14

IV. Grow Out Management

Proper management of fish and plants is a critical element that should be detailed in a production plan. Whether large or small scale, producers must implement strategies for best operation practices. This part of the plan should include, at minimum, fish and plant stocking densities, dates for planting and harvest, and their location or movement within the system (Bregnballe 2010). Additional components should include identification of a steady supply of fish year-round, maximization of space and resources, and a tailored or modified plan based on culture species and individual objectives.

Suitable Species of Fish for Culture

Unfortunately, not all fish species adapt well to tank culture, just as not all animal species adapt to being farm animals. Since fish are cold blooded, almost everything about their growth and health is influenced by temperature (see Tables 4 and 6 for details). The temperature of the culture water will partially dictate what species can or should be raised in your system. Other important factors will be how densely you intend to raise them and for what purpose or market. The rule of thumb for stocking density is 0.5 pound of fish weight per 1 gallon of water in grow out RAS. The following are considerations about what to grow for specific markets.

• What is selling in your current stores or restaurants?
• Can you address niche markets such as farmer's markets or are there minority groups in your area that have specific preferences?
• What seasonal markets do you want to address?
• What product forms will you be willing to address?
• What is your ambient temperature for your growing period? What energy implications does that have? What is the cost?

For some producers, fish are not an important part of the overall economics of the system and are

primarily “nutrient generators” for the plants. For others, selling food fish is an important profit center for the aquaponics system. Aquaponic producers may have the benefit of providing a one-stop-shop for both fish and vegetables. If that is the case, the aquaponics producer should plan ahead on what their final fish product will be. Will the fish be sold live, whole on ice, or processed? For product forms, see Figure 11. Once you are selling processed fish, there are many more issues to be considered in terms of product form and processing regulations, such as:

FIGURE 11 Fish processing forms
(a) Whole or round: completely intact, as caught.	(d) Steaks: cross-section slices, each containing a section of backbone.
(b) Drawn: viscera removed.	(e) Fillet: boneless sides of fish, with skin on or off.
(c) Dressed: viscera, scales, head, tail and fins removed.	(g) Sticks: cross section of fillets

• Do you have access to a certified processing facility?
• Do you have current HACCP regulations for the species you intend to process?
• What does the packaging cost?
• How will processing and packaging affect your budget?