Fixed effect Coefficient ± SE Z-value P-value
Izu Peninsula Intercept -1.24 ±0.48 -2.56 < 0.05
Shell Colour 0.28 ± 0.43 0.64 0.52
Growth Stage 1.61 ± 0.56 2.86 < 0.001
Interaction 0.09 ± 0.55 0.16 0.87
Niijima Island Intercept -3.17 ± 0.93 -3.41 < 0.001
Shell Colour -0.15 ± 0.83 -0.18 0.86
Growth Stage 0.49 ± 0.87 0.57 0.57
Interaction 0.55 0.60 0.55