How many cranking amps does the battery for a 70 HP Yamaha outboard require?

According to the owner's manual the battery requirement for the F70 4stroke is:

Minimum cold cranking amps (CCA/SAE): 380.0

A Minimum marine cranking amps (MCA/ABYC): 502.0

A Minimum reserve capacity (RC/SAE): 124 minutes

I don't know what the reserve capacity figure means.