Differential absorption of biochemical food components by the scallop Argopecten purpuratus exposed to different salinities and food concentrations

Abstract

The scallop Argopecten purpuratus is naturally distributed between central Chile and northern Peru. The objective of the present study was to determine some key acute and acclimated responses of A. purpuratus under a range of salinity and food conditions. The differential absorption of different biochemical components of the diet of this scallop was studied over short time periods (1,3, and 7 days), varied salinity (24, 27, and 30%c), and varied food availability (1.03 and 2.99 mg suspended matter litre ‐1 ). The results showed that variation in salinity explained most of the variance in the food ingestion rate, absorption efficiency, and absorption rates of dietary biochemical components. At high food levels, A. purpuratus acclimatised its absorption efficiency for proteins and carbohydrates after 7 days, but only at salinities of 27 and 30‰. Lipid absorption at 24‰ salinity was negative, with a tendency to show lower values over time. At salinities of 27 and 30‰ the absorption efficiency of lipid was negative for the first 3 days, followed by recuperation with positive values after 7 days of acclimation. However the acclimation process was not complete, as values of absorption at high food levels were significantly lower than those obtained by A. purpuratus at low food levels at the same salinities.

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