Effects of temperature and food availability on growth, survival, and RNA-DNA ratio of larval sand lance (Ammodytes americanus)

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Abstract
Beginning 2, 19 and 30 days after hatching, larvae of sand lance A. americanus were reared for 1 or 2 wk between 2.degree. and 9.degree. C in the absence of food and at nominal feeding levels of 200-1000 rotifers l-1 (0.16-0.80 cal l-1). Mortality of all age groups was unaffected by temperature. The mean daily instantaneous mortality coefficient of newly hatched larvae was 0.01 to day 16 and was unaffected by feeding level. Mean daily instantaneous mortality coefficients of older larvae ranged from 0.2 to 0.02 and decreased with increasing feeding level. Growth rate and RNA-DNA ratio increased with increasing feeding level. A direct linear relation observed between RNA-DNA ratio and growth rate was improved by adding temperature as a 2nd independent variable. The relation between RNA-DNA ratio, temperature and larval growth rate was insensitive to either larval size (protein content) or age.