Changes in selected blood serum constituents, as a function of salinity variations, in the marine elasmobranch, Sphyrna tiburo

Abstract

1. 1. Bonnethead sharks, Sphyrna tiburo, were acclimated to three salinities representative of hyposaline, ambient, and hypersaline conditions. 2. 2. Serum urea, TMAO, sodium, and chloride comprised the major portion of the osmotic pressure. 3. 3. Urea and TMAO made up most of the serum osmotic pressure difference noted between 20 and 30‰ Urea, TMAO, and sodium chloride contributed equally to the increase in osmotic pressure from 30 to 40‰ 4. 4. A number of possibilities are explored to explain the failure of the sharks to become hyperosmotic during the 40‰ trial, with particulate matter causing stress deemed the most likely explanation.