Clay , Douglas (1989) A Comparison of Two Stratification Schemes Used in Sampling Canadian Atlantic Cod, Gadus morhua. Marine Fisheries Review, 51(1), pp. 33-38.
Sampling is a key element in the assessment of any fish stock. It is often one of the most expensive activities of the management process; thus, improved efficiency can result in significant cost savings. In most cases a two-phase sampling strategy is employed. Two commonly used versions of such stratified random schemes were simulated using a test population based on Atlantic cod, Gadus morhua. A 1 otolith per 1 cm length frequency currently used for many flatfish and some smaller gadoids and a 3 otolith per 3 cm length frequency currently used for many of the larger gadoids. No difference was detected in the age composition or mean length at age for either scheme; however, 10 percent fewer otoliths were collected in 1 for 1 sampling than 3 for 3. There was an improvement of between 30 and 60 percent in the coefficient of variation of the estimated catch numbers at age using the 1 for 1 compared with the 3 for 3 stratified sampling. For these reasons and other operational considerations, the 1 for 1 stratified random design of sampling appears to be superior.
|Item Type: ||Article|
|Title: ||A Comparison of Two Stratification Schemes Used in Sampling Canadian Atlantic Cod, Gadus morhua|
|Personal Creator/Author: |
|Clay , Douglas|
|Journal or Publication Title: ||Marine Fisheries Review|
|Page Range: ||pp. 33-38|
|Issuing Agency: ||United States National Marine Fisheries Service|
|Item ID: ||9953|
|Depositing User: ||Patti M. Marraro|
|Date Deposited: ||22 Aug 2012 15:39|
|Last Modified: ||22 Aug 2012 15:39|
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