Growth dynamics of a ctenophore (Mnemiopsis) in relation to variable food supply. II. Carbon budgets and growth model

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Abstract
Our goal was to test our understanding of ingestion, assimilation efficiency and metabolism for Mnemiopsis mccradyi by formulating and validating a simulation model of growth under different conditions of food availability. The model was based on a carbon budget approach using formulations derived from empirical results, including how each process was affected by food availability and ctenophore size. An experimentally measured carbon budget for pulsed food availability indicated that, relative to total ingestion, growth was high (17–48%), respiration plus organic release was relatively low (24–48%) and little (2) and a high gross growth efficiency (>30%) for smaller ctenophores at high food concentrations (>20 prey l−1). Both growth rates and growth efficiencies were predicted to decrease for larger ctenophores. Model predictions were generally consistent with experimental results, including investigations using pulsed food availability to simulate environmental patchiness. Although the model underpredicted ctenophore growth in some experiments at low food densities, the model prediction of a minimum prey concentration of about 8 l−1 (24 μg C l−1) for sustaining a ctenophore population of reproductive size agreed with field observations.