Aquaculture

Urban Permaculture Institute

We can expect from 4-20 times the yield from water systems than that from the adjoining land.

Water supply is constant

Plant nutrients are soluble and available

Water organisms waste little energy in movement

Light, nutrients, plants, and organisms occupy a 3D space

Aquaculture systems are traditionaly polycultural

Bodies of water have more uses than food: energy production, transportation, recreation, irrigation.

Tenochtitlan pop. 200,000

Founded in 1325

Chinampas provided up to 2/3 of food

Destroyed in 1521 by Cortes

Water systems and energy

Water and its 3D environment absorbs solar radiation to deeper levels, feeding green systems and holding heat in its solar mass.

Fish require less cooking which save energy in preparation

A diverse ploycultural system may require little or no food input

Water is an energy efficient means of transporting a harvest.

Chinampas of Xochimilco

Fish, Food, and Feed

Salmon (very high needs, dies in freshwater)

Trout (feeds very high on food chain)

Bass (feeds high on foodchain)

Perch (yellow perch: lower on foodchain zooplankton, invertebrates, occasional small fish)

Catfish (omnivores, may be expensive to feed)

Carp (mostly does not eat other fish, many species feed on diverse sources. Best aquaculture species)

Tilapia (sometimes called water hog, eats vegetation primarily. Grows very fast in warm climates. Good food species. Up to 30-40% of food goes into body mass.)

Common Carp

Black Carp

Silver Carp

Grass Carp

Herbivore, grows fast

Filter feeders, phytoplankton

Grows large, favored food fisheats snails and mollusks

Omnivores, main foodspecies in China

Production Layers in Water Systems

Bank

Edge

Ebb-flow

Shallows

Semi-shallows

Deep

Floating

Bank Plants

Trees add bank stability and drink up water easily.

Shrubs add habitat and shading for water

Grasses and reeds may provide shelter and habitat for water animals

Edge Plants

Phragmites communis - Common Reed: growing in shallow waters and wet soils, can grow up to 12 feet tall.

Vaccinium palustre - Small Cranberry: The fruit is edible and is held by some to be the most delicious of our native wild fruits.

Shallows Plants

Acorus calamus - Sweet Flag: shallow edges of ponds and in most soils. The rhizomes, harvested in autumn or spring, are edible and can be used as a substitute for ginger, cinnamon or nutmeg - in the past the rhizomes were candied and used as a sweetmeat.

Semi-Shallows Plants

Sagittaria sagittifolia - Arrow Head: Native of Britain, it grows in water up to one and a half feet deep. Its tuber can be cooked and eaten and is much cultivated in China for this purpose.

Trapa natans - Water Chestnut: Native of Asia and the Mediterranean, this plant is hardy in all but the coldest parts of Britain and it grows in water up to two feet deep. Its seed, which is about 50% starch, can be eaten raw, cooked, or dried and ground into flour. It is often cultivated for its seed in Asia. Propagation is by seed only.

Deeps Plants

Nymphaea alba - White Water Lily: grows in the deeper parts of the pond - about four feet of water. Rootstocks that are several years old may be eaten - they contain about 40% starch. Roasted seeds may be used as a coffee substitute. Its young leaves and flower buds can be eaten cooked and young flowers can be eaten raw.

Water Lotus: Roots roasted or pickled. Seeds eaten raw or popped like popcorn. Stems peeled and eaten.

Eutrophication

Gulf Dead ZoneThe large region of low oxygen water often referred to as the 'Gulf Dead Zone,' shown here, crosses nearly 7,700 square miles of the Gulf of Mexico.

The dead zone starts in Midwestern corn country when farmers fertilize their fields with nitrogen. The fertilizer run-off flows down the Mississippi River into the Gulf of Mexico, making algae bloom on the surface and cutting oxygen to creatures that live on the bottom.

Tagari Farm