The original agreement among 42 male passengers on the voyage made before landfall was called the

Mayflower Compact

Explanation:

When the 102 people onboard the Mayflower landed in Massachusetts instead of Virginia to colonize the area, dissent arose and in order to quell this dissent and establish a united colony, 41 males aboard the ship signed the Mayflower Compact.

This was a self-governing document that included guidelines as to how the colonists were to act in their new colony. Provisions such as loyalty to the English Crown were included.

I believe the answer is:

The migrants worked in the fruit picking industries

The climates in california enable various varieties of fruits to grow and attract more than a million immigrants to come and work in the fruit picking industries. The term 'okies' were used in a derogatory manners because it sounded like an animal or a pet name.