Serum characteristics of spawning (Polyodon spathula)

• 1.

  1. Parallel estimates of thirteen serum parameters were made in four female and eight male paddlefish taken at spawning.

• 2.

  2. Sexual “dimorphism” was found in serum non-protein nitrogen, cholestrol, and cortisol.

• 3.

  3. Although paddlefish appeared to regulate the major electrolyte, Na, K and Cl, similar to other freshwater teleost, both sexes had lower serum Ca, NPN, protein and glucose concetrations.

• 4.

  4. Low serum Ca levels in paddlefish suggest physiological hypocalcemia and, in this respect, paddlefish show phylogeneitc affinity to the other chondrostei, the sturgeons.