COMPARISON OF GROWTH, BEHAVIOR AND LIPID CONCENTRATIONS OF WALLEYE POLLOCK THERAGRA-CHALCOGRAMMA LARVAE FED LIPID-ENRICHED, LIPID-DEFICIENT AND FIELD-COLLECTED PREY

While growth and survival of marine fish larvae in the sea may be dependent on prey type, size and concentration, nutritional quality of prey may also play an important role. This study investigates the relationships of lipid content of prey with growth, gas bladder size, sinking rate, behavior and survival for larval walleye pollock Theragra chalcogramma under controlled conditions in the laboratory. Larvae fed lipid-deficient brine shrimp Artemia spp. nauplii had reduced growth, gas bladder size and survival. These larvae also had to swim almost continuously to maintain vertical position in the water column. In contrast, larvae fed wild-caught copepods or Artemia spp. enriched with lipid showed alternating swimming and resting bouts. The potential for vagaries in meteorological and oceanographic conditions to cause larval fish prey to be nutrient deficient is discussed.