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RESPONSES OF JUVENILE LARGEMOUTH BASS TO DIFFERENT PH AND ALUMINUM LEVELS AT OVERWINTERING TEMPERATURES: CALCIUM, LIVER GLYCOGEN, AND DEPOT FAT
Citation:
Keino, R. AND J. McCormick. RESPONSES OF JUVENILE LARGEMOUTH BASS TO DIFFERENT PH AND ALUMINUM LEVELS AT OVERWINTERING TEMPERATURES: CALCIUM, LIVER GLYCOGEN, AND DEPOT FAT. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-94/190 (NTIS PB94163698), 1993.
Description:
Young-of-the-year largemouth bass were exposed to simulated overwintering conditions. our degrees centigrade in 113 days, in soft [CaCO3] 48 mg/L, [Ca] 13.4 mg/L, and very soft [CaC)3] 4.6 mg/L, [Ca] 1.5 mg/L) water. n some treatments pH was reduced to 5.0 and 4.5 with no added Al. n others, a monomeric Al level of 30 ug/L was maintained. n the neutral pH treatments the bass had greatly thickened gill respiratory epithelium and large numbers of chloride cells (compared with bass kept at 20 degrees C in a prior experiment), and blood osmolaties declined and stabilized at about 260 mosmol/kg. n the acid treatments the bass had thickened respiratory lamellae and chloride cell numbers similar to those found in the neutral pH treatments. n very soft water, mean blood osmolaties declined to 242 and 219 mosmol/kg at pH 5.0 and 4.5 respectively, and did not stabilize. n the acid + Al treatments, respiratory lamellae were frequently obliterated by hyperplasia of the interlamellar epithelium, suggesting markedly compromised respiratory ability. n addition, chloride cell numbers were usually depressed, and those cells that were present were often vacuolated or covered by layers of pavement epithelium: lood osmolalities declined to the lethal and near-lethal level of about 200 mosmol/kg, and heavy mortalities occurred.