ISO 



InYertehnilt's — Our Liviiii; Kcsaiirces 



Fig. 1. The Lake Huron-Lake Erie 

 corridor, including Lake St. Clair 

 and western Lake Erie (in red). 



(Fig. 1). Relatively pristine water enters the St. 

 Clair River, passes through Lake St. Clair and 

 the Detroit River, and enters western Lake Erie. 

 Freshwater native mussels were collected by 

 scuba divers in the Lake Huron-Lake Erie corri- 

 dor (Fig. 1) at 46 stations during six sampling 

 periods from 1961 to 1992. In Lake St. Clair, 

 mussels were collected at 29 stations in 1986, 

 1990, and 1992. Ten replicate quadrate samples 

 (0.5 m- each [5.4 tt-|) were obtained at each 

 station and sampling date. In western Lake Erie, 

 mussels were collected four times at one index 

 station in 1989-91 and once at 17 historically 

 sampled stations in 1961. 1982, and 1991. 

 Sampling at the index station was performed 

 with an epibenthic sled (46 x 25 cm [18 x 63 

 in]). Sampling at the 17 historically sampled 

 stations was performed with a Ponar grab sam- 

 pler. Three replicate Ponar (0.05 m- |().5 ft-]) 

 samples of the substrate were collected at each 

 station. Mussels were identified following 

 Clarke (1981) and comparisons with bivalve 

 taxonomic reference collections. Taxonomic 

 nomenclature follows Turgeon et al. ( 1988) and 

 Williams et al. (1993). 



Historical Status 



Around 1900 the Lake Huron-Lake Erie cor- 

 ridor was characterized as having one of the 

 most abundant freshwater mussel faunas in 

 North American lakes (Goodrich and van der 

 Schalie 1932: Mackie et al. 1980): 39 species 

 (Table 1 ). 



Before 1990 mussel populations existed in 

 most areas of the Lake Huron-Lake Erie corri- 

 dor (Fig. 2). In Lake St. Clair, mussel popula- 

 tions were similar in 1986 and 1990 (Table 2). 

 Numbers of mussels per unit area were relative- 



Table I. Species of native mussels historically found in 

 the Lake Huron-Lake Erie corridor of the Great Lakes 

 (modified from Clarke and Stansbery 1988). 



Species 



Muckel (Aclinonaias ligamenlina [carinala]) 



Elktoe {Alasmidonta marginala) 



Slippershell mussel {A viridis) 



Threeridge ( Amblema plicala plicata) i 



Cylindrical papershell {Anodonloides lerussaaanus) 



Purple wartyback (Cyclonaias luberculala) J 



Spike {Elliplio dilatala) 



Northern riffleshell {Epioblasma torulosa rangiana) 



Snuffbox (£ Inquelra) 



Wabash pigtoe (Fusconaia flava) 



Wavy-rayed lampmussel {Lampsilis lasciola) 



Pocketbook (/.. ovala) 



Eastern lampmussel {L siliquoidea) 



White heelsplitter (Lasmigona complanata complanata) 



Creek heelsplitter (L compressa) 



Fluted-shell (i. coslata) 



Fragile papershell (Leptodea tragilis ) 



Eastern pondmussel {Ligumia nasuta) 



Black sandshell (L recta] 



Threetiorn wartyback (Obliquaria reflexa) 



Hickorynut {Obovaria olivaria) 



Round hickorynut (0. subrolunda) 



Round pigtoe {Pleurobema coccmeum] 



Ohio pigtoe (P. cordatum) 



Pink heelsplitter {Potamilus alatus) 



Pink papershell (P. ohiensis) 



Kidneyshell {Plychobranchus fasciolaris) 



Giant floater (Pyganodbn grandis) 



Mapleleal (Quadrula quadrula) 



Pimpleback (0, puslulosa puslulosa) 



Salamander mussel (Simpsonaias ambigua) 



Squawfoot (Strophilus undulalus) 



Lilliput ( Toxolasma parvus) 



Fawnsfoot ( Truncilla donacitormis) 



Deertoe { T trur)cala) 



Pondhorn [Uniomerus tetralasmus) 



Paper pondshell (Utterbackia imbecillis) 



Rayed bean ( Villosa labalis) 



Rainbo w ( V. ins) 



Table 2. Number of species of native mussels and aver- 

 age (mean) density (number/m-) in Lake St. Clair and 

 western Lake Erie of the Lake Huron-Lake Erie corridor, 

 1961-92. 



Lake/year 



Total no. of species 



Average (mean) 

 no/m^ 



ly low (2/m- [0.2/ft-]), but consistent, and there 

 were 16-18 species found throughout the lake in 

 1990. The relatively healthy populations of 

 mussels are attributed to the pristine water flow- 

 ing into the lake from Lake Huron (Herdendorf 

 etal. 1986). 



In western Lake Erie, mussel populations 

 that had survived low water quality in the 

 1950"s declined between 1961 and 1982 (Table 

 2). Numbers declined from 10/m- (0.9/ft-) to 

 4/m- (0.4/ft-). and the number of species 



