 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. Stock indicates whether samples were from Georges Bank (GB) or the Gulf of Maine (GOM); if no stock area is specified, samples were from both areas combined. All samples were collected by the Northeast Fisheries Science Center except where indicated otherwise.
| Sample Source | Stock | Test Type | Date Completed | Age Reader | Number Aged | Number Tested | CV (%) | Agree-ment (%) | Bias |
|---|---|---|---|---|---|---|---|---|---|
| 2025 Commercial Samples (Q4) | Precision | 4/2026 | ER | 481 | 88 | 0.59 | 95.5 | ||
| 2025 Commercial Samples (Q3) | Precision | 4/2026 | ER | 131 | 31 | 0.65 | 96.8 | ||
| 2015 Observer Samples (Q1-Q4) | Precision | 3/2026 | ER | 430 | 50 | 2.92 | 90.0 | ||
| 2025 Commercial Samples (Q2) | Precision | 3/2026 | ER | 111 | 25 | 0.63 | 96.0 | ||
| 2025 Commercial Samples (Q1) | Precision | 8/2025 | ER | 600 | 79 | 1.36 | 91.1 | ||
| 2025 Spring Survey (202502) | Precision | 7/2025 | ER | 253 | 47 | 1.03 | 95.7 | ||
| 2024 Commercial Samples (Q4) | Precision | 5/2025 | ER vs. NS | 1453 | 75 | 2.60 | 86.7 | n/s | |
| 2024 Commercial Samples (Q3) | Precision | 2/2025 | NS | 365 | 60 | 0.00 | 100.0 | ||
| 2024 Autumn Survey (202404) | Precision | 12/2024 | NS | 165 | 39 | 0.73 | 97.4 | ||
| 2024 Commercial Samples (Q2) | Precision | 10/2024 | NS | 533 | 65 | 0.31 | 98.5 | ||
| 2024 Commercial Samples (Q1) | Precision | 9/2024 | NS | 577 | 72 | 0.00 | 100.0 | ||
| 2023 Canadian (DFO) Survey (VEN2023001) | GB | Exchange | Summer 2024 | NS vs. EW | — | 42 | 1.44 | 92.9 | |
| 2022 Canadian (DFO) Commercial Samples (Q2-4) | GB | Exchange | Summer 2024 | NS vs. EW | — | 115 | 1.52 | 91.3 | |
| 2024 Spring Survey (202402) | Precision | 7/2024 | NS | 274 | 45 | 0.00 | 100.0 | ||
| 2023 Commercial Samples (Q3-4) | Precision | 3/2024 | NS | 112 | 40 | 0.00 | 100.0 | ||
| 2023 Autumn Survey (202304) | Precision | 3/2024 | NS | 227 | 45 | 0.63 | 97.8 | ||
| 2023 Commercial Samples (Q2) | Precision | 12/2023 | NS | 127 | 40 | 0.00 | 100.0 | ||
| 2023 Commercial Samples (Q1) | Precision | 9/2023 | NS | 162 | 40 | 0.00 | 100.0 | ||
| 2021 Canadian (DFO) Survey (TEL2021002) | GB | Exchange | Fall 2023 | NS vs. EW | — | 60 | 0.42 | 96.7 | |
| 2020 Canadian (DFO) Commercial Samples (Q2-4) | GB | Exchange | Fall 2023 | NS vs. EW | — | 100 | 1.23 | 94.0 | |
| 2022 Canadian (DFO) Survey (CAR2022102) | GB | Exchange | Summer 2023 | NS vs. EW | — | 59 | 0.92 | 93.2 | |
| 2021 Canadian (DFO) Commercial Samples (Q2-4) | GB | Exchange | Summer 2023 | NS vs. EW | — | 114 | 0.98 | 93.9 | |
