Table B-2. Calculated number of quantitative samples required to estimate unionid species density at 

 Sylvan Slough (RM 485.8) in (a) 1994-95 (116 samples collected) and (b) 1985 (8 samples 

 collected) within x% of the actual density with a 0.05% probability of being incorrect. Based 

 on the formula : n = [(2 SD) ^ (xM)]-, where : n = number of samples required, SD = standard 

 deviation, x = desired level of accuracy (i.e., 10% = 0. 1), and M= mean unionid density based 

 on samples collected. Numbers within rectangles indicate the number of samples collected 

 met or exceeded the number of samples required for each level of accuracy (%). 



(b) 1985 (8 samples) 



Species 



Density (/m^) 



Samples Required 



Mean 



SD 



10% 



20% 



40% 



50% 



Amblema plicata 

 Lep to dea fragilis 

 Ouadnila pustulosa 

 Potamilus alatus 

 Ttvncilla truncata 

 Afegalonaias nerxosa 

 Utterbackia imbecillis 

 Quadrula quadrula 

 Obliquaria rejlexa 

 Etlipsaria lineolala 

 Quadivla metanevra 

 Pyganodon grandis 

 Truncilla donacifonnis 

 Potamilus ohiensis 

 Fusconaiaflava 

 Lampsilis cardium 

 Ligumia recta 

 A rcidens confragosus 

 Quadrula nodulata 

 Obovaria olivaria 

 Plethobasus cypfnus 



9.80 

 10.10 

 19.80 

 2.20 

 12.60 

 13.40 

 4.10 

 1.80 

 4.10 

 5.20 

 6.60 

 0.90 

 6.50 

 0.80 

 0.50 

 0.90 

 0.20 

 0.20 

 0.10 

 0.10 

 0.10 



260 

 2 90 

 6,20 

 0,70 

 430 

 4,70 

 1,80 

 0,80 

 2,00 

 2,80 

 4,10 

 0,60 

 4,70 

 0,70 

 0,50 

 0,90 

 0,40 

 0,40 

 0,30 

 0,30 

 0,30 



28 



33 



39 



40 



47 



49 



77 



79 



95 



116 



154 



178 



209 



306 



400 



400 



1600 



1600 



3600 



3600 



3600 



100 

 100 

 400 

 400 

 900 

 900 

 900 



44 



44 

 178 

 178 

 400 

 400 

 400 



100 

 100 

 225 



Page B-3 



Whitney et al,, Unionid Survey - Reach 1 5 UMR 



