Total lipid content, and lipid and fatty acid composition of the deep-water prawn Pandulus borealis from Balsfjord, northern Norway: growth and feeding relationships

Abstract

Variations in total lipid content (g of lipid, and as % of wet and drybody weights) of the prawn Pandalus borealis, ranging from eggs to 52mo old adults, indicate that lipid growth exhibits marked seasonaloscillations while growth in carapace length shows only comparativelyweak seasonality. Positive (anabolic) lipid growth occurs from aboutApril to September inclusive (with up to 40% of dry body weight aslipid), the major production season for both phytoplankton andherbivorous zooplankton. Negative (catabolic) lipid growth (with lipidbeing reduced to about 10% of dry weight) is prominent during thewinter. Correspondence analysis involving the relative body-content oftotal lipid, total protein, ash and water indicates that both 'age'and 'seasonally' related trends are visible; lipid tends to play anincreasingly important role with age but lipid levels oscillatebetween peaks in late summer (August/September) and troughs in latewinter (February/March). Qualitative investigations of gut contentsand analyses of lipid-class composition and fatty acid food-chainmarkers of selected sizes and ages of prawn indicate that lipid-richzooplankton (mainly copepods and krill) form the bulk of the food ofprawns from 1 to 4 yr old. Although benthic polychaetes and detritalmaterial tend to increase in relative importance with increasing sizeand age of prawn, they are of secondary importance compared to pelagicorganisms.