Table 2. Results of covariance analysis corresponding to the linear regressions drawn in Figure 2 A and B.

Species	Intercept Slope	Winter	Spring and Autumn	Summer
Cardium tuberculatum	Winter
	Spring and Autumn	0.005 *		<0.0001*
	Summer	0.007 *	0.94
Cardium glaucum	Winter		0.008*
	Spring and Autumn	0.08
	Summer	0.001 *	<0.0001 *

P-values are indicated for the comparison between slopes and intercepts for each season and species.

^*: statistically significant.