Accuracy and Precision of Fish Ages - Northeast

April 24, 2020

It is important to ensure consistency in fish ages used in fish population assessments. The Fishery Biology Program conducts regular testing to provide measures of consistency and accuracy.

Fishery Biology Program staff regularly test themselves to ensure their ages are precise and accurate. This table summarizes the results of precision testing for 2011-2015. Full information is linked above. 

Species

Number Aged

Number Tested

Agreement (%)

CV (%)

Bass, Black Sea

10115

1260

2.09

89.2

Bluefish

117

40

14.14

80.0

Butterfish

8418

558

4.22

90.0

Cod, Atlantic

25961

2049

0.48

98.0

Flounder, Fourspot

103

40

1.64

90.0

Flounder, Summer

21753

2860

3.98

81.5

Flounder, Windowpane

557

106

3.83

79.6

Flounder, Winter 

13576

1406

4.41

75.3

Flounder, Witch

14590

2690

1.25

88.0

Flounder, Yellowtail

27324

3811

1.78

91.0

Haddock

43826

2814

0.49

96.5

Hake, Red

2624

363

7.89

73.2

Hake, Silver

16315

1441

2.26

92.2

Hake, White

8272

1216

8.44

74.4

Herring, Atlantic

10384

1093

1.33

91.7

Mackerel, Atlantic

5107

1025

0.31

98.9

Plaice, American

17010

2625

4.03

68.8

Pollock

13878

2569

2.10

83.0

Redfish, Acadian

5815

614

2.76

71.8

Scup

13673

1312

2.12

88.9

Surfclam, Atlantic

1583

300

0.72

89.5

Tilefish

3878

665

3.96

63.8

 

Agreement: the percentage of fish where the ages agreed. A perfect result is 100%; over 80% is acceptable. 

 

CV: a statistic which accounts for the relative difference between ages. A perfect result is 0%; under 5% is acceptable.

Last updated by Northeast Fisheries Science Center on 04/24/2020

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