Table G-3. Formulas to calculate unionid age (yrs.) from shell length or height (mm) for species collected in 

 Reach 15 of the Upper Mississippi River in (a) 1994-95 and (b) 1987. All relationships were 

 best described by a third order polynomial regression formula. 



Example: Calculate the age of a A/ega/onfl/a5 wen 0.^(7 collected in 1994-95 with a height of 88.9 mm (3.5 inch). 

 Calculations: y = 0.0000688.\' - 0.0083326x- + 0.4076798x - 3. 1385823 



y = 0.0000688(88.9)' - 0.0083326(88.0)- + 0.4076798(88.9) - 3.1385823 



y = 0.0000688(702595.37) - 0.0083326(7903.2 1) + 0.4076798(88.9) - 3. 1385823 



y = 48.3385615 - 65.8542876 + 36.2427342 - 3. 1385823 



y= 15.59 years old 



(a) 1994-95 



(b) 1987 



Page G-4 



Whitney et al., Unionid Suney - Reach 15 UMR 



