Aquaculture

What we will cover

Theory

Aquatic Ecosystems What conditions determine life in an aquatic environment Creating our own aquatic systems

Practical

Pond building

Rivers- Rain Fed

Head Waters-Upper Reaches Middle Reaches-Un spoilt Lowland Rivers

Spring-Fed Rivers Lake Fed Rivers Short Mountain Rivers Estuaries

Brackish Still Water

Dune SlackSaltpans

Brackish Lagoons and Pools

Upland Still Waters

Acid, Peat-Bog Pools Tarns

Glacial, Linear Valley Lakes

Lowland Still Waters

Meres Fens

Ponds

What determines The Plant and Animal Biota ?

•Nutrient Content

•Depth and light penetration

•Acidity

Nutrient Content

A nutrient can be defined as a food substance for an organism.

The level of nutrients in the water underpins the existence of all life, plant and animal.

The nutrient content is affected by

The geology of the catchment. The topography of the catchment. Intensiveness of agriculture in the surrounding area Size of surrounding human population (sewage)

Nutrient Content

Nutrients and Light = Phytoplankton and Plants Phytoplankton and aquatic plants are the primary producers on which the entire food web relies upon.

Algae-Diatoms-Cyanobacteria

Nutrient Content -Oligotrophic Waters

Tarns

Glacial, Linear Valley Lakes

Nutrient Content - Eutrophic WatersMeres

Fens

Ponds

Depth and light penetration

A high density of phytoplankton quickly absorbs the light and reduces the depth at which the light can penetrate to approx 2m ,below this point nothing can grow and animals cannot live.

       

Acidity

Some species only live in PH 4-6 and some species only exist in slightly alkaline waters pH >7. Most species prefer 6 - 7.5.

An Optimum Aquatic Habitat

A good supply of Nutrients supporting a high diversity of Plant and Animal life A balanced level of phytoplankton (PRIMARY PRODUCERS) so that light can penetrate

through the water A water body deep enough for plants to grow on the floor utilizing the filtered light Moderate pH

We can easily design this optimum Habitat.

Chinampas

Aquaponics

Ponds

Niche habitats for Aquatic plants

Emergents

Phragmites australis – Common Reed

Uses Edible shoots, roots Insulation Fast growing biomass Basketry Tolerant of Wind

Deep Marginal

Nymphaea alba-White Water Lilly

Uses Edible roots and seeds Medicinal Shade

Oxygenators

Myriophyllum sp.-Water-mifoil USES

Forage for Fish Providing oxygen Edible roots

Floaters

Lemna minor- Duckweed USES Forage for Fish Shade the water Edible –great for Chickens The dried plant repels mosquitoes Medicinal properties

Common Carp - Cyprinus carpioUses High Protein food Tolerance of a lack of oxygen Rapid growth Easy to feed

Info •Common carps feed on small plants and zooplankton, molluscs, detritus and dead plants. •The deep water is needed for winter hibernation •Logs and rocks with cavities for young fish to shelter

Toads and Frogs

Uses

Frogs and Toads will keep pest populations low A single adult toad can eat as many as 10,000 insects per

summer. Including Mosquitoes Frogs legs, taste a bit like chicken apparently:- Rana esculenta Water quality control :they need clean water ,if you have them

around you can be assured your water is clean. If they start growing extra legs be concerned.

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Position

The ideal pond for frogs and toads includes plenty of shallows for toads to rest and breed.A deep area of at least 1.3 meters for overwintering frogs, and plenty of vegetation around the edges to hide out in.Provide shallow, not steep, edges so frogs and toads can easily climb in and out, or add a couple logs partly in and partly out of the water.Both frogs and toads will also really appreciate some rocks around the edges for sunning themselves

Edible Frog Rana esculenta

Edge

Paulownia Garden Pond Design