Glycogen concentration in the mantle tissue of freshwater mussels (Bivalvia : Unionidae) during starvation and controlled feeding

The effects of controlled feeding versus starvation during quarantine on ma ntle tissue glycogen concentration (represented as milligrams glycogen per gram of mantle tissue +/- SD) of two freshwater mussel species were compare d. Starved individuals were not provided with supplemental food during quar antine, while fed specimens were provided with 10(5) algal cells/ml, twice per day. Initial mean glycogen levels for Amblema plicata (Say, 1817) (9.4 +/- 2.4 mg/g) and Quadrula pustulosa (I. Lea, 1831) (7.9 +/- 1.8 mg/g) coll ected from Ohio River Mile (ORM) 175.5 in July 1997 were not significantly different (p > 0.3) from mean glycogen levels of A. plicata (8.1 +/- 4.2 mg /g) and Q. pustulosa (6.2 +/- 2.9 mg/g) collected from the same site in Jul y 1996. initial glycogen concentrations of quarantined mussels, therefore, were similar in both the starved and fed groups. After seven days of feedin g in quarantine, mean glycogen levels of A. plicata (12.3 +/- 2.3 mg/g) and Q. pustulosa (7.1 +/- 3.7 mg/g) did not change significantly (p > 0.1) rel ative to wild-caught specimens, and were significantly larger (p < 0.05) th an mean glycogen levels of starved individuals (3.6 +/- 1.8 mg/g and 3.5 +/ - 2.3 mg/g, respectively). Similarly, mean glycogen levels of A. plicata an d Q. pustulosa after 14 days (8.1 +/- 3.3 mg/g and 7.7 +/- 3.3 mg/g, respec tively) and 30 days (9.9 +/- 4.8 mg/g and 8.4 +/- 2.7 mg/g, respectively) o f feeding were significantly larger (p < 0.01) than mean glycogen levels of starved specimens after 14 days (3.27 +/- 1.74 mg/g and 5.37 +/- 3.06 mg/g , respectively) and 30 days (1.2 +/- 0.5 mg/g and 1.9 +/- 1.4 mg/g, respect ively). Adequate feeding of unionids in quarantine is essential to maintain animals in a condition that will increase the likelihood of survival follo wing relocation.