Along with other aspects of Hawaiian social life, the kapu system regulated fishing and farming seasons. One of the best known kapu covered aku (ocean bonito) and `opelu (mackerel). Alternating six-month restrictions on aku and `opelu allowed the fish stock to replenish itself while still providing a steady food source.
Summer was the time for inshore fishing, gathering seaweeds and shellfish, and harvesting salt. Large quantities of fish were salted; this was also the season for tilling crops. In leeward areas too dry for taro farming, sweet potatoes were planted. During winter, when rain flooded streams and shallows filled with mud and silt, inshore fishing and gathering was kapu but deep sea fishing was allowed.
Hawaiian fishermen paid close attention to the lunar cycle. The time of full moon was especially good for fishing. The days of the waning moon, between full and new, were least favorable.