| 2023 Spring Survey (202302) | Precision | 6/2023 | NS | 278 | 51 | 0.00 | 100.0 | ||
| 2022 Commercial Samples (Q1-Q4) | Precision | 2/2023 | NS | 150 | 45 | 0.00 | 100.0 | ||
| 2022 Autumn Survey (202204) | Precision | 2/2023 | NS | 283 | 42 | 0.00 | 100.0 | ||
| 2022 Spring Survey (202202) | Precision | 9/2022 | NS | 473 | 87 | 4.15 | 89.7 | n/s | |
| 2021 Commercial Samples (Q1-4) | Precision | 4/2022 | NS | 269 | 50 | 0.00 | 100.0 | ||
| 2021 Autumn Survey (202104) | Precision | 4/2022 | NS | 269 | 50 | 0.00 | 100.0 | ||
| 2021 Spring Survey (202102) | Precision | 7/2021 | NS | 383 | 80 | 0.84 | 97.5 | ||
| 2020 Commercial Samples (Q3) | Precision | 3/2021 | NS | 141 | 40 | 0.39 | 97.5 | ||
| 2020 Commercial Samples (Q2) | Precision | 3/2021 | NS | 223 | 41 | 0.00 | 100.0 | ||
| 2020 Commercial Samples (Q1) | Precision | 9/2020 | NS | 243 | 48 | 0.00 | 100.0 | ||
| 2019 Commercial Samples (Q4) | Precision | 5/2020 | NS | 291 | 60 | 0.00 | 100.0 | ||
| 2019 Commercial Samples (Q3) | Precision | 4/2020 | NS | 288 | 60 | 0.52 | 96.7 | ||
| 2019 Commercial Samples (Q2) | Precision | 4/2020 | NS | 303 | 60 | 0.21 | 98.3 | ||
| 2019 Commercial Samples (Q1) | Precision | 4/2020 | NS | 379 | 73 | 0.28 | 98.6 | ||
| 2019 Autumn Survey (201904) | Precision | 2/2020 | NS | 202 | 42 | 0.00 | 100.0 | ||
| 2019 Spring Survey (201902) | Precision | 2/2020 | NS | 447 | 92 | 1.76 | 97.8 | ||
| 2018 Autumn Survey (201804) | Precision | 5/2019 | NS | 247 | 56 | 0.00 | 100.0 | ||
| 2018 Commercial Samples (Q4) | Precision | 5/2019 | NS | 395 | 79 | 0.00 | 100.0 | ||
| 2018 Commercial Samples (Q3) | Precision | 5/2019 | NS | 463 | 56 | 0.00 | 100.0 | ||
| 2018 Commercial Samples (Q2) | Precision | 5/2019 | NS | 974 | 80 | 0.00 | 100.0 | ||
| 2018 Commercial Samples (Q1) | Precision | 5/2019 | NS | 1116 | 77 | 0.00 | 100.0 | ||
| 2018 Spring Survey (201802) | Precision | 6/2018 | NS | 310 | 64 | 0.74 | 98.4 | ||
| 2017 Commercial Samples (Q4) | Precision | 5/2018 | NS | 826 | 89 | 0.00 | 100.0 | ||
| 2017 Commercial Samples (Q3) | Precision | 4/2018 | NS | 1218 | 84 | 0.00 | 100.0 | ||
| 2017 Commercial Samples (Q2) | Precision | 3/2018 | NS | 1243 | 68 | 0.16 | 98.5 | ||
| 2017 Autumn Survey (201704) | Precision | 2/2018 | NS | 212 | 48 | 0.00 | 100.0 | ||
| 2017 Commercial Samples (Q1) | Precision | 1/2018 | NS | 1463 | 105 | 0.00 | 100.0 | ||
| 2017 Canadian (DFO) Spring Survey (TEL2017002) | GB | Exchange | Spring 2017 | QM vs. NS | — | 62 | 4.00 | 79.0 | 0.011 |
