Glycogen Content of Freshwater Mussels During Prolonged Starvation

Abstract

In view of the high glycogen content of the hepatopancreas of freshwater mussels, 1 the glycogen contained in the hepatopancreas and in the pedal muscle (“foot”), of 206 mussels representing 20 species, was determined during periods of starvation ranging from 2 to 536 days, to ascertain whether the utilization of stored glycogen by these invertebrates during starvation is comparable to the utilization of stored glycogen by mammals during periods of inanition. 2

The mussels in this series were collected in September and October before the water became cold, from beds where colonies of healthy mussels were thriving, so that each animal was started in these starvation tests after a summer of normal feeding, which had prepared the animal presumably for the winter period of reduced activity. The individual mussels, between 4 and 7 years of age, were isolated either in glass hatchery jars or metal hatchery tanks, through which well-aerated water from deep wells was flowing. This water, which had been found previously to constitute a satisfactory environment for mussels as regards inorganic salts, pH, and dissolved gasses, contained no plankton, organic detritus, or organic salts. The recording thermograph showed that the water temperature fell from 18°C. in October to 11°C. in February, rising slowly to 22°C. in August and dropping to 18°C. again by October, i.e., the animals under observation were subjected to a slowly changing temperature cycle comparable to that of their natural habitat.