The physiological
mechanisms involved in maintaining the plasmatic
hydromineral equilibrium under brackish water condition,
however, are unknown. Sturgeon and teleosts
that move between fresh water and salt water must
maintain rather tight control of serum water and ion
concentration for efficient physiological function
(Natochin et al. 1985; Krayushkina et al. 1995). Regulatory
mechanisms are similar in sturgeon and teleosts
(Krayushkina et al. 1995). In elevated salinities,
osmotic water, lost across the integument, is replaced
by drinking sea water (Krayushkina et al. 1995).
Excess sodium and chloride is removed from blood
serum by chloride cells located in the gill epithelium
while calcium and potassium are excreted via the
kidneys (Krayushkina et al. 1995; Cataldi et al. 1995a;
McCormick et al. 1996).