Aquaculture Foundations

Lesson Structure

There are 6 lessons in this course:

1. SCOPE AND NATURE OF AQUACULTURE
   • Introduction/Terminology
   • Farmed vs wild fish
   • Commercial aquaculture systems
   • Hatchery systems
   • Nursery systems
   • Grow Our Systems
   • Land based Freshwater aquaculture
2. METHODS OF FARMING
   • Extensive production (EP)
   • Stocking and cropping
   • Maximum sustained yield (MSY)
   • Intensive production (IP)
   • Open systems
   • Semi closed systems
   • Closed systems
   • Types of hatcheries
   • Clear water - intensive
   • Green water - semi intensive
   • Pond rearing
   • Nursery cages
   • Grow out systems
   • Land-based systems - water containment
   • Concrete, wood, brick, stone, fibreglass, earth construction
   • Lined ponds
   • Soil characteristics
   • Pesticides
   • Extensive production (EP)
   • Intensive production (IP)
   • Land-based systems - water containment
   • Review what you have been learning
3. FISH SPECIES TO GROW
   • Choosing what to farm
   • Trout
   • Catfish
   • Perch
   • Bream
   • Bass
   • Carp
   • Milkfish
   • Murray Cod
   • Snakeheads
   • Roach
   • Saratoga
   • Sturgeon (Acipenser and Huso)
   • Tilapia
   • Red Drum
   • Other species
   • Review what you have been learning
4. FEED
   • Fish food production
   • Pelleted food
   • Live feed
   • Night lights
   • Fishmeal
   • Oil meals
   • Fish food production
   • Beef hart
   • Legumes
   • Seafood and vegetable mix
   • Earthworms
   • Compost
   • Other feed organisms
   • Lesson 4 additional reading
   • Review what you have been learning
5. PATHOLOGY
   • Introduction
   • Symptoms of ill health
   • Pathogens
   • Fish health
   • Rules to reduce infection
   • Common pests and diseases in aquaculture
   • Fish diseases in different types of fish
   • Review what you have been learning
6. HARVESTING and PROCESSING
   • Harvesting techniques
   • Seine nets
   • Gill nets
   • Traps, Funnel trap, Flyke trap
   • Long lines, Fish pumps, etc
   • Mechanical graders
   • Fish poisons and electric shocking techniques
   • Lesson review
   • Final Assessment

Scope of this Course

This course focuses on growing freshwater fish to harvest and eat; but it still has a relevance to growing other things or for other purposes.  Many of the concepts and principles applied to farming fish will apply to other aquaculture circumstances as well. Given the limited time devoted to study in this course though, the focus is kept tight to ensure it is as meaningful and useful as possible.

Aquaculture systems are generally confined environments, where growing conditions have been optimised to support more animals being farmed in a smaller space than those found in nature — e.g., tanks (specialised systems) or fenced off areas of leased or owned bodies of water (e.g., parts of a coastal lagoon), rather than free-swimming in the natural environment. Although this can result in an increased harvest, it also presents problems. One common problem is that when fish are grown at such close quarters, competition can be strong, and cannibalisation may become an issue. 

To protect against this, commercial systems must separate small or developing fish from larger specimens. This protects the long-term harvest.

As such, pisciculture — or fish only — systems tend to be one of three types:

1. Hatchery Systems that produce fertile eggs, larva or fingerlings. 
Aquaculture seedstock are produced in hatcheries and these supply the industry. Depending on the industry approach, the technology needed can be complex for a successful hatchery. One critical element is ensuring the bloodstock are extremely well and healthy – this in turn ensures the seedstock are the best of health with the highest survival rates. The investment comes because the brood stock holding facility can take up a large area and require investment in pondage and water. Additionally many hatcheries are kept indoors and tend to run through intensive systems (using flow-through or recirculation technologies). This ensures the greatest control and ultimately the most reliable production. If the hatchery is outdoor production – open ponds – the infrastructure requirements are extensive, however the pond management is intensive.  Freshwater species are easier to breed than saltwater species, therefore depending on the species, a hatchery system may not be required. It is suggested that an aquaculturist in that start of their career may find it most valuable to buy stock from an established hatchery. 

2. Nursery Systems that nurse small larvae to fingerlings or juveniles.
The purpose of the nursery system is simple – to allow for the safe growing stage in the young stock. In the wild this life stage has the highest mortality rate.  Nursery technology differs again depending on the species. As in hatcheries, many nurseries will use the same intensive through-flow approach or recirculation technology. They are capital intensive systems. They great news is once functioning, the offer a high level of reliability. Having reliability in the system is necessary –this allows for purchasing seedstock on a broader scale production schedule. Other ways of growing stock include placing the fish in the plankton-rich ponds and leaving them for a number of weeks. When stock has grown to the right size, the pond is drained, and the juveniles are harvested. This is most often the cheapest approach at this stage in production. This stage is important for the early growth of the fish. Well fed fish in a correctly maintained system can achieve growth rates which outgrow the grow-out stage. The dietary management here is critical – whether natural of artificial – it is the deciding factor in maximising the growth at the nursery stage.  

3. Grow-out Systems that grow fingerlings or juveniles to marketable sizes.
This stage in the system allows the fish to grow only to a size that the market demands. This stage will take place in any system and the management of the system is less technically demanding. Although the fish can be left for a long time during the grow out stage, they still need looked after every day. When the fish have reached their size in this system, they are worth so much more value to the farmer and therefore the risk (potential loss) is also higher. Consider in the example of Murray Cod – the stock may have only been 1.5kg (total) when in the nursery, have now grown into an enormous 150 tonnes of fish as the final product. 

This course is relevant to all of these systems.

WHO IS THIS COURSE FOR?

• Anyone with an interest in becoming involved with aquaculture - as a grower, investor, or industry worker.
• Hobby farmers, permaculturists, home owners, seeking to produce their own fish to eat.
• Farmers, property owners - considering diversifying their land use
• Agriculture professionals may do this course for professional development, to broaden or refresh their knowledge
• Teachers, consultants, media professionals who want to convey information about aquaculture