Nursery ponds are one stage of a series of ponds used in aquaculture (fish production). This particular pond type is devoted to supporting baby fish and (or shellfish) as they grow from fry to fingerling stages. Since the aquaculture industry is found all over the world, especially Southeast Asia, working nursery ponds can range from extremely automated setups in a completely artificial environment, to exclusively manual operations in dirt ponds. Regardless of where they’re located, nursery ponds typically occupy quite a small area compared to a full egg-to-harvest production site, but they are considered one of the most critical areas to invest in to ensure a successful aquaculture operation.
What are the Advantages of Using a Nursery Pond?
The fry-to-fingerling stage represents the most vulnerable stage of fish production in aquaculture, not unlike human infancy. This is the stage where the fry are so tiny they make easy prey for predators, including larger fish, amphibians, insects and land animals. They are easily outcompeted for resources, and they are extremely vulnerable to environmental changes such as temperature and water chemistry. In fact, aquaculture operators may see their total production drop over 50% if the nursery stage is not carefully managed.
It makes sense, then, that any extra time and money spent on nursery pond design and management will pay off in the long run with much larger yields during each growth cycle, thanks to stable and protected conditions.
There are actually three significant advantages to devoting space and effort to a well-run nursery pond:
- In a dedicated pond, the fish farmer can exercise close control of the environment during the early, most vulnerable weeks of life; substantially boosting survival rates.
- Since they’re so closely focused, it’s possible to operate nursery ponds at very high fish densities, making them extremely efficient in producing healthy fingerlings for the next stage of growing out.
- Fry raised in ideal conditions, where predation and other stresses are low while water quality and nutrition is high, grow much faster than those in more challenging conditions. Happy and healthy fry, shrimp, and shellfish will grow to harvest size much more quickly, which may permit multiple harvests each year.
Are There Different Kinds of Nursery Ponds?
Nursery ponds are used in all sorts of aquaculture, both freshwater and marine. Some of the more popular commercial harvests include food fish like shrimp, Indian prawns, salmon, and tilapia. Sport fish, bait fish, and ornamental fish are produced as well. It’s not hard to imagine that a koi will need different conditions than a salmon, while tropical aquarium fish are not likely to do well in a bass pond.
In fact, during the fry-to-fingerling stage, where the emphasis should be on survival above all, nursery ponds must be carefully adjusted to provide the optimum environment for a single species of fish - compromises in pH, water temperature or other factors will almost certainly reduce overall survival rates. Raising trout in a pond designed for tilapia, for example, is bound to produce disastrous results: slow growth, increased cannibalization, and extensive losses.
Is Species Selection Important for a Nursery Pond?
Because different types of fish have very unique needs, it’s necessary to settle on one species or a mix of species with similar requirements before you begin to design a nursery pond. Even details like growth rate must be considered: ignoring all other incompatibilities, rapidly growing warm water species like tropical aquarium fish will mature and be ready to move on long before ornamental koi have grown even an inch. Even if you’re able to switch environments back and forth, having different species share time with a single nursery pond will drastically cut your production rates.
Building a successful nursery pond requires you to choose a fish or mix of species first so you can tailor your design to their specific mix of needs. Consider every element of their requirements - even variances in dissolved oxygen from the ideal can have a negative impact on your little fish babies.