| 2016 Canadian (DFO) Spring Survey (TEL2016002) | GB | Exchange | Spring 2017 | QM vs. NS | — | 65 | 4.81 | 75.4 | n/s |
| 2016 Canadian (DFO) Commercial Samples (Q2-4) | GB | Exchange | Spring 2017 | QM vs. NS | — | 114 | 3.46 | 82.5 | n/s |
| 2016 Commercial Samples (Q1-2) | GB | Exchange | Spring 2017 | QM vs. NS | — | 152 | 2.36 | 84.9 | n/s |
| 2016 Autumn Survey (201604) | GB | Exchange | Spring 2017 | QM vs. NS | — | 72 | 1.18 | 95.8 | |
| 2016 Commercial Samples (Q4) | Precision | 7/2017 | NS | 1409 | 105 | 0.15 | 99.0 | ||
| 2017 Spring Survey (201702) | Precision | 7/2017 | NS | 659 | 94 | 0.00 | 100.0 | ||
| 2016 Commercial Samples (Q3) | Precision | 7/2017 | NS | 1201 | 86 | 0.00 | 100.0 | ||
| 2016 Autumn Survey (201604) | Precision | 5/2017 | NS | 667 | 78 | 0.00 | 100.0 | ||
| 2016 Commercial Samples (Q2) | Precision | 4/2017 | NS | 1314 | 96 | 0.00 | 100.0 | ||
| 2016 Spring Survey (201602) | Precision | 4/2017 | NS | 982 | 91 | 0.22 | 98.9 | ||
| 2016 Commercial Samples (Q1) | Precision | 3/2017 | NS | 2002 | 94 | 0.00 | 100.0 | ||
| 2015 Commercial Samples (Q4) | Precision | 4/2016 | NS | 1761 | 94 | 0.00 | 100.0 | ||
| 2015 Commercial Samples (Q3) | Precision | 4/2016 | NS | 824 | 95 | 0.00 | 100.0 | ||
| 2015 Commercial Samples (Q2) | Precision | 4/2016 | NS | 1034 | 95 | 0.00 | 100.0 | ||
| 2015 Commercial Samples (Q1) | Precision | 4/2016 | NS | 1561 | 93 | 0.00 | 100.0 | ||
| 2015 Autumn Survey (201504) | Precision | 4/2016 | NS | 813 | 94 | 0.00 | 100.0 | ||
| 2015 Spring Survey (201502) | Precision | 7/2015 | NS | 925 | 97 | 0.00 | 100.0 | ||
| Cod Reference Collection | GB | Accuracy | 4/2015 | NS | — | 69 | 0.00 | 100.0 | |
| 2014 Autumn Survey (201404) | Precision | 4/2015 | NS | 303 | 65 | 2.18 | 98.5 | ||
| 2014 Spring Survey (201402) | Precision | 4/2015 | NS | 478 | 96 | 0.00 | 100.0 | ||
| 2014 Commercial Samples (Q4) | Precision | 4/2015 | NS | 1072 | 97 | 0.00 | 100.0 | ||
| 2014 Commercial Samples (Q3) | Precision | 4/2015 | NS | 987 | 98 | 0.00 | 100.0 | ||
| 2014 Commercial Samples (Q2) | Precision | 4/2015 | NS | 1456 | 96 | 0.00 | 100.0 | ||
| 2014 Commercial Samples (Q1) | Precision | 4/2015 | NS | 1049 | 100 | 0.00 | 100.0 | ||
| 2013 Commercial Samples (Q3-4) | Precision | 4/2014 | NS | 3010 | 102 | 0.00 | 100.0 | ||
| 2013 Commercial Samples (Q2) | Precision | 4/2014 | NS | 1796 | 96 | 0.00 | 100.0 | ||
| 2013 Autumn Survey (201304) | Precision | 2/2014 | NS | 404 | 84 | 0.00 | 100.0 | ||
| 2013 Commercial Samples (Q1) | Precision | 1/2014 | NS | 1597 | 99 | 0.10 | 99.0 | ||
