However, Chris M. Wood (McMaster University) and coauthors found that naked carp respond to the increased salinity of the lake water in a surprising way--by taking a "metabolic holiday." In the first forty-eight hours after transitioning from the freshwater river system to lake water, the carps' oxygen consumption falls --eventually reaching just 60 percent of that in river fish.

Both gill and kidney functions also decline. The sodium/potassium pump (Na+/K+-ATPase), which is a protein critical for cellular function, operated at only 30 percent of its capacity in lake-water fish compared to river-water fish. Ammonia-N secretion by the kidneys declines by a surprising 70 percent, and urine flow decreases drastically to less than 5 percent of its rate in the freshwater river water.