chapter 6 ends with Karana's tribe deciding to take a journey. what is the purpose for that journey?

In Chapter Six, after Kimki has been gone for several months, the tribe chooses a man named Matasaip to replace him as chief. Matasaip is particularly worried that the Aleuts might return, as they arrived in late spring of the year before. Since the tribe now lacks men to fight, they agree to flee by canoe to the nearby island of Santa Catalina, and stockpile some food in case that happens.