| 2012 Commercial Samples (Q2-4) | GOM | Precision | 11/2013 | NS | 2988 | 98 | 0.38 | 96.9 | |
| 2013 Spring Survey (201302) | Precision | 10/2013 | NS | 697 | 97 | 4.95 | 81.4 | 0.015 | |
| 2012 Commercial Samples (Q2-4) | GB | Precision | 5/2013 | NS | 1345 | 98 | 1.48 | 92.9 | |
| 2012 Autumn Survey (201204) | Precision | 4/2013 | NS | 383 | 80 | 0.35 | 98.8 | ||
| 2012 Commercial Samples (Q1) | GB | Precision | 12/2012 | NS | 499 | 50 | 1.10 | 92.0 | |
| 2012 Commercial Samples (Q1) | GOM | Precision | 12/2012 | NS | 711 | 51 | 0.47 | 94.1 | |
| 2011 Massachusetts Survey (201191) | Precision | 3/2012 | NS | 268 | 74 | 0.00 | 100.0 | ||
| 2008 Commercial Samples (Q1-4) | GOM | Precision | 10/2011 | NS | 4333 | 96 | 0.64 | 95.8 | |
| 2010 Commercial Samples (Q2-4) | GOM | Precision | 9/2011 | NS | 4127 | 83 | 0.84 | 94.0 | |
| 2010 Commercial Samples (Q1) | GOM | Precision | 9/2011 | ER | 1243 | 102 | 1.39 | 90.2 | |
| 2010 Commercial Samples (Q1) | GOM | Precision | 9/2011 | NS vs. ER | 1243 | 101 | 4.13 | 66.3 | <0.001 |
| 2009 Commercial Samples (Q2-4) | GOM | Precision | 9/2011 | NS | 5260 | 92 | 1.68 | 85.9 | 0.030 |
| 2010 Canadian (DFO) Commercial Samples (Q2-Q4) & 2010 DFO Spring Surveys (NED201001 & NED201102) | GB | Exchange | Summer 2011 | NS vs. BH | — | 186 | 2.42 | 91.4 | |
| 2010 Commercial Samples (Q1-Q4) | GB | Precision | 4/2011 | NS | 3548 | 146 | 0.39 | 97.3 | |
| 2009 Commercial Samples (Q1) | GOM | Precision | 2/2011 | NS | 953 | 102 | 0.51 | 96.1 | |
| 2010 Spring Survey (201001) | Precision | 2/2011 | NS | 932 | 96 | 1.26 | 93.8 | ||
| 2008 Commercial Samples (Q4) | GB | Precision | 5/2009 | NS | 559 | 76 | 0.00 | 100.0 | |
| 2008 Commercial Samples (Q2) | GB | Precision | 4/2009 | NS | 659 | 50 | 0.13 | 98.0 | |
| 2008 Autumn Survey (200807) | Precision | 3/2009 | NS | 390 | 50 | 2.18 | 92.0 | ||
| 2003-2004 Massachusetts Surveys (2391, 2392, 2491, & 2492) | Precision | 7/2008 | NM | 761 | 100 | 4.65 | 90.0 | ||
| 2007 Commercial Samples (Q1-2) | GB | Exchange | Spring 2008 | NS vs. BH | — | 99 | 1.80 | 88.9 | n/s |
| 2006 Fall Survey (200610) | GB | Exchange | Spring 2008 | NS vs. BH | — | 60 | 2.83 | 88.3 | n/s |
| 2007 Commercial Samples (Q3-4) | Precision | 6/2008 | NS | 3139 | 81 | 0.35 | 97.5 | ||
| 2007 Commercial Samples (Q1-2) | Precision | 6/2008 | NS | 3486 | 100 | 0.13 | 99.0 | ||
| Cod Reference Collection | GB | Accuracy | 6/2008 | NS | — | 75 | 0.27 | 98.7 | |
| 2008 Spring Survey (200803) | Precision | 6/2008 | NS | 548 | 100 | 0.11 | 99.0 | ||
| 2007 Autumn Survey (200709) | Precision | 6/2008 | NS | 250 | 50 | 0.00 | 100.0 | ||
