Age Determination in the White Sucker

Abstract

The purpose of this study was to test the reliability of the scale method for determining the age of white suckers. To do so, an alternative method of "aging" was explored, using sections cut from the first four rays of the pectoral fin. Two hundred and fifty white suckers were tagged, and a piece of one pectoral fin was removed before they were released. A year later, 25 were recaptured, and the rays of the remaining pectoral fin were aged. Of the recaptures, 22 showed clearly the addition of one annulus.Having confirmed the fin-ray method, the age of another 157 suckers was determined by scales and fin rays and compared. The results indicated the scale method was reliable, in this population, until the fish reach an age of 5 years. Beyond 5 years there was not close agreement between scale and fin ages. After 8 years, age as determined by scales was invariably less than from fin rays, and sometimes was in error by as much as 5 years.