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.

Abstract

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 often
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 th? 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