ABSTRACT An individual-based model was developed to simulate growth of the hard clam, Mercenaria mercenaria, in response to temperature, salinity and food supply conditions. Unique characteristics of the model are that: (1) length and tissue weight are related only by condition index, so that weight, up to a point, can vary independently of length, and (2) age is decoupled from length. Tissue weight changes result from the difference in assimilation and respiration. Changes in hard ...
<48 mm after 5 y, for all initial lengths (Fig. 17A). Production of clams larger than 85 mm requires assimilation efficiencies that are><1) compress the Gaussian distribution, as these animals' scope for growth is insufficient to permit normal fecundity. Similarly, respiration rates that are higher than the mean rate (>