Daniel Forsythe: Aquaponics: The Pinnacle of Sustainable Agriculture

Aquaponics: The Pinnacle of Sustainable Agriculture

What is Aquaponics?

Aquaponics is a farming technique that combines aquaculture (growing fish in tanks) with hydroponics (growing plants in water).

In aquaponics water from an artificial fish pond is pumped into beds where plants grow. Plants clean the water and it's pumped back into the fish pond, and recirculated, saving water.

How do plants grow?

Seeds are planted in small pots with coconut husk. The coconut husk gives them the right balance of air and nutrient-rich water. When they get older, they're transplanted into new beds.

Higher density plants like strawberries grow in gravel.

Lower density plants like lettuce grow in pots suspended in foam boards, with their roots dangling over the water.

How does it work?

Fish release ammonia in their waste

Bacteria in the water convert ammonia to nitrites, and then nitrites to nitrates

Plants need nitrites to grow, so they filter them out of the water

Clean water is pumped back into fish pond

What Aquaponics Projects are on Lana'i?

Kumu Ola (Roots of Life) is an aquaponic farm that:

Aims to create food security for Lana'i. At present, almost all food is shipped in.

Uses no pesticides or fertilizers

Uses solar power for energy (is completely off-grid)

Grows its own fish food

Is local

What does Kumu Ola do?

At Kumu Ola, new crops are planted weekly. This makes it possible to harvest each week too.

Fish are constantly bred in a separate tank so that harvested fish can be replaced.

These practices ensure that the system is always in balance.

Why Aquaponics on Lana'i?

When foreign ungulates (hooved animals) like axis deer, moufflon sheep, and antelopes were introduced, they grazed on the groundcover which had no natural defense against them.

This caused massive erosion and damage to beaches and reefs.

In the 1800's when Lana'i first started being used as a farming hub, the mountain forest was scaled back and thinned out.

Why Aquaponics on Lana'i?

With deforestation, and damaged groundcover, the land got hotter, and that made clouds evaporate, reducing rainfall.

This caused Lana'i to become even more dry than it already was as a small island.

However, from 1922 to 1992, Lana'i was used as a pineapple plantation. Pineapples are native to South America, not Hawaii, so after 70 years of growing only pineapple, the soil was devoid of nutrients plants need to grow.

Aquaponics to the Rescue?

Lana'i Aquaponics/Kumu Ola

Is dry Uses 90% less water than traditional farming, because water is recirculated, not absorbed into soil

Is infertile Creates its own nutrients by using fish waste

Is dependent on imports Is local

Has high electricity costs Uses very little electricity/creates own electricity via solar panel

Has damaged reefs Produces fish, easing stress on wild populations