Upper Midwest Environmental Sciences Center
Nonlethal evaluation of the physiological health of unionid mussels: methods for biopsy and glycogen analysis
Naimo, T. J., Damschen, E. D., Rada, R. G., and Monroe, E. M., 1998, Nonlethal evaluation of the physiological health of unionid mussels: methods for biopsy and glycogen analysis: Journal of the North American Benthological Society, v. 17, no. 1, p. 121-128.
In long-lived unionid mussels, many short-term measures
of growth are of limited value. Changes in physiological condition may be an early
indication of stress, because the increased energy demand associated with stress
results in a depletion of glycogen reserves, the principal storage form of carbohydrates in unionid mussels. Our goal was to nonlethally extract tissue from freshwater mussels and then to develop a rapid and dependable method
for the analysis of glycogen in the tissue extracts. A biopsy technique was developed to remove between 5 and 10 mg of foot tissue in Amblema plicata plicata. The survival rate did not differ between biopsied and non-biopsied mussels during a 581-d observation period, demonstrating that the biopsy technique Mill allow nonlethal evaluation of the physiological condition of individual mussels through measurement of changes in contaminant, genetic, and biochemical indicators in tissue. We also modified the standard alkaline digestion and phenol-sulfuric acid analysis of glycogen for use on the small samples of biopsied tissue and to reduce analysis time and cost. We present quality control data, including method detection limits and estimates of precision and bias. The modified analytical method is rapid and accurate and has a method detection limit of 0.014 mg glycogen. Glycogen content in the biopsied samples was well above the method detection limit; it ranged from 0.09 to 0.36 mg, indicating that the method should be applicable to native mussels.
Keywords: Unionidae, nonlethal sampling, glycogen,
foot biopsy, freshwater mussels, Amblema, physiological condition, fresh-water
mussels, heavy-metals, conservation, survival, bivalves