Chase, R.,   R. F. McMahon, 1994.   Effects of Starvation at Different Temperatures on Dry Tissue and Dry Shell Weights in the Zebra Mussel, Dreissena polymorpha (Pallas).  Center for Biological Macrofouling Research The University of Texas at Arlington.

Proceedings of The Fourth International Zebra Mussel Conference, Madison, Wisconsin, March 1994

Effects of Starvation at Different Temperatures on Dry Tissue and Dry Shell Weights in the Zebra Mussel, Dreissena polymorpha (Pallas)

Abstract
Starvation effects on dry tissue and shell biomass were investigated in the zebra mussel, Dreissena polymorpha at 5°, 15° and 25°C. Subsamples of 30 individuals were examined daily for mortality. A second group was periodically randomly subsampled for dry tissue and shell weights. At 25°C, 100% mortality occurred after 166 days. No mortality occurred at 5°C or 15°C after 229 days. Dry shell weight (DSW) was constant in mussels starved at 25°C or 5°C, but increased significantly (P < 0.05) at 15°C, likely due to deposition of shell nacre in shells not increasing in length. Dry tissue weight (DTW) in starving mussels was significantly correlated with both shell length (SL) and days of starvation (P < 0.00001) and was significantly lower at higher test temperatures. Pre-starvation DTW of a 20 mm SL individual was 19.7 mg. DTW declined to 4.66 mg after 132 days at 25°C, and to 9.95 mg and 15.9 mg after 229 days at 15°C and 5°C, respectively, corresponding to tissue biomass reductions of 73.8%, 46.9% and 22.9%. DTW loss rates of 0.102, 0.043, and 0.021 mg/day were recorded for standard mussels starving at 25°, 15° and 5°C, respectively. As estimated from DTW loss rates, O₂ consumption rates in starving standard mussels were 0.196 µl O₂ · mg^-l · h^-l at 25°C, 0.0837 µl O₂ · mg^-l · h^-l at 15°C and 0.0399 µl 0₂ · mg^-1 · h^-l at 5°C, approximately 22.1%, 13.5% and 8.5%, respectively, of O₂ uptake rates recorded directly in nonstarved individuals. Mussels held at 25°C lost 73.8% of body mass just prior to death suggesting that an = 75% DTW loss is lethal and indicating that 365 days of starvation will be required for 100% mortality of mussels at 15°C and 747 days at 5°C. Extensive starvation tolerance in D. polymorpha is associated with ability to greatly reduce metabolic demand. As this capacity is maximized at low temperatures, mussels may survive winter months with minimal energy store reduction. Extensive tolerance, makes starvation impractical for mitigation of D. polymorpha fouling.

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Keywords: Basic_biology, Biological_control, Zebra_mussel
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