Page "Seafarers of Catan" Paragraph 28

Hexes on the main island for which there are no number tokens do not produce resources, but number tokens are moved in such a way so as to avoid rendering a city unproductive ; furthermore, whenever possible number tokens must be reassigned from hexes bordering a player's own settlements and cities, so as to prevent harming another player's economy without harming a player's own economy at the same time.