Within- and among-lake variation in shell morphology of the freshwater clam Elliptio complanata (Bivalvia: Unionidae) from south-central Ontario lakes

Hydrobiologia ◽  
1988 ◽  
Vol 157 (1) ◽  
pp. 27-32 ◽  
Author(s):  
Scott G. Hinch ◽  
Robert C. Bailey
Keyword(s):  
Shell Morphology ◽  
Freshwater Clam ◽  
Elliptio Complanata ◽  
South Central ◽  
Lake Variation

Morphological variation of Elliptio complanata (Bivalvia: Unionidae) in differing sediments of soft-water lakes exposed to acidic deposition

1989 ◽  
Vol 67 (8) ◽  
pp. 1895-1899 ◽  
Author(s):  
Scott G. Hinch ◽  
Laura J. Kelly ◽  
Roger H. Green
Keyword(s):  
Water Chemistry ◽  
Acidic Deposition ◽  
Principal Component ◽  
Environmental Water ◽  
Shell Morphology ◽  
Environmental Data ◽  
Sediment Type ◽  
Elliptio Complanata ◽  
Lake Water Chemistry ◽  
South Central

Clam shell morphology was related to lake water chemistry and sediment properties for Elliptio complanata from 40 south central Ontario lakes. Principal component analyses described the major trends in the environmental data. Relationships between shell morphology and the environmental trends were ascertained through a canonical correlation analysis. Thicker shells were related to increasing alkalinity, conductivity, and pH, suggesting that shell formation is favoured in well-buffered habitats that are not affected by acidic deposition. We also determined that narrow shells were related to coarse sediment in deeper water. This pattern of variation in shell morphology may be adaptive because streamlined shells would better enable clams to maintain their position in turbulent habitats. The water chemistry and sediment property correlates with shell morphology were independent of each other. Any attempt to use unionid shells as long-term indicators of changes in environmental water chemistry must be preceded by a consideration of other habitat variables such as water turbulence, sediment type, and depth.

The effects of source and destination on growth and metal uptake in freshwater clams reciprocally transplanted among south central Ontario lakes

1989 ◽  
Vol 67 (4) ◽  
pp. 855-863 ◽  
Author(s):  
Scott G. Hinch ◽  
Roger H. Green
Keyword(s):  
Metal Uptake ◽  
Soft Tissues ◽  
Common Source ◽  
Transplant Experiment ◽  
Reciprocal Transplant Experiment ◽  
Post Transplant ◽  
Elliptio Complanata ◽  
South Central ◽  
Freshwater Clams ◽  
Strong Source

The relative contributions of genotype and environment to growth and metal uptake in freshwater unionid clams (Elliptio complanata) were evaluated using a reciprocal transplant experiment. In August 1985, comparable sites were selected in three south central Ontario lakes with alkalinities of 22, 153, and 238 μequiv.∙L−1. Shell length, height, and width varied in a manner that could not be related to lake alkalinities. There were differences among the clam populations in allelic frequencies (at the Pgm and Lap-2 loci). Clams were marked, measured, and reciprocally transplanted among the three lakes. In August 1986, marked individuals were recovered, remeasured, and analysed for levels of Cu, Zn, Mn, and Cd in soft tissues. The transplant source had a strong influence on clam growth during the post-transplant year. This source effect may result from genetic differences among the populations. Tissue metal concentrations at the end of the post-transplant year were a function of both source and destination. The use of freshwater clams as transplant biomonitors must be reassessed since there is a strong source component to growth and metal uptake. In transplant experiments a common source (a particular site within a particular lake) should be used, and post-transplant periods of more than 1 year may be necessary for the influence of the destination environment to dominate the influence of the source environment.

Size- and age-specific patterns of trace metal concentrations in freshwater clams from an acid-sensitive and a circumneutral lake

1987 ◽  
Vol 65 (10) ◽  
pp. 2436-2442 ◽  
Author(s):  
Scott G. Hinch ◽  
Linda A. Stephenson
Keyword(s):  
Tissue Concentrations ◽  
Metal Concentrations ◽  
Elliptio Complanata ◽  
South Central ◽  
Freshwater Clams ◽  
Metal Levels ◽  
Water Competition ◽  
Specific Manner ◽  
Clam Tissue ◽  
Binding Substrate

We collected freshwater clams (Elliptio complanata) from an acid-sensitive and a circumneutral lake in south central Ontario and compared tissue metal concentrations. Clams from the acid-sensitive lake had higher concentrations of Cu and Cd and lower concentrations of Zn and Mn than clams from the circumneutral lake. Tissue concentrations did not reflect metal levels in the water. Competition may be occurring between metals for binding substrate in clam tissue. Clam size and (or) age successfully predicted tissue metal concentrations, but in a metal-specific and tissue-specific manner. Clam biomonitoring studies should therefore control for size and age variability. Lake buffering capability was not very important in influencing size- and age-specific patterns of tissue metal concentrations. However, this conclusion is based solely on data from two lakes.

Shell Etching on Clams from Low-Alkalinity Ontario Lakes: A Physical or Chemical Process?

1988 ◽  
Vol 45 (12) ◽  
pp. 2110-2113 ◽  
Author(s):  
Scott G. Hinch ◽  
Roger H. Green
Keyword(s):  
High Water ◽  
Analysis Of Covariance ◽  
Log Analysis ◽  
Elliptio Complanata ◽  
Lake Water Chemistry ◽  
External Shell ◽  
Lake Variation ◽  
Sediment Particles ◽  
Low Exposure ◽  
Water Turbulence

Elliptio complanata (Unionidae: Bivalvia) were sampled from sites of low and high water turbulence in four Ontario lakes that varied in pH (6.0–7.5) and alkalinity (22–243 μeq∙L−1). External shell etching on each clam was quantified using an image analysis digitizer system. Within-lake variation in shell etching was contrasted using a log–log analysis of covariance approach. Clams exposed to higher turbulence regimes (and large sediment particles) were significantly more etched than low-exposure clams (P < 0.05). Approximately 52% of the total shell etching variability resulted from within-lake differences between high- and low-exposure clams. The remaining variation was accounted for by differences among individual clams. Shell etching in these lakes appears to be primarily a physical process probably related to water turbulence. Etching was not related to variation in lake water chemistry and thus is likely not influenced by lake acidification.

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