Altering Clam Growth Rates, Size at Maturity, and Spawning Times

Clam growth rate was altered so that clams achieved sexual maturity (2 cm) after $\approx$ 1 year and reached 3.25 cm shell length after $\approx 3$ years. Clam spawning times were also altered from the ends of March and August to the ends of February and October and only clams $> 2$ cm were able to reproduce (previously, was $> 1$ cm). All other aspects were kept the same.

Clam biomass increased by a factor of 2.5 to 842 g/m$^2$ from 334 g/m$^2$ under the original model parameterization. Background prey remained the same. Crab densities for 7-12, 13-17 and 18+ instars were 0.1396, 0.0228 and 0.0181 (#/m$^2$) respectively (originally 0.111, 0.0265 and 0.0145 #/m$^2$ Table 1) while average gut fullness for the same instar classes was 0.41, 0.48 and 0.49 respectively (originally 0.438, 0.478 and 0.492). Since a bigger clam contains more biomass than a smaller clam, food limitation is thus more likely under the original model parameterization than the modified parameterization.