| 2004 Canadian (DFO) Commercial & Observer Samples (Q3-4) | GB | Exchange | Spring 2007 | NM/NS vs. BH | — | 56 | 1.40 | 91.1 | |
| 2005 Canadian (DFO) Spring Survey (TEL2005545) | GB | Exchange | Spring 2007 | NM/NS vs. BH | — | 50 | 0.89 | 94.0 | |
| 2005 Commercial Samples (Q1) | GB | Exchange | Spring 2007 | NM/NS vs. BH | — | 53 | 2.28 | 84.9 | n/s |
| 2005 Autumn Survey (200510) | GB | Exchange | Spring 2007 | NM/NS vs. BH | — | 56 | 1.79 | 91.1 | |
| Cod Reference Collection | GB | Accuracy | 5/2007 | NS | — | 100 | 0.61 | 97.0 | |
| 2006 Commercial Samples (Q1-4) | Precision | 5/2007 | NS | 7039 | 99 | 1.01 | 90.9 | ||
| 2006 Autumn Survey (200610) & 2007 Spring Survey (200703) | Precision | 5/2007 | NS | 1157 | 100 | 1.61 | 92.0 | ||
| Cod Reference Collection | GB | Accuracy | 5/2006 | NS | — | 45 | 3.85 | 86.7 | n/a |
| 2006 Spring Survey (200604) | Precision | 5/2006 | NS | 421 | 50 | 0.19 | 98.0 | ||
| 2005 Commercial Samples (Q1-4) | Precision | 5/2006 | NS | 5103 | 80 | 1.20 | 93.8 | ||
| 2005 Autumn Survey (200510) | Precision | 5/2006 | NS | 377 | 50 | 0.22 | 98.0 | ||
| 2004 Commercial Samples (Q1-4) | GOM | Precision | 7/2005 | NS | 3618 | 112 | 0.75 | 93.8 | |
| 2003 Canadian (DFO) Commercial Samples (Q4) & 2004 DFO Observer Samples (Q3) | GB | Exchange | Spring 2005 | NM/NS vs. BH | — | 50 | 0.88 | 94.0 | |
| 2004 Canadian (DFO) Spring Survey (TEM2004004) | GB | Exchange | Spring 2005 | NM/NS vs. BH | — | 50 | 1.98 | 84.0 | n/s |
| 2004 Commercial Samples (Q2) | GB | Exchange | Spring 2005 | NM/NS vs. BH | — | 51 | 3.59 | 80.4 | n/s |
| 2004 Autumn Survey (200407) | GB | Exchange | Spring 2005 | NM/NS vs. BH | — | 49 | 2.59 | 85.7 | n/s |
| Cod Reference Collection | GB | Accuracy | 6/2005 | NM | — | 106 | 1.53 | 90.6 | |
| 2003 Commercial Samples (Q4) | GOM | Precision | 4/2005 | NS | 1490 | 105 | 2.68 | 85.7 | 0.021 |
| 2004 Autumn Survey (200407) | GOM | Precision | 2/2005 | NM vs. NS | 174 | 60 | 0.00 | 100.0 | |
| Cod Reference Collection | GB | Accuracy | 6/2004 | NS | — | 99 | 1.94 | 90.9 | |
| 2002 Canadian (DFO) Commercial Samples (Q3-4) | GB | Exchange | Winter 2003-2004 | NM/NS vs. BH | — | 46 | 2.60 | 78.3 | n/s |
| 2003 Canadian (DFO) Spring Survey (NED2003002) | GB | Exchange | Winter 2003-2004 | NM/NS vs. BH | — | 47 | 5.26 | 68.1 | n/s |
| 2002 Commercial Samples (Q1) | GB | Exchange | Winter 2003-2004 | NM/NS vs. BH | — | 46 | 2.40 | 89.1 | n/s |
| 2002 Autumn Survey (200209) | GB | Exchange | Winter 2003-2004 | NM/NS vs. BH | — | 52 | 3.83 | 88.5 | n/s |
