Overall nursery pond design is very flexible and while it should always be tailored to the needs of the species produced, consideration for existing facilities, geographic location, site profile and available funding are also important to the operation’s overall success. We’ll discuss a few specifics below:
Site Selection
Land
- Land with steep grades are generally unsuitable for nursery ponds because the amount of buildout necessary to establish adequate surface area wouldn't be economical.
- Avoid low-lying areas prone to floods that could wash your baby fish out into the wild blue yonder.
- A regularly shaped land parcel will make design, construction, and maintenance easier. Consider your future plans as well: a parcel with adequate space to expand is undoubtedly a good investment.
- It’s a good idea to check into zoning and long-term planning for the general area. A new quarry or industrial plant next door could seriously affect the well-being of all your fish.
- Check that the water table is low enough that you won’t encounter underground erosion problems that are hard to detect and may be impossible to repair.
- If you suspect a freshwater aquifer is nearby, that may be ideal for drilling a well to fill your ponds, but make sure you don’t risk land subsidence from overdrawing the aquifer.
Accessibility & Utilities
- If roads large enough to handle construction equipment and regular delivery trucks don’t exist, you may have to build them. Easy access around the facility is important when you’re selling your product, receiving deliveries, or performing maintenance
- Make sure that you’ll have access to electric or gas power and high quality water for cleaning and maintaining your facilities as well as filling your ponds.
- Overhead high-power electric lines running over or adjacent to your ponds may be prohibited and aren’t a good idea in any case.
- On the other hand, certain underground utilities may render the site unsuitable. Check with local utilities and your county resources to see if there’s something down there you don’t know about.
- If you’re in an area where high winds are common, an established wind break of mature trees is a good idea. Wide shallow ponds, especially, are vulnerable to wave action and surfing fish babies aren’t really the goal.
- In today’s day and age, reliable internet access shouldn’t be overlooked.
Soil Types and the Need for Liners
- Most kinds of soil can support a pond lined with impermeable materials like geosynthetic membranes.
- Ponds with plain soil or clay bottoms are vulnerable to loss of water through leakage, and incursion of unwanted water or even creatures that are eager to snack on your fry.
- Parasites and disease-causing microorganisms can also travel through surrounding soil that lacks a barrier.
- If you’re using a liner, your primary concern will be whether the soil can support the weight of what could be a considerable amount of water over time.
- If you’re planning on a clay liner, keep in mind that seasonal nursery ponds require drying the pond completely and allowing it to bake in the sun until the clay cracks. Once your clay liner cracks, it will no longer reliably hold water and you’ll be faced with expensive and inconvenient annual repairs.
Climate
Temperature moderates the growth and development of all fish species. Some fish require a minimum temperature and day length to trigger spawning. Fish eggs will even go dormant if the water temperature is too low. Metabolism rates depend on temperature, which means that cooler water correlates to slower growth (within an individual species’ tolerance, of course). If you’re locating your aquaculture operations in a cooler climate and hope to operate year-round, you’ll need to invest in pond heaters and circulators and plan for the power bills. Insulation installed between the soil and your liner can also minimize heat loss.
Large amounts of rain can be detrimental, as it will affect not only the temperature but the water parameters, and can even present flooding risks if your ponds do not have enough freeboard. Consider historic data on both, but it’s probably worth it to put emphasis on more recent data, since weather patterns are shifting around the globe.
