PHOSPHORUS-METABOLISM MONITORED BY P-31 NMR IN JUVENILE SEA SCALLOP (PLACOPECTEN-MAGELLANICUS) OVERWINTERING IN PEARL NETS AT A NOVA-SCOTIAN AQUACULTURE SITE

P-31 Nuclear magnetic resonance (NMR) spectroscopy has been used to ex amine in vivo phosphorus metabolism in juvenile sea scallop (Placopect en magellanicus) from an aquaculture site in Nova Scotia. NMR-visible arginine phosphate (Arg P) concentrations declined from summer to wint er whereas inorganic phosphate (P-i) levels increased and those of ade nosine triphosphate (ATP) remained relatively constant. Our results in dicate that, in the scallop that uses the phosphagen Arg P to replenis h ATP, the ratio of Arg P to P-i is a better indicator of energetic st atus than is the ratio of adenylate concentrations known as adenylate energy charge. Scallops collected in fall and winter, when exposed to hypoxic conditions, showed pronounced decreases in Arg P associated wi th increases in P-i and decreases in ATP levels whereas these remained relatively unchanged in scallops collected in summer. Scallops mainta ined under simulated winter conditions showed lower levels of Arg P as sociated with poor nutrition, and a response to hypoxia similar to fie ld scallops. The marked seasonality in concentrations of phosphorus me tabolites emphasizes their potential importance as useful biomarkers i n environmental stress assessment and the optimization of hatchery and grow-out conditions.